[FFmpeg-devel] [PATCH]Support for Frame Duplication (Doubling/ Tripling) by FFMPEG's HEVC Decoder by parsing the picture_struct SEI value (Requirement: http://ffmpeg.org/pipermail/ffmpeg-devel/2019-June/245521.html)

[Hendrik Leppkes]

On Tue, Jan 7, 2020 at 12:38 PM Praveen Kumar <praveenkumar at outlook.com> wrote:
>
> Hi,
>
> This patch has the implementation for supporting frame duplication (doubling/ tripling) by FFmpeg's HEVC decoder based on the picture_structre SEI value present in the encoded video.
> picture_structure value of 7 implies doubling and 8 implies tripling. The value of picture_structure is set while encoding.
>
> This addresses the requirement mentioned in the thread http://ffmpeg.org/pipermail/ffmpeg-devel/2019-June/245521.html
>

You cannot cast a logctx to AVCodecContext (in
decode_nal_sei_pic_timing), its intentionally not passed in as a codec
context to allow it being used more more flexibly from eg. both the
decoder and the parsers.
If you need to change something in the avctx in response to this, I
recommend you do it wherever you interpret the value in
HEVCSEIPictureTiming later (ie. in parse_nal_units, apparently).

It does seem slightly odd that you are changing ticks_per_frame
without a change in the timebase or something like that, though.

- Hendrik