Segmenting .flac files with ffmpeg truncates audio but not file length-CodePudding

I am trying to get Twitter spaces audio (.ts) files into a format I can easily edit, on OSX.

So far I was able to convert the files in bulk to .flac with this:

for i in *.ts;
do name=`echo "$i" | cut -d'.' -f1`
echo "$name"
ffmpeg -i "$i" -sample_fmt s16 -ar 41000 "${name}.flac"
done

That worked, and reduced the file sizes somewhat, but.. Because most of the files are around 7 hours long, my editor of choice cannot process that much audio in one file.

So I looked around and was able to find this command to segment the files into 3hr long sections.

ffmpeg -i space-1OdKrBealBqKX_0.flac -map 0 -f segment -segment_time 10800 -c copy space-1OdKrBealBqKX_0__d.flac

This works, but each file contains as much empty / silent space at the end as the orginal file. That's going to be a problem for sharing with a team that will help edit these files, as each file has the original file's length and file size. There are a lot of files. The audio segments and naming did work though.

How to truncate the actual length of the file to the audio segment?

Caveat: I am no expert on any of these matters, I just managed to google and get this far, so if someone knows and wants to provide working code that would be very much appreciated!

CodePudding user response：

FLAC files contain metadata of stream duration. When streamcopying, ffmpeg cannot overwrite that metadata, so it is retained.

Your workaround is to segment in the original step.

ffmpeg -i "$i" -sample_fmt s16 -ar 44100 -f segment -segment_time 10800 "${name}__d.flac"