What does the FFmpeg warning "Missing picture in access unit with size x" mean?

I’ve recently updated to the most recent version of ffmpeg and now every time I edit a flv, I always get endless warnings:

[Null @ 002de180] Missing Missing picture in access unit with size xxxx (size varies per file)

[Null @ 002de180] AVC: nal size xxxx (size also varies per file)

.....

...

I’ve checked other versions too and it seems like any version above 2.1.4 will start giving these warnings.

The command I'm using is ffmpeg.exe -t 0:03:00 -y -i "C:\test.flv" -vcodec copy -acodec copy "C:\Desktop\newvid.flv" to cut sections of a video.

Even with these warnings, the output file plays fine and the video seems to be in sync. The file size is also the same as if I edit the vid with ffmpeg 2.1.4. But the versions with these warnings take much longer to encode. Any idea what is happening or what these warnings mean?

Dan

Posted 2014-07-19T23:33:44.140

Reputation: 191

I'm using 3.2 and can't replicate your problem. AVC: nal size xxxx would indicate to me that it's actually a H.264 codec but FLV should be vp6f. Not sure though. – fie – 2017-03-15T14:42:27.563

What does the FFmpeg warning "Missing picture in access unit with size x" mean?

Answers