Patent Publication Number: US-2023141788-A1

Title: Conditional Content Enhancement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 17/745,726 filed May 16, 2022, and entitled “Conditional Content Enhancement,” which is a continuation of U.S. application Ser. No. 17/128,696, now U.S. Pat. No. 11,337,018, filed Dec. 21, 2020, and entitled “Conditional Content Enhancement,” which is a continuation of U.S. application Ser. No. 16/696,316, now U.S. Pat. No. 10,873,820, filed Nov. 26, 2019, and entitled “Conditional Content Enhancement,” which is a continuation of U.S. application Ser. No. 15/973,443, now U.S. Pat. No. 10,524,070, filed May 7, 2018, and entitled “Conditional Content Enhancement,” which is a continuation of U.S. application Ser. No. 15/280,979, now U.S. Pat. No. 9,967,689, filed Sep. 29, 2016, and entitled “Conditional Content Enhancement,” the contents of each of which are explicitly incorporated by reference herein in their entirety. The present application also incorporates by reference U.S. patent application Ser. No. 13/239,077, now U.S. Pat. No. 9,286,384, filed on Sep. 21, 2011, for “Methods and Systems to Share Media,” and U.S. patent application Ser. No. 14/971,796, now U.S. Pat. No. 10,098,082, filed on Dec. 16, 2015, for “Synchronization of Content Between Networked Devices.” 
    
    
     FIELD OF THE DISCLOSURE 
     The disclosure is related to consumer goods and, more particularly, to methods, systems, products, features, services, and other elements directed to media playback or some aspect thereof. 
     BACKGROUND 
     Options for accessing and listening to digital audio in an out-loud setting were limited until in 2003, when SONOS, Inc. filed for one of its first patent applications, entitled “Method for Synchronizing Audio Playback between Multiple Networked Devices,” and began offering a media playback system for sale in 2005. The Sonos Wireless HiFi System enables people to experience music from many sources via one or more networked playback devices. Through a software control application installed on a smartphone, tablet, or computer, one can play what he or she wants in any room that has a networked playback device. Additionally, using the controller, for example, different songs can be streamed to each room with a playback device, rooms can be grouped together for synchronous playback, or the same song can be heard in all rooms synchronously. 
     Given the ever growing interest in digital media, there continues to be a need to develop consumer-accessible technologies to further enhance the listening experience. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, aspects, and advantages of the presently disclosed technology may be better understood with regard to the following description, appended claims, and accompanying drawings where: 
         FIG.  1    shows an example media playback system configuration in which certain embodiments may be practiced; 
         FIG.  2    shows a functional block diagram of an example playback device; 
         FIG.  3    shows a functional block diagram of an example control device; 
         FIG.  4    shows an example controller interface; 
         FIG.  5    shows an example flow diagram for the conditional enhancement of audio content; 
         FIG.  6    shows an example playback device and example audio content sources; 
         FIG.  7    shows example audio characteristics of audio content and corresponding playback device capabilities; 
         FIG.  8    shows example audio characteristics of audio content and corresponding playback device capabilities. 
     
    
    
     The drawings are for the purpose of illustrating example embodiments, but it is understood that the inventions are not limited to the arrangements and instrumentality shown in the drawings. 
     DETAILED DESCRIPTION 
     I. Overview 
     Examples described herein involve the conditional enhancement of audio content based on the capability of one or more playback devices that may play back the audio content. For instance, a playback device may determine that playback of a first version of audio content may be improved by retrieving a second version of the same audio content having audio characteristics that more closely match the capability of the playback device. 
     For example, a playback device within a media playback system may have access to numerous content sources, such as audio and video streaming services, content libraries, and local device storage, among other examples. Many of the sources available to the playback device may contain versions of the same audio content, such as a particular song by a particular artist, or an audio track that accompanies a particular movie. However, the audio characteristics of each version of the same audio content may not be the same. For example, a first version of the audio content, available from a first source, may have a first bit depth, sample rate and/or number of audio output channels, whereas a second version of the same audio content, available from a second source, may have second bit depth, sample rate, and/or number of audio output channels. 
     Accordingly, when the playback device identifies a first version of audio content that is to be played back, the playback device may determine whether the audio content can be enhanced by identifying and retrieving an improved version of the audio content. For instance, the playback device may identify the value of one or more audio characteristics of the first version of the audio content, such as the audio characteristics discussed above. The playback device may then determine that the value of the audio characteristic does not match the capability of the playback device. In other words, the playback device may determine that it, either alone or in combination with other playback devices in the media playback system, has the capability to play back an improved version of the audio content. 
     The playback device may then identify, by searching available content sources, a second version of the audio content that has an improved value for the audio characteristic that more closely matches the capability of the playback device. The playback device may then cause the second version of the audio content to be played back, improving the listening experience within the media playback system  100 . 
     As indicated above, the examples involve the conditional enhancement of audio content. In one aspect, a method is provided. The method involves identifying, by a playback device, a first version of audio content for play back from a first source and identifying, by the playback device, a first value of an audio characteristic of the first version of the audio content, where the playback device includes a capability corresponding to the audio characteristic. The method also includes determining, by the playback device, that the first value of the audio characteristic of the first version of the audio content does not match the capability of the playback device. The method further includes identifying, by the playback device, a second version of the audio content from a second source, where the second version of the audio content includes the audio characteristic having a second value, and where the second value of the audio characteristic is closer to the capability of the playback device. The method also involves causing playback of the second version of the audio content. 
     In another aspect, a device is provided. The device includes a processor, a non-transitory computer readable medium, and program instructions stored on the non-transitory computer readable medium that, when executed by the processor, cause the playback device to perform functions including identifying a first version of audio content for play back from a first source, and identifying a first value of an audio characteristic of the first version of the audio content, where the playback device includes a capability corresponding to the audio characteristic. The functions also include determining that the first value of the audio characteristic of the first version of the audio content does not match the capability of the playback device. The functions further include identifying a second version of the audio content from a second source, where the second version of the audio content includes the audio characteristic having a second value, and where the second value of the audio characteristic is closer to the capability of the playback device. The functions also include causing playback of the second version of the audio content. 
