Patent Publication Number: US-11653037-B2

Title: Content-modification system with responsive transmission of reference fingerprint data feature

Description:
RELATED DISCLOSURES 
     This disclosure claims priority to U.S. Provisional Pat. App. No. 62/846,385 filed May 10, 2019 and U.S. Provisional Pat. App. No. 62/846,391 filed May 10, 2019, both of which are hereby incorporated by reference herein in their entirety. 
    
    
     USAGE AND TERMINOLOGY 
     In this disclosure, unless otherwise specified and/or unless the particular context clearly dictates otherwise, the terms “a” or “an” mean at least one, and the term “the” means the at least one. 
     SUMMARY 
     In one aspect, a method for use in connection with a content-modification system that includes a content-distribution system and a content-presentation device is disclosed. The method includes (i) identifying an upcoming content modification opportunity on an identified channel, wherein the identifying is based on detecting a match between first reference fingerprint data representing an initial portion of a modifiable content-segment and query fingerprint data representing content transmitted by the content-distribution system to the content-presentation device, wherein the first reference fingerprint data was generated before the query fingerprint data was generated; and (ii) responsive to identifying the upcoming content modification opportunity, transmitting to the content-presentation device, second reference fingerprint data representing more than the initial portion of the modifiable content-segment to facilitate the content-presentation device to, at a later time, continue performing a content-modification operation related to the identified content modification opportunity. 
     In another aspect, a non-transitory computer-readable storage medium is disclosed. The non-transitory computer-readable storage medium has stored thereon program instructions that, upon execution by a processor, cause performance of a set of operations for use in connection with a content-modification system that includes a content-distribution system and a content-presentation device. The set of operations includes (i) identifying an upcoming content modification opportunity on an identified channel, wherein the identifying is based on detecting a match between first reference fingerprint data representing an initial portion of a modifiable content-segment and query fingerprint data representing content transmitted by the content-distribution system to the content-presentation device, wherein the first reference fingerprint data was generated before the query fingerprint data was generated; and (ii) responsive to identifying the upcoming content modification opportunity, transmitting to the content-presentation device, second reference fingerprint data representing more than the initial portion of the modifiable content-segment to facilitate the content-presentation device to, at a later time, continue performing a content-modification operation related to the identified content modification opportunity. 
     In another aspect, a computing system is disclosed. The computing system includes a processor and a non-transitory computer-readable storage medium, having stored thereon program instructions that, upon execution by the processor, cause performance of a set of operations for use in connection with a content-modification system that includes a content-distribution system and a content-presentation device. The set of operations includes (i) identifying an upcoming content modification opportunity on an identified channel, wherein the identifying is based on detecting a match between first reference fingerprint data representing an initial portion of a modifiable content-segment and query fingerprint data representing content transmitted by the content-distribution system to the content-presentation device, wherein the first reference fingerprint data was generated before the query fingerprint data was generated; and (ii) responsive to identifying the upcoming content modification opportunity, transmitting to the content-presentation device, second reference fingerprint data representing more than the initial portion of the modifiable content-segment to facilitate the content-presentation device to, at a later time, continue performing a content-modification operation related to the identified content modification opportunity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a simplified block diagram of an example content-modification system in which various described principles can be implemented. 
         FIG.  2    is a simplified block diagram of an example computing system in which various described principles can be implemented. 
         FIG.  3    is a diagram of example linear sequences of content and related concepts. 
         FIGS.  4 A,  4 B,  4 C,  4 D,  4 E, and  4 F  collectively make up a table showing example time-periods and corresponding operations that can be performed in connection with the example content-modification system. 
         FIG.  5    is a flow chart of an example method. 
         FIG.  6    is a flow chart of another example method. 
     
    
    
     DETAILED DESCRIPTION 
     I. Overview 
     To deliver and present content to end-users, a content provider can transmit the content to one or more content-distribution systems, each of which can in turn transmit the content to one or more respective content-presentation devices to be output for presentation to respective end-users. Such a hierarchical arrangement can facilitate convenient, widespread distribution of content. 
     By way of example, in order for a video content provider to deliver video content to end-users throughout the United States, the video content provider can transmit the video content by satellite or another medium to content-distribution systems that serve respective designated market areas (DMAs) within the United States. Each such content-distribution system can therefore receive the national satellite feed carrying the video content and can transmit the video content to television sets and/or set-top boxes in the content-distribution system&#39;s DMA, such that the video content can be output for presentation to respective end-users in that DMA. In practice, these content-distribution systems and their means of transmission to content-presentation devices can take various forms. For instance, a content-distribution system can be associated with a cable-television provider and can transmit video content to content-presentation devices of end-users who are cable-television subscribers through hybrid fiber/coaxial cable connections. 
     As such, in various scenarios, a content-distribution system can transmit content to a content-presentation device, which can receive and output the content for presentation to an end-user. In some situations, even though the content-presentation device receives content from the content-distribution system, it can be desirable for the content-presentation device to perform a content-modification operation so that the content-presentation device can output for presentation alternative content instead of at least a portion of that received content. 
     For example, in the case where the content-presentation device receives a linear sequence of content segments that includes a given advertisement segment (which can be considered a modifiable content-segment) positioned somewhere within the sequence, it can be desirable for the content-presentation device to replace the given advertisement segment with a different advertisement segment that is perhaps more targeted to the end-user (e.g., more targeted to the end-user&#39;s interests, demographics, etc.). As another example, it can be desirable for the content-presentation device to overlay on the given advertisement segment, overlay content that enhances the given advertisement segment in a way that is again perhaps more targeted to the end-user. 
     In some instances, while the content-presentation device is performing a content-modification operation, the content-presentation device can monitor the underlying content that it is receiving, to detect whether the content-presentation device is continuing to receive a modifiable content-segment, as expected. If the content-presentation device is continuing to receive the modifiable content-segment as expected, the content-presentation device can continue to perform the content-modification operation, as originally planned. 
     On the other hand, if the content-presentation device is not continuing to receive the modifiable content-segment as expected (e.g., resulting from the content-presentation device changing channels), the content-presentation device can abort performing the partially performed content-modification operation instead. 
     Among other things, this functionality can help ensure that the content-presentation device operates in a way that better adheres to the overall desired functionality of the content-modification system and that helps provide a better user experience. The described content-modification system can facilitate providing these and other related features, which are described in greater detail below. 
     II. Architecture 
     A. Content-Modification System 
       FIG.  1    is a simplified block diagram of an example content-modification system  100 . The content-modification system  100  can include various components, such as a content-distribution system  102 , a content-presentation device  104 , a fingerprint-matching server  106 , a content-management system  108 , a data-management system  110 , and/or a supplemental-content delivery system  112 . 
     The content-modification system  100  can also include one or more connection mechanisms that connect various components within the content-modification system  100 . For example, the content-modification system  100  can include the connection mechanisms represented by lines connecting components of the content-modification system  100 , as shown in  FIG.  1   . 
     In this disclosure, the term “connection mechanism” means a mechanism that connects and facilitates communication between two or more components, devices, systems, or other entities. A connection mechanism can be or include a relatively simple mechanism, such as a cable or system bus, and/or a relatively complex mechanism, such as a packet-based communication network (e.g., the Internet). In some instances, a connection mechanism can be or include a non-tangible medium, such as in the case where the connection is at least partially wireless. In this disclosure, a connection can be a direct connection or an indirect connection, the latter being a connection that passes through and/or traverses one or more entities, such as a router, switcher, or other network device. Likewise, in this disclosure, communication (e.g., a transmission or receipt of data) can be a direct or indirect communication. 
     The content-modification system  100  and/or components thereof can take the form of a computing system, an example of which is described below. 
     Notably, in practice, the content-modification system  100  is likely to include many instances of at least some of the described components. For example, the content-modification system  100  is likely to include many content-distribution systems and many content-presentation devices. 
     B. Computing System 
       FIG.  2    is a simplified block diagram of an example computing system  200 . The computing system  200  can be configured to perform and/or can perform one or more operations, such as the operations described in this disclosure. The computing system  200  can include various components, such as a processor  202 , a data-storage unit  204 , a communication interface  206 , and/or a user interface  208 . 
     The processor  202  can be or include a general-purpose processor (e.g., a microprocessor) and/or a special-purpose processor (e.g., a digital signal processor). The processor  202  can execute program instructions included in the data-storage unit  204  as described below. 
