Application enhancement tracks

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.

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.