[FFmpeg-devel] [PATCH] cbs_h266: add range extension support
Frank Plowman
post at frankplowman.com
Wed Jul 5 15:38:17 EEST 2023
On 05/07/2023 12:45, James Almer wrote:
> On 7/5/2023 8:38 AM, Nuo Mi wrote:
>> From: frankplow <post at frankplowman.com>
>>
>> ---
>> libavcodec/cbs_h266.h | 18 ++++++
>> libavcodec/cbs_h266_syntax_template.c | 79 +++++++++++++++++++++++++--
>> 2 files changed, 93 insertions(+), 4 deletions(-)
>>
>> diff --git a/libavcodec/cbs_h266.h b/libavcodec/cbs_h266.h
>> index e33d08a0f5..40aba9eb13 100644
>> --- a/libavcodec/cbs_h266.h
>> +++ b/libavcodec/cbs_h266.h
>> @@ -120,6 +120,13 @@ typedef struct H266GeneralConstraintsInfo {
>> uint8_t gci_no_virtual_boundaries_constraint_flag;
>> uint8_t gci_num_reserved_bits;
>> uint8_t gci_reserved_zero_bit[255];
>> +
>> + uint8_t gci_all_rap_pictures_constraint_flag;
>> + uint8_t gci_no_extended_precision_processing_constraint_flag;
>> + uint8_t gci_no_ts_residual_coding_rice_constraint_flag;
>> + uint8_t gci_no_rrc_rice_extension_constraint_flag;
>> + uint8_t gci_no_persistent_rice_adaptation_constraint_flag;
>> + uint8_t gci_no_reverse_last_sig_coeff_constraint_flag;
>> } H266GeneralConstraintsInfo;
>> typedef struct H266RawProfileTierLevel {
>> @@ -451,6 +458,15 @@ typedef struct H266RawSPS {
>> uint8_t sps_extension_flag;
>> + uint8_t sps_range_extension_flag;
>> + uint8_t sps_extension_7bits;
>> +
>> + uint8_t sps_extended_precision_flag;
>> + uint8_t sps_ts_residual_coding_rice_present_in_sh_flag;
>> + uint8_t sps_rrc_rice_extension_flag;
>> + uint8_t sps_persistent_rice_adaptation_enabled_flag;
>> + uint8_t sps_reverse_last_sig_coeff_enabled_flag;
>> +
>> H266RawExtensionData extension_data;
>> } H266RawSPS;
>> @@ -734,6 +750,8 @@ typedef struct H266RawSliceHeader {
>> uint8_t sh_sign_data_hiding_used_flag;
>> uint8_t sh_ts_residual_coding_disabled_flag;
>> + uint8_t sh_ts_residual_coding_rice_idx_minus1;
>> + uint8_t sh_reverse_last_sig_coeff_flag;
>> uint16_t sh_slice_header_extension_length;
>> uint8_t sh_slice_header_extension_data_byte[256];
>> diff --git a/libavcodec/cbs_h266_syntax_template.c
>> b/libavcodec/cbs_h266_syntax_template.c
>> index 485c02f590..893fa55369 100644
>> --- a/libavcodec/cbs_h266_syntax_template.c
>> +++ b/libavcodec/cbs_h266_syntax_template.c
>> @@ -61,7 +61,7 @@ static int FUNC(general_constraints_info)
>> (CodedBitstreamContext *ctx,
>> RWContext *rw,
>> H266GeneralConstraintsInfo *current)
>> {
>> - int err, i;
>> + int err, i, num_additional_bits_used;
>> flag(gci_present_flag);
>> if (current->gci_present_flag) {
>> @@ -149,7 +149,25 @@ static int FUNC(general_constraints_info)
>> (CodedBitstreamContext *ctx,
>> flag(gci_no_ladf_constraint_flag);
>> flag(gci_no_virtual_boundaries_constraint_flag);
>> ub(8, gci_num_reserved_bits);
>
> This should be renamed to gci_num_additional_bits while at it.
