Gradual decoding refresh in video coding

1. A method implemented by a decoder, the method comprising:

receiving a coded video bitstream;

determining whether a value for a first flag is set by an external input;

setting the first flag equal to the value provided by the external input and a second flag equal to the first flag to prevent a gradual decoding refresh (GDR) picture from being output when the value for the first flag is provided by the external input, wherein the coded video bitstream comprises a sequence of access units (AUs) that comprise, in decoding order, a GDR AU, including the GDR picture with the second flag equal to one, and subsequent AUs;

decoding the GDR picture; and

storing the GDR picture in a decoded picture buffer (DPB).

2. The method of claim 1 , wherein the first flag is set equal to the value provided by the external input and the second flag equal to the first flag to prevent any trailing pictures between the GDR picture and a recovery point picture in output order from being output when the value for the first flag is set by the external input.

3. The method of claim 1 , wherein the external input is a graphic user interface (GUI) of the decoder, wherein the value of the first flag is provided by a user of the decoder using the external input.

4. The method of claim 1 , wherein the first flag is designated HandleGdrAsCvsStartFlag.

5. The method of claim 1 , wherein the value of the first flag and the second flag are set to one (1) to prevent the GDR picture and any trailing pictures between the GDR picture and a recovery point picture in output order from being output.

6. The method of claim 1 , wherein the value of the first flag is set to zero (0) when the value for the first flag is not provided by the external input.

7. A non-transitory computer readable medium comprising a computer program product for use by a decoding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the decoding device to:

receive a coded video bitstream;

determine whether a value for a first flag is provided by an external input;

set the first flag equal to the value provided by the external input and a second flag equal to the first flag to prevent a gradual decoding refresh (GDR) picture from being output when the value for the first flag is provided by the external input, wherein the coded video bitstream comprises a sequence of access units (AUs) that comprise, in decoding order, a GDR AU, including the GDR picture with the second flag equal to one, and subsequent AUs;

decode the GDR picture; and

store the GDR picture in a decoded picture buffer (DPB).

8. The non-transitory computer readable medium of claim 7 , wherein the first flag is set equal to the value provided by the external input and a second flag equal to the first flag to prevent a gradual decoding refresh (GDR) picture and any trailing pictures between the GDR picture and a recovery point picture in output order from being output when the value for the first flag is provided by the external input.

9. The non-transitory computer readable medium of claim 7 , wherein the external input is a graphic user interface (GUI) of the decoding device, and wherein the value of the first flag is provided by a user of the decoding device using the external input.

10. The non-transitory computer readable medium of claim 7 , wherein the first flag is designated HandleGdrAsCvsStartFlag.

11. The non-transitory computer readable medium of claim 7 , wherein the value of the first flag and the second flag are set to one (1) to prevent the GDR picture and any trailing pictures between the GDR picture and a recovery point picture in output order from being output.

12. The non-transitory computer readable medium of claim 7 , wherein the value of the first flag is set to zero (0) when the value for the first flag is not provided by the external input.

13. A decoder comprising:

a receiver configured to receive a coded video bitstream;

a processor coupled to the receiver and configured to determine:

whether a value for a first flag is set by an external input;

set the first flag equal to the value provided by the external input and a second flag equal to the first flag to prevent a gradual decoding refresh (GDR) picture from being output when the value for the first flag is provided by the external input, wherein the coded video bitstream comprises a sequence of access units (AUs) that comprise, in decoding order, a GDR AU, including the GDR picture with the second flag equal to one, and subsequent AUs; and

decode the GDR picture; and

a memory coupled to the processor and configured to store the GDR picture in a decoded picture buffer (DPB).

14. The decoder of claim 13 , wherein the first flag is set equal to the value provided by the external input and the second flag equal to the first flag to prevent any trailing pictures between the GDR picture and a recovery point picture in output order from being output when the value for the first flag is set by the external input.

15. The decoder of claim 13 , wherein the external input is a graphic user interface (GUI) of the decoder, wherein the value of the first flag is provided by a user of the decoder using the external input.

16. The decoder of claim 13 , wherein the first flag is designated HandleGdrAsCvsStartFlag.

17. The decoder of claim 13 , wherein the value of the first flag and the second flag are set to one (1) to prevent the GDR picture and any trailing pictures between the GDR picture and a recovery point picture in output order from being output.

18. The decoder of claim 13 , wherein the value of the first flag is set to zero (0) when the value for the first flag is not provided by the external input.