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 /libavutil | |
| 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 'libavutil')
| -rw-r--r-- | libavutil/film_grain_params.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/libavutil/film_grain_params.h b/libavutil/film_grain_params.h index 7350dfc5b8..f3bd0a4a6a 100644 --- a/libavutil/film_grain_params.h +++ b/libavutil/film_grain_params.h @@ -221,6 +221,9 @@ typedef struct AVFilmGrainParams { /** * Seed to use for the synthesis process, if the codec allows for it. + * + * @note For H.264, this refers to `pic_offset` as defined in + * SMPTE RDD 5-2006. */ uint64_t seed; |