     The data-storage unit  204  can be or include one or more volatile, non-volatile, removable, and/or non-removable storage components, such as magnetic, optical, and/or flash storage, and/or can be integrated in whole or in part with the processor  202 . Further, the data-storage unit  204  can be or include a non-transitory computer-readable storage medium, having stored thereon program instructions (e.g., compiled or non-compiled program logic and/or machine code) that, upon execution by the processor  202 , cause the computing system  200  and/or another computing system to perform one or more operations, such as the operations described in this disclosure. These program instructions can define, and/or be part of, a discrete software application. 
     In some instances, the computing system  200  can execute program instructions in response to receiving an input, such as an input received via the communication interface  206  and/or the user interface  208 . The data-storage unit  204  can also store other data, such as any of the data described in this disclosure. 
     The communication interface  206  can allow the computing system  200  to connect with and/or communicate with another entity according to one or more protocols. Therefore, the computing system  200  can transmit data to, and/or receive data from, one or more other entities according to one or more protocols. In one example, the communication interface  206  can be or include a wired interface, such as an Ethernet interface or a High-Definition Multimedia Interface (HDMI). In another example, the communication interface  206  can be or include a wireless interface, such as a cellular or WI-FI interface. 
     The user interface  208  can allow for interaction between the computing system  200  and a user of the computing system  200 . As such, the user interface  208  can be or include an input component such as a keyboard, a mouse, a remote controller, a microphone, and/or a touch-sensitive panel. The user interface  208  can also be or include an output component such as a display device (which, for example, can be combined with a touch-sensitive panel) and/or a sound speaker. 
     The computing system  200  can also include one or more connection mechanisms that connect various components within the computing system  200 . For example, the computing system  200  can include the connection mechanisms represented by lines that connect components of the computing system  200 , as shown in  FIG.  2   . 
     The computing system  200  can include one or more of the above-described components and can be configured or arranged in various ways. For example, the computing system  200  can be configured as a server and/or a client (or perhaps a cluster of servers and/or a cluster of clients) operating in one or more server-client type arrangements, for instance. 
     As noted above, the content-modification system  100  and/or components thereof can take the form of a computing system, such as the computing system  200 . In some cases, some or all these entities can take the form of a more specific type of computing system. For instance, in the case of the content-presentation device  104 , it can take the form of a desktop computer, a laptop, a tablet, a mobile phone, a television set, a set-top box, a television set with an integrated set-top box, a media dongle, or a television set with a media dongle connected to it, among other possibilities. 
     III. Example Operations 
     The content-modification system  100  and/or components thereof can be configured to perform and/or can perform one or more operations. Examples of these operations and related features will now be described. 
     As noted above, in practice, the content-modification system  100  is likely to include many instances of at least some of the described components. Likewise, in practice, it is likely that at least some of described operations will be performed many times (perhaps on a routine basis and/or in connection with additional instances of the described components). 
     A. Operations Related to the Content-Distribution System Transmitting Content and the Content-Presenting Device Receiving and Outputting Content 
     For context, general operations and examples related to the content-distribution system  102  transmitting content and the content-presentation device  104  receiving and outputting content will now be described. 
     To begin, the content-distribution system  102  can transmit content (e.g., that it received from a content provider) to one or more entities such as the content-presentation device  104 . Content can be or include audio content and/or video content, for example. In some examples, content can take the form of a linear sequence of content segments (e.g., program segments and advertisement segments) or a portion thereof. In the case of video content, a portion of the video content may be one or more frames, for example. 
     The content-distribution system  102  can transmit content on one or more channels (sometimes referred to as stations or feeds). As such, the content-distribution system  102  can be associated with a single channel content distributor or a multi-channel content distributor such as a multi-channel video program distributor (MVPD). 
     The content-distribution system  102  and its means of transmission of content on the channel to the content-presentation device  104  can take various forms. By way of example, the content-distribution system  102  can be or include a cable-television head-end that is associated with a cable-television provider and that transmits the content on the channel to the content-presentation device  104  through hybrid fiber/coaxial cable connections. As another example, the content-distribution system  102  can be or include a satellite-television head-end that is associated with a satellite-television provider and that transmits the content on the channel to the content-presentation device  104  through a satellite transmission. As yet another example, the content-distribution system  102  can be or include a television-broadcast station that is associated with a television-broadcast provider and that transmits the content on the channel through a terrestrial over-the-air interface to the content-presentation device  104 . In these and other examples, the content-distribution system  102  can transmit the content in the form of an analog or digital broadcast stream representing the content. 
     The content-presentation device  104  can receive content from one or more entities, such as the content-distribution system  102 . In one example, the content-presentation device  104  can select (e.g., by tuning to) a channel from among multiple available channels, perhaps based on input received via a user interface, such that the content-presentation device  104  can receive content on the selected channel. 
     In some examples, the content-distribution system  102  can transmit content to the content-presentation device  104 , which the content-presentation device  104  can receive, and therefore the transmitted content and the received content can be the same. However, in other examples, they can be different, such as where the content-distribution system  102  transmits content to the content-presentation device  104 , but the content-presentation device  104  does not receive the content and instead receives different content from a different content-distribution system. 
     The content-presentation device  104  can also output content for presentation. As noted above, the content-presentation device  104  can take various forms. In one example, in the case where the content-presentation device  104  is a television set (perhaps with an integrated set-top box and/or media dongle), outputting the content for presentation can involve the television set outputting the content via a user interface (e.g., a display device and/or a sound speaker), such that it can be presented to an end-user. As another example, in the case where the content-presentation device  104  is a set-top box or a media dongle, outputting the content for presentation can involve the set-top box or the media dongle outputting the content via a communication interface (e.g., an HDMI interface), such that it can be received by a television set and in turn output by the television set for presentation to an end-user. 
     As such, in various scenarios, the content-distribution system  102  can transmit content to the content-presentation device  104 , which can receive and output the content for presentation to an end-user. In some situations, even though the content-presentation device  104  receives content from the content-distribution system  102 , it can be desirable for the content-presentation device  104  to perform a content-modification operation so that the content-presentation device  104  can output for presentation alternative content instead of at least a portion of that received content. 
     For example, in the case where the content-presentation device  104  receives a linear sequence of content segments that includes a given advertisement segment positioned somewhere within the sequence, it can be desirable for the content-presentation device  104  to replace the given advertisement segment with a different advertisement segment that is perhaps more targeted to the end-user (i.e., more targeted to the end-user&#39;s interests, demographics, etc.). As another example, it can be desirable for the content-presentation device  104  to overlay on the given advertisement segment, overlay content that enhances the given advertisement segment in a way that is again perhaps more targeted to the end-user. The described content-modification system  100  can facilitate providing these and other related features. 
     As noted above, in one example, content can take the form of a linear sequence of content segments. As such, in one example, the content-distribution system  102  can transmit a linear sequence of content segments. This is referred to herein as a “transmission sequence.” Likewise, the content-presentation device  104  can receive a linear sequence of content segments. This is referred to herein as a “receipt sequence.” In line with the discussion above, the transmission sequence and the receipt sequence can be the same or they can be different. 
       FIG.  3    illustrates some examples of these concepts. In one example, the transmission sequence is the TRANSMISSION SEQUENCE  302  shown in  FIG.  3   . As shown, the TRANSMISSION SEQUENCE  302  includes a PROGRAM SEGMENT A, followed by an AD SEGMENT B, followed by an AD SEGMENT C. 
     Likewise, in one example, the receipt sequence is the RECEIPT SEQUENCE  304  shown in  FIG.  3   . In this example, the content-distribution system  102  transmits the TRANSMISSION SEQUENCE  302  to the content-presentation device  104 , which the content-presentation device  104  receives as the RECEIPT SEQUENCE  304 , and therefore the TRANSMISSION SEQUENCE  302  and the RECEIPT SEQUENCE  304  are the same. As such, as shown, the RECEIPT SEQUENCE  304  also includes the PROGRAM SEGMENT A, followed by the AD SEGMENT B, followed by the AD SEGMENT C. 
     In  FIG.  3   , the transmission time of the TRANSMISSION SEQUENCE  302  and the receipt time of the RECEIPT SEQUENCE  304  are shown by way of their relationship to a TIMELINE  350 . Notably, the transmission time and the receipt time are offset from each other due to a content-transmission delay, which is described in greater detail below. 
