[FFmpeg-user] libvpx + libopus creates files with negative starttime for audio

[Mike Martin]

Hi
I have come across an oddity with transcoding files to vp9/libopus from mp4

The resulting files have a negative starttime for audio , nearly all the
time this is -.007.

I noticed it when I was concating files using demux concat and specifying
video duration

This resulted in concat operation stopping at end of first file.

Removing the duration from the conf file seems to resolve this.

Seems to be just this combination of codecs