> On Feb 11, 2025, at 23:37, Andreas Rheinhardt
> <andreas.rheinha...@outlook.com> wrote:
>
> Zhao Zhili:
>> From: Zhao Zhili <zhiliz...@tencent.com>
>>
>> Signed-off-by: Zhao Zhili <zhiliz...@tencent.com>
>> ---
>> libavcodec/hevc/hevcdec.c | 73 ++++++++++++++++++++++++++++++++++++++-
>> libavcodec/hevc/hevcdec.h | 2 ++
>> libavcodec/hevc/refs.c | 35 ++++++++++++++++++-
>> 3 files changed, 108 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavcodec/hevc/hevcdec.c b/libavcodec/hevc/hevcdec.c
>> index e9c045f7a1..f71edf213b 100644
>> --- a/libavcodec/hevc/hevcdec.c
>> +++ b/libavcodec/hevc/hevcdec.c
>> @@ -466,6 +466,25 @@ static int export_multilayer(HEVCContext *s, const
>> HEVCVPS *vps)
>> return 0;
>> }
>>
>> +int ff_hevc_is_alpha_video(const HEVCContext *s)
>> +{
>> + 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 +492,18 @@ 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 +561,34 @@ 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 +599,13 @@ 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 +727,8 @@ 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 +3259,12 @@ 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..6f10efd0ac 100644
>> --- a/libavcodec/hevc/refs.c
>> +++ b/libavcodec/hevc/refs.c
>> @@ -79,6 +79,31 @@ void ff_hevc_flush_dpb(HEVCContext *s)
>> }
>> }
>>
>> +static int replace_alpha_plane(AVFrame *alpha, AVFrame *base)
>> +{
>> + AVBufferRef *base_a = av_frame_get_plane_buffer(base, 3);
>> + uintptr_t data = (uintptr_t)alpha->data[0];
>> + int ret;
>> +
>> + for (int i = 0; i < FF_ARRAY_ELEMS(alpha->buf) && alpha->buf[i]; i++) {
>> + AVBufferRef *buf = alpha->buf[i];
>> + uintptr_t buf_begin = (uintptr_t)buf->data;
>> +
>> + if (data >= buf_begin && data < buf_begin + buf->size) {
>> + ret = av_buffer_replace(&alpha->buf[i], base_a);
>> + if (ret < 0)
>> + return ret;
>> +
>> + alpha->linesize[0] = base->linesize[3];
>> + alpha->data[0] = base->data[3];
>> +
>> + return 0;
>> + }
>> + }
>
> Why does the decoding process actually need multiple references to the
> buffer of the alpha plane?
I’m not sure if I understand your question correctly.
1. Both the base layer and the alpha layer are decoded as yuv420p.
2. The y plane of alpha layer is actually alpha.
3. The decoder finally output yuva, not two yuv420p.
So here make y plane of alpha frame reference the alpha plane of base frame.
When output, the base frame will contain YUV and alpha from two layers.
>
>> +
>> + return AVERROR_BUG;
>> +}
>> +
>> static HEVCFrame *alloc_frame(HEVCContext *s, HEVCLayerContext *l)
>> {
>> const HEVCVPS *vps = l->sps->vps;
>> @@ -103,7 +128,7 @@ 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 +186,15 @@ 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;
>> + ret = replace_alpha_plane(alpha, base);
>> + if (ret < 0)
>> + goto fail;
>> + }
>>
>> return frame;
>> fail:
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
