Re: [linux-audio-user] command-line mp3 tools

On Thu, Apr 07, 2005 at 01:03:26PM +0200, derek holzer wrote:
> I would like to cut MP3s uploaded to a server into 2 minute sections,
> fade in the first 30 seconds, and fade out the last 30 seconds. Then I
> would like to be able to overlap the various sections so that they
> crossfade into each other using the 30 second fades. I can see that
> mpgtx will work fine for the cutting, but what about the fading and
> mixing? Are there any command-line tools to manipulate the volume of
> mp3s without converting to WAV first?

The only way to change the volume of MP3 data without
decoding/re-encoding is to change the scaling factor of each data frame.
I think this only changes it in fairly coarse steps, which would explain why
it's usually used over a whole file, not for fade-in and fade-out.

I'd do it with Audacity, but if you want command line I'd be surprised
if ecasound can't handle it.

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