[FFmpeg-devel] [PATCH v4 2/3] avcodec/hevc/ps: Add basic HEVC_SCALABILITY_AUXILIARY support
James Almer
jamrial at gmail.com
Thu Feb 6 15:25:31 EET 2025
On 2/6/2025 12:49 AM, Zhao Zhili wrote:
> From: Zhao Zhili <zhilizhao at tencent.com>
>
> Only implementing what's needed for HEVC with alpha.
>
> Signed-off-by: Zhao Zhili <zhilizhao at tencent.com>
> ---
> libavcodec/hevc/hevc.h | 5 ++
> libavcodec/hevc/ps.c | 126 +++++++++++++++++++++++++++++------------
> libavcodec/hevc/ps.h | 4 ++
> 3 files changed, 98 insertions(+), 37 deletions(-)
>
> diff --git a/libavcodec/hevc/hevc.h b/libavcodec/hevc/hevc.h
> index b2229fda40..710786a89d 100644
> --- a/libavcodec/hevc/hevc.h
> +++ b/libavcodec/hevc/hevc.h
> @@ -170,4 +170,9 @@ enum HEVCScalabilityMask {
> HEVC_SCALABILITY_MASK_MAX = 0xFFFF,
> };
>
> +enum HEVCAuxId {
> + HEVC_AUX_ALPHA = 1,
> + HEVC_AUX_DEPTH = 2,
> +};
> +
> #endif /* AVCODEC_HEVC_HEVC_H */
> diff --git a/libavcodec/hevc/ps.c b/libavcodec/hevc/ps.c
> index 861a6bb0a2..4f18cd72e4 100644
> --- a/libavcodec/hevc/ps.c
> +++ b/libavcodec/hevc/ps.c
> @@ -460,14 +460,17 @@ static int decode_vps_ext(GetBitContext *gb, AVCodecContext *avctx, HEVCVPS *vps
> uint64_t layer1_id_included)
> {
> PTL ptl_dummy;
> - uint8_t max_sub_layers[HEVC_MAX_LAYERS];
> + uint8_t max_sub_layers[HEVC_MAX_LAYERS] = {1, 1};
> + uint8_t dimension_id_len[16] = {0};
> + uint8_t dimension_id[16] = {0};
> + unsigned n;
>
> - int splitting_flag, dimension_id_len, view_id_len, num_add_olss, num_scalability_types,
> + int splitting_flag, view_id_len, num_add_olss, num_scalability_types,
> default_output_layer_idc, direct_dep_type_len, direct_dep_type,
> sub_layers_max_present, sub_layer_flag_info_present_flag, nb_ptl;
> unsigned non_vui_extension_length;
>
> - if (vps->vps_max_layers == 1 || vps->vps_num_layer_sets == 1) {
> + if (vps->vps_max_layers == 1) {
> av_log(avctx, AV_LOG_VERBOSE, "Ignoring VPS extensions with a single layer\n");
> return 0;
> }
> @@ -520,7 +523,8 @@ static int decode_vps_ext(GetBitContext *gb, AVCodecContext *avctx, HEVCVPS *vps
> */
> vps->nb_layers = 2;
>
> - if (parse_ptl(gb, avctx, 0, &ptl_dummy, vps->vps_max_sub_layers) < 0)
> + if (vps->vps_base_layer_internal_flag &&
What's the point checking for this flag if this code will not be reached
if it's false?
> + parse_ptl(gb, avctx, 0, &ptl_dummy, vps->vps_max_sub_layers) < 0)
> return AVERROR_INVALIDDATA;
>
> splitting_flag = get_bits1(gb);
> @@ -529,20 +533,25 @@ static int decode_vps_ext(GetBitContext *gb, AVCodecContext *avctx, HEVCVPS *vps
> if (!num_scalability_types) {
> av_log(avctx, AV_LOG_ERROR, "Missing scalability mask\n");
> return AVERROR_INVALIDDATA;
> - } else if (num_scalability_types > 1) {
> - av_log(avctx, AV_LOG_ERROR, "Scalability number %d not supported\n",
> - num_scalability_types);
> - return AVERROR_PATCHWELCOME;
> }
>
> - if (!(vps->scalability_mask_flag & HEVC_SCALABILITY_MULTIVIEW)) {
> + if (!(vps->scalability_mask_flag &
> + (HEVC_SCALABILITY_MULTIVIEW | HEVC_SCALABILITY_AUXILIARY))) {
> av_log(avctx, AV_LOG_ERROR, "Scalability type %d not supported\n",
> 15 - ff_ctz(vps->scalability_mask_flag));
> return AVERROR_PATCHWELCOME;
> }
> + // x265 specify MULTIVIEW when the stream really is alpha video only.
