I want to cut the audio from frame 2928 to frame 5177 of a 23.976 fps blu-ray-movie.
I have read through some articles but don't see how to do that accurate.
Cutting videos at exact frames with ffmpeg select filter
How to cut at exact frames using ffmpeg?
From my point of view I have to extract the audio first:
ffmpeg.exe -i movie.mkv -map 0:1 -c:a flac -sample_fmt:a s16 audio.flac
Check if audio and video starts at the same time:
ffprobe -show_entries stream=codec_type,start_time -v 0 -of compact=p=1:nk=0 movie.mkv
stream|codec_type=video|start_time=0.000000
stream|codec_type=audio|start_time=0.000000
And cut the audio with frame/time-calculation:
ffmpeg.exe -i audio.flac -ss (2928/(24000/1001)) -to (5177/(24000/1001)) -codec flac audio_cut.flac
ffmpeg.exe -i audio.flac -ss 122.122 -to 215.9240417 -codec flac audio_cut.flac
A frame is a moment in time for video but a time slot for audio. So I have to include frame 2928 and frame 5177. But I'm not sure, where I have to start and stop the cutting.
From ffmpeg-documentation:
-ss: When used as an output option [...] decodes but discards input until the timestamps reach position.
-to: Stop writing the output or reading the input at position.
So when I want to extract audio for first frame I have to cut like this:
ffmpeg.exe -i audio.flac -ss (0/(24000/1001)) -to (1/(24000/1001)) -codec flac audio_cut.flac
With that in mind I have to cut for 2928 to 5177 like this:
ffmpeg.exe -i audio.flac -ss (2927/(24000/1001)) -to (5177/(24000/1001)) -codec flac audio_cut.flac
Is that correct?