     In yet another aspect, a non-transitory computer readable memory is provided. The non-transitory computer readable memory has stored thereon instructions executable by a playback device to cause the playback device to perform functions. The functions include identifying a first version of audio content for play back from a first source and identifying a first value of an audio characteristic of the first version of the audio content, where the playback device includes a capability corresponding to the audio characteristic. The functions also include determining that the first value of the audio characteristic of the first version of the audio content does not match the capability of the playback device. The functions further include identifying a second version of the audio content from a second source, where the second version of the audio content includes the audio characteristic having a second value, and where the second value of the audio characteristic is closer to the capability of the playback device. The functions also include causing playback of the second version of the audio content. 
     It will be understood by one of ordinary skill in the art that this disclosure includes numerous other embodiments. It will be understood by one of ordinary skill in the art that this disclosure includes numerous other examples. While some examples described herein may refer to functions performed by given actors such as “users” and/or other entities, it should be understood that this description is for purposes of explanation only. The claims should not be interpreted to require action by any such example actor unless explicitly required by the language of the claims themselves. 
     While some examples described herein may refer to functions performed by given actors such as “users” and/or other entities, it should be understood that this is for purposes of explanation only. The claims should not be interpreted to require action by any such example actor unless explicitly required by the language of the claims themselves. 
     II. Example Operating Environment 
       FIG.  1    shows an example configuration of a media playback system  100  in which one or more embodiments disclosed herein may be practiced or implemented. The media playback system  100  as shown is associated with an example home environment having several rooms and spaces, such as for example, a master bedroom, an office, a dining room, and a living room. As shown in the example of  FIG.  1   , the media playback system  100  includes playback devices  102 - 124 , control devices  126  and  128 , and a wired or wireless network router  130 . 
     Further discussions relating to the different components of the example media playback system  100  and how the different components may interact to provide a user with a media experience may be found in the following sections. While discussions herein may generally refer to the example media playback system  100 , technologies described herein are not limited to applications within, among other things, the home environment as shown in  FIG.  1   . For instance, the technologies described herein may be useful in environments where multi-zone audio may be desired, such as, for example, a commercial setting like a restaurant, mall or airport, a vehicle like a sports utility vehicle (SUV), bus or car, a ship or boat, an airplane, and so on. 
     a. Example Playback Devices 
       FIG.  2    shows a functional block diagram of an example playback device  200  that may be configured to be one or more of the playback devices  102 - 124  of the media playback system  100  of  FIG.  1   . The playback device  200  may include a processor  202 , software components  204 , memory  206 , audio processing components  208 , audio amplifier(s)  210 , speaker(s)  212 , and a network interface  214  including wireless interface(s)  216  and wired interface(s)  218 . In one case, the playback device  200  may not include the speaker(s)  212 , but rather a speaker interface for connecting the playback device  200  to external speakers. In another case, the playback device  200  may include neither the speaker(s)  212  nor the audio amplifier(s)  210 , but rather an audio interface for connecting the playback device  200  to an external audio amplifier or audio-visual receiver. 
     In one example, the processor  202  may be a clock-driven computing component configured to process input data according to instructions stored in the memory  206 . The memory  206  may be a tangible computer-readable medium configured to store instructions executable by the processor  202 . For instance, the memory  206  may be data storage that can be loaded with one or more of the software components  204  executable by the processor  202  to achieve certain functions. In one example, the functions may involve the playback device  200  retrieving audio data from an audio source or another playback device. In another example, the functions may involve the playback device  200  sending audio data to another device or playback device on a network. In yet another example, the functions may involve pairing of the playback device  200  with one or more playback devices to create a multi-channel audio environment. 
     Certain functions may involve the playback device  200  synchronizing playback of audio content with one or more other playback devices. During synchronous playback, a listener will preferably not be able to perceive time-delay differences between playback of the audio content by the playback device  200  and the one or more other playback devices. U.S. Pat. No. 8,234,395 entitled, “System and method for synchronizing operations among a plurality of independently clocked digital data processing devices,” which is hereby incorporated by reference, provides in more detail some examples for audio playback synchronization among playback devices. 
     The memory  206  may further be configured to store data associated with the playback device  200 , such as one or more zones and/or zone groups the playback device  200  is a part of, audio sources accessible by the playback device  200 , or a playback queue that the playback device  200  (or some other playback device) may be associated with. The data may be stored as one or more state variables that are periodically updated and used to describe the state of the playback device  200 . The memory  206  may also include the data associated with the state of the other devices of the media system, and shared from time to time among the devices so that one or more of the devices have the most recent data associated with the system. Other embodiments are also possible. 
     The audio processing components  208  may include one or more digital-to-analog converters (DAC), an audio preprocessing component, an audio enhancement component or a digital signal processor (DSP), and so on. In one embodiment, one or more of the audio processing components  208  may be a subcomponent of the processor  202 . In one example, audio content may be processed and/or intentionally altered by the audio processing components  208  to produce audio signals. The produced audio signals may then be provided to the audio amplifier(s)  210  for amplification and playback through speaker(s)  212 . Particularly, the audio amplifier(s)  210  may include devices configured to amplify audio signals to a level for driving one or more of the speakers  212 . The speaker(s)  212  may include an individual transducer (e.g., a “driver”) or a complete speaker system involving an enclosure with one or more drivers. A particular driver of the speaker(s)  212  may include, for example, a subwoofer (e.g., for low frequencies), a mid-range driver (e.g., for middle frequencies), and/or a tweeter (e.g., for high frequencies). In some cases, each transducer in the one or more speakers  212  may be driven by an individual corresponding audio amplifier of the audio amplifier(s)  210 . In addition to producing analog signals for playback by the playback device  200 , the audio processing components  208  may be configured to process audio content to be sent to one or more other playback devices for playback. 
     Audio content to be processed and/or played back by the playback device  200  may be received from an external source, such as via an audio line-in input connection (e.g., an auto-detecting 3.5 mm audio line-in connection) or the network interface  214 . 
     The network interface  214  may be configured to facilitate a data flow between the playback device  200  and one or more other devices on a data network. As such, the playback device  200  may be configured to receive audio content over the data network from one or more other playback devices in communication with the playback device  200 , network devices within a local area network, or audio content sources over a wide area network such as the Internet. In one example, the audio content and other signals transmitted and received by the playback device  200  may be transmitted in the form of digital packet data containing an Internet Protocol (IP)-based source address and IP-based destination addresses. In such a case, the network interface  214  may be configured to parse the digital packet data such that the data destined for the playback device  200  is properly received and processed by the playback device  200 . 
