Scalable nesting SEI messages for all layers
A video coding mechanism is disclosed. The mechanism includes receiving a bitstream at a decoder. The bitstream comprises one or more layers and a scalable nesting supplemental enhancement information (SEI) message in a current SEI network abstraction layer (NAL) unit. The scalable nesting SEI message contains scalable-nested SEI messages and a scalable nesting all layers flag (all_layers_flag) that specifies whether the scalable-nested SEI messages apply to all layers that have a layer identifier (Id) that is greater than or equal to a layer Id of the current SEI NAL unit. A coded picture is decoded from the one or more layers to produce a decoded picture. The decoded picture is forwarded for display as part of a decoded video sequence.
1. A method implemented in a decoder, the method comprising:
receiving a bitstream comprising one or more layers and a scalable nesting supplemental enhancement information (SEI) message in a current SEI network abstraction layer (NAL) unit, wherein the scalable nesting SEI message contains scalable-nested SEI messages and a scalable nesting all layers flag (all_layers_flag) that specifies whether the scalable-nested SEI messages apply to all layers that have a layer identifier (Id) that is greater than or equal to a layer Id of the current SEI NAL unit;
deriving a number of nesting layers (nestingNumLayers) variable that specifies a number of layers to which the scalable-nested SEI messages apply and a list of nesting layer Ids (NestingLayerId[i]) that specifies a list of NAL unit header layer Id (nuh_layer_id) values of the layers to which the scalable-nested SEI messages apply for i in a range of zero to nestingNumLayers minus one, inclusive, wherein the nestingNumLayers and the NestingLayerId[i] are derived as follows:
if(scalable nesting all_layers_flag){
nestingNumLayers=vps_max_layers_minus1+1−GeneralLayerIdx[nuh_layer_id]
for(i=0; i<nestingNumLayers; i++)
NestingLayerId[i]=vps_layer_id[GeneralLayerIdx[nuh_layer_id]+i]} else {nestingNumLayers=scalable nesting_num_layers_minus1+1
for(i=0; i<nestingNumLayers; i++)
NestingLayerId[i]=(i==0)?nuh_layer_id:scalable nesting layer_id[i]}
where vps_max_layers_minus1 plus one specifies a number of layers specified by a video parameter set (VPS), GeneralLayerIdx is a variable specifying a layer index of a layer with nuh_layer_id equal to vps_layer_id[i], vps_layer_id[i] specifies a nuh_layer_id value of an i-th layer, scalable nesting num_layers_minus1 plus one specifies a number of layers to which the scalable-nested SEI messages apply, and scalable nesting layer_id[i] specifies a nuh_layer_id value of an i-th layer to which the scalable-nested SEI messages apply; and
decoding a coded picture from the one or more layers to produce a decoded picture.
2. The method of claim 1 , wherein the scalable nesting all_layers_flag equals one, specifying that the scalable-nested SEI messages apply to all layers that have a NAL unit header layer Id (nuh_layer_id) greater than or equal to a nuh_layer_id of the current SEI NAL unit.
3. The method of claim 1 , wherein the scalable nesting all_layers_flag equals zero, specifying that the scalable-nested SEI messages might or might not apply to all layers that have a NAL unit header layer Id (nuh_layer_id) greater than or equal to a nuh_layer_id of the current SEI NAL unit.
4. The method of claim 1 , wherein the scalable nesting SEI message provides a mechanism to associate SEI messages with specific layers.
5. The method of claim 1 , wherein the coded picture is decoded based on the scalable nested SEI messages.
6. A method implemented in an encoder, the method comprising:
encoding a picture into a bitstream comprising one or more layers;
encoding into the bitstream a scalable nesting supplemental enhancement information (SEI) message in a current SEI network abstraction layer (NAL) unit, wherein the scalable nesting SEI message contains scalable-nested SEI messages and a scalable nesting all layers flag (all_layers_flag) that specifies whether the scalable-nested SEI messages apply to all layers that have a layer identifier (Id) that is greater than or equal to a layer Id of the current SEI NAL unit;
performing a set of bitstream conformance tests on the layers based on the scalable-nested SEI messages, wherein the set of bitstream conformance tests include deriving a number of nesting layers (nestingNumLayers) variable that specifies a number of layers to which the scalable-nested SEI messages apply and a list of nesting layer Ids (NestingLayerId[i]) that specifies a list of NAL unit header layer Id (nuh_layer_id) values of the layers to which the scalable-nested SEI messages apply for i in a range of zero to nestingNumLayers minus one, inclusive, wherein the nestingNumLayers and the NestingLayerId[i] are derived as follows:
if(scalable nesting all layers flag) {
nestingNumLayers=vps_max_layers_minus1+1−GeneralLayerIdx[nuh_layer_id]
for(i=0; i<nestingNumLayers; i++)
NestingLayerId[i]=vps_layer_id [GeneralLayerIdx[nuh_layer_id]+i]} else {
nestingNumLayers=scalable nesting num_layers_minus1+1
for(i=0; i<nestingNumLayers; i++)
NestingLayerId[i]=(i==0)? nuh_layer_id: scalable nesting layer id [i]}
where vps_max_layers_minus1 plus one specifies a number of layers specified by a video parameter set (VPS), GeneralLayerIdx is a variable specifying a layer index of a layer with nuh_layer_id equal to vps_layer_id[i], vps_layer_id[i] specifies a nuh_layer_id value of an i-th layer, scalable nesting num_layers_minus1 plus one specifies a number of layers to which the scalable-nested SEI messages apply, and scalable nesting layer id[i] specifies a nuh_layer_id value of an i-th layer to which the scalable-nested SEI messages apply.
