[FFmpeg-user] Rotating webm videos

[Moritz Barsnick]

On Sat, Mar 23, 2019 at 19:33:22 +0900, Rex East wrote:
> I tried this command:
> ffmpeg -i input.webm -vf “transpose=1” -t 20 output.webm
> But this re-encodes the video (slow) and there is noticeable quality loss.

Regarding the quality loss: Then apparently, ffmpeg's encoding defaults
are too low for your material. You need to choose a higher bitrate or
encoding quality:

https://trac.ffmpeg.org/wiki/Encode/VP9#constantq

(Assuming your ffmpeg supports and therefore uses libvpx-vp9. If you
show us your complete console output, we would know.)

Cheers,
Moritz