     As shown, the network interface  214  may include wireless interface(s)  216  and wired interface(s)  218 . The wireless interface(s)  216  may provide network interface functions for the playback device  200  to wirelessly communicate with other devices (e.g., other playback device(s), speaker(s), receiver(s), network device(s), control device(s) within a data network the playback device  200  is associated with) in accordance with a communication protocol (e.g., any wireless standard including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4G mobile communication standard, and so on). The wired interface(s)  218  may provide network interface functions for the playback device  200  to communicate over a wired connection with other devices in accordance with a communication protocol (e.g., IEEE 802.3). While the network interface  214  shown in  FIG.  2    includes both wireless interface(s)  216  and wired interface(s)  218 , the network interface  214  may in some embodiments include only wireless interface(s) or only wired interface(s). 
     In one example, the playback device  200  and one other playback device may be paired to play two separate audio components of audio content. For instance, playback device  200  may be configured to play a left channel audio component, while the other playback device may be configured to play a right channel audio component, thereby producing or enhancing a stereo effect of the audio content. The paired playback devices (also referred to as “bonded playback devices”) may further play audio content in synchrony with other playback devices. 
     In another example, the playback device  200  may be sonically consolidated with one or more other playback devices to form a single, consolidated playback device. A consolidated playback device may be configured to process and reproduce sound differently than an unconsolidated playback device or playback devices that are paired, because a consolidated playback device may have additional speaker drivers through which audio content may be rendered. For instance, if the playback device  200  is a playback device designed to render low frequency range audio content (i.e. a subwoofer), the playback device  200  may be consolidated with a playback device designed to render full frequency range audio content. In such a case, the full frequency range playback device, when consolidated with the low frequency playback device  200 , may be configured to render only the mid and high frequency components of audio content, while the low frequency range playback device  200  renders the low frequency component of the audio content. The consolidated playback device may further be paired with a single playback device or yet another consolidated playback device. 
     By way of illustration, SONOS, Inc. presently offers (or has offered) for sale certain playback devices including a “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any other past, present, and/or future playback devices may additionally or alternatively be used to implement the playback devices of example embodiments disclosed herein. Additionally, it is understood that a playback device is not limited to the example illustrated in  FIG.  2    or to the SONOS product offerings. For example, a playback device may include a wired or wireless headphone. In another example, a playback device may include or interact with a docking station for personal mobile media playback devices. In yet another example, a playback device may be integral to another device or component such as a television, a lighting fixture, or some other device for indoor or outdoor use. 
     b. Example Playback Zone Configurations 
     Referring back to the media playback system  100  of  FIG.  1   , the environment may have one or more playback zones, each with one or more playback devices. The media playback system  100  may be established with one or more playback zones, after which one or more zones may be added, or removed to arrive at the example configuration shown in  FIG.  1   . Each zone may be given a name according to a different room or space such as an office, bathroom, master bedroom, bedroom, kitchen, dining room, living room, and/or balcony. In one case, a single playback zone may include multiple rooms or spaces. In another case, a single room or space may include multiple playback zones. 
     As shown in  FIG.  1   , the balcony, dining room, kitchen, bathroom, office, and bedroom zones each have one playback device, while the living room and master bedroom zones each have multiple playback devices. In the living room zone, playback devices  104 ,  106 ,  108 , and  110  may be configured to play audio content in synchrony as individual playback devices, as one or more bonded playback devices, as one or more consolidated playback devices, or any combination thereof. Similarly, in the case of the master bedroom, playback devices  122  and  124  may be configured to play audio content in synchrony as individual playback devices, as a bonded playback device, or as a consolidated playback device. 
     In one example, one or more playback zones in the environment of  FIG.  1    may each be playing different audio content. For instance, the user may be grilling in the balcony zone and listening to hip hop music being played by the playback device  102  while another user may be preparing food in the kitchen zone and listening to classical music being played by the playback device  114 . In another example, a playback zone may play the same audio content in synchrony with another playback zone. For instance, the user may be in the office zone where the playback device  118  is playing the same rock music that is being playing by playback device  102  in the balcony zone. In such a case, playback devices  102  and  118  may be playing the rock music in synchrony such that the user may seamlessly (or at least substantially seamlessly) enjoy the audio content that is being played out-loud while moving between different playback zones. Synchronization among playback zones may be achieved in a manner similar to that of synchronization among playback devices, as described in previously referenced U.S. Pat. No. 8,234,395. 
     As suggested above, the zone configurations of the media playback system  100  may be dynamically modified, and in some embodiments, the media playback system  100  supports numerous configurations. For instance, if a user physically moves one or more playback devices to or from a zone, the media playback system  100  may be reconfigured to accommodate the change(s). For instance, if the user physically moves the playback device  102  from the balcony zone to the office zone, the office zone may now include both the playback device  118  and the playback device  102 . The playback device  102  may be paired or grouped with the office zone and/or renamed if so desired via a control device such as the control devices  126  and  128 . On the other hand, if the one or more playback devices are moved to a particular area in the home environment that is not already a playback zone, a new playback zone may be created for the particular area. 
     Further, different playback zones of the media playback system  100  may be dynamically combined into zone groups or split up into individual playback zones. For instance, the dining room zone and the kitchen zone  114  may be combined into a zone group for a dinner party such that playback devices  112  and  114  may render audio content in synchrony. On the other hand, the living room zone may be split into a television zone including playback device  104 , and a listening zone including playback devices  106 ,  108 , and  110 , if the user wishes to listen to music in the living room space while another user wishes to watch television. 
     c. Example Control Devices 
       FIG.  3    shows a functional block diagram of an example control device  300  that may be configured to be one or both of the control devices  126  and  128  of the media playback system  100 . As shown, the control device  300  may include a processor  302 , memory  304 , a network interface  306 , and a user interface  308 . In one example, the control device  300  may be a dedicated controller for the media playback system  100 . In another example, the control device  300  may be a network device on which media playback system controller application software may be installed, such as for example, an iPhone™, iPad™ or any other smart phone, tablet or network device (e.g., a networked computer such as a PC or Mac™). 
     The processor  302  may be configured to perform functions relevant to facilitating user access, control, and configuration of the media playback system  100 . The memory  304  may be configured to store instructions executable by the processor  302  to perform those functions. The memory  304  may also be configured to store the media playback system controller application software and other data associated with the media playback system  100  and the user. 
