Method for Efficient Database Formation and Search on Media Devices Acting Synchronously with Television Programming
Techniques for efficient database formation and search in applications embedded in a media device are provided. The search may be performed synchronously with presentation of media programming content on a nearby media presentation device. A mobile media device captures some temporal fragments of the presented audio/video content on its microphone and camera, and then generates query fingerprints for the captured fragment. A local reference database resides on the mobile media device and a master reference database resides on a remote server with a most recent chunk of reference fingerprints transferred dynamically to the local mobile media device. A chunk of the query fingerprints generated locally on the mobile media device are searched on the local reference database for continuous content search and identification. The method presented automatically switches between the local search on the mobile media device and a remote search on an external search server.
1 . A method for simultaneous capture and querying on a mobile media device, the method comprising:
capturing a first fragment of media content from a media presentation device during background operations on a mobile media device, wherein the captured first fragment of media content is saved to a circular buffer;
fingerprinting the first fragment of captured media content retrieved from the circular buffer to generate signatures representing the first fragment of captured media content; and
querying a local reference database on the mobile media device with the generated signatures while a second fragment of media content is being captured from the media presentation device.
2 . The method of claim 1 , wherein the querying a local reference database further comprises:
searching a first portion of the local reference database that limits searching to a portion of media content in the reference database that is adjacent to a previous successful search match content and slightly larger in time span than the current query length;
searching a second portion of the local reference database that limits searching to a time span content around the previous successful search match content that is plus or minus N seconds, wherein for a selected value of N the second portion of the local reference database is larger than the first portion; and
searching the local reference database as a full search of media content stored on the mobile media device.
3 . The method of claim 2 , wherein the querying a local reference database further comprises:
transmitting the query to an external search server upon finding no match situation on the mobile media device;
searching for the query on the external search server;
upon finding a match to the query on the external search server, downloading a chunk of reference media content from the match and in an area surrounding the match to be stored in the local reference database on the mobile media device.
4 . A method for manual and automatic local signature cache management, the method comprising:
forming a signature cache on a mobile media device to hold one set of signatures that is automatically managed for switching between a local search and a remote search, wherein downloading of reference media signatures and signature cache management are performed automatically based on search responses from the local search and from the remote search; and
forming a manually managed signature cache with functions provided that allow for explicit downloading of the reference media signatures to the signature cache.
5 . The method of claim 4 , wherein the signature cache is partitioned into a number of signature cache slots, wherein each signature cache slot holds a plurality of the reference media signatures.
6 . The method of claim 4 , wherein the reference media signatures to be downloaded are specified by asset identification numbers and are downloaded to a specified signature cache slot.
7 . The method of claim 4 , wherein a list of the asset identification numbers, slot index, starting signature timestamp, ending signature timestamp, and number of signatures for each non-empty signature cache slot are returned to the mobile media device.