[Libav-user] Rotating video while transcoding

[Corey Taylor]

On Mon, Jan 15, 2018 at 4:51 PM, Davood Falahati
<falahati.davood at gmail.com> wrote:
> Dear all,
>
> I am using transcoding.c example. I want to know how should I rotate the
> video by 90 degrees. The same thing that applies with
> $ ffmpeg -i input_video -vf "transpose=1"  output_video
> in cli tool.

There doesn't seem to be many replies on this mailing list, so I hope
I can help.

You can create a filter graph and add a filter to rotate the frame.
As you are looking at examples, this is one for creating filter
graphs:

https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/filtering_video.c

You can add a rotate filter to rotate by any amount:

http://ffmpeg.org/ffmpeg-filters.html#rotate

You can also flip horizontal or vertical with specific filters.

http://ffmpeg.org/ffmpeg-filters.html#hflip