     In one example, the network interface  306  may be based on an industry standard (e.g., infrared, radio, wired standards including IEEE 802.3, wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4G mobile communication standard, and so on). The network interface  306  may provide a means for the control device  300  to communicate with other devices in the media playback system  100 . In one example, data and information (e.g., such as a state variable) may be communicated between control device  300  and other devices via the network interface  306 . For instance, playback zone and zone group configurations in the media playback system  100  may be received by the control device  300  from a playback device or another network device, or transmitted by the control device  300  to another playback device or network device via the network interface  306 . In some cases, the other network device may be another control device. 
     Playback device control commands such as volume control and audio playback control may also be communicated from the control device  300  to a playback device via the network interface  306 . As suggested above, changes to configurations of the media playback system  100  may also be performed by a user using the control device  300 . The configuration changes may include adding/removing one or more playback devices to/from a zone, adding/removing one or more zones to/from a zone group, forming a bonded or consolidated player, separating one or more playback devices from a bonded or consolidated player, among others. Accordingly, the control device  300  may sometimes be referred to as a controller, whether the control device  300  is a dedicated controller or a network device on which media playback system controller application software is installed. 
     The user interface  308  of the control device  300  may be configured to facilitate user access and control of the media playback system  100 , by providing a controller interface such as the controller interface  400  shown in  FIG.  4   . The controller interface  400  includes a playback control region  410 , a playback zone region  420 , a playback status region  430 , a playback queue region  440 , and an audio content sources region  450 . The user interface  400  as shown is just one example of a user interface that may be provided on a network device such as the control device  300  of  FIG.  3    (and/or the control devices  126  and  128  of  FIG.  1   ) and accessed by users to control a media playback system such as the media playback system  100 . Other user interfaces of varying formats, styles, and interactive sequences may alternatively be implemented on one or more network devices to provide comparable control access to a media playback system. 
     The playback control region  410  may include selectable (e.g., by way of touch or by using a cursor) icons to cause playback devices in a selected playback zone or zone group to play or pause, fast forward, rewind, skip to next, skip to previous, enter/exit shuffle mode, enter/exit repeat mode, enter/exit cross fade mode. The playback control region  410  may also include selectable icons to modify equalization settings, and playback volume, among other possibilities. 
     The playback zone region  420  may include representations of playback zones within the media playback system  100 . In some embodiments, the graphical representations of playback zones may be selectable to bring up additional selectable icons to manage or configure the playback zones in the media playback system, such as a creation of bonded zones, creation of zone groups, separation of zone groups, and renaming of zone groups, among other possibilities. 
     For example, as shown, a “group” icon may be provided within each of the graphical representations of playback zones. The “group” icon provided within a graphical representation of a particular zone may be selectable to bring up options to select one or more other zones in the media playback system to be grouped with the particular zone. Once grouped, playback devices in the zones that have been grouped with the particular zone will be configured to play audio content in synchrony with the playback device(s) in the particular zone. Analogously, a “group” icon may be provided within a graphical representation of a zone group. In this case, the “group” icon may be selectable to bring up options to deselect one or more zones in the zone group to be removed from the zone group. Other interactions and implementations for grouping and ungrouping zones via a user interface such as the user interface  400  are also possible. The representations of playback zones in the playback zone region  420  may be dynamically updated as playback zone or zone group configurations are modified. 
     The playback status region  430  may include graphical representations of audio content that is presently being played, previously played, or scheduled to play next in the selected playback zone or zone group. The selected playback zone or zone group may be visually distinguished on the user interface, such as within the playback zone region  420  and/or the playback status region  430 . The graphical representations may include track title, artist name, album name, album year, track length, and other relevant information that may be useful for the user to know when controlling the media playback system via the user interface  400 . 
     The playback queue region  440  may include graphical representations of audio content in a playback queue associated with the selected playback zone or zone group. In some embodiments, each playback zone or zone group may be associated with a playback queue containing information corresponding to zero or more audio items for playback by the playback zone or zone group. For instance, each audio item in the playback queue may comprise a uniform resource identifier (URI), a uniform resource locator (URL) or some other identifier that may be used by a playback device in the playback zone or zone group to find and/or retrieve the audio item from a local audio content source or a networked audio content source, possibly for playback by the playback device. 
     In one example, a playlist may be added to a playback queue, in which case information corresponding to each audio item in the playlist may be added to the playback queue. In another example, audio items in a playback queue may be saved as a playlist. In a further example, a playback queue may be empty, or populated but “not in use” when the playback zone or zone group is playing continuously streaming audio content, such as Internet radio that may continue to play until otherwise stopped, rather than discrete audio items that have playback durations. In an alternative embodiment, a playback queue can include Internet radio and/or other streaming audio content items and be “in use” when the playback zone or zone group is playing those items. Other examples are also possible. 
     When playback zones or zone groups are “grouped” or “ungrouped,” playback queues associated with the affected playback zones or zone groups may be cleared or re-associated. For example, if a first playback zone including a first playback queue is grouped with a second playback zone including a second playback queue, the established zone group may have an associated playback queue that is initially empty, that contains audio items from the first playback queue (such as if the second playback zone was added to the first playback zone), that contains audio items from the second playback queue (such as if the first playback zone was added to the second playback zone), or a combination of audio items from both the first and second playback queues. Subsequently, if the established zone group is ungrouped, the resulting first playback zone may be re-associated with the previous first playback queue, or be associated with a new playback queue that is empty or contains audio items from the playback queue associated with the established zone group before the established zone group was ungrouped. Similarly, the resulting second playback zone may be re-associated with the previous second playback queue, or be associated with a new playback queue that is empty, or contains audio items from the playback queue associated with the established zone group before the established zone group was ungrouped. Other examples are also possible. 
     Referring back to the user interface  400  of  FIG.  4   , the graphical representations of audio content in the playback queue region  440  may include track titles, artist names, track lengths, and other relevant information associated with the audio content in the playback queue. In one example, graphical representations of audio content may be selectable to bring up additional selectable icons to manage and/or manipulate the playback queue and/or audio content represented in the playback queue. For instance, a represented audio content may be removed from the playback queue, moved to a different position within the playback queue, or selected to be played immediately, or after any currently playing audio content, among other possibilities. A playback queue associated with a playback zone or zone group may be stored in a memory on one or more playback devices in the playback zone or zone group, on a playback device that is not in the playback zone or zone group, and/or some other designated device. 