     As noted above, in some situations, even though the content-presentation device  104  receives content from the content-distribution system  102 , it can be desirable for the content-presentation device  104  to perform a content-modification operation so that the content-presentation device  104  can output for presentation alternative content instead of at least a portion of that received content. For example, in the case where the content-presentation device  104  receives the receipt sequence, rather than outputting for presentation the receipt sequence, the content-presentation device  104  can output for presentation a modified version of the receipt sequence instead. This is referred to herein as a “modified sequence.” 
     For example, in the case where the receipt sequence includes a given advertisement segment positioned somewhere within the receipt sequence, it can be desirable for the content-presentation device  104  to replace the given advertisement segment with a different advertisement segment that is perhaps more targeted to the end-user (i.e., more targeted to the end-user&#39;s interests, demographics, etc.), thereby resulting in a modified sequence that the content-presentation device  104  can output for presentation. 
     To illustrate this, in one example, the modified sequence is the FIRST MODIFIED SEQUENCE  306  shown in  FIG.  3   . As shown, the FIRST MODIFIED SEQUENCE  306  includes the PROGRAM SEGMENT A, followed by the AD SEGMENT D (which replaced the AD SEGMENT B), followed by the AD SEGMENT C. 
     As another example, it can be desirable for the content-presentation device  104  to overlay on the given advertisement segment, overlay content that enhances the given advertisement segment in a way that is again perhaps more targeted to the end-user, thereby resulting in a modified sequence that the content-presentation device  104  can output for presentation. 
     To illustrate this, in another example, the modified sequence is the SECOND MODIFIED SEQUENCE  308  shown in  FIG.  3   . As shown, the SECOND MODIFIED SEQUENCE  308  includes the PROGRAM SEGMENT A, followed by the AD SEGMENT B′ (which is the AD SEGMENT B modified with overlay content), followed by the AD SEGMENT C. 
     Other portions of  FIG.  3    will be described later in this disclosure as related concepts are introduced and described. 
     Moving on in view of the context provided above,  FIGS.  4 A,  4 B,  4 C,  4 D,  4 E, and  4 F , collectively make up a table showing example time-periods and corresponding operations that can be performed in connection with the content-modification system  100 . These and other related operations will now be described. 
     B. Operations Related to the Content-Distribution System Transmitting First Content on a Channel 
     During a time-period T 1 , the content-distribution system  102  can transmit content on a channel to the content-presentation device  104 . This content is referred to herein as “first content.” In one example, the first content is the FIRST CONTENT  310  shown in  FIG.  3   . 
     During a time-period T 2 , the content-distribution system  102  can generate fingerprint data representing the first content. This fingerprint data is referred to herein as “first fingerprint data.” The content-distribution system  102  can generate the first fingerprint data using any content fingerprinting process now known or later developed. An example fingerprint generation technique is described in U.S. Pat. No. 9,495,451 issued Nov. 15, 2016, the entirety of which is hereby incorporated by reference herein. The content-distribution system  102  can generate first fingerprint data at a given rate, such as at the rate of one fingerprint per frame of the first content. The first fingerprint data can be or include some or all of these generated fingerprints. 
     The content-distribution system  102  can access the first content at various points within the content-distribution system  102 . As one example, the content-distribution system  102  can access the first content after it is output by a distribution amplifier within the content-distribution system  102 . 
     Also during the time-period T 2 , the content-distribution system  102  can generate metadata associated with the first content and/or the first fingerprint data. This metadata is referred to herein as “first metadata.” In one example, the first metadata can be or include a transmission time-stamp, which represents a time-point at which the content-distribution system  102  transmitted the first content. The content-distribution system  102  can determine the transmission time-stamp in various ways, such as based on a time clock that is synchronized to a reference clock. 
     As another example, the first metadata can be or include a channel identifier, which identifies the channel on which the content-distribution system  102  is transmitting the first content. The content-distribution system  102  can determine the channel identifier in various ways such as based on mapping data that maps the content-distribution system  102  and/or physical inputs and/or outputs within the content-distribution system  102  to respective channel identifiers. In one example, in the case where the content-distribution system  102  transmits content A on channel A, content B on channel B, and content C on channel C, the mapping data can specify which of three different outputs (perhaps on three different distribution amplifiers) maps to which channel identifier, such that the content-distribution system  102  can determine the appropriate channel identifier for content of a given channel. 
     As another example, the first metadata can be or include SCTE-104 data, a watermark, or a similar type of metadata, any of which can themselves encode other metadata, such as a program identifier, an advertisement identifier (e.g., an industry standard coding identification (ISCI) key), a program genre, or another type of textual or numeric metadata, for instance. 
     The content-distribution system  102  can associate the first fingerprint data with the first metadata in various ways. For instance, in the case where the first fingerprint data includes multiple fingerprints with each fingerprint representing a corresponding frame of the first content, the content-distribution system  102  can associate each fingerprint with a corresponding transmission time-stamp and/or with other corresponding first metadata. 
     During a time-period T 3 , the content-distribution system  102  can transmit the first fingerprint data and the first metadata to the fingerprint-matching server  106 . The content-distribution system  102  can transmit the first fingerprint data and the first metadata at a given interval. For example, every two seconds, the content-distribution system  102  can transmit the first fingerprint data and the first metadata that it generated during that most recent two-second time-period. 
     C. Operations Related to the Content-Presentation Device Receiving Second Content 
     During a time-period T 4 , the content-presentation device  104  can receive content from the content-distribution system  102 . This content is referred to herein as “second content.” In one example, the second content is the SECOND CONTENT  312  shown in  FIG.  3   . 
     During a time-period T 5 , the content-presentation device  104  can generate fingerprint data representing the second content. This fingerprint data is referred to herein as “second fingerprint data.” The content-presentation device  104  can generate the second fingerprint data using any content fingerprinting process now known or later developed. The content-presentation device  104  can generate the second fingerprint data at various rates, such as at the rate of one fingerprint per frame of the second content. The second fingerprint data can be or include some or all of these generated fingerprints. 
     The content-presentation device  104  can access the second content at various points within the content-presentation device  104 . As one example, the content-presentation device  104  can access the second content as it is being received by an input buffer (e.g., an HDMI buffer) of the content-presentation device  104 . In another configuration, the content-presentation device  104  can access the second content as it is being received by a display buffer of the content-presentation device  104 . In this configuration, the second content can therefore be content that the content-presentation device  104  not only receives, but also outputs for presentation. 
     Also during the time-period T 5 , the content-presentation device  104  can generate metadata associated with the second content and/or the second fingerprint data. This metadata is referred to herein as “second metadata.” As one example, the second metadata can be or include a receipt time-stamp, which represents a time-point at which the content-presentation device  104  received the second content. The content-presentation device  104  can determine the receipt time-stamp in various ways, such as based on a time clock that is synchronized to a reference clock. As noted above, the content-presentation device  104  can access the second content at various points within the content-presentation device  104 . In one example, the point at which the second content is accessed can be considered the “receipt” point for purposes of determining the receipt time-stamp. 
     In practice, while the first metadata is likely to be or include a channel identifier, the second metadata is likely to not be nor include a channel identifier. 
     The content-presentation device  104  can associate the second fingerprint data with the second metadata in various ways. For instance, where the second fingerprint data includes multiple fingerprints with each fingerprint representing a corresponding frame of second content, the content-presentation device  104  can associate each second fingerprint with a corresponding receipt time-stamp and/or other corresponding metadata. 
     During a time-period T 6 , the content-presentation device  104  can transmit the second fingerprint data and the second metadata to the fingerprint-matching server  106 . The content-presentation device  104  can transmit the second fingerprint data and the second metadata at a given interval. For example, every two seconds, the content-presentation device  104  can transmit the second fingerprint data and the second metadata that it generated during that most recent two-second time-period. 
     D. Operations Related to Identifying a Channel on which the Content-Presentation Device is Receiving the Second Content 
     During a time-period T 7 , the fingerprint-matching server  106  can receive the first fingerprint data and the first metadata from the content-distribution system  102 . As noted above, the first fingerprint data represents the first content transmitted by the content-distribution system  102  on the channel. As noted above, the first metadata can, and for the purposes of this described example does, identify the channel. In this way, the first content can be considered as content being transmitted on an identified channel. 
