print warning for "-c:v copy" + "-ss non-key-frame"
|Reported by:||Hans Henrik Bergan||Owned by:|
|Blocking:||Reproduced by developer:||no|
|Analyzed by developer:||no|
as explained in comment 1 of https://trac.ffmpeg.org/ticket/7640#comment:1 , if you cut a video using
-c:v copy +
-ss and the frame at -ss is not a keyframe, then everything until the first keyframe is usually rendered black / random colors. it would be nice if ffmpeg printed a stderr warning in this scenario, warning that the black/random-color frames are expected behavior and not a bug in ffmpeg.