     The audio content sources region  450  may include graphical representations of selectable audio content sources from which audio content may be retrieved and played by the selected playback zone or zone group. Discussions pertaining to audio content sources may be found in the following section. 
     d. Example Audio Content Sources 
     As indicated previously, one or more playback devices in a zone or zone group may be configured to retrieve for playback audio content (e.g. according to a corresponding URI or URL for the audio content) from a variety of available audio content sources. In one example, audio content may be retrieved by a playback device directly from a corresponding audio content source (e.g., a line-in connection). In another example, audio content may be provided to a playback device over a network via one or more other playback devices or network devices. 
     Example audio content sources may include a memory of one or more playback devices in a media playback system such as the media playback system  100  of  FIG.  1   , local music libraries on one or more network devices (such as a control device, a network-enabled personal computer, or a networked-attached storage (NAS), for example), streaming audio services providing audio content via the Internet (e.g., the cloud), or audio sources connected to the media playback system via a line-in input connection on a playback device or network devise, among other possibilities. 
     In some embodiments, audio content sources may be regularly added or removed from a media playback system such as the media playback system  100  of  FIG.  1   . In one example, an indexing of audio items may be performed whenever one or more audio content sources are added, removed or updated. Indexing of audio items may involve scanning for identifiable audio items in all folders/directory shared over a network accessible by playback devices in the media playback system, and generating or updating an audio content database containing metadata (e.g., title, artist, album, track length, among others) and other associated information, such as a URI or URL for each identifiable audio item found. Other examples for managing and maintaining audio content sources may also be possible. 
     The above discussions relating to playback devices, controller devices, playback zone configurations, and media content sources provide only some examples of operating environments within which functions and methods described below may be implemented. Other operating environments and configurations of media playback systems, playback devices, and network devices not explicitly described herein may also be applicable and suitable for implementation of the functions and methods. 
     III. Example Implementations of Conditional Content Enhancement 
     As discussed above, embodiments described herein may involve the conditional enhancement of audio content based on the capability of one or more playback devices that may play back the audio content. 
     Method  500  shown in  FIG.  5    presents an embodiment of a method that can be implemented within an operating environment involving, for example, the media playback system  100  of  FIG.  1   , one or more of the playback device  200  of  FIG.  2   , and one or more of the control device  300  of  FIG.  3   . Method  500  may include one or more operations, functions, or actions as illustrated by one or more of blocks  502 - 510 . Although the blocks are illustrated in sequential order, these blocks may also be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation. 
     In addition, for the method  500  and other processes and methods disclosed herein, the flowchart shows functionality and operation of one possible implementation of present embodiments. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by a processor for implementing specific logical functions or steps in the process. The program code may be stored on any type of computer readable medium, for example, such as a storage device including a disk or hard drive. The computer readable medium may include non-transitory computer readable medium, for example, such as computer-readable media that stores data for short periods of time like register memory, processor cache and Random Access Memory (RAM). The computer readable medium may also include non-transitory media, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, for example, or a tangible storage device. In addition, for the method  500  and other processes and methods disclosed herein, each block in  FIG.  5    may represent circuitry that is wired to perform the specific logical functions in the process. 
     At block  502  of the method  500 , a playback device may identify a first version of audio content for play back from a first source. The playback device may be, for example, the playback device  200  shown in  FIG.  2   , and may further correspond to one of the playback devices  102 - 124  in the media playback system  100  shown in  FIG.  1   .  FIG.  6    illustrates an example implementation. The playback device  108  of  FIG.  1    is shown, which identifies the first version of audio content  601  from the first source  603 . 
     The first version of the audio content  601  may be any audio content that may be played back by the playback device  200 , and the first source  603  may be any source that can provide content to the playback device  200 , such as those discussed in section II.d. above. For instance, the first version of the audio content  601  may be a music track. The first version of the audio content  601  might take other forms as well, such as an audiobook or a podcast, among other examples. Further, although it is illustrated as a cloud-based source in  FIG.  6   , such as an internet-based streaming music provider, the first source  603  may alternatively be a local network connected device, or a control device such as the control device  300 , among other examples. 
     In further examples, the first version of the audio content  601  may be audio content that accompanies video content. For instance, the media playback system  100  and the playback device  108  may be integrated with a home theater system, and the first version of the audio content  601  may be the audio corresponding to a movie, television show, music video or other video content on a television. Similarly, a control device, such as the control device  300 , may include a display capable of playing back video content in synchrony with audio content via the playback device  108 . In such cases, the first version of the audio content  601  may be received from the same source that originates the video content. For example, the first source  603  may be a locally-connected device such as a cable box, a satellite tuner, a DVD or Blu-ray player. Alternatively, the first source  603  for the first version of the audio content  601  may be an internet-based video streaming service that also transmits audio corresponding to the video stream. Numerous other possibilities exist. 
     The playback device  108  may identify the first version of the audio content in a number of ways. For instance, the playback device  108  may receive a URI or a URL to the first version of the audio content  601  as part of a command to play the audio content from the first source  603 . In other implementations, where the first version of the audio content  601  is pushed to the playback device  108 , the playback device  108  may identify the first version of the audio content  601  based on metadata that is received in addition to the first version of the audio content  601 . In other examples, such as an example where metadata identifying the first version of the audio content  601  is not available, the playback device  108  may sample the first version of the audio content  601  and identify it based on an audio recognition algorithm. Other examples are also possible. 
     At block  504 , the playback device  108  may identify a first value of an audio characteristic of the first version of the audio content  601 , wherein the playback device  108  comprises a capability corresponding to the audio characteristic. The audio characteristic of the first version of the audio content  601  may be any audio characteristic that affects the playback of the audio content. For instance,  FIG.  7    shows a representation of the audio content  601 , including a list of audio characteristics such as bit depth  701   a,  sample rate  701   b,  and number of channels  701   c.  For the bit depth  701   a,  the playback device  108  identifies a first value of 8-bit  702   a,  also shown in  FIG.  7   . Similarly, the playback device  108  identifies a first value of 32 kHz  702   b  for the sample rate  702   a , and a first value of 1 (mono)  702   c  for the number of channels  701   c.    
     The playback device  108  may identify a value for other audio characteristics as well, in addition to those discussed above and shown in  FIG.  7   . For instance, the playback device  108  may identify the audio format, which may indicate the audio codec used to compress and decompress the first version of the audio content  601 , such as MP3, AAC, or FLAC, among other possibilities. As another example, some audio content may be object-based rather than channel-based, and the playback device  108  may identify values for object-based audio characteristics, such as polar resolution, or polar coordinates. Other possibilities also exist. 
