[asterisk-users] How does format_mp3 work?

[Tony Mountifield]

In article <1329920656.2027.37.camel at localhost.localdomain>,
Ishfaq Malik <ish at pack-net.co.uk> wrote:
> Hi
> 
> I was using the Playback application to play an MP3 file after compiling
> and installing asterisk 1.8.7.0 with format_mp3 and it seems to me that
> asterisk is transcoding the file to an slin on the fly rather than
> playing the mp3 itself. Is this what it does?

Of course. You are not going to send mp3-encoded audio over a phone line,
are you? That would require an mp3 decoder in every phone.

In fact, any mp3 player is transcoding to linear on the fly, since that
is part of converting it to audio for the speaker or earphones!

What did you think was the difference between "trascoding to slin" and
"playing the mp3"?

> Also, does this mean I might as well change the format of MP3s to WAV
> seeing as I'm used to doing that anyway?

If you have the storage space available for the larger WAV files, then yes,
this would reduce the CPU consumption of playback.

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org