     During a time-period T 8 , the fingerprint-matching server  106  can receive the second fingerprint data and the second metadata from the content-presentation device  104 . As noted above, the second fingerprint data represents the second content received by the content-presentation device  104 . However, as noted above, the associated metadata may not, and for the purposes of this described example does not, identify the channel. In this way, the second content can be considered as content being received on an unidentified channel. 
     During a time-period T 9 , the fingerprint-matching server  106  can compare the first fingerprint data and the second fingerprint data to determine whether there is a match. In this disclosure, this type of match attempt, namely a match attempt between (i) reference fingerprint data representing content being transmitted on an identified channel and (ii) query fingerprint data representing content being received on an unidentified channel, is referred to herein as a “cold match attempt.” 
     During a time-period T 10 , based on the comparing, the fingerprint-matching server  106  can detect a match between the first fingerprint data and the second fingerprint data. The fingerprint-matching server  106  can compare and/or detect a match between fingerprint data using any content fingerprint comparing and matching technique now known or later developed. An example fingerprint comparing and matching technique is described in U.S. Pat. No. 9,146,990 issued Sep. 29, 2015, the entirety of which is hereby incorporated by reference herein. 
     To effectively compare the first fingerprint data and the second fingerprint data, the fingerprint-matching server  106  may need to account for a content-transmission delay. For context, in the case where the content-distribution system  102  transmits a given frame of content on a given channel at a time-point A, for various reasons, the content-presentation device  104  may not receive that frame until a time-point B that is later (e.g., ten seconds later) than the time-point A. This type of delay is referred to herein as a “content-transmission delay.” 
     In one example, the time-point A, the time-point B, and the content-transmission delay can be the TIME-POINT A  314 , the TIME-POINT B  316 , and the CONTENT-TRANSMISSION DELAY  318 , respectively, shown  FIG.  3   . Note that  FIG.  3    is for illustration purposes and is not necessarily to scale at least with respect to time. In practice, the actual amount of content-transmission delay may be different from the amount shown. 
     To help the fingerprint-matching server  106  effectively compare the first fingerprint data with the second fingerprint data, the fingerprint-matching server  106  may need to account for such a content-transmission delay. In one example, the fingerprint-matching server  106  can do this by comparing the first fingerprint data that it receives at a receipt time-point with the second fingerprint data that it receives during a time-period defined by a starting time-point and an ending time-point. The starting time-point can be the receipt time-point plus an offset representing an anticipated content-transmission delay (e.g., ten seconds), minus a tolerance a time-period (e.g., two seconds). The ending time-point can be the receipt time-point plus the offset (e.g., ten seconds), plus the tolerance a time-period (e.g., two seconds). As such, in one example where the anticipated content-transmission delay is 10 seconds, the fingerprint-matching server  106  can compare first fingerprint data that it receives at a receipt time-point with second fingerprint data that it receives during a time-period between (i) the receipt time-point plus eight seconds and (ii) receipt time-point plus twelve seconds. 
     In some cases, the fingerprint-matching server  106  can determine a content-transmission delay, which it can use to select an appropriate offset for use in determining the starting and ending time-points, as described above. The fingerprint-matching server  106  can determine the content-transmission delay in various ways. For example, after the fingerprint-matching server  106  detects a match based on a cold match attempt, the fingerprint-matching server  106  can determine the content-transmission delay as a difference between the corresponding transmission time-stamp (of the first metadata) and the corresponding receipt time-stamp (of the second metadata), for example. Notably, the content-transmission delay can vary from channel to channel. 
     During a time-period T 11 , based on the detected match, the fingerprint-matching server  106  can identify the channel on which the second content is being received by the content-presentation device  104 . In one example, the fingerprint-matching server  106  can identify the channel based on the channel identifier metadata associated with the first fingerprint data used to detect the match. 
     Notably, in practice, since there are likely to be multiple potential channels on which the content-presentation device  104  is receiving the second content, the fingerprint-matching server  106  is likely to compare the second fingerprint data with multiple instances of first fingerprint data (each representing a different respective instance of first content on a different respective channel), to determine which of those multiple instances matches the second fingerprint data. 
     Also, in some cases, the fingerprint-matching server  106  can detect a match between the second fingerprint data and each of multiple instances of first fingerprint data (each representing a different respective instance of first content on a different respective channel). This is referred to herein as a “multimatch scenario” and can occur for various reasons. For example, this can occur when the content-distribution system  102  is transmitting the same or similar content on more than one channel at or about the same time. In this scenario, the fingerprint-matching server  106  can perform additional operations to identity, from among the multiple channels associated with the multimatch scenario, on which specific channel the content-presentation device  104  is receiving the second content. The fingerprint-matching server  106  can do this using any channel multimatch disambiguation technique now known or later developed. An example channel multimatch disambiguation technique is described in U.S. Pat. No. 9,992,533 issued Jun. 5, 2018, the entirety of which is hereby incorporated by reference herein. 
     E. Operations Related to Determining Historical Content Consumption Data 
     During a time-period T 12 , the fingerprint-matching server  106  can generate metadata associated with the identified channel. For example, the metadata can be or include a channel identification time-stamp. The fingerprint-matching server  106  can determine the channel identification time-stamp in various ways, such as based on a time clock that is synchronized to a reference clock. In another example, the metadata can be or include a device identifier that identifies the content-presentation device  104  that is receiving content on the identified channel. The fingerprint-matching server  106  can determine the device identifier in various ways, such as by receiving it from the content-presentation device  104 . In another example, the fingerprint-matching server  106  can receive data (e.g., device registration data) from the content-presentation device  104  and can use mapping data to map the received data to determine the device identifier. 
     During a time-period T 13 , the fingerprint-matching server  106  can transmit an indication of the identified channel and the associated metadata to the data-management system  110 . 
     During a time-period T 14 , the data-management system  110  can receive the indication of the identified channel and the associated metadata from the fingerprint-matching server  106 . 
     The data-management system  110  can use the received indication of the identified channel and the associated metadata, perhaps with other data, to determine when the content-presentation device  104  has received content on the identified channel, what specific content the content-presentation device  104  has received, etc. This type of data is referred to herein as “historical content consumption data.” 
     As such, during a time-period T 15 , the data-management system  110  can determine historical content consumption data associated with the content-presentation device  104 . 
     F. Operations Related to the Content-Distribution System Transmitting Third Content 
     As noted above, the fingerprint-matching server  106  can identify the channel on which the content-presentation device  104  is receiving the second content. 
     During a time-period T 16 , the content-distribution system  102  can transmit content on the identified channel to the content-presentation device  104 . This content is referred to herein as “third content.” In one example, the third content is the THIRD CONTENT  320  shown in  FIG.  3   . In practice, the content-distribution system  102  is likely to transmit the third content shortly after (e.g., immediately after or a few seconds or minutes after) transmitting the first content. 
     During a time-period T 17 , the content-distribution system  102  can generate fingerprint data representing the third content. This fingerprint data is referred to herein as “third fingerprint data.” 
     Also during the time-period T 17 , the content-distribution system  102  can generate metadata associated with the third content and/or the third fingerprint data. This metadata is referred to herein as “third metadata.” The content-distribution system  102  can also associate the third fingerprint data with the third metadata. 
     During a time-period T 18 , the content-distribution system  102  can transmit the third fingerprint data and the third metadata to the fingerprint-matching server  106 . 
     The content-distribution system  102  can transmit the third content, generate the third fingerprint data, generate the third metadata, associate the third fingerprint data with the third metadata, and transmit the third fingerprint data and the third metadata in various ways, such as ways that are the same as or similar to those described above in connection with transmitting the first content, generating the first fingerprint data, generating the first metadata, associating the first fingerprint data with the first metadata, and transmitting the first fingerprint data and the first metadata. 
     G. Operations Related to the Content-Management System Receiving a Modifiable Content-Segment 
     During a time-period T 19 , the content-management system  108  can receive content in the form of a content segment that has been identified as a candidate to be modified. This content is referred to herein as a “modifiable content-segment” or “fourth content.” In one example, the modifiable content-segment is the MODIFIABLE CONTENT-SEGMENT shown in  FIG.  3   . 
     The modifiable content-segment can take various forms. For example, the modifiable content-segment can be an advertisement segment (e.g., a commercial) or a program segment. As such, in one example, the modifiable content-segment can be an advertisement segment that has been identified as a candidate to be modified, perhaps by way of being replaced with a different advertisement segment, and/or by way of having content overlaid thereon. 
