Sub-pictures for pixel rate balancing on multi-core platforms
A method for decoding a compressed video bit stream in a video decoder to recover a video sequence, the video decoder including a plurality of decoder processing cores is provided. The method includes determining that a picture is encoded in the compressed bit stream as a pre-determined number of independently encoded sub-pictures, and dispatching a first encoded sub-picture of the pre-determined number of sub-pictures to a first decoder processing core of the plurality of decoder processing cores and a second encoded sub-picture of the pre-determined number of sub-pictures to a second decoder processing core of the plurality of decoder processing cores, wherein the first encoded sub-picture and the second encoded sub-picture are independently decoded in parallel on the respective first and second decoder processing cores.
1. A video decoder comprising:
a first decoder processing core;
a second decoder processing core;
a decoder controller coupled to the first decoder processing core and the second decoder processing core, wherein the decoder controller is operable to:
receive an input compressed bit stream that includes a picture;
determine that a portion of the picture is encoded in a first and second encoded sub-pictures, where the first encoded sub-picture is associated with a first identifier and includes an integer number of first coding units, and where the second encoded sub-picture is associated with a second identifier and includes an integer number of second coding units;
determine which of the first and second encoded sub-pictures is identified by decoding a first syntax element of a first slice header of a first slice of one of the first or second encoded sub-pictures;
determine which of the first and second encoded sub-pictures is identified by decoding a second syntax element of a second slice header of a second slice of one of the first or second encoded sub-pictures, the first and second syntax elements identifying at least one of the first or second encoded sub-pictures, the second syntax element of the second slice header different than the first syntax element of the first slice header;
dispatch the first slice to the first decoder processing core in response to a determination the first encoded sub-picture is identified by the first slice; and
dispatch the second slice to the second decoder processing core in response to a determination the second encoded sub-picture is identified by the second slice;
the first decoder processing core operable to decode the first encoded sub-picture; and
the second decoder processing core operable to decode the second encoded sub-picture, wherein the second decoder processing core decodes the second slice in parallel with the first decoder processing core decoding the first slice.
2. The decoder of claim 1 , wherein the first and second slices are respectively dispatched by the decoder controller without parsing through additional slice header data of the first and second slices.
3. The decoder of claim 1 , wherein the first and second encoded sub-pictures are specified as a required number of sub-picture rows and a required number of sub-picture columns.
4. The decoder of claim 1 , wherein the first and second encoded sub-pictures are specified as a required number of sub-pictures and a minimum number of sub-picture columns.
5. The decoder of claim 1 , wherein a size difference between a number of rows of coding units in the first encoded sub-picture and a number of rows of coding units in the second encoded sub-picture is less than or equal to one coding unit, and wherein a size difference between a number of columns of coding units in the first sub-picture and a number of columns of coding units in the second sub-picture is less than or equal to one coding unit.
6. The decoder of claim 1 , wherein sub-picture partitioning of the picture is signaled in the input compressed bit stream using a tile signaling protocol.
7. The decoder of claim 1 , wherein dispatching further comprises:
determining an entry point of a first sub-picture bit stream in the input compressed bit stream, the first sub-picture bit stream corresponding to a first sub-picture of the sub-pictures;
determining an entry point of a second sub-picture bit stream in the input compressed bit stream, the second sub-picture bit stream corresponding to a second sub-picture of the sub-pictures;
directing the first sub-picture bit stream to the first decoder processing core; and
directing the second sub-picture bit stream to the second decoder processing core.
8. The decoder of claim 7 , wherein the entry points of the first and second sub-picture bit streams are signaled in the input compressed bit stream.
9. The decoder of claim 7 , wherein dispatching further comprises:
wherein the first slice and the second slice are interleaved in the input compressed bit stream.
10. The decoder of claim 1 , wherein first and second encoded sub-pictures are independently encoded.
11. The decoder of claim 1 , wherein the integer number of coding units are in a rectangle.
12. The decoder of claim 1 , wherein the first and second slices are transmitted in interleaved order.
13. The decoder of claim 1 , wherein the first slice header includes a first plurality of elements, the first of which being the first syntax element, and wherein the second slice header includes a second plurality of elements, the first of which being the second syntax element.