Re: how to record sound to mp3
On Thu, 25 Mar 2021 19:51:42 +0100
Nicolas George <george@nsup.org> wrote:
> Greg Wooledge (12021-03-25):
> > However, this is NOT something you can do with MP3 files. They are not
> > designed to be concatenated. (Ogg Vorbis files *are*. MP3 files aren't.)
>
> It's the other way around. Pure MP3 files are just a concatenation of
> self-delimited packets, concatenation will just work.
>
> MP3 files will usually have ID3 and/or XING packets for metadata at the
> beginning or the end, concatenation will include them, and the metadata
> will be invalid, but it will not prevent the file from being played.
>
> On the other hand, Ogg files are NOT concatenable, even those that
> contain only Vorbis audio. Some player will ignore the discontinuity at
> the concatenation points, but not all.
>
> Also, let it be said that: decoding playing, recording and encoding
> audio files to concatenate them is a terrible idea, because it will lose
> quality both because of the decoding-encoding step and because of the
> numeric-analog-numeric step.
The FFmpeg wiki has some very useful information on concatenating media
files where a simple 'cat' won't work - I use its 'concat demuxer'
regularly to contatenate MP4 files (Android starts a new video file when
a 4GB limit is hit):
https://trac.ffmpeg.org/wiki/Concatenate
Celejar
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