[FFmpeg-user] rotating a video losses quality

[Paul B Mahol]

On 2/13/13, Mauricio Ulargui <mulargui at hotmail.com> wrote:
> Hi, I want to rotate a video recorded with an iPhone and keep its quality.
> Below is the command that I use, but it losses quality. Suggestions?
> The file before rotating is 189,889 Kb
> The file after rotating is 78,866 Kb
>
>   ffmpeg -i "kendama.mp4" -acodec copy -vf "transpose=2" "kendama2.mp4"
>

Transcoding do affect quality.
The only way to not lose quality it to use lossless preset.