     In some cases, the first version of the audio content  601  may include metadata that the playback device  108  may use to identify the first value of the audio characteristic. However, in some examples the metadata may be unavailable or incomplete. In these instances, the playback device  108  may, before identifying the first value of the audio characteristic, play back the first version of the audio content  601 . Based on the sample of playback of the first version of the audio content  601 , the playback device  108  may identify the first value of the audio characteristic. 
     In other implementations, such as those where the first version of the audio content  601  is streamed from an internet-based source, the first value of the audio characteristic may change during the stream. For instance, the bit depth or sample rate of an incoming audio stream may be reduced due to network latency or bandwidth considerations. Therefore, the playback device  108  may identify the first value for the audio characteristic at regular or irregular intervals during playback of the first version of the audio content  601 . Additionally or alternatively, the playback device  108  may identify the first value for the audio characteristic whenever a change in the incoming audio stream is detected. 
     Additionally, the playback device  108  includes a capability corresponding to the audio characteristic. For example,  FIG.  7    illustrates a representation of the playback device  108 , including a list the same audio characteristics  701   a - c  that are listed for the first version of the audio content  601 . For each audio characteristic  701   a - c , the capability of the playback device  108  is listed. For instance, for bit depth  701   a,  the capability of the playback device  108  is 16 bit  703   a.  Similarly, for sample rate  701   b,  the capability of the playback device  108  is 44.1 kHz  703   b,  and for number of channels, the capability is 1 (mono)  703   c.  In each instance, the listed capability of the playback device  108  may generally correspond to the highest quality audio that the playback device  108  can play. For instance, a higher bit depth or sample rate may generally correspond to better quality audio and an improved listening experience. Similarly, some audio codecs utilize compression that results in data loss and degradation of the audio content, whereas other file formats result in less data loss, utilize lossless compression, or are uncompressed. Thus, the capability of the playback device  108  with respect to audio format may correspond to the audio format(s) that result in the least data loss. 
     At block  506 , the playback device  108  may determine that the first value of the audio characteristic of the first version of the audio content  601  does not match the capability of the playback device  108 . For instance, as shown in  FIG.  7   , the playback device  108  may determine that the bit depth  701   a  of the first version of the audio content  601 , namely, 8 bit  702   a,  does not match the capability, 16 bit  703   a,  of the playback device  108 . The playback device may make a similar determination regarding the sample rate  701   b,  as 32 kHz  702   b  is also below the 44.1 kHz  703   b  capability. 
     At block  508 , the playback device  108  may identify a second version of the audio content from a second source.  FIG.  6    illustrates the playback device  108 , which identifies the second version of the audio content  602  from the second source  604 . Like the first source  603 , the second source  604  may be any of the audio content sources discussed above in section II.d. For example, the first version of the audio content  601  may be a particular song by a particular artist, and the first source  603  may be a control device  300  in the media playback system  100  that includes the first version of the audio content  601  stored in its memory  304 . The second version of the audio content  602  is a second version of the same song, by the same artist, but the source  604  may instead be an internet-based music streaming service or content library. 
     Although the first and second versions of the audio content are the same song, by the same artist, the audio characteristics of the two versions in this example are different. In particular, the second version of the audio content  602  includes the audio characteristic having a second value, and the second value of the audio characteristic is closer to the capability of the playback device  108 . The example shown in  FIG.  7    is illustrative. As noted above, the capability of the playback device  108  with respect to both bit depth  701   a  and sample rate  701   b  exceeds the values of those two audio characteristics for the first version of the audio content  601 . However, the playback device  108  identifies a second version of the audio content  602  that, although it is the same song by the same artist, has a bit depth  701   a  with a second value of 16 bit  704   a,  and a sample rate  701   b  with a second value of 44.1 kHz  704   b.  Thus, the playback device  108  has identified a higher-quality version of the same audio content, the playback of which may enhance the listening experience. 
     Accordingly, at block  510 , the playback device  108  may cause playback of the second version of the audio content  602 . In some examples, before causing playback of the second version of the audio content  602 , the playback device  108  may synchronize playback of the second version of the audio content  602  with playback of the first version of the audio content  601 . For instance, the playback device may align the start and end times of the two versions of the audio content and then match a presentation time stamp for upcoming samples that are to be played. This may allow for the second version of the audio content  602  to be played at the same time or nearly the same time that the first version of the audio content  601  was to be played, which may be important where the audio content is synced with video content. 
     Further, in some instances where the second version of the audio content  602  is identified after the first version of the audio content  601  is already being played back, the playback device  108  may perform additional processing, such as cross-fading the volume between the two versions, in order to provide a smooth transition between the playback of the content. Other possibilities for synchronizing the playback of the first and second versions of the audio content  601 ,  602  are also possible. 
     Numerous other examples exist where the playback device  108  may identify multiple version of the same audio content, where the versions have different audio characteristics. For instance,  FIG.  8    illustrates another example in which the first version of the audio content  801  is spatialized for only 1 (mono) channel  802   c  of audio output. On the other hand, the playback device  108 , which in isolation might be capable of only single channel playback, may be grouped with playback device  106  for synchronous playback of audio content. Therefore, the capability of playback device  108  with respect to the number of channels  701   c  is 2 (stereo)  803   c.  Accordingly, the second version of the audio content  804  that is identified by the playback device  108  has a value of 2 (stereo)  805   c  for the number of channels  701   c,  which matches the capability of the playback device  108 . 
     In some implementations, the playback device  108  may determine an update to the capability of the playback device  108 , and then determine that the first value of the audio characteristic of the first version of the audio content  601  does not match the updated capability of the playback device  108 . For example, the playback device  108  may determine that a second playback device in the media playback system  100  has been grouped with the playback device  108  for synchronous playback. For instance, the playback device  108  may be grouped with the playback device  106 , as shown in  FIG.  1   , for stereo playback. Accordingly, the number of channels that the playback device  108  is capable of playing in its updated configuration may be 2 (stereo). Thus, the playback device  108  would determine that the number of channels  701   c  of the first version of the audio content  601  does not match the updated capability of the playback device  108 . 
     As another example, the capability of the playback device  108  may change if the playback device  108  receives a software update that increases the bit depth or sample rate that it is capable of playing, or that updates the file formats it is able to play. 
