[FFmpeg-user] A query on FFmpeg's s12m timecode in H264 NVENC

[Dennis Mungai]

On Sun, 23 Feb 2025 at 03:48, Timo Rothenpieler <timo at rothenpieler.org>
wrote:

> On 22.02.2025 21:32, Dennis Mungai wrote:
> > On Sat, 22 Feb 2025 at 23:15, Timo Rothenpieler <timo at rothenpieler.org
> > <mailto:timo at rothenpieler.org>> wrote:
> >
> >     On 17.02.2025 23:45, Dennis Mungai wrote:
> >      > Hello there,
> >      >
> >      > In FFmpeg's HEVC & AV1 encoder wrappers, the private codec option
> -
> >      > s12m_tc , documented as  "Use timecode (if available)", is
> >     present, but
> >      > unmapped in the H.264 encode wrapper.
> >      >
> >      > This, however, should also be present in h264_nvenc, as indicated
> in
> >      > ffnvcodec's https://github.com/FFmpeg/nv-codec-headers/blob/
> >     master/ <https://github.com/FFmpeg/nv-codec-headers/blob/master/>
> >      > include/ffnvcodec/nvEncodeAPI.h#L2432 <https://github.com/FFmpeg/
> >     nv- <https://github.com/FFmpeg/nv->
> >      > codec-headers/blob/master/include/ffnvcodec/nvEncodeAPI.h#L2432>
> >      >
> >      > Is there a reason why this timecode SEI is omitted in h264_nvenc?
> >
> >     Those time codes are not S12M side data, they'd be a completely new
> >     thing to implement, of which I'm not sure where to source the data
> for.
> >     Not sure what exactly they are or what the difference is, but h264
> does
> >     not seem to support S12M time code sitedata, at least from looking at
> >     the lavc code.
> >
> >
> >
> > This is well noted.
> > FFmpeg  4.1 (as per the changelog) https://github.com/FFmpeg/FFmpeg/
> > blob/master/Changelog <https://github.com/FFmpeg/FFmpeg/blob/master/
> > Changelog> does support decoding S12M timecode in h264.
> >
> > Circling back to the original question(s) with your additions above:
> > 1.  Can h264_nvenc be likewise configured to emit the equivalent "s12m
> > timecode(s)" with a similar option as the av1 & hevc_nvenc encoder
> wrappers?
> > 2. Is pic timing SEI signalling implemented in h264_nvenc?
>
> Are you able to test this?
> I pushed patches to https://github.com/BtbN/FFmpeg that should in theory
> write those h264 picture timing SEI messages, but I can't find a single
> sample that includes such time codes.
>

I can test the pic-timing SEI insertion(s) in NVENC, will run a build and
report back shortly.