     In one example, a user, perhaps associated with the content-distribution system  102 , can facilitate uploading the modifiable content-segment to the content-management system  108 , such that the content-management system  108  can receive it in this way. 
     During a time-period T 20 , the content-management system  108  can generate fingerprint data representing the modifiable content-segment. This fingerprint data is referred to herein as “fourth fingerprint data.” The content-management system  108  can generate the fourth fingerprint data using any fingerprint generation technique now known or later developed. The content-management system  108  can generate the fourth fingerprint data at a given rate, such as at the rate of one fingerprint per frame of the fourth content. The fourth fingerprint data can be or include some or all of these generated fingerprints. 
     Also during the time-period T 20 , the content-management system  108  can generate metadata associated with the modifiable content-segment and/or the fourth fingerprint data. This metadata is referred to herein as “fourth metadata.” As one example, the fourth metadata can be or include a duration of the modifiable content-segment. The content-management system  108  can determine the duration in various ways, such as based on the fingerprint generation process. For example, in the case where the content-management system  108  generating the fourth fingerprint data involves generating one fingerprint per frame, where the modifiable content-segment has a frame rate of 30 frames per second, and where the fingerprinting process results in 300 fingerprints being generated, the content-management system  108  can deduce that the modifiable content-segment has a duration of ten seconds. The metadata can also be or include other information about the modifiable content-segment, such as a content segment identifier, a title, and/or specifics about permissible ways in which the modifiable content-segment can be modified, etc. 
     During a time-period T 21 , the content-management system  108  can transmit the fourth fingerprint data and the fourth metadata to the fingerprint-matching server  106 . 
     In practice, the content-management system  108  is likely to receive many modifiable content-segments. In such situations, the content-management system  108  can perform one or more of the operations described above, as appropriate for each of the many received modifiable content-segments. As such, the content-management system  108  can transmit many instances of fourth fingerprint data, each corresponding with a different respective modifiable content-segment, to the fingerprint-matching server  106 . 
     H. Operations Related to the Fingerprint-Matching Server Identifying an Upcoming Content Modification Opportunity on the Identified Channel 
     During a time-period T 22 , the fingerprint-matching server  106  can receive the third fingerprint data and the third metadata from the content-distribution system  102 . As noted above, the third fingerprint data represents the third content transmitted by the content-distribution system  102  on the identified channel. 
     During a time-period T 23 , the fingerprint-matching server  106  can receive the fourth fingerprint data and the fourth metadata from the content-management system  108 . As noted above, the fourth fingerprint data represents the modifiable content-segment. 
     During a time-period T 24 , the fingerprint-matching server  106  can compare at least a portion of the third fingerprint data with at least a portion of the fourth fingerprint data to determine whether there is a match. 
     During a time-period T 25 , based on the comparing, the fingerprint-matching server  106  can detect a match between the at least a portion of the third fingerprint data and the at least a portion of the fourth fingerprint data. The fingerprint-matching server  106  can compare and/or detect a match between fingerprint data using any content fingerprint comparing and matching process now known or later developed. 
     During a time-period T 26 , based on the detected match, the fingerprint-matching server  106  can determine that at least a portion of the modifiable content-segment is included within the third content, and therefore can identify an upcoming content modification opportunity on the identified channel. For example, the fingerprint-matching server  106  can determine that at least a beginning portion of the MODIFIABLE CONTENT-SEGMENT is included within the THIRD CONTENT  320 , as shown in  FIG.  3   , and therefore can identify an upcoming content modification opportunity. 
     As noted above, the fingerprint-matching server  106  can generate third metadata, which can be the same as or similar to the first metadata. As such, the third metadata can be or include a transmission time-stamp and/or a channel identifier, for example. However, the third metadata can also be or include a position of at least a portion of the modifiable content-segment within the third content. In one example, the metadata can specify this using a starting frame marker and an ending frame marker, each corresponding with a respective frame of the third content. The fingerprint-matching server  106  can determine the starting frame marker and the ending frame marker based on the matching. 
     Notably, in practice, since there are likely to be multiple potential modifiable content-segments where portions thereof could be included within the third content, the fingerprint-matching server  106  is likely to compare at least a portion of the third fingerprint data with at least a portion of multiple instances of fourth fingerprint data (each representing a different respective instance of a modifiable content-segment), to determine which of those multiple instances of the fourth fingerprint data has a portion that matches the at least a portion of the third fingerprint data. 
     I. Operations Related to Preparing the Content-Presentation Device to Perform a Content-Modification Operation in Connection with the Identified Upcoming Content Modification Opportunity 
     During a time-period T 27 , based on the detected match, the fingerprint-matching server  106  can transmit the third fingerprint data and the third metadata to the content-presentation device  104  data to facilitate preparing the content-presentation device  104  to perform a content-modification operation in connection with the identified upcoming content modification opportunity. 
     During a time-period T 28 , the content-presentation device  104  can receive the third fingerprint data and the third metadata from the fingerprint-matching server  106 . 
     During a time-period T 29 , the content-presentation device  104  can receive content on the identified channel. This content is referred to herein as “fifth content.” In one example, the fifth content is the FIFTH CONTENT  324  shown in  FIG.  3   . 
     For various reasons (e.g., due to a transmission delay associated with transmitting fingerprint data and metadata being shorter that the content-transmission delay), the content-presentation device  104  can receive the third fingerprint data and the third metadata from the fingerprint-matching server  106  before receiving the fifth content from the content-distribution system  102 . In this way, the content-presentation device  104  can receive fingerprint data representing content that the content-presentation device  104  is expecting to receive shortly thereafter, and that the content-presentation device should actually receive shortly thereafter unless an interruption event (e.g., a channel-change event) occurs. 
     In practice, similar to how the content-distribution system  102  is likely to transmit the third content shortly after (e.g., immediately after or a few seconds or minutes after) transmitting the first content, the content-presentation device  104  is likely to receive the fifth content shortly after (e.g., immediately after or a few seconds or minutes after) receiving the second content. 
     During a time-period T 30 , the content-presentation device  104  can output for presentation at least a portion of the fifth content. For example, referring to  FIG.  3   , the content-presentation device can output for presentation the portion of the FIFTH CONTENT  324  that is the end portion of the PROGRAM SEGMENT A. 
     As noted above, in some situations, even though the content-presentation device  104  receives content from the content-distribution system  102 , it can be desirable for the content-presentation device  104  to perform a content-modification operation so that the content-presentation device  104  can output for presentation alternative content instead of at least a portion of the received content. 
     As such, even though the content-presentation device  104  receives the fifth content and outputs for presentation at least a portion of the fifth content, it can be desirable for the content-presentation device  104  to perform a content-modification operation so that the content-presentation device  104  can also output for presentation alternative content instead of at least another portion (e.g., the remaining portion) of the fifth content. For example, referring to  FIG.  3   , it can be desirable for the content-presentation device  104  to replace at least a portion of the AD SEGMENT B with at least a portion of a different advertisement segment that is perhaps more targeted to the end-user. As another example, it can be desirable for the content-presentation device  104  to overlay on at least a portion of the AD SEGMENT B, overlay content that enhances at least a portion of the AD SEGMENT B in a way that is again perhaps more targeted to the end-user. 
     During a time-period T 31 , the content-presentation device  104  can generate fingerprint data representing the fifth content. This fingerprint data is referred to herein as “fifth fingerprint data.” The content-presentation device  104  can generate the fifth fingerprint data using any content fingerprinting process now known or later developed. The content-presentation device  104  can generate the fifth fingerprint data at various rates, such as at the rate of one fingerprint per frame of the fifth content. The fifth fingerprint data can be or include some or all of these generated fingerprints. 
     Also during the time-period T 31 , the content-presentation device  104  can generate metadata associated with the fifth content and/or the fifth fingerprint data. This metadata is referred to herein as “fifth metadata.” 
     The content-presentation device  104  can receive the fifth content, generate the fifth fingerprint data, generate the fifth metadata, associate the fifth fingerprint data with the fifth metadata in various ways, such as ways that are the same as or similar to those described above in connection with receiving the second content, generating the second fingerprint data, generating the second metadata, and associating the second fingerprint data with the second metadata. 
