I guess the problem is that you use -vcodec copy
that says don't touch the video codec. I would just omit that argument for a full reencoding.
From the ffmpeg documentation:
Stream copy is a mode selected by supplying the copy parameter to the ‘-codec’ option. It makes ffmpeg omit the decoding and encoding step for the specified stream, so it does only demuxing and muxing. It is useful for changing the container format or modifying container-level metadata.
Please note that -vcodec
is an alias for -codec:v
that is the reason why -codec
answers you problem.