     Similar examples exist with respect to audio that is played in synchrony with video. For instance, the playback device  108  may receive a first version of audio content corresponding to a television program via a first source, such as a satellite tuner. The first version of the audio content may include two channels of audio playback. However, the playback device  108  may be grouped with other playback devices in the media playback system  100  and as a result, be capable of playing back  5 . 1  channel audio content. The playback device  108  may then identify a second version of the same television program from a second source, such as an internet-based video service provider, that includes an audio stream spatialized for 5.1 channel audio output. The playback device may then retrieve and synchronize the second version of the audio content with the video stream, and play back the second version of the audio content. Additional examples of synchronization of audio and video content are described in U.S. patent application Ser. No. 14/971,796, which is incorporated by reference. 
     In some examples, before identifying the second version of the audio content  602  from the second source, the playback device  108  may determine a likelihood that an improved version of the audio content  601  exists and is retrievable. For example, the playback device  108  may identify the first source  603  of the first version of the audio content  601  as a line-in input from a microphone. This may correspond to audio content that is being generated live, and for which a second version of the same audio content is unlikely to exist. Therefore, the playback device  108  may not attempt to identify a second version of the audio content. 
     Conversely, the first version of the audio content  601  may be identified as a music track having a URI at the first content source  603 , such as a streaming music service. Based on this identification, the playback device  108  may determine that it is likely that a second version of the same music track may exist elsewhere at a second content source  604 , and therefore the playback device  108  may undertake to identify a second version of the audio content  602  with improved audio characteristic having the second value. 
     In some cases, identifying the second version of the audio content  602  from the second source  604  may include the playback device  108  searching available sources for the second version of the audio content  602  having the second value. The search may include one or more queries, such as a search a based on a universal content identifier, such as UUID, or a search of available sources for metadata identifying the audio content in question having the desired audio characteristic values. The playback device  108  may also sample and fingerprint versions of the audio content from different sources, in order to determine the values of the audio characteristics in those versions. Additional methods of searching for and identifying audio content are discussed in U.S. Pat. No. 9,286,384, which is incorporated by reference. 
     Additionally or alternatively, the playback device may identify a second version of the audio content  602  having values for the audio characteristics that more closely match the capabilities of the playback device  108 , but which is available from a second source  604  to which the playback device  108  does not have access. In this situation, the playback device  108  may cause a message to be sent to a control device of the media playback system  100 , such as the control device  300 , suggesting that a higher-quality version of the desired audio content is available from the second source  604 . 
     Other similar messages or indications may be generated in conjunction with the operations of the method  500 . These messages or indications may be displayed on a control device  300  in the media playback system  100 . For example, after identifying and playing back the second version of the audio content  602 , the playback device  108  may cause an indication that better quality audio content was retrieved and is now being played. Additionally or alternatively, the first playback device  108  may transmit a message to the first source  603  indicting that the first playback device  108  is retrieving a higher quality version of the audio content from a different source. Other possibilities also exist. 
     In some cases, causing playback of the second version of the audio content  602  may include causing playback by a second playback device in the media playback system  100 . For example, the first version of the audio content  801  shown in  FIG.  8    is spatialized for 1 (mono) channel of audio output. However, the playback device  108  in the example of  FIG.  8    is grouped with playback device  106 , and therefore capable of 2 (stereo) channel audio output. Accordingly, the playback device  108  may identify the second version of the audio content  804  spatialized for 2 (stereo) channel audio output, and cause playback of the second version of the audio content  804  on both the playback device  108  and the second playback device  106 . 
     In another implementation, the playback device  108  may be grouped with other playback devices for synchronous playback, where a second playback device in the group, such as the playback device  104 , has different capabilities than the playback device  108 . For example, the playback device  104  may be a newer model device that is capable of playing audio content with a greater bit depth or a higher sample rate, or perhaps a wider range of audio formats than the playback device  108 . In these situations, the playback device  108  may determine that the value of the audio characteristic of the first version of the audio content  601  does not match the capability of the second playback device  104 , and then identify a second version of the audio content  602  to match the capability of the second playback device  104 . The playback device  104  may then play the second version of the audio content  602  in synchrony with the playback of the first version of the audio content  601  by the playback device  108 . 
     Extending this example, the playback device  108  might also identify a third version of the audio content. The third version of the audio content may have audio characteristics with values that match the capability of the playback device  108 , and are of higher quality than the first version of the audio content  601 , yet are of lower quality than the second version of the audio content  602  that was identified for the playback device  104 . Thus, the playback device  108  may enhance the playback of audio content by identifying, for each playback device in the group, the highest quality version of the audio content that that playback device is capable of playing, and then coordinating the synchronous playback of all versions of the audio content. 
     Alternatively, the playback device  108  may identify a second version of the audio content  602  that exceeds the audio quality that the playback device  108  is capable of playing, as shown in  FIG.  6   . For example, the playback device  108  may identify a second version the audio content that includes a bit depth of 24 bit and a sample rate of 48 kHz. Additionally, the playback device  108  may identify a second playback device within the media playback system  100 , such as the playback device  112 , that has capabilities that meet or exceed these values. The playback device  108  may cause an indication to be displayed on a control device  300  that a higher quality version the audio content has been identified and can be played back on the playback device  112 . The control device  300  may present an option to begin playback of the second version of the audio content  602 , and to optionally form a group for synchronous playback with the playback device  108 . 
     Similarly, the playback device  108  may identify a second version of the audio content that exceeds the audio quality of all of the playback devices in the media playback system. In this situation, the playback device  108  may present an indication, via a control device  300 , suggesting to a user that playback devices capable of playing back higher quality audio content are available for purchase. 
     Although the examples described thus far have involved the enhancement of audio content by identifying a second version of the audio content having a higher bit depth, sample rate, or number of audio channels, it is important to note that the playback of audio content might alternatively be improved by reducing the value of these audio characteristics. In other words, an enhanced listening experience may not always involve “better” audio content. For example, the capability of the playback device  108  may be reduced in some situations, such as when there is a change in the network bandwidth associated with the playback device  108 , or if a second playback device that is grouped with the playback device  108  fails or is ungrouped. In these instances, the first version of the audio content  601  may have a sample rate that is too high for the updated network bandwidth, which may lead to undesirable dropouts or pauses during playback of the audio content. Similarly, the first version the audio content  601  may be spatialized for 2-channel stereo output when the playback device  108  is grouped with the playback device  106 . However, if the playback device  106  is regrouped into a different configuration, the playback device  108  is only capable of 1-channel mono playback. This in turn may lead to the undesirable playback of only 1 of the 2 channels of audio output in the first version of the audio content  601 . 
