Patent Publication Number: US-10776629-B2

Title: Scene and activity identification in video summary generation

Description:
BACKGROUND 
     Technical Field 
     This disclosure relates to a camera system, and more specifically, to processing video data captured using a camera system. 
     Description of the Related Art 
     Digital cameras are increasingly used to capture videos in a variety of settings, for instance outdoors or in a sports environment. However, as users capture increasingly more and longer videos, video management becomes increasingly difficult. Manually searching through raw videos (“scrubbing”) to identify the best scenes is extremely time consuming. Automated video processing to identify the best scenes can be very resource-intensive, particularly with high-resolution raw-format video data. Accordingly, an improved method of automatically identifying the best scenes in captured videos and generating video summaries including the identified best scenes can beneficially improve a user&#39;s video editing experience. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       The disclosed embodiments have other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram of a camera system environment according to one embodiment. 
         FIG. 2  is a block diagram illustrating a camera system, according to one embodiment. 
         FIG. 3  is a block diagram of a video server, according to one embodiment. 
         FIG. 4  is a flowchart illustrating a method for selecting video portions to include in a video summary, according to one embodiment. 
         FIG. 5  is a flowchart illustrating a method for generating video summaries using video templates, according to one embodiment. 
         FIG. 6  is a flowchart illustrating a method for generating video summaries of videos associated with user-tagged events, according to one embodiment. 
         FIG. 7  is a flowchart illustrating a method of identifying an activity associated with a video, according to one embodiment. 
         FIG. 8  is a flowchart illustrating a method of sharing a video based on an identified activity within the video, according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The figures and the following description relate to preferred embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed. 
     Reference will now be made in detail to several embodiments, examples of which are illustrated in the accompanying figures. It is noted that wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality. The figures depict embodiments of the disclosed system (or method) for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein. 
     Example Camera System Configuration 
       FIG. 1  is a block diagram of a camera system environment, according to one embodiment. The camera system environment  100  includes one or more metadata sources  110 , a network  120 , a camera  130 , a client device  135  and a video server  140 . In alternative configurations, different and/or additional components may be included in the camera system environment  100 . Examples of metadata sources  110  include sensors (such as accelerometers, speedometers, rotation sensors, GPS sensors, altimeters, and the like), camera inputs (such as an image sensor, microphones, buttons, and the like), and data sources (such as external servers, web pages, local memory, and the like). Although not shown in  FIG. 1 , it should be noted that in some embodiments, one or more of the metadata sources  110  can be included within the camera  130 . 
     The camera  130  can include a camera body having a camera lens structured on a front surface of the camera body, various indicators on the front of the surface of the camera body (such as LEDs, displays, and the like), various input mechanisms (such as buttons, switches, and touch-screen mechanisms), and electronics (e.g., imaging electronics, power electronics, metadata sensors, etc.) internal to the camera body for capturing images via the camera lens and/or performing other functions. As described in greater detail in conjunction with  FIG. 2  below, the camera  130  can include sensors to capture metadata associated with video data, such as motion data, speed data, acceleration data, altitude data, GPS data, and the like. A user uses the camera  130  to record or capture videos in conjunction with associated metadata which the user can edit at a later time. 
     The video server  140  receives and stores videos captured by the camera  130  allowing a user to access the videos at a later time. In one embodiment, the video server  140  provides the user with an interface, such as a web page or native application installed on the client device  135 , to interact with and/or edit the videos captured by the user. In one embodiment, the video server  140  generates video summaries of various videos stored at the video server, as described in greater detail in conjunction with  FIG. 3  and  FIG. 4  below. As used herein, “video summary” refers to a generated video including portions of one or more other videos. A video summary often includes highlights (or “best scenes”) of a video captured by a user. In some embodiments, best scenes include events of interest within the captured video, scenes associated with certain metadata (such as an above threshold altitude or speed), scenes associated with certain camera or environment characteristics, and the like. For example, in a video captured during a snowboarding trip, the best scenes in the video can include jumps performed by the user or crashes in which the user was involved. In addition to including one or more highlights of the video, a video summary can also capture the experience, theme, or story associated with the video without requiring significant manual editing by the user. In one embodiment, the video server  140  identifies the best scenes in raw video based on the metadata associated with the video. The video server  140  may then generate a video summary using the identified best scenes of the video. The metadata can either be captured by the camera  130  during the capture of the video or can be retrieved from one or more metadata sources  110  after the capture of the video. 
     Metadata includes information about the video itself, the camera used to capture the video, the environment or setting in which a video is captured or any other information associated with the capture of the video. For example, metadata can include acceleration data representative of the acceleration of a camera  130  attached to a user as the user captures a video while snowboarding down a mountain. Such acceleration metadata helps identify events representing a sudden change in acceleration during the capture of the video, such as a crash the user may encounter or a jump the user performs. Thus, metadata associated with captured video can be used to identify best scenes in a video recorded by a user without relying on image processing techniques or manual curation by a user. 