     As noted above, the content-presentation device  104  can receive the third fingerprint data from the fingerprint-matching server  106  and can generate the fifth fingerprint data. 
     During a time-period T 32 , the content-presentation device  104  can compare the third fingerprint data and the fifth fingerprint data to determine whether there is a match. 
     During a time-period T 33 , based on the comparing, the content-presentation device  104  can detect a match between the third fingerprint data and the fifth fingerprint data. In this disclosure, this type of match attempt, namely a match attempt between (i) reference fingerprint data representing content transmitted by the content-distribution system  102  on an identified channel (at least based on the most recent channel identification analysis), and (ii) query fingerprint data representing content being received by the content-presentation device  104  on the same identified channel, is referred to herein as a “hot match attempt.” The content-presentation device  104  can compare and/or detect a match between fingerprint data using any content fingerprint comparing and matching process now known or later developed. 
     During a time-period T 34 , based on the detected match, the content-presentation device  104  can determine a time-point at which the identified upcoming modification opportunity starts. This is referred to herein as the “modification start-time.” In one example, the modification start-time is the MODIFICATION START-TIME  326  as shown  FIG.  3   . 
     In one example, the content-presentation device  104  can determine the modification start-time by starting with the transmission time-stamp associated with the starting frame marker (which, as described above, can be or be included in the third metadata) and adding the content-transmission delay to that transmission time-stamp, to arrive at the modification start-time. 
     As another example, the content-presentation device  104  can determine the modification start-time by first establishing a synchronous lock between the third content, the third fingerprint data, and/or the third metadata on the one hand, and the fifth content, the fifth fingerprint data, and/or the fifth metadata, on the other hand. The content-presentation device  104  can establish the synchronous lock using any synchronous lock technique now known or later developed. An example synchronous lock technique is described in U.S. Pat. No. 10,506,275 issued Dec. 10, 2019, the entirety of which is hereby incorporated by reference herein. Another example synchronous lock technique is described in U.S. Pat. App. Pub. No. 2020/0029108 published Jan. 23, 2020, the entirety of which is hereby incorporated by reference herein. 
     The content-presentation device  104  can then determine the modification start-time by determining a time-period between (i) a current receipt time-stamp associated with a first portion of the fifth content that the content-presentation device  104  is currently receiving and (ii) based on the synchronous lock, an anticipated receipt time-stamp associated with a second portion of the fifth content that is the start of the modifiable content-segment, and then adding the determined time-period to the current receipt time-stamp, to arrive at the modification start-time. 
     Also during the time-period T 34 , based on the detected match, the content-presentation device  104  can determine a time-point at which the identified upcoming modification opportunity ends. This is referred to herein as the “modification end-time.” In one example, the modification end-time is the MODIFICATION END-TIME  328  as shown  FIG.  3   . 
     In one example, the content-presentation device  104  can determine the modification end-time by starting with the modification start-time and adding the duration of the modifiable content-segment (which, as described above, can be or be included in the fourth metadata) to the modification start-time, to arrive at the modification end-time. 
     Notably, if the content-presentation device  104  performs a hot match attempt and does not detect a match, the content-presentation device  104  can determine that the content-presentation device  104  is no longer receiving content on the most recently identified channel. In response, the content-presentation device  104  can repeat one or more of the operations described above so that the fingerprint-matching server  106  can perform another cold match attempt, to attempt to identify the channel again. 
     During a time-period T 35 , the content-presentation device  104  can transmit a request for content for use in connection with performing the content-modification operation, to the content-management system  108 . This content is referred to herein as “supplemental content.” In one example, the content-presentation device  104  can transmit the request before the modification start-time (e.g., ten seconds before). In some cases, the request can include selection criteria for the supplemental content, which the content-presentation device  104  can determine based on the third metadata that the content-presentation device  104  receives from the fingerprint-matching server  106 , for instance. 
     For example, the selection criteria can specify a requested type of content (e.g., a replacement content segment or overlay content), duration (e.g., 15 seconds, 30 seconds, or 60 seconds), aspect ratio (e.g., 4:3 or 16:9), and/or resolution (e.g., 720p or 1080p). 
     During a time-period T 36 , the content-management system  108  can receive the request and use it as a basis to select supplemental content from among multiple supplemental content items that are available for selection. In some cases, the content-management system  108  can receive and consider various data to help inform which supplemental content to select. For example, the content-management system  108  can receive historical content consumption data for the content-presentation device  104  from the data-management system  110  and/or the content-management system  108  can receive demographic data from a demographic data provider. The content-management system  108  can then use at least the received historical content consumption data and/or the received demographic data as a basis to select the supplemental content. 
     The content-management system  108  can cause the selected supplemental content to be transmitted to the content-presentation device  104 . In one example, the content-management system  108  can do this by communicating with a supplemental-content delivery system  112  that can host the supplemental content. The supplemental-content delivery system  112  can take various forms and can include various components, such as a content distribution network (CDN). 
     During a time-period T 37 , the content-management system  108  can transmit a request for a link (e.g., a Uniform Resource Identifier (URI) or a Uniform Resource Locator (URL)) pointing to the hosted supplemental content, to the supplemental-content delivery system  112 . 
     During a time-period T 38 , the supplemental-content delivery system  112  can receive and respond to the request for the link by transmitting the requested link to the content-management system  108 . 
     During a time-period T 39 , the content-management system  108  can then in turn transmit the link to the content-presentation device  104 . 
     During a time-period T 40 , the content-presentation device  104  can receive the link, which it can use to retrieve the supplemental content from the supplemental-content delivery system  112 , such that the content-presentation device  104  can use the retrieved supplemental content in connection with performing the content-modification operation. In one example, the content-presentation device  104  can retrieve the supplemental content and store the supplemental content in a data-storage unit of the content-presentation device  104 . 
     As such, in some examples, the content-presentation device  104  can receive the modifiable content-segment from one source (e.g., the content-distribution system  102 ), and the supplemental content from another source (e.g., the supplemental-content delivery system  112 ). These segments can be transmitted to, and received by, the content-presentation device  104  in different ways. For example, the content-distribution system  102  can transmit, and the content-presentation device  104  can receive, the modifiable content-segment as a broadcast stream transmission, whereas the supplemental-content delivery system  112  can transmit, and the content-presentation device  104  can receive, the supplemental content as an over-the-top (OTT) transmission. In this context, in one example, the content-distribution system  102  can receive the modifiable content-segment via one communication interface (e.g., an HDMI interface), and the content-presentation device  104  can receive the supplemental content via a different communication interface (e.g., an Ethernet or WI-FI interface). 
     J. Operations Related to the Content-Presentation Device Performing a Content-Modification Operation 
     At a time-period T 41 , the content-presentation device  104  can perform the content-modification operation. The content-presentation device  104  can do this in various ways, perhaps depending on the type of content-modification operation to be performed. 
     In one example, the content-presentation device  104  performing a content-modification operation can involve the content-presentation device  104  modifying the modifiable content-segment by replacing it with supplemental content. This is referred to herein as a “content-replacement operation.” For example, in this scenario, the content-presentation device  104  can receive a linear sequence of content segments that includes the modifiable content-segment and the associated metadata, and can also receive the supplemental content segment, as described above. The content-presentation device  104  can output for presentation the sequence of content segments up until the modification start-time (which corresponds to the start of the modifiable content-segment), at which time the content-presentation device  104  can switch to outputting for presentation the supplemental content instead. Then, at the modification end-time (which corresponds to the end of the modifiable content-segment), the content-presentation device  104  can switch back to outputting for presentation the content that follows in the linear sequence of content segments (or perhaps to other content, such as additional supplemental content that is replacing another modifiable content-segment). 
     In one example, the operation of the content-presentation device  104  switching from outputting the sequence of content segments to outputting the supplemental content can involve using various buffers of the content-presentation device  104 . For example, this can involve the content-presentation device  104  switching from using first data in a first input buffer where the sequence of content segments is being received to using second data in a second input buffer where the supplemental content is being received, to populate a display buffer. 
     As such, according to one example as illustrated in  FIG.  3   , by performing a content replacement operation, the content-presentation device  104  can replace the AD SEGMENT B with the AD SEGMENT D. As a result, rather than outputting for presentation the RECEIPT SEQUENCE  304 , the content-presentation device can instead output for presentation the FIRST MODIFIED SEQUENCE  306 . 