     In these situations, the playback of audio content by the playback device  108  may actually be enhanced by identifying and playing back a second version of the audio content  602  having audio characteristics of a lower quality, such as a lower sample rate or bit depth, a lesser number of audio output channels, or a file format that is more compressed and includes more data loss. 
     For many of the same reasons, the playback device  108  may assess network conditions before identifying and playing back a second version of the audio content  602  that corresponds to a higher nominal capability of the playback device  108 . This may reduce the likelihood of a situation where the actual capability of the playback device  108 , as limited by network conditions, is exceeded. 
     In some examples, the playback device  108  may prioritize multiple available versions of the audio content based on an extent to which each audio characteristics may affect playback quality. For instance, using the previous example, the playback device  108  may experience a drop in network bandwidth, and as a result may attempt to identify a second version of the audio content  602  that is of lower quality. In doing so, the playback device  108  may first query available content sources for a version of the audio content having a lower sample rate. If a version having a reduced sample rate cannot be found, or if a version having the recued sample rate is not sufficient to compensate for the decreased bandwidth, the playback device may search for a version of the audio content additionally or alternatively having a reduced bit depth. Reducing the value of these audio characteristics may be prioritized over reducing the number of audio channels, because the effect of reducing the sample rate or bit depth may be less noticeable to the overall audio quality than a reduction in the number of audio channels. 
     In a similar manner, the playback device  108  may also prioritize available versions of the audio content in situations where the audio quality is improved. For instance, the playback device  108  may prioritize an increase in the number of audio channels to match the capability of the playback device  108  over changes in the bit depth of sample rate.  FIG.  8    illustrates such an example, where the first version of the audio content includes a bit depth  701   a  of 16 bit  802   a,  a sample rate  701   b  of  44 . 1  kHz  802   b,  and a number of channels  701   c  of 1 (mono)  802   c.  Meanwhile, the playback device  108 , which is grouped with playback device  106  in this example, has the capability of playing 16 bit  803   a,  44.1 kHz  803   b  audio content having 2 (stereo) channel audio output. As shown in  FIG.  8   , the playback device  108  identified the second version of the audio content  804  having an improved number of audio channels, 2 (stereo)  805   c,  to match the capability of the playback device  108 . However, the second version of the audio content  804  has a reduced sample rate of 32 kHz  805   b.  In this case, the playback device  108  has prioritized the number of audio channels over the sample rate. In other examples, the values of the audio characteristics such as sample rate and/or bit depth may have minimum thresholds below which an improved number of audio channels would no longer be prioritized. Other possibilities also exist. 
     Finally, although the examples above discuss the playback device  108  performing the operations associated with the method  500 , it is also possible that a computing device that is separate from the playback device  108  may carry out these actions. For example, a control device, such as the control device  300 , or a remote server may determine the capabilities of the playback device  108  and other playback devices in the media playback system  100 , as discussed above. The computing device may then identify and retrieve an appropriate version of the audio content from an appropriate source, and send it to the playback device  108  for playback. Further, a combination of computing devices, including the playback device  108 , may perform the operations in combination. 
     IV. Conclusion 
     The description above discloses, among other things, various example systems, methods, apparatus, and articles of manufacture including, among other components, firmware and/or software executed on hardware. It is understood that such examples are merely illustrative and should not be considered as limiting. For example, it is contemplated that any or all of the firmware, hardware, and/or software aspects or components can be embodied exclusively in hardware, exclusively in software, exclusively in firmware, or in any combination of hardware, software, and/or firmware. Accordingly, the examples provided are not the only way(s) to implement such systems, methods, apparatus, and/or articles of manufacture. 
     As indicated above, the examples involve the conditional enhancement of audio content. In one aspect, a method is provided. The method involves identifying, by a playback device, a first version of audio content for play back from a first source and identifying, by the playback device, a first value of an audio characteristic of the first version of the audio content, where the playback device includes a capability corresponding to the audio characteristic. The method also includes determining, by the playback device, that the first value of the audio characteristic of the first version of the audio content does not match the capability of the playback device. The method further includes identifying, by the playback device, a second version of the audio content from a second source, where the second version of the audio content includes the audio characteristic having a second value, and where the second value of the audio characteristic is closer to the capability of the playback device. The method also involves causing playback of the second version of the audio content. 
     In another aspect, a device is provided. The device includes a processor, a non-transitory computer readable medium, and program instructions stored on the non-transitory computer readable medium that, when executed by the processor, cause the playback device to perform functions including identifying a first version of audio content for play back from a first source, and identifying a first value of an audio characteristic of the first version of the audio content, where the playback device includes a capability corresponding to the audio characteristic. The functions also include determining that the first value of the audio characteristic of the first version of the audio content does not match the capability of the playback device. The functions further include identifying a second version of the audio content from a second source, where the second version of the audio content includes the audio characteristic having a second value, and where the second value of the audio characteristic is closer to the capability of the playback device. The functions also include causing playback of the second version of the audio content. 
     In yet another aspect, a non-transitory computer readable memory is provided. The non-transitory computer readable memory has stored thereon instructions executable by a playback device to cause the playback device to perform functions. The functions include identifying a first version of audio content for play back from a first source and identifying a first value of an audio characteristic of the first version of the audio content, where the playback device includes a capability corresponding to the audio characteristic. The functions also include determining that the first value of the audio characteristic of the first version of the audio content does not match the capability of the playback device. The functions further include identifying a second version of the audio content from a second source, where the second version of the audio content includes the audio characteristic having a second value, and where the second value of the audio characteristic is closer to the capability of the playback device. The functions also include causing playback of the second version of the audio content. 
     Additionally, references herein to “embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one example embodiment of an invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. As such, the embodiments described herein, explicitly and implicitly understood by one skilled in the art, can be combined with other embodiments. 
     The specification is presented largely in terms of illustrative environments, systems, procedures, steps, logic blocks, processing, and other symbolic representations that directly or indirectly resemble the operations of data processing devices coupled to networks. These process descriptions and representations are typically used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it is understood to those skilled in the art that certain embodiments of the present disclosure can be practiced without certain, specific details. In other instances, well known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the forgoing description of embodiments. 
     When any of the appended claims are read to cover a purely software and/or firmware implementation, at least one of the elements in at least one example is hereby expressly defined to include a tangible, non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on, storing the software and/or firmware.