[Libav-user] H264 SEI Information from libavcodec/libavformat

[Alan Johnson]

Addition of the pic_timing as an SEI message as per h264 ISO-IEC14496-10.
It can be embedded as an additional NAL unit before any NAL coded slice.
Extracting the H264 bitstream to a file I can write my own parser for it to
extract SPS/PPS etc and add a NAL unit. I know x264 adds SEI User messages
as it adds system encoder information, I was wondering if there was anyway
to access the same units using the avcodec parsing routines?

I haven't looked at the SMPTE 12M - might work. Is there a way to add it?

Lance



On Fri, Jun 25, 2021 at 11:23 AM Brad Hards <bradh at frogmouth.net> wrote:

> On Friday, 25 June 2021 8:18:22 PM AEST you wrote:
>
> > On Friday, 25 June 2021 6:00:24 PM AEST Alan Johnson wrote:
>
> > > Is there anyway to add a h264 NAL (SEI Timecode) unit to an existing
>
> >>stream
>
> >
>
> > > without access libavcodec source (i.e. only linking against the DLL)?
>
> >
>
> > I don't think so.
>
> >
>
> > AFAICT, the H.264 encoders don't support SEI writing in any released
>
> > version. It should work in nvenc as of the next release. Others are a
> work
>
> > in progress.
>
> Ah, maybe I was too fast. What timecode do you want? SMPTE 12M should work
> in at least nvenc and x264.
>
> What have you tried?
>
> Brad
>
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