Methods and systems for combined lossless and lossy coding

1. A decoder, the decoder comprising circuitry configured to:

receive, in a bitstream, a coded picture, the picture comprising a first region, a second region, and a third region, wherein the first region is a first independently coded sub-picture and includes a first group of one or more coding tree units, the second region is a second independently coded subpicture and includes a second group of one or more coding tree units and the third region is the remainder of the picture and includes a third group of coding tree units;

detect, in the bitstream, that the first region is encoded using block differential pulse code modulation;

detect, in the bitstream, that the second region is encoded using transform skip mode but not block differential pulse code modulation; and

detect, in the bitstream, that the third region is encoded using lossy encoding, wherein the lossy encoding includes at least one of inter-prediction or intra-prediction, discrete cosine transform of residual pixel values, and quantization of transform coefficients.

2. The decoder of claim 1 , wherein the decoder is further configured to:

decode the first region using a first processor thread; and

decode the second region using a second processor thread.

3. The decoder of claim 1 , where the location of the first sub-picture in the picture is signaled in the bitstream and the location of the second sub-picture in the picture is signaled in the bitstream.

4. A method of combined lossless and lossy decoding, the method comprising:

receiving, by a decoder comprising circuitry, in a bitstream, a coded picture, the picture comprising a first region, a second region, and a third region, wherein the first region is a first independently coded sub-picture and includes a first group of one or more coding tree units, the second region is a second independently coded subpicture and includes a second group of one or more coding tree units and the third region is the remainder of the picture and includes a third group of coding tree units;

detecting, by the decoder and in the bitstream, that the first region is encoded using block differential pulse code modulation;

detecting, by the decoder and in the bitstream, that the second region is encoded using transform skip mode but not block differential pulse code modulation; and

detecting, by the decoder and in the bitstream, that the third region is encoded using lossy encoding, wherein the lossy encoding includes at least one of inter-prediction or intra-prediction, discrete cosine transform of residual pixel values, and quantization of transform coefficients.

5. The method of claim 4 , further comprising:

decoding the first region using a first processor thread; and

decoding the third region element using a second processor thread.

6. A decoder, the decoder comprising circuitry configured to:

receive, in a bitstream, a coded picture, the picture comprising a first region, a second region, and a third region, wherein the first region comprises a first plurality of coding units, the second region comprises a second plurality of coding units and the third region comprises the remainder of the picture;

detect, in the bitstream, that the first region is encoded using block differential pulse code modulation;

detect, in the bitstream, that the second region is encoded using transform skip mode but not block differential pulse code modulation; and

detect, in the bitstream, that the third region is encoded using lossy encoding, wherein the lossy encoding includes at least one of inter-prediction or intra-prediction, discrete cosine transform of residual pixel values, and quantization of transform coefficients.

7. A video encoder configured to:

encode a bitstream for decoding by a decoder;

the decoder comprising circuitry configured to:

receive, in a bitstream, a coded picture, the picture comprising a first region, a second region, and a third region, wherein the first region is a first independently coded sub-picture and includes a first group of one or more coding tree units, the second region is a second independently coded subpicture and includes a second group of one or more coding tree units and the third region is the remainder of the picture and includes a third group of coding tree units;

detect, in the bitstream, that the first region is encoded using block differential pulse code modulation;

detect, in the bitstream, that the second region is encoded using transform skip mode but not block differential pulse code modulation; and

detect, in the bitstream, that the third region is encoded using lossy encoding, wherein the lossy encoding includes at least one of inter-prediction or intra-prediction, discrete cosine transform of residual pixel values, and quantization of transform coefficients.

8. A video encoder configured to:

encode a bitstream for decoding by a decoder;

the decoder comprising circuitry configured to:

receive, in a bitstream, a coded picture, the picture comprising a first region, a second region, and a third region, wherein the first region comprises a first plurality of coding units, the second region comprises a second plurality of coding units and the third region comprises the remainder of the picture;

detect, in the bitstream, that the first region is encoded using block differential pulse code modulation;

detect, in the bitstream, that the second region is encoded using transform skip mode but not block differential pulse code modulation; and

detect, in the bitstream, that the third region is encoded using lossy encoding, wherein the lossy encoding includes at least one of inter-prediction or intra-prediction, discrete cosine transform of residual pixel values, and quantization of transform coefficients.