[FFmpeg-devel] [PATCH v5 3/3] avcodec/hevc: Add alpha layer support
Zhao Zhili
quinkblack at foxmail.com
Tue Feb 11 12:41:30 EET 2025
> On Feb 11, 2025, at 16:16, Andreas Rheinhardt <andreas.rheinhardt at outlook.com> wrote:
>
> Zhao Zhili:
>> From: Zhao Zhili <zhilizhao at tencent.com>
>>
>> Signed-off-by: Zhao Zhili <zhilizhao at tencent.com>
>> ---
>> libavcodec/hevc/hevcdec.c | 72 ++++++++++++++++++++++++++++++++++++++-
>> libavcodec/hevc/hevcdec.h | 2 ++
>> libavcodec/hevc/refs.c | 11 +++++-
>> 3 files changed, 83 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavcodec/hevc/hevcdec.c b/libavcodec/hevc/hevcdec.c
>> index e9c045f7a1..1cdc28de50 100644
>> --- a/libavcodec/hevc/hevcdec.c
>> +++ b/libavcodec/hevc/hevcdec.c
>> @@ -466,6 +466,24 @@ static int export_multilayer(HEVCContext *s, const HEVCVPS *vps)
>> return 0;
>> }
>>
>> +int ff_hevc_is_alpha_video(const HEVCContext *s) {
>
> '{’ should be on its own line.
Fixed in v6.
>
>> + const HEVCVPS *vps = s->vps;
>> + int ret = 0;
>> +
>> + if (vps->nb_layers != 2 || !vps->layer_id_in_nuh[1])
>> + return 0;
>> +
>> + /* decode_vps_ext() guarantees that SCALABILITY_AUXILIARY with AuxId other
>> + * than alpha cannot reach here.
>> + */
>> + ret = (s->vps->scalability_mask_flag & HEVC_SCALABILITY_AUXILIARY);
>> +
>> + av_log(s->avctx, AV_LOG_DEBUG, "Multi layer video, %s alpha video\n",
>> + ret ? "is" : "not");
>> +
>> + return ret;
>> +}
>> +
>> static int setup_multilayer(HEVCContext *s, const HEVCVPS *vps)
>> {
>> unsigned layers_active_output = 0, highest_layer;
>> @@ -473,6 +491,18 @@ static int setup_multilayer(HEVCContext *s, const HEVCVPS *vps)
>> s->layers_active_output = 1;
>> s->layers_active_decode = 1;
>>
>> + if (ff_hevc_is_alpha_video(s)) {
>> + const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
>> +
>> + if (!(desc->flags & AV_PIX_FMT_FLAG_ALPHA))
>> + return 0;
>> +
>> + s->layers_active_decode = (1 << vps->nb_layers) - 1;
>> + s->layers_active_output = 1;
>> +
>> + return 0;
>> + }
>> +
>> // nothing requested - decode base layer only
>> if (!s->nb_view_ids)
>> return 0;
>> @@ -530,6 +560,34 @@ static int setup_multilayer(HEVCContext *s, const HEVCVPS *vps)
>> return 0;
>> }
>>
>> +static enum AVPixelFormat map_to_alpha_format(HEVCContext *s,
>> + enum AVPixelFormat pix_fmt)
>> +{
>> + switch (pix_fmt) {
>> + case AV_PIX_FMT_YUV420P:
>> + case AV_PIX_FMT_YUVJ420P:
>> + return AV_PIX_FMT_YUVA420P;
>> + case AV_PIX_FMT_YUV420P10:
>> + return AV_PIX_FMT_YUVA420P10;
>> + case AV_PIX_FMT_YUV444P:
>> + return AV_PIX_FMT_YUVA444P;
>> + case AV_PIX_FMT_YUV422P:
>> + return AV_PIX_FMT_YUVA422P;
>> + case AV_PIX_FMT_YUV422P10LE:
>> + return AV_PIX_FMT_YUVA422P10LE;
>> + case AV_PIX_FMT_YUV444P10:
>> + return AV_PIX_FMT_YUVA444P10;
>> + case AV_PIX_FMT_YUV444P12:
>> + return AV_PIX_FMT_YUVA444P12;
>> + case AV_PIX_FMT_YUV422P12:
>> + return AV_PIX_FMT_YUVA422P12;
>> + default:
>> + av_log(s->avctx, AV_LOG_WARNING, "No alpha pixel format map for %s\n",
>> + av_get_pix_fmt_name(pix_fmt));
>> + return AV_PIX_FMT_NONE;
>> + }
>> +}
>> +
>> static enum AVPixelFormat get_format(HEVCContext *s, const HEVCSPS *sps)
>> {
>> #define HWACCEL_MAX (CONFIG_HEVC_DXVA2_HWACCEL + \
>> @@ -540,9 +598,13 @@ static enum AVPixelFormat get_format(HEVCContext *s, const HEVCSPS *sps)