     Examples of metadata include: telemetry data (such as motion data, velocity data, and acceleration data) captured by sensors on the camera  130 ; location information captured by a GPS receiver of the camera  130 ; compass heading information; altitude information of the camera  130 ; biometric data such as the heart rate of the user, breathing of the user, eye movement of the user, body movement of the user, and the like; vehicle data such as the velocity or acceleration of the vehicle, the brake pressure of the vehicle, or the rotations per minute (RPM) of the vehicle engine; or environment data such as the weather information associated with the capture of the video. The video server  140  may receive metadata directly from the camera  130  (for instance, in association with receiving video from the camera), from a client device  135  (such as a mobile phone, computer, or vehicle system associated with the capture of video), or from external metadata sources  110  such as web pages, blogs, databases, social networking sites, or servers or devices storing information associated with the user (e.g., a user may use a fitness device recording fitness data). 
     A user can interact with interfaces provided by the video server  140  via the client device  135 . The client device  135  is any computing device capable of receiving user inputs as well as transmitting and/or receiving data via the network  120 . In one embodiment, the client device  135  is a conventional computer system, such as a desktop or a laptop computer. Alternatively, the client device  135  may be a device having computer functionality, such as a personal digital assistant (PDA), a mobile telephone, a smartphone or another suitable device. The user can use the client device to view and interact with or edit videos stored on the video server  140 . For example, the user can view web pages including video summaries for a set of videos captured by the camera  130  via a web browser on the client device  135 . 
     One or more input devices associated with the client device  135  receive input from the user. For example, the client device  135  can include a touch-sensitive display, a keyboard, a trackpad, a mouse, a voice recognition system, and the like. In some embodiments, the client device  135  can access video data and/or metadata from the camera  130  or one or more metadata sources  110 , and can transfer the accessed metadata to the video server  140 . For example, the client device may retrieve videos and metadata associated with the videos from the camera via a universal serial bus (USB) cable coupling the camera  130  and the client device  135 . The client device can then upload the retrieved videos and metadata to the video server  140 . 
     In one embodiment, the client device  135  executes an application allowing a user of the client device  135  to interact with the video server  140 . For example, a user can identify metadata properties using an application executing on the client device  135 , and the application can communicate the identified metadata properties selected by a user to the video server  140  to generate and/or customize a video summary. As another example, the client device  135  can execute a web browser configured to allow a user to select video summary properties, which in turn can communicate the selected video summary properties to the video server  140  for use in generating a video summary. In one embodiment, the client device  135  interacts with the video server  140  through an application programming interface (API) running on a native operating system of the client device  135 , such as IOS® or ANDROID™. While  FIG. 1  shows a single client device  135 , in various embodiments, any number of client devices  135  may communicate with the video server  140 . 
     The video server  140  communicates with the client device  135 , the metadata sources  110 , and the camera  130  via the network  120 , which may include any combination of local area and/or wide area networks, using both wired and/or wireless communication systems. In one embodiment, the network  120  uses standard communications technologies and/or protocols. In some embodiments, all or some of the communication links of the network  120  may be encrypted using any suitable technique or techniques. It should be noted that in some embodiments, the video server  140  is located within the camera  130  itself. 
     Example Camera Configuration 
       FIG. 2  is a block diagram illustrating a camera system, according to one embodiment. The camera  130  includes one or more microcontrollers  202  (such as microprocessors) that control the operation and functionality of the camera  130 . A lens and focus controller  206  is configured to control the operation and configuration of the camera lens. A system memory  204  is configured to store executable computer instructions that, when executed by the microcontroller  202 , perform the camera functionalities described herein. A synchronization interface  208  is configured to synchronize the camera  130  with other cameras or with other external devices, such as a remote control, a second camera  130 , a smartphone, a client device  135 , or a video server  140 . 
     A controller hub  230  transmits and receives information from various I/O components. In one embodiment, the controller hub  230  interfaces with LED lights  236 , a display  232 , buttons  234 , microphones such as microphones  222 , speakers, and the like. 
     A sensor controller  220  receives image or video input from an image sensor  212 . The sensor controller  220  receives audio inputs from one or more microphones, such as microphone  212   a  and microphone  212   b . Metadata sensors  224 , such as an accelerometer, a gyroscope, a magnetometer, a global positioning system (GPS) sensor, or an altimeter may be coupled to the sensor controller  220 . The metadata sensors  224  each collect data measuring the environment and aspect in which the video is captured. For example, the accelerometer  220  collects motion data, comprising velocity and/or acceleration vectors representative of motion of the camera  130 , the gyroscope provides orientation data describing the orientation of the camera  130 , the GPS sensor provides GPS coordinates identifying the location of the camera  130 , and the altimeter measures the altitude of the camera  130 . The metadata sensors  224  are rigidly coupled to the camera  130  such that any motion, orientation or change in location experienced by the camera  130  is also experienced by the metadata sensors  224 . The sensor controller  220  synchronizes the various types of data received from the various sensors connected to the sensor controller  220 . For example, the sensor controller  220  associates a time stamp representing when the data was captured by each sensor. Thus, using the time stamp, the measurements received from the metadata sensors  224  are correlated with the corresponding video frames captured by the image sensor  212 . In one embodiment, the sensor controller begins collecting metadata from the metadata sources when the camera  130  begins recording a video. In one embodiment, the sensor controller  220  or the microcontroller  202  performs operations on the received metadata to generate additional metadata information. For example, the microcontroller may integrate the received acceleration data to determine the velocity profile of the camera  130  during the recording of a video. 
