[FFmpeg-user] Accurate Trimming Without Transcoding

[Robert Nagy]

Is it possible to achieve frame accurate trimming of clips without
transcoding?

e.g. if I have a 50 fps file with a fixed gop of 50 frames and I'd like to
trim the first 24 frames without transcoding. Shouldn't ffmpeg simply
generate a remuxed file with a startTime of 0.48s and a duration adjusted
accordingly?

Is this possible to achieve?

I've tried:

ffmpeg -ss 0.48 -i in.mxf -c copy out.mxf

However, this produces a file with startTime 0. Which isn't correct...