     In another example, the content-presentation device  104  performing a content-modification operation can involve the content-presentation device  104  modifying a modifiable content-segment by overlaying on the modifiable content-segment, overlay content (referred to herein as a “content overlay operation”). For example, in this scenario, the content-presentation device  104  can again receive a linear sequence of content segments that includes the modifiable content-segment and the associated metadata, and the content-presentation device  104  can also receive the supplemental content, as described above. 
     The content-presentation device  104  can then output for presentation the modifiable content-segment as it ordinarily would, except that starting at the modification start-time, the content-presentation device  104  can start overlaying the supplemental content on the modifiable content-segment. The content-presentation device  104  can continue overlaying the supplemental content until the modification end-time. In this way, the content-presentation device  104  can overlay the supplemental content during at least some temporal portion of the modifiable content-segment. 
     In one example, the operation of the content-presentation device  104  overlaying supplemental content on the modifiable content-segment can involve using various buffers of the content-presentation device  104 . For example, this can involve the content-presentation device  104  using a portion of first data in a first input buffer where the sequence of content segments is being received together with second data in a second input buffer where the supplemental content is being received, for the purposes of populating a display buffer. In this way, the content-presentation device can combine relevant portions of the modifiable content-segment (i.e., all portions except those representing region where the supplemental content is to be overlaid) together with the supplemental content to be used as an overlay, to create the desired modifiable content-segment plus the supplemental content overlaid thereon. 
     As such, according to one example as illustrated in  FIG.  3   , by performing a content overlay operation, the content-presentation device  104  can overlay supplemental content on the AD SEGMENT B, thereby modifying it to AD SEGMENT B′. As a result, rather than outputting for presentation the RECEIPT SEQUENCE  304 , the content-presentation device can instead output for presentation the SECOND MODIFIED SEQUENCE  308 . 
     K. Tracking and Reporting Operation-Related Data 
     To help facilitate performance of various operations such as the content-presentation device  104  performing a content-modification operation and to help allow for the tracking and reporting of such operations, the content-modification system  100  and/or components thereof can track and report various operation-related data at various times and in various ways. 
     As just a few illustrative examples, responsive to certain operations being performed, such as those described herein, the fingerprint-matching server  106 , the content-presentation device  104 , and/or another entity can generate, store, and/or transmit messages that indicate (i) that a modifiable content-segment has been identified, (ii) that a channel has been identified/confirmed (perhaps based on a match detected as a result of a cold or hot match attempt), (iii) that an upcoming content modification opportunity on the identified channel has been identified, (iv) that supplemental content has been requested, (v) that supplemental content has been received, (vi), that a content-modification operation has started, (vii) that a content-modification operation has ended, and/or (viii) that a scheduled content-modification operation was aborted and/or not performed for any given reason. In some cases, these messages can include other metadata related to these operations. For example, the metadata can specify relevant timing information, device identifiers, channel identifiers, content segment identifiers, etc. 
     L. Watermark-Based Techniques 
     Although this disclosure has described the content-modification system  100  using fingerprint-based technology to perform various operations and to provide various features, in some examples, the content-modification system  100  can use watermark-based techniques instead of, or in addition to, fingerprint-based techniques, to perform these and other operations and to provide these and other features. 
     For example, as an alternative to the fingerprint-based technique described above in which the fingerprint-matching server  106  identifies the channel on which the second content is being received by the content-presentation device  104 , the content-distribution system  102  or another entity can insert a channel identifier in the form of a watermark into the second content, such that the fingerprint-matching server  106 , the content-presentation device  104 , or another entity can extract the channel identifier and use it to identify the channel on which the second content is being received by the content-presentation device  104 . 
     In this context, the content-modification system  100  can employ any watermark technique now known or later developed. 
     M. Operations Related to the Content-Presentation Device Monitoring Received Content while Performing a Content-Modification Operation 
     In some instances, while the content-presentation device  104  is performing a content-modification operation, the content-presentation device  104  can monitor the content that it is receiving, to detect whether the content-presentation device  104  is continuing to receive the modifiable content-segment, as expected. If the content-presentation device  104  is continuing to receive the modifiable content-segment as expected, the content-presentation device  104  can continue to perform the content-modification operation, as originally planned. 
     On the other hand, if the content-presentation device  104  is not continuing to receive the modifiable content-segment as expected (e.g., resulting from the content-presentation device  104  changing channels), the content-presentation device  104  can abort performing the partially performed content-modification operation. Among other things, this functionality can help ensure that the content-presentation device  104  operates in a way that better adheres to the overall desired functionality of the content-modification system  100  and that helps provide a better user experience. 
     To help provide such functionality, the fingerprint-matching server  106  can transmit certain fingerprint data to the content-presentation device  104 . These operations and related features will now be described. 
     To begin with, the fingerprint-matching server  106  can identify an upcoming content modification opportunity on an identified channel. The fingerprint-matching server  106  can do this in any of the various ways described above and/or based on detecting a match between fingerprint data (referred to herein as “sixth fingerprint data”) representing an initial portion (e.g., the first two seconds) of a modifiable content-segment and other fingerprint data (referred to herein as “seventh fingerprint data”) representing content transmitted by the content-distribution system  102  to the content-presentation device  104 . The fingerprint-matching server  106  can compare and/or detect a match between fingerprint data using any content fingerprint comparing and matching technique now known or later developed. 
     Notably, the sixth fingerprint data can be, include, or be part of the fourth fingerprint data as described above, and all the related operations described above in connection with the fourth fingerprint data can likewise be performed in connection with the sixth fingerprint data. In addition, the seventh fingerprint data can be, include, or be part of the third fingerprint data described above, and all the related operations described above in connection with the third fingerprint data can likewise be performed in connection with the seventh fingerprint data. 
     Notably, the sixth fingerprint data can be generated before the seventh fingerprint data is generated. This can happen because the sixth fingerprint data can be generated when the corresponding modifiable content-segment is ingested by the content-management system  108  as described above. On the other hand, the seventh fingerprint data may not be able to be generated until a later time when the represented content is channeled through some portion of the content-distribution system  102  (such that it can be accessed by the content-distribution system  102  and used to generate the seventh fingerprint data). In other words, in one example, while the seventh fingerprint data is generated in “real time” at or about the time that the represented content is being transmitted by the content-distribution system  102  to the content-presentation device  104 , the sixth fingerprint data can be generated in advance of that time as the one or more modifiable-content segments are being ingested. 
     This can provide a benefit in that the fingerprint-matching server  106  can transmit to the content-presentation device  104  sixth fingerprint data that represents a portion of a modifiable content-segment that the content-distribution system  102  has not yet transmitted, but that it is scheduled to transmit soon. By transmitting the content-presentation device  104  in this way, the content-presentation device  104  can perhaps use the sixth fingerprint data to perform one or more of the operations described below, even in the case that the content-distribution system  102  and the content-presentation device  104  experience a network outage or some other type of communication issue. 
     Responsive to the fingerprint-matching server  106  identifying the upcoming content modification opportunity, the fingerprint-matching server  106  can transmit to the content-presentation device  104 , fingerprint data (referred to herein as “eighth fingerprint data”) representing more than the initial portion of the modifiable content-segment. The fingerprint-matching server  106  can transmit the eight fingerprint data to the content-presentation device  104  to facilitate the content-presentation device  104  to, at a later time, either (i) continue performing a content-modification operation related to the identified content modification opportunity, or (ii) abort performance of the (partially performed) content-modification operation related to the identified content modification opportunity. 
     Starting with the first path, the content-presentation device  104  can receive the eighth fingerprint data, which it can use to facilitate continuing to perform the content-modification operation. The content-presentation device  104  can do this by detecting a match between at least a portion of the eight fingerprint data and other fingerprint data (referred to herein as the “ninth fingerprint data”) representing content received by the content-presentation device  104  (which suggests that the content-presentation device  104  is receiving the modifiable content as expected), and responsive to detecting the match, continuing to perform the content-modification operation. Notably, the ninth fingerprint data can be, include, or be part of the fifth fingerprint data as described above, and all the related operations described above in connection with the fifth fingerprint data can likewise be performed in connection with the ninth fingerprint data. 