     Additional components connected to the microcontroller  202  include an I/O port interface  238  and an expansion pack interface  240 . The I/O port interface  238  may facilitate the receiving or transmitting video or audio information through an I/O port. Examples of I/O ports or interfaces include USB ports, HDMI ports, Ethernet ports, audioports, and the like. Furthermore, embodiments of the I/O port interface  238  may include wireless ports that can accommodate wireless connections. Examples of wireless ports include Bluetooth, Wireless USB, Near Field Communication (NFC), and the like. The expansion pack interface  240  is configured to interface with camera add-ons and removable expansion packs, such as a display module, an extra battery module, a wireless module, and the like. 
     Example Video Server Architecture 
       FIG. 3  is a block diagram of an architecture of the video server. The video server  140  in the embodiment of  FIG. 3  includes a user storage module  305  (“user store” hereinafter), a video storage module  310  (“video store” hereinafter), a template storage module  315  (“template store” hereinafter), a video editing module  320 , a metadata storage module  325  (“metadata store” hereinafter), a web server  330 , an activity identifier  335 , and an activity storage module  340  (“activity store” hereinafter). In other embodiments, the video server  140  may include additional, fewer, or different components for performing the functionalities described herein. Conventional components such as network interfaces, security functions, load balancers, failover servers, management and network operations consoles, and the like are not shown so as to not obscure the details of the system architecture. 
     Each user of the video server  140  creates a user account, and user account information is stored in the user store  305 . A user account includes information provided by the user (such as biographic information, geographic information, and the like) and may also include additional information inferred by the video server  140  (such as information associated with a user&#39;s previous use of a camera). Examples of user information include a username, a first and last name, contact information, a user&#39;s hometown or geographic region, other location information associated with the user, and the like. The user store  305  may include data describing interactions between a user and videos captured by the user. For example, a user account can include a unique identifier associating videos uploaded by the user with the user&#39;s user account. 
     The video store  310  stores videos captured and uploaded by users of the video server  140 . The video server  140  may access videos captured using the camera  130  and store the videos in the video store  310 . In one example, the video server  140  may provide the user with an interface executing on the client device  135  that the user may use to upload videos to the video store  315 . In one embodiment, the video server  140  indexes videos retrieved from the camera  130  or the client device  135 , and stores information associated with the indexed videos in the video store. For example, the video server  140  provides the user with an interface to select one or more index filters used to index videos. Examples of index filters include but are not limited to: the type of equipment used by the user (e.g., ski equipment, mountain bike equipment, etc.), the type of activity being performed by the user while the video was captured (e.g., snowboarding, mountain biking, etc.), the time and data at which the video was captured, or the type of camera  130  used by the user. 
     In some embodiments, the video server  140  generates a unique identifier for each video stored in the video store  310 . In some embodiments, the generated identifier for a particular video is unique to a particular user. For example, each user can be associated with a first unique identifier (such as a 10-digit alphanumeric string), and each video captured by a user is associated with a second unique identifier made up of the first unique identifier associated with the user concatenated with a video identifier (such as an 8-digit alphanumeric string unique to the user). Thus, each video identifier is unique among all videos stored at the video store  310 , and can be used to identify the user that captured the video. 
     The metadata store  325  stores metadata associated with videos stored by the video store  310 . For instance, the video server  140  can retrieve metadata from the camera  130 , the client device  135 , or one or more metadata sources  110 , can associate the metadata with the corresponding video (for instance by associating the metadata with the unique video identifier), and can store the metadata in the metadata store  325 . The metadata store  325  can store any type of metadata, including but not limited to the types of metadata described herein. It should be noted that in some embodiments, metadata corresponding to a video is stored within a video file itself, and not in a separate storage module. 
     The web server  330  provides a communicative interface between the video server  140  and other entities of the environment of  FIG. 1 . For example, the web server  330  can access videos and associated metadata from the camera  130  or the client device  135  to store in the video store  310  and the metadata store  325 , respectively. The web server  330  can also receive user input provided to the client device  135 , can request video summary templates or other information from a client device  135  for use in generating a video summary, and can provide a generated video summary to the client device or another external entity. 
     Event of Interest/Activity Identification 
     The video editing module  320  analyzes metadata associated with a video to identify best scenes of the video based on identified events of interest or activities, and generates a video summary including one or more of the identified best scenes of the video. The video editing module  320  first accesses one or more videos from the video store  310 , and accesses metadata associated with the accessed videos from the metadata store  325 . The video editing module  320  then analyzes the metadata to identify events of interest in the metadata. Examples of events of interest can include abrupt changes or anomalies in the metadata, such as a peak or valley in metadata maximum or minimum values within the metadata, metadata exceeding or falling below particular thresholds, metadata within a threshold of predetermine values (for instance, within 20 meters of a particular location or within), and the like. The video editing module  320  can identify events of interest in videos based on any other type of metadata, such as a heart rate of a user, orientation information, and the like. 
