diff options
| author | Niklas Haas <git@haasn.dev> | 2021-08-17 21:25:31 +0200 |
|---|---|---|
| committer | James Almer <jamrial@gmail.com> | 2021-08-24 09:58:52 -0300 |
| commit | cf37c3fb6c84d8eb61079520b4c57e3c969bc25d (patch) | |
| tree | d449ba2158a00e4f606f1ce9faea50811ee32086 /libavcodec/h264_slice.c | |
| parent | 61b38f7aef8d2f34135eb6a1e1e637d4fef667d2 (diff) | |
avcodec/h264_slice: compute and export film grain seed
From SMPTE RDD 5-2006, the grain seed is to be computed from the
following definition of `pic_offset`:
> When decoding H.264 | MPEG-4 AVC bitstreams, pic_offset is defined as
> follows:
> - pic_offset = PicOrderCnt(CurrPic) + (PicOrderCnt_offset << 5)
> where:
> - PicOrderCnt(CurrPic) is the picture order count of the current frame,
> which shall be derived from [the video stream].
>
> - PicOrderCnt_offset is set to idr_pic_id on IDR frames. idr_pic_id
> shall be read from the slice header of [the video stream]. On non-IDR I
> frames, PicOrderCnt_offset is set to 0. A frame shall be classified as I
> frame when all its slices are I slices, which may be optionally
> designated by setting primary_pic_type to 0 in the access delimiter NAL
> unit. Otherwise, PicOrderCnt_offset it not changed. PicOrderCnt_offset is
> updated in decoding order.
Co-authored-by: James Almer <jamrial@gmail.com>
Signed-off-by: Niklas Haas <git@haasn.dev>
Signed-off-by: James Almer <jamrial@gmail.com>
Diffstat (limited to 'libavcodec/h264_slice.c')
| -rw-r--r-- | libavcodec/h264_slice.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c index 0d7107d455..9244d2d5dd 100644 --- a/libavcodec/h264_slice.c +++ b/libavcodec/h264_slice.c @@ -406,6 +406,7 @@ int ff_h264_update_thread_context(AVCodecContext *dst, h->next_output_pic = h1->next_output_pic; h->next_outputed_poc = h1->next_outputed_poc; + h->poc_offset = h1->poc_offset; memcpy(h->mmco, h1->mmco, sizeof(h->mmco)); h->nb_mmco = h1->nb_mmco; @@ -1335,6 +1336,7 @@ static int h264_export_frame_props(H264Context *h) return AVERROR(ENOMEM); fgp->type = AV_FILM_GRAIN_PARAMS_H274; + fgp->seed = cur->poc + (h->poc_offset << 5); fgp->codec.h274.model_id = fgc->model_id; if (fgc->separate_colour_description_present_flag) { @@ -1543,6 +1545,11 @@ static int h264_field_start(H264Context *h, const H264SliceContext *sl, h->poc.delta_poc[0] = sl->delta_poc[0]; h->poc.delta_poc[1] = sl->delta_poc[1]; + if (nal->type == H264_NAL_IDR_SLICE) + h->poc_offset = sl->idr_pic_id; + else if (h->picture_intra_only) + h->poc_offset = 0; + /* Shorten frame num gaps so we don't have to allocate reference * frames just to throw them away */ if (h->poc.frame_num != h->poc.prev_frame_num) { @@ -1891,7 +1898,7 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl, } if (nal->type == H264_NAL_IDR_SLICE) - get_ue_golomb_long(&sl->gb); /* idr_pic_id */ + sl->idr_pic_id = get_ue_golomb_long(&sl->gb); sl->poc_lsb = 0; sl->delta_poc_bottom = 0; |