     To facilitate detecting such a match, in one example, the content-presentation device  104  can establish synchronous lock between a portion of the eight fingerprint data and/or the represented content on the one hand, and a portion of the ninth fingerprint data and/or the represented content, on the other hand. After establishing synchronous lock, the content-presentation device can then detect the match by detecting a match between other respective portions of the eight fingerprint data and/or the represented content on the one hand, and other respective portions of the ninth fingerprint data and/or the represented content, on the other hand. 
     Turning now to the second path, the content-presentation device  104  can receive the eighth fingerprint data, which it can use to facilitate aborting performance of the partially performed content-modification operation. The content-presentation device  104  can do this by detecting a mismatch between the eight fingerprint data and the ninth fingerprint data (which suggests that the content-presentation device  104  is not receiving the modifiable content as expected, perhaps due to the content-presentation device  104  changing channels), and responsive to detecting the mismatch, aborting the partially performed content-modification operation. 
     To facilitate detecting such a mismatch, in one example, the content-presentation device  104  can establish synchronous lock between a portion of the eight fingerprint data and/or the represented content on the one hand, and a portion of the ninth fingerprint data and/or the represented content, on the other hand. After establishing synchronous lock, the content-presentation device can then detect the mismatch by detecting a mismatch between other respective portions of the eight fingerprint data and/or the represented content on the one hand, and other respective portions of the ninth fingerprint data and/or the represented content, on the other hand. 
     In one example, the content-presentation device  104  can abort performance of the content-modification operation by switching from outputting supplemental content to outputting the sequence of the content that it would otherwise output. This process can involve using various buffers of the content-presentation device  104 . For example, this can involve the content-presentation device  104  switching from using first data in a first input buffer where the supplemental content is being received to using second data in a second input buffer where the other content is being received, to populate a display buffer. 
     In some examples, the fingerprint-matching server  106  transmitting the eighth fingerprint data can occur while the supplemental content is being transmitted to the content-presentation device  104  for use in connection with the content-presentation device  104  performing the content-modification operation, as described above. 
     In some instances, responsive to identifying the upcoming content modification opportunity on the identified channel, the fingerprint-matching server  106  can also identify a content-presentation device (e.g., content-presentation device  104 ) the tuned to the identified channel. In such case, transmitting the eighth reference fingerprint data to the content-presentation device can involve transmitting the eighth fingerprint data to the identified content-presentation device. 
       FIG.  3    can help illustrate some of the above-described concepts. As shown, in connection with the TRANSMISSION SEQUENCE  302 , the fingerprint-matching server  106  can identify an upcoming content modification opportunity on the identified channel by detecting a match between fingerprint data representing an initial portion of the MODIFIABLE CONTENT-SEGMENT and fingerprint data representing an initial portion of the AD SEGMENT B. Responsive to identifying the upcoming content modification opportunity, the fingerprint-matching server  106  can transmit to the content-presentation device  104 , fingerprint data representing more than the initial portion of the MODIFIABLE CONTENT-SEGMENT (e.g., the entire MODIFIABLE CONTENT-SEGMENT) to facilitate the content-presentation device  104  to, at a later time, either (i) continue to perform a content-modification operation that involves replacing AD SEGMENT B with AD SEGMENT D or (ii) abort performance of the partially performed content-modification operation that involves replacing AD SEGMENT B with AD SEGMENT D. 
       FIG.  5    is a flow chart of an example method  500 . 
     At block  502 , the method  500  includes identifying an upcoming content modification opportunity on an identified channel, wherein the identifying is based on detecting a match between first reference fingerprint data representing an initial portion of a modifiable content-segment and query fingerprint data representing content transmitted by a content-distribution system to a content-presentation device, wherein the first reference fingerprint data was generated before the query fingerprint data was generated. 
     At block  504 , the method involves responsive to identifying the upcoming content modification opportunity, transmitting to the content-presentation device, second reference fingerprint data representing more than the initial portion of the modifiable content-segment to facilitate the content-presentation device to, at a later time, continue performing a content-modification operation related to the identified content modification opportunity. 
     In one example, the second reference fingerprint data represents the entire modifiable content-segment. In some instances, transmitting the second reference fingerprint data occurs while supplemental content is being transmitted to the content-presentation device for use in connection with the content-presentation device performing the content-modification operation. Also, transmitting the second reference fingerprint data can involve transmitting the second reference fingerprint data before the content represented by the second reference fingerprint data is being channeled through any portion of the content-distribution system. 
     In some examples, the method can also involve, responsive to identifying the upcoming content modification opportunity on the identified channel, identifying a content-presentation device tuned to the identified channel. In such case, transmitting the second reference fingerprint data to the content-presentation device can involve transmitting the second reference fingerprint data to the identified content-presentation device. 
     In various examples, the content-presentation device can be configured to perform a set of acts including: (i) receiving the transmitted second reference fingerprint data; (ii) detecting a match between at least a portion of the received second reference fingerprint data and at least a portion of second query fingerprint data representing content received by the content-presentation device; and (iii) responsive to detecting the match, continuing to perform the content-modification operation. 
       FIG.  6    is a flow chart of an example method  600 . 
     At block  602 , the method  600  includes identifying an upcoming content modification opportunity on an identified channel, wherein the identifying is based on detecting a match between first reference fingerprint data representing an initial portion of a modifiable content-segment and query fingerprint data representing content transmitted by a content-distribution system to a content-presentation device, wherein the first reference fingerprint data was generated before the query fingerprint data was generated. 
     At block  604 , the method involves responsive to identifying the upcoming content modification opportunity, transmitting to the content-presentation device, second reference fingerprint data representing more than the initial portion of the modifiable content-segment to facilitate the content-presentation device to, at a later time, abort performance of a partially performed content-modification operation related to the identified content modification opportunity. 
     In one example, the second reference fingerprint data represents the entire modifiable content-segment. In some instances, transmitting the second reference fingerprint data occurs while supplemental content is being transmitted to the content-presentation device for use in connection with the content-presentation device performing the content-modification operation. Also, transmitting the second reference fingerprint data can involve transmitting the second reference fingerprint data before the content represented by the second reference fingerprint data is being channeled through any portion of the content-distribution system. 
     In some examples, the method can also involve, responsive to identifying the upcoming content modification opportunity on the identified channel, identifying a content-presentation device tuned to the identified channel. In such case, transmitting the second reference fingerprint data to the content-presentation device can involve transmitting the second reference fingerprint data to the identified content-presentation device. 
     In various examples, the content-presentation device can be configured to perform a set of acts including: (i) receiving the transmitted second reference fingerprint data; (ii) detecting a mismatch between at least a portion of the received second reference fingerprint data and at least a portion of second query fingerprint data representing content received by the content-presentation device; and (iii) responsive to detecting the mismatch, aborting performance of the partially performed content-modification operation. 
     IV. Example Variations 
     Although the examples and features described above have been described in connection with specific entities and specific operations, in practice, there are likely to be many instances of these entities and many instances of these operations being performed, perhaps contemporaneously or simultaneously, on a large-scale basis. Indeed, in practice, the content-modification system  100  is likely to include many content-distribution systems (each potentially transmitting content on many channels) and many content-presentation devices, with some or all of the described operations being performed on a routine and repeating basis in connection with some or all of these entities. 
     In addition, although some of the operations described in this disclosure have been described as being performed by a particular entity, the operations can be performed by any entity, such as the other entities described in this disclosure. Further, although the operations have been recited in a particular order and/or in connection with example temporal language, the operations need not be performed in the order recited and need not be performed in accordance with any particular temporal restrictions. However, in some instances, it can be desired to perform one or more of the operations in the order recited, in another order, and/or in a manner where at least some of the operations are performed contemporaneously/simultaneously. Likewise, in some instances, it can be desired to perform one or more of the operations in accordance with one more or the recited temporal restrictions or with other timing restrictions. Further, each of the described operations can be performed responsive to performance of one or more of the other described operations. Also, not all of the operations need to be performed to achieve one or more of the benefits provided by the disclosure, and therefore not all of the operations are required. 
     Although certain variations have been described in connection with one or more examples of this disclosure, these variations can also be applied to some or all of the other examples of this disclosure as well and therefore aspects of this disclosure can be combined and/or arranged in many ways. The examples described in this disclosure were selected at least in part because they help explain the practical application of the various described features. 
     Also, although select examples of this disclosure have been described, alterations and permutations of these examples will be apparent to those of ordinary skill in the art. Other changes, substitutions, and/or alterations are also possible without departing from the invention in its broader aspects as set forth in the following claims.