Chunk header incorporating binary flags and correlated variable-length fields
View Patent ↗Playback and distribution systems and methods for multimedia files are provided. The multimedia files are encoded with flags associated with the content data of the multimedia files. Through the use of the flags, playback of the content is enhanced without significantly increasing the file size of the multimedia file.
1. A method of playing back content comprising a plurality of media frames by a playback device, where the content is stored in a media file, the method comprising:
providing a media file having a plurality of elements that each include:
a header, wherein the header includes a plurality of flags and data fields, the plurality of data fields includes a backward offset data field that has a pointer to a previous key-frame element, the plurality of flags includes a backward access flag that references the backward offset data field, and the previous key-frame element is arranged to be decoded independently of any other element, and
content data comprising at least one media frame;
decoding content data contained within elements using a playback device;
displaying decoded content on a display;
receiving a user request;
identifying the header of a first element in response to the received user request;
identifying a data field in the header of the first element that references a second element;
retrieving the second element from the plurality of elements; and
decoding one or more media frames contained in the retrieved second-element.
2. The method of claim 1 wherein the plurality of flags are ordered from highest importance to lowest importance.
3. The method of claim 1 , wherein the plurality of flags include a forward access flag and the plurality of data fields include a forward offset data field, the forward access flag referencing the forward offset data field and the forward offset data field has a pointer to a next key-frame element.
4. The method of claim 3 , wherein the next key-frame element is arranged to be decoded independently of any other element.
5. The method of claim 1 wherein the previous key-frame element provides an access point during trick-play operations.
6. The method of claim 1 wherein the pointer is an offset value calculated from a position of a frame being displayed.
7. The method of claim 1 wherein the backward offset data field defines a bit-field representation relative to a start point in the media file.
8. The method of claim 1 wherein each flag of the plurality of flags has a one to one corresponding reference to each data field of the plurality of data fields.
9. The method of claim 8 further comprising decoding the element in which at least one flag of the plurality of flags is decoded.
10. The method of claim 9 further comprising bypassing decoding of a remainder of the element based on the decoded flag.
11. The method of claim 10 further comprising bypassing decoding of a portion of the element based on the decoded flag.
12. The method of claim 9 further comprising decoding only a portion of the element based on the decoded flag.
13. The method of claim 12 wherein the decoded flag references a data field of the plurality of data fields that points directly to a particular media frame of the content data.
14. The method of claim 9 further comprising decoding another element within the media file based on the decoded flag.
15. The method of claim 1 wherein the plurality of flags and the plurality of data fields include information located within an element in the content data.