     For example, the video editing module  320  can identify any of the following as an event of interest within the metadata: a greater than threshold change in acceleration or velocity within a pre-determined period of time, a maximum or above-threshold velocity or acceleration, a maximum or local maximum altitude, a maximum or above-threshold heart rate or breathing rate of a user, a maximum or above-threshold audio magnitude, a user location within a pre-determined threshold distance from a pre-determined location, a threshold change in or pre-determined orientation of the camera or user, a proximity to another user or location, a time within a threshold of a pre-determined time, a pre-determined environmental condition (such as a particular weather event, a particular temperature, a sporting event, a human gathering, or any other suitable event), or any other event associated with particular metadata. 
     In some embodiments, a user can manually indicate an event of interest during capture of the video. For example, a user can press a button on the camera or a camera remote or otherwise interact with the camera during the capture of video to tag the video as including an event of interest. The manually tagged event of interest can be indicated within metadata associated with the captured video. For example, if a user is capturing video while snowboarding and presses a camera button associated with manually tagging an event of interest, the camera creates metadata associated with the captured video indicating that the video includes an event of interest, and indicating a time or portion within the captured video at which the tagged event of interest occurs. In some embodiments, the manual tagging of an event of interest by a user while capturing video is stored as a flag within a resulting video file. The location of the flag within the video file corresponds to a time within the video at which the user manually tags the event of interest. 
     In some embodiments, a user can manually indicate an event of interest during capture of the video using a spoken command or audio signal. For instance, a user can say “Tag” or “Tag my moment” during the capture of video to tag the video as including an event of interest. The audio-tagged event of interest can be indicated within metadata associated with the captured video. The spoken command can be pre-programmed, for instance by a manufacturer, programmer, or seller of the camera system, or can be customized by a user of the camera system. For instance, a user can speak a command or other audio signal into a camera during a training period (for instance, in response to configuring the camera into a training mode, or in response to the selection of a button or interface option associated with training a camera to receive a spoken command). The spoken command or audio signal can be repeated during the training mode a threshold number of times (such as once, twice, or any number of times necessary for the purposes of identifying audio patterns as described herein), and the camera system can identify an audio pattern associated with the spoken commands or audio signals received during the training period. The audio pattern is then stored at the camera, and, during a video capture configuration, the camera can identify the audio pattern in a spoken command or audio signal received from a user of the camera, and can manually tag an event of interest during the capture of video in response to detecting the stored audio pattern within the received spoken command or audio signal. In some embodiments, the audio pattern is specific to spoken commands or audio signals received from a particular user and can be detected only in spoken commands or audio signals received from the particular user. In other embodiments, the audio pattern can be identified within spoken commands or audio signals received from any user. It should be noted that manually identified events of interest can be associated with captured video by the camera itself, and can be identified by a system to which the captured video is uploaded from the camera without significant additional post-processing. 
     As noted above, the video editing module  320  can identify events of interest based on activities performed by users when the videos are captured. For example, a jump while snowboarding or a crash while skateboarding can be identified as events of interest. Activities can be identified by the activity identifier module  335  based on metadata associated with the video captured while performing the activities. Continuing with the previous example, metadata associated with a particular altitude and a parabolic upward and then downward velocity can be identified as a “snowboarding jump”, and a sudden slowdown in velocity and accompanying negative acceleration can be identified as a “skateboarding crash”. 
     The video editing module  320  can identify events of interest based on audio captured in conjunction with the video. In some embodiments, the video editing module identifies events of interest based on one or more spoken words or phrases in captured audio. For example, if audio of a user saying “Holy Smokes!” is captured, the video editing module can determine that an event of interest just took place (e.g., within the previous 5 seconds or other threshold of time), and if audio of a user saying “Oh no! Watch out!” is captured, the video editing module can determine that an event of interest is about to occur (e.g., within the next 5 seconds or other threshold of time). In addition to identifying events of interest based on captured dialogue, the video editing module can identify an event of identify based on captured sound effects, captured audio exceeding a magnitude or pitch threshold, or captured audio satisfying any other suitable criteria. 
     In some embodiments, the video editing module  320  can identify video that does not include events of interest. For instance, the video editing module  320  can identify video that is associated with metadata patterns determined to not be of interest to a user. Such patterns can include metadata associated with a below-threshold movement, a below-threshold luminosity, a lack of faces or other recognizable objects within the video, audio data that does not include dialogue or other notable sound effects, and the like. In some embodiments, video determined to not include events of interest can be disqualified from consideration for inclusion in a generated video summary, or can be hidden from a user viewing captured video (in order to increase the chance that the remaining video presented to the user does include events of interest). 
     The activity identifier module  335  can receive a manual identification of an activity within videos from one or more users. In some embodiments, activities can be tagged during the capture of video. For instance, if a user is about to capture video while performing a snowboarding jump, the user can manually tag the video being captured or about to be captured as “snowboarding jump”. In some embodiments, activities can be tagged after the video is captured, for instance during playback of the video. For instance, a user can tag an activity in a video as a skateboarding crash upon playback of the video. 
     Activity tags in videos can be stored within metadata associated with the videos. For videos stored in the video store  310 , the metadata including activity tags associated with the videos is stored in the metadata store  325 . In some embodiments, the activity identifier module  335  identifies metadata patterns associated with particular activities and/or activity tags. For instance, metadata associated with several videos tagged with the activity “skydiving” can be analyzed to identify similarities within the metadata, such as a steep increase in acceleration at a high altitude followed by a high velocity at decreasing altitudes. Metadata patterns associated with particular activities are stored in the activity store  340 . 
