Rotate and scale params don't use transcoding and change video using metadata.

[harryqt]

On Readme file, it is stated:

PS. Rotate and scale params don't use transcoding and change video using metadata.

But upon my testing, rotation actually done by using -vf transpose=1 which requires re-encoding.

I've a RTSP stream, I wanted to rotate the stream without re-encoding (by avoid using -vf transpose=1)

rotate: ffmpeg:rtsp://12345678@192.168.1.123/av_stream/ch0#video=h264#rotate=90

^ this re-encode stream, which is CPU-intensive :(

Is there any way to rotate stream without re-encoding?

Something like -metadata:s:v rotate=-90 (old ffmpeg) or -display_rotation:v:0 -90 (new ffmpeg) ?

I tried these but did not work. :(

[AlexxIT]

The problem with the metadata rotate is compatibility. This works in some streaming technologies and in some browsers. Not all of them. Go2rtc support this only for stream.mp4 as query param ?rotate=90.