>
>> - for (i = 0; i < current->gci_num_reserved_bits; i++) {
>> + if (current->gci_num_reserved_bits > 5) {
>> + flag(gci_all_rap_pictures_constraint_flag);
>> + flag(gci_no_extended_precision_processing_constraint_flag);
>> + flag(gci_no_ts_residual_coding_rice_constraint_flag);
>> + flag(gci_no_rrc_rice_extension_constraint_flag);
>> + flag(gci_no_persistent_rice_adaptation_constraint_flag);
>> + flag(gci_no_reverse_last_sig_coeff_constraint_flag);
>> + num_additional_bits_used = 6;
>> + } else {
>> + infer(gci_all_rap_pictures_constraint_flag, 0);
>> + infer(gci_no_extended_precision_processing_constraint_flag, 0);
>> + infer(gci_no_ts_residual_coding_rice_constraint_flag, 0);
>> + infer(gci_no_rrc_rice_extension_constraint_flag, 0);
>> + infer(gci_no_persistent_rice_adaptation_constraint_flag, 0);
>> + infer(gci_no_reverse_last_sig_coeff_constraint_flag, 0);
>> + num_additional_bits_used = 0;
>> + }
>> +
>> + for (i = 0; i < current->gci_num_reserved_bits -
>> num_additional_bits_used; i++) {
>> flags(gci_reserved_zero_bit[i], 1, i);
>> }
>> }
>> @@ -963,6 +981,23 @@ static int FUNC(vps) (CodedBitstreamContext
>> *ctx, RWContext *rw,
>> return 0;
>> }
>> +static int FUNC(sps_range_extension)(CodedBitstreamContext *ctx,
>> RWContext *rw,
>> + H266RawSPS *current)
>> +{
>> + int err;
>> +
>> + flag(sps_extended_precision_flag);
>> + if (current->sps_transform_skip_enabled_flag) {
>> + flag(sps_ts_residual_coding_rice_present_in_sh_flag);
>> + } else {
>> + infer(sps_ts_residual_coding_rice_present_in_sh_flag, 0);
>> + }
>> + flag(sps_rrc_rice_extension_flag);
>> + flag(sps_persistent_rice_adaptation_enabled_flag);
>> + flag(sps_reverse_last_sig_coeff_enabled_flag);
>> +
>> + return 0;
>> +}
>> static int FUNC(sps)(CodedBitstreamContext *ctx, RWContext *rw,
>> H266RawSPS *current)
>> @@ -1518,9 +1553,33 @@ static int FUNC(sps)(CodedBitstreamContext
>> *ctx, RWContext *rw,
>> } else {
>> CHECK(FUNC(vui_parameters_default) (ctx, rw, ¤t->vui));
>> }
>> +
>> flag(sps_extension_flag);
>> - if (current->sps_extension_flag)
>> - CHECK(FUNC(extension_data) (ctx, rw,
>> ¤t->extension_data));
>> + if (current->sps_extension_flag) {
>> + flag(sps_range_extension_flag);
>> + ub(7, sps_extension_7bits);
>> +
>> + if (current->sps_range_extension_flag) {
>> + CHECK(FUNC(sps_range_extension)(ctx, rw, current));
>> + } else {
>> + infer(sps_extended_precision_flag, 0);
>> + infer(sps_ts_residual_coding_rice_present_in_sh_flag, 0);
>> + infer(sps_rrc_rice_extension_flag, 0);
>> + infer(sps_persistent_rice_adaptation_enabled_flag, 0);
>> + infer(sps_reverse_last_sig_coeff_enabled_flag, 0);
>> + }
>> + } else {
>> + infer(sps_range_extension_flag, 0);
>> + infer(sps_extension_7bits, 0);
>> + infer(sps_extended_precision_flag, 0);
>> + infer(sps_ts_residual_coding_rice_present_in_sh_flag, 0);
>> + infer(sps_rrc_rice_extension_flag, 0);
>> + infer(sps_persistent_rice_adaptation_enabled_flag, 0);
>> + infer(sps_reverse_last_sig_coeff_enabled_flag, 0);
>> + }
>> +
>> + if (current->sps_extension_7bits)
>> + CHECK(FUNC(extension_data)(ctx, rw, ¤t->extension_data));
>> CHECK(FUNC(rbsp_trailing_bits) (ctx, rw));
>> @@ -3005,6 +3064,18 @@ static int FUNC(slice_header)
>> (CodedBitstreamContext *ctx, RWContext *rw,
>> flag(sh_ts_residual_coding_disabled_flag);
>> else
>> infer(sh_ts_residual_coding_disabled_flag, 0);
>> +
>> + if (!current->sh_ts_residual_coding_disabled_flag &&
>> + sps->sps_ts_residual_coding_rice_present_in_sh_flag)
>> + ub(3, sh_ts_residual_coding_rice_idx_minus1);
>> + else
>> + infer(sh_ts_residual_coding_rice_idx_minus1, 0);
>> +
>> + if (sps->sps_reverse_last_sig_coeff_enabled_flag)
>> + flag(sh_reverse_last_sig_coeff_flag);
>> + else
>> + infer(sh_reverse_last_sig_coeff_flag, 0);
>
> Do you know what sample if any in the conformance suite covers this?
A matrix showing which test bitstreams test which range extension
features is available here:
https://github.com/ffvvc/FFmpeg/issues/83#issuecomment-1575658232
>
>> +
>> if (pps->pps_slice_header_extension_present_flag) {
>> ue(sh_slice_header_extension_length, 0, 256);
>> for (i = 0; i < current->sh_slice_header_extension_length;
>> i++)
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