     In some embodiments, metadata patterns associated with particular activities can include audio data patterns. For instance, particular sound effects, words or phrases of dialogue, or the like can be associated with particular activities. For example, the spoken phrase “nice wave” can be associated with surfing, and the sound of a revving car engine can be associated with driving or racing a vehicle. In some embodiments, metadata patterns used to identify activities can include the use of particular camera mounts associated with the activities in capturing video. For example, a camera can detect that it is coupled to a snowboard mount, and video captured while coupled to the snowboard mount can be associated with the activity of snowboarding. 
     Once metadata patterns associated with particular activities are identified, the activity identifier module  335  can identify metadata patterns in metadata associated with other videos, and can tag or associate other videos associated with metadata including the identified metadata patterns with the activities associated with the identified metadata patterns. The activity identifier module  335  can identify and store a plurality of metadata patterns associated with a plurality of activities within the activity store  340 . Metadata patterns stored in the activity store  340  can be identified within videos captured by one user, and can be used by the activity identifier module  335  to identify activities within videos captured by the user. Alternatively, metadata patterns can be identified within videos captured by a first plurality of users, and can be used by the activity identifier module  335  to identify activities within videos captured by a second plurality of users including at least one user not in the first plurality of users. In some embodiments, the activity identifier module  335  aggregates metadata for a plurality of videos associated with an activity and identifies metadata patterns based on the aggregated metadata. As used herein, “tagging” a video with an activity refers to the association of the video with the activity. Activities tagged in videos can be used as a basis to identify best scenes in videos (as described above), and to select video clips for inclusion in video summary templates (as described below). 
     Videos tagged with activities can be automatically uploaded to or shared with an external system. For instance, if a user captures video, the activity identifier module  335  can identify a metadata pattern associated with an activity in metadata of the captured video, in real-time (as the video is being captured), or after the video is captured (for instance, after the video is uploaded to the video server  140 ). The video editing module  320  can select a portion of the captured video based on the identified activity, for instance a threshold amount of time or frames around a video clip or frame associated with the identified activity. The selected video portion can be uploaded or shared to an external system, for instance via the web server  330 . The uploading or sharing of video portions can be based on one or more user settings and/or the activity identified. For instance, a user can select one or more activities in advance of capturing video, and captured video portions identified as including the selected activities can be uploaded automatically to an external system, and can be automatically shared via one or more social media outlets. 
     Best Scene Identification and Video Summary Generation 
     The video editing module  320  identifies best scenes associated with the identified events of interest for inclusion in a video summary. Each best scene is a video clip, portion, or scene (“video clips” hereinafter), and can be an entire video or a portion of a video. For instance, the video editing module  320  can identify video clips occurring within a threshold amount of time of an identified event of interest (such as 3 seconds before and after the event of interest), within a threshold number of frames of an identified event of interest (such as 24 frames before and after the event of interest), and the like. The amount of length of a best scene can be pre-determined, and/or can be selected by a user. 
     The amount or length of video clip making up a best scene can vary based on an activity associated with captured video, based on a type or value of metadata associated with captured video, based on characteristics of the captured video, based on a camera mode used to capture the video, or any other suitable characteristic. For example, if an identified event of interest is associated with an above-threshold velocity, the video editing module  320  can identify all or part of the video corresponding to above-threshold velocity metadata as the best scene. In another example, the length of a video clip identified as a best scene can be greater for events of interest associated with maximum altitude values than for events of interest associated with proximity to a pre-determined location. 
     For events of interest manually tagged by a user, the length of a video clip identified as a best scene can be pre-defined by the user, can be manually selected by the user upon tagging the event of interest, can be longer than automatically-identified events of interest, can be based on a user-selected tagging or video capture mode, and the like. The amount or length of video clips making up best scenes can vary based on the underlying activity represented in captured video. For instance, best scenes associated with events of interest in videos captured while boating can be longer than best scenes associated with events of interest in videos captured while skydiving. 
     The identified video portions make up the best scenes as described herein. The video editing module  320  generates a video summary by combining or concatenating some or all of the identified best scenes into a single video. The video summary thus includes video portions of events of interest, beneficially resulting in a playable video including scenes likely to be of greatest interest to a user. The video editing module  320  can receive one or more video summary configuration selections from a user, each specifying one or more properties of the video summary (such as a length of a video summary, a number of best scenes for inclusion in the video summary, and the like), and can generate the video summary according to the one or more video summary configuration selections. In some embodiments, the video summary is a renderable or playable video file configured for playback on a viewing device (such as a monitor, a computer, a mobile device, a television, and the like). The video summary can be stored in the video store  310 , or can be provided by the video server  140  to an external entity for subsequent playback. Alternatively, the video editing module  320  can serve the video summary from the video server  140  by serving each best scene directly from a corresponding best scene video file stored in the video store  310  without compiling a singular video summary file prior to serving the video summary. It should be noted that the video editing module  320  can apply one or more edits, effects, filters, and the like to one or more best scenes within the video summary, or to the entire video summary during the generation of the video summary. 
