Detailed Description

Attribute value for VAConfigAttribEncRateControlExt.

Member Data Documentation

◆ max_num_temporal_layers_minus1

uint32_t VAConfigAttribValEncRateControlExt::max_num_temporal_layers_minus1

The maximum number of temporal layers minus 1.

max_num_temporal_layers_minus1 plus 1 specifies the maximum number of temporal layers that supported by the underlying driver. max_num_temporal_layers_minus1 equal to 0 implies the underlying driver doesn't support encoding with temporal layer.

◆ temporal_layer_bitrate_control_flag

uint32_t VAConfigAttribValEncRateControlExt::temporal_layer_bitrate_control_flag

/brief support temporal layer bit-rate control flag

temporal_layer_bitrate_control_flag equal to 1 specifies the underlying driver can support bit-rate control per temporal layer when (#VAConfigAttribRateControl == VA_RC_CBR || #VAConfigAttribRateControl == VA_RC_VBR).

The underlying driver must set temporal_layer_bitrate_control_flag to 0 when max_num_temporal_layers_minus1 is equal to 0

To use bit-rate control per temporal layer, an application must send the right layer structure via VAEncMiscParameterTemporalLayerStructure at the beginning of a coded sequence and then followed by VAEncMiscParameterRateControl and VAEncMiscParameterFrameRate structures for each layer, using the temporal_id field as the layer identifier. Otherwise the driver doesn't use bitrate control per temporal layer if an application doesn't send the layer structure via VAEncMiscParameterTemporalLayerStructure to the driver. The driver returns VA_STATUS_ERROR_INVALID_PARAMETER if an application sends a wrong layer structure or doesn't send VAEncMiscParameterRateControl and VAEncMiscParameterFrameRate for each layer.

The driver will ignore VAEncMiscParameterTemporalLayerStructure and the temporal_id field in VAEncMiscParameterRateControl and VAEncMiscParameterFrameRate if temporal_layer_bitrate_control_flag is equal to 0 or #VAConfigAttribRateControl == VA_RC_CQP

The documentation for this union was generated from the following file:

va.h