[FFmpeg-devel] [PATCH] avformat: add AV1 RTP depacketizer and packetizer

[Tristan Matthews]

Hi,

On Monday, November 25th, 2024 at 2:29 AM, Chris Hodges <Chris.Hodges at axis.com> wrote:

> Hi Anton (sorry for the PM),
> 
> > Your mailer mangled the newlines in the patch. Consider a different
> > mailer or sending it as an attachment.
> 
> 
> Thanks for the info, had sent it with Thunderbird. Resending it as
> attachment.

I haven't done an in-depth review but I tested this locally and it's working well. I'm impressed you were able to implement the packetization without allocating scratch buffers.

One nit I'd add is that since the RTP AV1 spec is still in draft (according to https://aomediacodec.github.io/av1-rtp-spec/) this feature should probably be marked experimental as is done for VP9 in RTP, see:
https://git.ffmpeg.org/gitweb/ffmpeg.git/blob/f8e91ab05ff3d111626ab8a3b5d570865a934f07:/libavformat/rtpenc.c#l221

in which case CLI users will have to add `-strict experimental` to their options.

For the keyframe detection issue I'm not sure if this is something missing in FFMPEG's RTP stack (e.g. I've noticed that both GStreamer and libwebrtc signal that a buffer contains a keyframe at a higher level), but if not could you set it if you're dealing with a FRAME OBU of type 0 (keyframe) or 2 (intra-only)? You'd need to parse the OBU to extract that however.

Best,
Tristan