     In some embodiments, the video editing module  320  ranks identified best scenes. For instance, best scenes can be ranked based on activities with which they are associated, based on metadata associated with the best scenes, based on length of the best scenes, based on a user-selected preference for characteristics associated with the best scenes, or based on any other suitable criteria. For example, longer best scenes can be ranked higher than shorter best scenes. Likewise, a user can specify that best scenes associated with above-threshold velocities can be ranked higher than best scenes associated with above-threshold heart rates. In another example, best scenes associated with jumps or crashes can be ranked higher than best scenes associated with sitting down or walking. Generating a video summary can include identifying and including the highest ranked best scenes in the video summary. 
     In some embodiments, the video editing module  320  classifies scenes by generating a score associated with each of one or more video classes based on metadata patterns associated with the scenes. Classes can include but are not limited to: content-related classes (“snow videos”, “surfing videos”, etc.), video characteristic classes (“high motion videos”, “low light videos”, etc.), video quality classes, mode of capture classes (based on capture mode, mount used, etc.), sensor data classes (“high velocity videos”, “high acceleration videos”, etc.), audio data classes (“human dialogue videos”, “loud videos”, etc.), number of cameras used (“single-camera videos”, “multi-camera videos”, etc.), activity identified within the video, and the like. Scenes can be scored for one or more video classes, the scores can be weighted based on a pre-determined or user-defined class importance scale, and the scenes can be ranked based on the scores generated for the scenes. 
     In one example, the video editing module  320  analyzes metadata associated with accessed videos chronologically to identify an order of events of interest presented within the video. For example, the video editing module  320  can analyze acceleration data to identify an ordered set of video clips associated with acceleration data exceeding a particular threshold. In some embodiments, the video editing module  320  can identify an ordered set of events occurring within a pre-determined period of time. Each event in the identified set of events can be associated with a best scene; if the identified set of events is chronologically ordered, the video editing module  320  can generate a video summary by a combining video clips associated with each identified event in the order of the ordered set of events. 
     In some embodiments, the video editing module  320  can generate a video summary for a user using only videos associated with (or captured by) the user. To identify such videos, the video editing module  320  can query the video store  310  to identify videos associated with the user. In some embodiments, each video captured by all users of the video server  140  includes a unique identifier identifying the user that captured the video and identifying the video (as described above). In such embodiments, the video editing module  320  queries the video store  310  with an identifier associated with a user to identify videos associated with the user. For example, if all videos associated with User A include a unique identifier that starts with the sequence “X1Y2Z3” (an identifier unique to User A), the video editing module  320  can query the video store  310  using the identifier “X1Y2Z3” to identify all videos associated with User A. The video editing module  320  can then identify best scenes within such videos associated with a user, and can generate a video summary including such best scenes as described herein. 
     In addition to identifying best scenes, the video editing module  320  can identify one or more video frames that satisfy a set of pre-determined criteria for inclusion in a video summary, or for flagging to a user as candidates for saving as images/photograph stills. The pre-determined criteria can include metadata criteria, including but not limited to: frames with high motion (or blur) in a first portion of a frame and low motion (or blur) in another portion of a frame, frames associated with particular audio data (such as audio data above a particular magnitude threshold or audio data associated with voices or screaming), frames associated with above-threshold acceleration data, or frames associated with metadata that satisfies any other metadata criteria as described herein. In some embodiments, users can specify metadata criteria for use in flagging one or more video frames that satisfy pre-determined criteria. Similarly, in some embodiments, the video editing module  320  can identify metadata patterns or similarities in frames selected by a user to save as images/photograph stills, and can identify subsequent video frames that include the identified metadata patterns or similarities for flagging as candidates to save as images/photograph stills. 
     Video Summary Templates 
     In one embodiment, the video editing module  320  retrieves video summary templates from the template store  315  to generate a video summary. The template store  315  includes video summary templates each describing a sequence of video slots for including in a video summary. In one example, each video summary template may be associated with a type of activity performed by the user while capturing video or the equipment used by the user while capturing video. For example, a video summary template for generating video summaries of a ski tip can differ from the video summary template for generating video summaries of a mountain biking trip. 
     Each slot in a video summary template is a placeholder to be replaced by a video clip or scene when generating a video summary. Each slot in a video summary template can be associated with a pre-defined length, and the slots collectively can vary in length. The slots can be ordered within a template such that once the slots are replaced with video clips, playback of the video summary results in the playback of the video clips in the order of the ordered slots replaced by the video clips. For example, a video summary template may include an introductory slot, an action slot, and a low-activity slot. When generating the video summary using such a template, a video clip can be selected to replace the introductory slot, a video clip of a high-action event can replace the action slot, and a video clip of a low-action event can replace the low-activity slot. It should be noted that different video summary templates can be used to generate video summaries of different lengths or different kinds. 
     In some embodiments, video summary templates include a sequence of slots associated with a theme or story. For example, a video summary template for a ski trip may include a sequence of slots selected to present the ski trip narratively or thematically. In some embodiments, video summary templates include a sequence of slots selected based on an activity type. For example, a video summary template associated with surfing can include a sequence of slots selected to highlight the activity of surfing. 