> + if (num_scalability_types > 1)
> + av_log(avctx, AV_LOG_WARNING, "Multiple scalability types presented\n");
>
> - if (!splitting_flag)
> - dimension_id_len = get_bits(gb, 3) + 1;
> + n = 0;
> + for (int i = 0; i < num_scalability_types - splitting_flag; i++) {
> + dimension_id_len[i] = get_bits(gb, 3) + 1;
> + n += dimension_id_len[i];
> + }
> + if (splitting_flag)
> + dimension_id_len[num_scalability_types - 1] = 5 - n;
>
> if (get_bits1(gb)) { /* vps_nuh_layer_id_present_flag */
> int layer_id_in_nuh = get_bits(gb, 6);
> @@ -559,28 +568,57 @@ static int decode_vps_ext(GetBitContext *gb, AVCodecContext *avctx, HEVCVPS *vps
> }
>
> if (!splitting_flag) {
> - int view_idx = get_bits(gb, dimension_id_len);
> - if (view_idx != 1) {
> - av_log(avctx, AV_LOG_ERROR, "Unexpected ViewOrderIdx: %d\n", view_idx);
> + int index = 0;
> +
> + for (int i = 0; i < num_scalability_types; i++)
> + dimension_id[i] = get_bits(gb, dimension_id_len[i]);
> +
> + if (vps->scalability_mask_flag & HEVC_SCALABILITY_MULTIVIEW)
> + index++;
> +
> + /* AuxId 1 is alpha, 2 is depth. Only support alpha */
> + if (vps->scalability_mask_flag & HEVC_SCALABILITY_AUXILIARY &&
> + dimension_id[index] != HEVC_AUX_ALPHA) {
> + av_log(avctx, AV_LOG_WARNING,
> + "Unsupported dimension_id %d for HEVC_SCALABILITY_AUXILIARY\n",
> + dimension_id[index]);
> return AVERROR_PATCHWELCOME;
> }
> }
>
> view_id_len = get_bits(gb, 4);
> - if (view_id_len)
> - for (int i = 0; i < 2 /* NumViews */; i++)
> + if (view_id_len) {
> + n = (vps->scalability_mask_flag & HEVC_SCALABILITY_MULTIVIEW) ? 2 : 1;
> + for (int i = 0; i < n; i++)
> vps->view_id[i] = get_bits(gb, view_id_len);
> + }
>
> - if (!get_bits1(gb) /* direct_dependency_flag */) {
> - av_log(avctx, AV_LOG_WARNING, "Independent output layers not supported\n");
> - return AVERROR_PATCHWELCOME;
> + /* direct_dependency_flag */
> + vps->num_direct_ref_layers[1] = get_bits1(gb);
> + if (!vps->num_direct_ref_layers[1]) {
> + vps->num_add_layer_sets = get_ue_golomb(gb);
> + if (vps->num_add_layer_sets > 1) {
> + av_log(avctx, AV_LOG_WARNING,
> + "Unsupported num_add_layer_sets: %d\n", vps->num_add_layer_sets);
> + return AVERROR_PATCHWELCOME;
> + }
> +
> + if (vps->num_add_layer_sets) {
> + /* highest_layer_idx_plus1 */
> + if (!get_bits1(gb))
> + return AVERROR_PATCHWELCOME;
> + }
> }
> - vps->num_direct_ref_layers[1] = 1;
> + vps->num_output_layer_sets = vps->vps_num_layer_sets + vps->num_add_layer_sets;
> + if (vps->num_output_layer_sets != 2)
> + return AVERROR_INVALIDDATA;
>
> sub_layers_max_present = get_bits1(gb); // vps_sub_layers_max_minus1_present_flag
> - for (int i = 0; i < vps->vps_max_layers; i++)
> - max_sub_layers[i] = sub_layers_max_present ? get_bits(gb, 3) + 1 :
> - vps->vps_max_sub_layers;
> + if (sub_layers_max_present) {
> + for (int i = 0; i < vps->vps_max_layers; i++)
> + max_sub_layers[i] = sub_layers_max_present ? get_bits(gb, 3) + 1 :
> + vps->vps_max_sub_layers;
> + }
>
> if (get_bits1(gb) /* max_tid_ref_present_flag */)
> skip_bits(gb, 3); // max_tid_il_ref_pics_plus1
> @@ -613,18 +651,24 @@ static int decode_vps_ext(GetBitContext *gb, AVCodecContext *avctx, HEVCVPS *vps
> }
>
> /* Consequence of established layer dependencies */
> - if (layer1_id_included != ((1 << vps->layer_id_in_nuh[0]) |
> + if (layer1_id_included &&
> + layer1_id_included != ((1 << vps->layer_id_in_nuh[0]) |
> (1 << vps->layer_id_in_nuh[1]))) {
> - av_log(avctx, AV_LOG_ERROR, "Dependent layer not included in layer ID?\n");