7. The method of claim 6 , further comprising setting the scalable nesting all_layers_flag equal to one, specifying that the scalable-nested SEI messages apply to all layers that have a NAL unit header layer Id (nuh_layer_id) greater than or equal to a nuh_layer_id of the current SEI NAL unit.
8. The method of claim 6 , further comprising setting the scalable nesting all_layers_flag equal to zero, specifying that the scalable-nested SEI messages might or might not apply to all layers that have a NAL unit header layer Id (nuh_layer_id) greater than or equal to a nuh_layer_id of the current SEI NAL unit.
9. The method of claim 6 , wherein the scalable nesting SEI message provides a mechanism to associate SEI messages with specific layers.
10. A video coding device comprising:
a receiver configured to receive a bitstream comprising one or more layers and a scalable nesting supplemental enhancement information (SEI) message in a current SEI network abstraction layer (NAL) unit, wherein the scalable nesting SEI message contains scalable-nested SEI messages and a scalable nesting all layers flag (all_layers_flag) that specifies whether the scalable-nested SEI messages apply to all layers that have a layer identifier (Id) that is greater than or equal to a layer Id of the current SEI NAL unit; and
a processor coupled to the receiver and configured to:
derive a number of nesting layers (nestingNumLayers) variable that specifies a number of layers to which the scalable-nested SEI messages apply and a list of nesting layer Ids (NestingLayerId[i]) that specifies a list of NAL unit header layer Id (nuh_layer_id) values of the layers to which the scalable-nested SEI messages apply for i in a range of zero to nestingNumLayers minus one, inclusive, wherein the nestingNumLayers and the NestingLayerId[i] are derived as follows:
if(scalable nesting all layers flag) {
nestingNumLayers=vps_max_layers_minus1+1−GeneralLayerIdx[nuh_layer_id]
for(i=0; i<nestingNumLayers; i++)
NestingLayerId[i]=vps_layer_id [GeneralLayerIdx[nuh_layer_id]+i]}else {
nestingNumLayers=scalable nesting num_layers_minus1+1
for(i=0; i<nestingNumLayers; i++)
NestingLayerId[i]=(i==0)? nuh_layer_id: scalable nesting layer_id[i]}
where vps_max_layers_minus1 plus one specifies a number of layers specified by a video parameter set (VPS), GeneralLayerIdx is a variable specifying a layer index of a layer with nuh_layer_id equal to vps_layer_id[i], vps_layer_id[i] specifies a nuh_layer_id value of an i-th layer, scalable nesting num_layers_minus1 plus one specifies a number of layers to which the scalable-nested SEI messages apply, and scalable nesting layer_id[i] specifies a nuh_layer_id value of an i-th layer to which the scalable-nested SEI messages apply; and
decode a coded picture from the one or more layers to produce a decoded picture.
11. The video coding device of claim 10 , wherein the scalable nesting all_layers_flag equals one when specifying that the scalable-nested SEI messages apply to all layers that have a NAL unit header layer Id (nuh_layer_id) greater than or equal to a nuh_layer_id of the current SEI NAL unit.
12. The video coding device of claim 10 , wherein the scalable nesting all_layers_flag equals zero when specifying that the scalable-nested SEI messages might or might not apply to all layers that have a NAL unit header layer Id (nuh_layer_id) greater than or equal to a nuh_layer_id of the current SEI NAL unit.
13. The video coding device of claim 10 , wherein the scalable nesting SEI message provides a mechanism to associate SEI messages with specific layers.
14. The video coding device of claim 10 , wherein the coded picture is decoded based on the scalable nested SEI messages.