     Each slot in a video summary template can identify characteristics of a video clip to replace the slot within the video summary template, and a video clip can be selected to replace the slot based on the identified characteristics. For example, a slot can identify one or more of the following video clip characteristics: motion data associated with the video clip, altitude information associated with the video clip, location information associated with the video clip, weather information associated with the clip, or any other suitable video characteristic or metadata value or values associated with a video clip. In these embodiments, a video clip having one or more of the characteristics identified by a slot can be selected to replace the slot. 
     In some embodiments, a video clip can be selected based on a length associated with a slot. For instance, if a video slot specifies a four-second length, a four-second (give or take a pre-determined time range, such as 0.5 seconds) video clip can be selected. In some embodiments, a video clip shorter than the length associated with a slot can be selected, and the selected video clip can replace the slot, reducing the length of time taken by the slot to be equal to the length of the selected video clip. Similarly, a video clip longer than the length associated with a slot can be selected, and either 1) the selected video clip can replace the slot, expanding the length of time associated with the slot to be equal to the length of the selected video clip, or 2) a portion of the selected video clip equal to the length associated with the slot can be selected and used to replace the slot. In some embodiments, the length of time of a video clip can be increased or decreased to match the length associated with a slot by adjusting the frame rate of the video clip to slow down or speed up the video clip, respectively. For example, to increase the amount of time taken by a video clip by 30%, 30% of the frames within the video clip can be duplicated. Likewise, to decrease the amount of time taken by a video clip by 60%, 60% of the frames within the video clip can be removed. 
     To generate a video summary using a video summary template, the video editing module  320  accesses a video summary template from the template store  315 . The accessed video summary template can be selected by a user, can be automatically selected (for instance, based on an activity type or based on characteristics of metadata or video for use in generating the video summary), or can be selected based on any other suitable criteria. The video editing module  320  then selects a video clip for each slot in the video summary template, and inserts the selected video clips into the video summary in the order of the slots within the video summary template. 
     To select a video clip for each slot, the video editing module  320  can identify a set of candidate video clips for each slot, and can select from the set of candidate video clips (for instance, by selecting the determined best video from the set of candidate video clips according to the principles described above). In some embodiments, selecting a video clip for a video summary template slot identifying a set of video characteristics includes selecting a video clip from a set of candidate video clips that include the identified video characteristics. For example, if a slot identifies a video characteristic of “velocity over 15 mph”, the video editing module  320  can select a video clip associated with metadata indicating that the camera or a user of the camera was traveling at a speed of over 15 miles per hour when the video was captured, and can replace the slot within the video summary template with the selected video clip. 
     In some embodiments, video summary template slots are replaced by video clips identified as best scenes (as described above). For instance, if a set of candidate video clips are identified for each slot in a video summary template, if one of the candidate video slips identified for a slot is determined to be a best scene, the best scene is selected to replace the slot. In some embodiments, multiple best scenes are identified for a particular slot; in such embodiments, one of the best scenes can be selected for inclusion into the video summary based on characteristics of the best scenes, characteristics of the metadata associated with the best scenes, a ranking of the best scenes, and the like. It should be noted that in some embodiments, if a best scene or other video clip cannot be identified as an above-threshold match for clip requirements associated with a slot, the slot can be removed from the template without replacing the slot with a video clip. 
     In some embodiments, instead of replacing a video summary template slot with a video clip, an image or frame can be selected and can replace the slot. In some embodiments, an image or frame can be selected that satisfies one or more pre-determined criteria for inclusion in a video summary as described above. In some embodiments, an image or frame can be selected based on one or more criteria specified by the video summary template slot. For example, if a slot specifies one or more characteristics, an image or frame having one or more of the specified characteristics can be selected. In some embodiments, the video summary template slot can specify that an image or frame is to be selected to replace the slot. When an image or frame is selected and used to replace a slot, the image or frame can be displayed for the length of time associated with the slot. For instance, if a slot is associated with a four-second period of display time, an image or frame selected and used to replace the slot can be displayed for the four-second duration. 
     In some embodiments, when generating a video summary using a video summary template, the video editing module  320  can present a user with a set of candidate video clips for inclusion into one or more video summary template slots, for instance using a video summary generation interface. In such embodiments, the user can presented with a pre-determined number of candidate video clips for a particular slot, and, in response to a selection of a candidate scene by the user, the video editing module  320  can replace the slot with the selected candidate video clip. In some embodiments, the candidate video clips presented to the user for each video summary template slot are the video clips identified as best scenes (as described above). Once a user has selected a video clip for each slot in a video summary template, the video editing module  320  generates a video summary using the user-selected video clips based on the order of slots within the video summary template. 
     In one embodiment, the video editing module  320  generates video summary templates automatically, and stores the video summary templates in the template store  315 . The video summary templates can be generated manually by experts in the field of video creation and video editing. The video editing module  320  may provide a user with a user interface allowing the user to generate video summary templates. Video summary templates can be received from an external source, such as an external template store. Video summary templates can be generated based on video summaries manually created by users, or based on an analysis of popular videos or movies (for instance by including a slot for each scene in a video). 
