Methods and apparatus for indicating picture buffer size for coded scalable video

1. A method for encoding a video sequence in a scalable video encoder to generate a scalable bitstream, the method comprising:

encoding the video sequence in a first layer encoder of the scalable video encoder to generate a first sub-bitstream;

encoding the video sequence in a second layer encoder of the scalable video encoder to generate a second sub-bitstream, wherein portions of the video sequence being encoded in the second layer encoder are predicted using reference portions of the video sequence encoded in the first layer encoder;

combining the first sub-bitstream and the second sub-bitstream to generate the scalable bitstream;

signaling in the scalable bitstream an indication of a maximum decoded picture buffer (DPB) size needed for decoding the second sub-bitstream and the first sub-bitstream when the second sub-bitstream is a target sub-bitstream for decoding, wherein the indication of the maximum DPB size comprises an indication of a maximum DPB size needed for decoding the first sub-bitstream as a reference sub-bitstream; and

signaling in a video parameter set a highest temporal layer having pictures used for inter-layer prediction.

2. The method of claim 1 , wherein the first layer encoder layer is a base layer encoder of the scalable video encoder.

3. The method of claim 1 , wherein the first layer encoder is an enhancement layer encoder of the scalable video encoder.

4. The method of claim 1 , wherein the indication of the maximum DPB size is signaled in a video parameter set.

5. A method for decoding a scalable bitstream in a scalable video decoder to generate a video sequence, the method comprising:

decoding from the scalable bitstream an indication of a maximum decoded picture buffer (DPB) size needed to decode a first enhancement layer sub-bitstream of the scalable bitstream and a reference layer sub-bitstream for the first enhancement layer sub-bitstream when the first enhancement layer sub-bitstream is decoded as a target sub-bitstream; and

using the indication of the maximum DPB size for further processing of the scalable bitstream, wherein the indication of the maximum DPB size comprises an indication of a maximum DPB size needed for decoding the reference layer sub-bitstream as a non-target sub-bitstream,

wherein an indication of a highest temporal level is decoded from a video parameter set.

6. The method of claim 5 , wherein using the indication of the maximum DPB size comprises using the indication of the maximum DPB size to determine if the scalable video decoder has sufficient DPB memory to decode the first enhancement layer sub-bitstream.

7. The method of claim 5 , wherein the reference layer sub-bitstream is a base layer sub-bitstream.

8. The method of claim 5 , wherein the reference layer sub-bitstream is a second enhancement layer sub-bitstream.

9. An apparatus configured to decode a scalable bitstream, the apparatus comprising:

means for decoding from the scalable bitstream an indication of a maximum decoded picture buffer (DPB) size needed to decode a first enhancement layer sub-bitstream of the scalable bitstream and a reference layer sub-bitstream for the first enhancement layer sub-bitstream when the first enhancement layer sub-bitstream is decoded as a target sub-bitstream, wherein at least one picture in the reference layer sub-bitstream need not be decoded for predicting the first enhancement layer sub-bitstream; and

means for using the indication of the maximum DPB size for further processing of the scalable bitstream, wherein the indication of the maximum DPB size comprises an indication of a maximum DPB size needed for decoding the reference layer sub-bitstream as a non-target sub-bitstream,

wherein an indication of a highest temporal level is decoded from a video parameter set.

10. The apparatus of claim 9 , wherein the means for using the indication of the maximum DPB size uses the indication of the maximum DPB size to determine if the scalable video decoder has sufficient DPB memory to decode the first enhancement layer sub-bitstream.

11. The apparatus of claim 9 , wherein the reference layer sub-bitstream is a base layer sub-bitstream.

12. The apparatus of claim 9 , wherein the reference layer sub-bitstream is a second enhancement layer sub-bitstream.