> - return AVERROR_PATCHWELCOME;
> + av_log(avctx, AV_LOG_ERROR,
> + "Dependent layer not included in layer ID?\n");
> + return AVERROR_PATCHWELCOME;
> }
> + if (!layer1_id_included)
> + vps->ols[1] = 2;
> + else
> + vps->ols[1] = 3;
>
> - vps->num_output_layer_sets = 2;
> - vps->ols[1] = 3;
> + if (vps->vps_num_layer_sets == 1 || default_output_layer_idc == 2)
> + skip_bits1(gb);
>
> for (int j = 0; j < av_popcount64(vps->ols[1]); j++) {
> int ptl_idx = get_bits(gb, av_ceil_log2(nb_ptl));
> - if (ptl_idx < 1 || ptl_idx >= nb_ptl) {
> + if (ptl_idx >= nb_ptl) {
> av_log(avctx, AV_LOG_ERROR, "Invalid PTL index: %d\n", ptl_idx);
> return AVERROR_INVALIDDATA;
> }
> @@ -667,6 +711,8 @@ static int decode_vps_ext(GetBitContext *gb, AVCodecContext *avctx, HEVCVPS *vps
>
> vps->max_one_active_ref_layer = get_bits1(gb);
> vps->poc_lsb_aligned = get_bits1(gb);
> + if (!vps->num_direct_ref_layers[1])
> + vps->poc_lsb_not_present = get_bits1(gb) << 1;
Huh, so this was being checked in hls_slice_header() but never set
before now?
>
> sub_layer_flag_info_present_flag = get_bits1(gb);
> for (int j = 0; j < FFMAX(max_sub_layers[0], max_sub_layers[1]); j++) {
> @@ -688,12 +734,14 @@ static int decode_vps_ext(GetBitContext *gb, AVCodecContext *avctx, HEVCVPS *vps
> return AVERROR_INVALIDDATA;
> }
>
> - skip_bits1(gb); /* direct_depenency_all_layers_flag */
> - direct_dep_type = get_bits_long(gb, direct_dep_type_len);
> - if (direct_dep_type > HEVC_DEP_TYPE_BOTH) {
> - av_log(avctx, AV_LOG_WARNING, "Unsupported direct_dep_type: %d\n",
> - direct_dep_type);
> - return AVERROR_PATCHWELCOME;
> + /* direct_dependency_all_layers_flag */
> + if (get_bits1(gb) || vps->num_direct_ref_layers[1]) {
> + direct_dep_type = get_bits_long(gb, direct_dep_type_len);
> + if (direct_dep_type > HEVC_DEP_TYPE_BOTH) {
> + av_log(avctx, AV_LOG_WARNING, "Unsupported direct_dep_type: %d\n",
> + direct_dep_type);
> + return AVERROR_PATCHWELCOME;
> + }
> }
>
> non_vui_extension_length = get_ue_golomb(gb);
> @@ -741,8 +789,12 @@ int ff_hevc_decode_nal_vps(GetBitContext *gb, AVCodecContext *avctx,
> }
> vps->vps_id = vps_id;
>
> - if (get_bits(gb, 2) != 3) { // vps_reserved_three_2bits
> - av_log(avctx, AV_LOG_ERROR, "vps_reserved_three_2bits is not three\n");
> + vps->vps_base_layer_internal_flag = get_bits1(gb);
> + vps->vps_base_layer_available_flag = get_bits1(gb);
> + if (!vps->vps_base_layer_internal_flag || !vps->vps_base_layer_available_flag) {
> + av_log(avctx, AV_LOG_ERROR,
> + "vps_base_layer_internal_flag or vps_base_layer_available_flag not set\n");
> + ret = AVERROR_PATCHWELCOME;
> goto err;
> }
>
> diff --git a/libavcodec/hevc/ps.h b/libavcodec/hevc/ps.h
> index d3465e3d27..f706b889e6 100644
> --- a/libavcodec/hevc/ps.h
> +++ b/libavcodec/hevc/ps.h
> @@ -171,6 +171,9 @@ typedef struct RepFormat {
> typedef struct HEVCVPS {
> unsigned int vps_id;
>
> + uint8_t vps_base_layer_internal_flag;
> + uint8_t vps_base_layer_available_flag;
These two can be variables local to ff_hevc_decode_nal_vps() instead of
being in this struct.
> +
> uint8_t vps_temporal_id_nesting_flag;
> int vps_max_layers;
> int vps_max_sub_layers; ///< vps_max_temporal_layers_minus1 + 1
> @@ -237,6 +240,7 @@ typedef struct HEVCVPS {
>
> // NumDirectRefLayers[layer_idx]
> uint8_t num_direct_ref_layers[HEVC_VPS_MAX_LAYERS];
> + uint8_t num_add_layer_sets;
>
> RepFormat rep_format;
>
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