     System Operation 
       FIG. 4  is a flowchart illustrating a method for selecting video portions to include in a video summary, according to one embodiment. A request to generate a video summary is received  410 . The request can identify one or more videos for which a video summary is to be generated. In some embodiments, the request can be received from a user (for instance, via a video summary generation interface on a computing device), or can be received from a non-user entity (such as the video server  140  of  FIG. 1 ). In response to the request, video and associated metadata is accessed  420 . The metadata includes data describing characteristics of the video, the context or environment in which the video was captured, characteristics of the user or camera that captured the video, or any other information associated with the capture of the video. As described above, examples of such metadata include telemetry data describing the acceleration or velocity of the camera during the capture of the video, location or altitude data describing the location of the camera, environment data at the time of video capture, biometric data of a user at the time of video capture, and the like. 
     Events of interest within the accessed video are identified  430  based on the accessed metadata associated with the video. Events of interest can be identified based on changes in telemetry or location data within the metadata (such as changes in acceleration or velocity data), based on above-threshold values within the metadata (such as a velocity threshold or altitude threshold), based on local maximum or minimum values within the data (such as a maximum heart rate of a user), based on the proximity between metadata values and other values, or based on any other suitable criteria. Best scenes are identified  440  based on the identified events of interest. For instance, for each event of interest identified within a video, a portion of the video corresponding to the event of interest (such as a threshold amount of time or a threshold number of frames before and after the time in the video associated with the event of interest) is identified as a best scene. A video summary is then generated  450  based on the identified best scenes, for instance by concatenating some or all of the best scenes into a single video. 
       FIG. 5  is a flowchart illustrating a method for generating video summaries using video templates, according to one embodiment. A request to generate a video summary is received  510 . A video summary template is selected  520  in response to receiving the request. The selected video summary template can be a default template, can be selected by a user, can be selected based on an activity type associated with captured video, and the like. The selected video summary template includes a plurality of slots, each associated with a portion of the video summary. The video slots can specify video or associated metadata criteria (for instance, a slot can specify a high-acceleration video clip). 
     A set of candidate video clips is identified  530  for each slot, for instance based on the criteria specified by each slot, based on video clips identified as “best scenes” as described above, or based on any other suitable criteria. For each slot, a candidate video clip is selected  540  from among the set of candidate video clips identified for the slot. In some embodiments, the candidate video clips in each set of candidate video clips are ranked, and the most highly ranked candidate video clip is selected. The selected candidate video clips are combined  550  to generate a video summary. For instance, the selected candidate video clips can be concatenated in the order of the slots of the video summary template with which the selected candidate video clips correspond. 
       FIG. 6  is a flowchart illustrating a method for generating video summaries of videos associated with user-tagged events, according to one embodiment. Video is captured  610  by a user of a camera. During video capture, an input is received  620  from the user indicating an event of interest within the captured video. The input can be received, for instance, through the selection of a camera button, a camera interface, or the like. An indication of the user-tagged event of interest is stored in metadata associated with the captured video. A video portion associated with the tagged event of interest is selected  630 , and a video summary including the selected video portion is generated  640 . For instance, the selected video portion can be a threshold number of video frames before and after a frame associated with the user-tagged event, and the selected video portion can be included in the generated video summary with one or more other video portions. 
       FIG. 7  is a flowchart illustrating a method  700  of identifying an activity associated with a video, according to one embodiment. A first video and associated metadata is accessed  710 . An identification of an activity associated with the first video is received  720 . For instance, a user can identify an activity in the first video during post-processing of the first video, or during the capture of the first video. A metadata pattern associated with the identified activity is identified  730  within the accessed metadata. The metadata pattern can include, for example, a defined change in acceleration metadata and altitude metadata. 
     A second video and associated metadata is accessed  740 . The metadata pattern is identified  750  within the metadata associated with the second video. Continuing with the previous example, the metadata associated with the second video is analyzed and the defined change in acceleration metadata and altitude metadata is identified within the examined metadata. In response to identifying the metadata pattern within the metadata associated with the second video, the second video is associated  750  with the identified activity. 
       FIG. 8  is a flowchart illustrating a method  800  of sharing a video based on an identified activity within the video, according to one embodiment. Metadata patterns associated with one or more pre-determined activities are stored  810 . Video and associated metadata are subsequently captured  820 , and a stored metadata pattern associated with an activity is identified  830  within the captured metadata. A portion of the captured video associated with the metadata pattern is selected  840 , and is outputted  850  based on the activity associated with the identified metadata pattern and/or one or more user settings. For instance, a user can select “snowboarding jump” and “3 seconds before and after” as an activity and video portion length, respectively. In such an example, when a user captures video, a metadata pattern associated with a snowboarding jump can be identified, and a video portion consisting of 3 seconds before and 3 seconds after the video associated with the snowboarding jump can automatically be uploaded to a social media outlet. 
     Additional Configuration Considerations 
     Throughout this specification, some embodiments have used the expression “coupled” along with its derivatives. The term “coupled” as used herein is not necessarily limited to two or more elements being in direct physical or electrical contact. Rather, the term “coupled” may also encompass two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other, or are structured to provide a thermal conduction path between the elements. 
     Likewise, as used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. 
     In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. 
     Finally, as used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
     Upon reading this disclosure, those of skill in the art will appreciate still additional alternative structural and functional designs for a camera expansion module as disclosed from the principles herein. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, which will be apparent to those skilled in the art, may be made in the arrangement, operation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.