Granted Patent B2

US 8,997,161 · App. 12/260,404 · Granted Mar 31, 2015

Abstract

Claims (56)

1. A method of encoding and playing back a media file, comprising:

extracting a video track from an original media file, where content is encoded in the video track;

using the encoded content to encode a tricky-play track configured to enable the visual-search of the video track, where encoding the tricky-play track includes encoding at least one key frame that corresponds to a frame in the encoded content that is not a key frame and where the distance between key frames in the encoded content is not uniform;

requesting portions of the encoded content from a media server using HTTP using a playback device;

playing back a portion of the compressed video track using the playback device;

receiving a trick-play request using the playback device;

determining, in response to the received trick-play request, a position in the trick-play track corresponding to the position of the compressed video track being played using a first index using the playback device;

playing back a portion of the trick-play track starting from the determined position in the trick-play track using the playback device;

receiving a normal-play request using the playback device;

determining, in response to the received normal-play request, a position in the compressed video track corresponding to the position of the trick-play track being played using a second index using the playback device;

locating a key frame with the closest timestamp preceding the determined position in the compressed video track;

recursively decoding the located key frame and decoding the difference frames between the located key frame and the difference frame at the determined position in the compressed video track; and

playing back a portion of the compressed video track starting from the difference frame at the determined position in the compressed video track.

2. The method of claim 1 wherein information is discarded from the content by sub-sampling the content.

3. The method of claim 2 wherein sub-sampling the content further comprises reducing a spatial resolution scale of the content by a particular factor to generate the trick-play track.

4. The method of claim 2 wherein sub-sampling the content further comprises reducing a frame rate of the content by a particular factor to generate the trick-play track.

5. The method of claim 4 wherein creating the media file further comprises embedding portions of the accompanying trick-play track throughout the video track encoding the content.

6. The method of claim 4 wherein creating the media file further comprises incorporating the accompanying trick-play track as a block within the media file.

7. The method of claim 1 wherein the trick-play track contains only video.

8. The method of claim 1 wherein the trick-play track contains key frames spaced at specific time intervals between each key-frame.

9. The method of claim 1 wherein creating a media file including the content from the original media file encoded in a video track and the accompanying trick-play track further comprises:

re-encoding the content of the video track to create a compressed video track possessing the same resolution and frame rate as the video track, where the video track includes a plurality of key frames and the compressed video track includes fewer key frames than the video track; and

creating a media file including the compressed video track and the accompanying trick-play track;

wherein the media file including the compressed video track and the trick-play track is smaller than the original media file.

10. The method of claim 1 wherein the content is compressed content.

11. A method of decoding a media file for playing back, comprising:

requesting portions of a media file from a media server using HTTP using a playback device, where the media file contains compressed video content and is associated with an accompanying trick-play track which contains at least one key frame that corresponds to a frame in the compressed video content that is not a key frame and where the distance between key frames in the compressed video content is not uniform;

playing back a potion of the compressed video content;

receiving a trick-play request using the payback device

determining, in response to the received trick-play request, a position in the trick-play track corresponding to the position of the compressed video content being played back using a first index using the playback device;

decoding frames of the trick-play track at a rate proportional to a visual-search speed and from a the determined position in the trick-play track using the playback device;

receiving a normal-play request using the playback device;

determining, in response to the received normal-play request, a position in the compressed video content corresponding to the position of the trick-play track being played using a second index using the playback device;

locating a key frame with the closest timestamp preceding the determined position in the compressed video content;

recursively decoding the located key frame and decoding the difference frames between the located key frame and the difference frame at the determined position in the compressed video content; and

playing back a portion of the compressed video content starting from the difference frame at the determined position in the compressed video content.

12. The method of claim 11 wherein the trick-play track includes only key-frames.

13. The method of claim 11 further comprising at least one delta frame placed within a constant time difference to adjacent frames.

14. The method of claim 11 wherein only key-frames are decoded when a predetermined visual-search speed is exceeded.

15. The method of claim 11 wherein a select number of key-frames are skipped along with any associated delta frames when a predetermined visual-search speed is exceeded.

16. The method of claim 11 wherein the trick-play track is part of the media file and is the compressed content at a reduced frame rate and at a reduced resolution.

17. A system for playback of a media file, comprising:

a media server configured to

generate at least one trick-play track from an original media file, the at least one trick-play track containing at least one key frame that corresponds to a frame encoded content contained in the original media file that is not a key frame, and where the distance between key frames in the encoded content is not uniform; and

create a media file including encoding content from the original media file encoded in a compressed video track and an accompanying trick-play track and being substantially smaller in file size than the original media file; and

a client processor in network communication with the media server and configured to:

send requests for portions of the media file to the media server using HTTP, the media server configured to transmit the requested media file using HTTP;

play back a portion of the compressed video track;

receive a trick-play request;

determine, in response to the received trick-play request, a position in the trick-play track corresponding to the position of the compressed video track being played using a first index;

play back a portion of the trick-play track starting from the determined position in the trick-play track;

receive a normal-play request using the playback device;

determine, in response to the received normal-play request, a position in the compressed video track corresponding to the position of the trick-play track being played using a second index using the playback device;

locate a key frame with the closest timestamp preceding the determined position in the compressed video track;

recursively decode the located key frame and decoding the difference frames between the located key frame and the difference frame at the determined position in the compressed video track; and

play back a portion of the compressed video track starting from the difference frame at the determined position in the compressed video track.

Assignments (9)