>> CONFIG_HEVC_VIDEOTOOLBOX_HWACCEL + \
>> CONFIG_HEVC_VDPAU_HWACCEL + \
>> CONFIG_HEVC_VULKAN_HWACCEL)
>> - enum AVPixelFormat pix_fmts[HWACCEL_MAX + 2], *fmt = pix_fmts;
>> + enum AVPixelFormat pix_fmts[HWACCEL_MAX + 3], *fmt = pix_fmts;
>> + enum AVPixelFormat alpha_fmt = AV_PIX_FMT_NONE;
>> int ret;
>>
>> + if (ff_hevc_is_alpha_video(s))
>> + alpha_fmt = map_to_alpha_format(s, sps->pix_fmt);
>> +
>> switch (sps->pix_fmt) {
>> case AV_PIX_FMT_YUV420P:
>> case AV_PIX_FMT_YUVJ420P:
>> @@ -664,6 +726,8 @@ static enum AVPixelFormat get_format(HEVCContext *s, const HEVCSPS *sps)
>> break;
>> }
>>
>> + if (alpha_fmt != AV_PIX_FMT_NONE)
>> + *fmt++ = alpha_fmt;
>> *fmt++ = sps->pix_fmt;
>> *fmt = AV_PIX_FMT_NONE;
>>
>> @@ -3194,6 +3258,12 @@ static int hevc_frame_start(HEVCContext *s, HEVCLayerContext *l,
>> !sps->vui.common.video_signal_type_present_flag)
>> pix_fmt = sps_base->pix_fmt;
>>
>> + // Ignore range mismatch between base layer and alpha layer
>> + if (ff_hevc_is_alpha_video(s) &&
>> + sps_base->pix_fmt == AV_PIX_FMT_YUV420P &&
>> + pix_fmt == AV_PIX_FMT_YUVJ420P)
>> + pix_fmt = sps_base->pix_fmt;
>> +
>> if (pix_fmt != sps_base->pix_fmt ||
>> sps->width != sps_base->width ||
>> sps->height != sps_base->height) {
>> diff --git a/libavcodec/hevc/hevcdec.h b/libavcodec/hevc/hevcdec.h
>> index 4e95035688..b2b725b5cd 100644
>> --- a/libavcodec/hevc/hevcdec.h
>> +++ b/libavcodec/hevc/hevcdec.h
>> @@ -714,6 +714,8 @@ void ff_hevc_hls_residual_coding(HEVCLocalContext *lc, const HEVCPPS *pps,
>>
>> void ff_hevc_hls_mvd_coding(HEVCLocalContext *lc, int x0, int y0, int log2_cb_size);
>>
>> +int ff_hevc_is_alpha_video(const HEVCContext *s);
>> +
>> extern const uint8_t ff_hevc_qpel_extra_before[4];
>> extern const uint8_t ff_hevc_qpel_extra_after[4];
>> extern const uint8_t ff_hevc_qpel_extra[4];
>> diff --git a/libavcodec/hevc/refs.c b/libavcodec/hevc/refs.c
>> index dd7f7f95a8..da99f79742 100644
>> --- a/libavcodec/hevc/refs.c
>> +++ b/libavcodec/hevc/refs.c
>> @@ -103,7 +103,7 @@ static HEVCFrame *alloc_frame(HEVCContext *s, HEVCLayerContext *l)
>> }
>>
>> // add view ID side data if it's nontrivial
>> - if (vps->nb_layers > 1 || view_id) {
>> + if (!ff_hevc_is_alpha_video(s) && (vps->nb_layers > 1 || view_id)) {
>> HEVCSEITDRDI *tdrdi = &s->sei.tdrdi;
>> AVFrameSideData *sd = av_frame_side_data_new(&frame->f->side_data,
>> &frame->f->nb_side_data,
>> @@ -161,7 +161,16 @@ static HEVCFrame *alloc_frame(HEVCContext *s, HEVCLayerContext *l)
>> if (ret < 0)
>> goto fail;
>>
>> +
>> frame->pps = av_refstruct_ref_c(s->pps);
>> + if (l != &s->layers[0] && ff_hevc_is_alpha_video(s)) {
>> + AVFrame *alpha = frame->f;
>> + AVFrame *base = s->layers[0].cur_frame->f;
>> +
>> + av_buffer_replace(&alpha->buf[0], base->buf[3]);
>> + alpha->linesize[0] = base->linesize[3];
>> + alpha->data[0] = base->data[3];
>> + }
>
> This code seems to presume that the AVBufferRef backing data[i] is
> buf[i]. But there is no such requirement (the documentation merely
> states "All pointers in data and extended_data must point into one of
> the AVBufferRef in buf or extended_buf").
> Apart from that: Missing check for av_buffer_replace().
Fixed in v6.
>
>>
>> return frame;
>> fail:
>
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