[FFmpeg-soc] ALAC Testing Report

[Mike Melanson]

Hi,

At Jai's behest, I have started to test the ALAC encoder. I am using a 
test suite consisting of 13 "open source" music tracks that come from a 
CD called OpenMusic that I received at LinuxTag 2007. I actually like 2 
of the songs. Plus, they present varying types of music and sounds. I 
will post a link as soon as I can get all the raw CD rips uploaded to my 
server.

Anyway, here's the first report:

02-JeffreyAltergott-IcarusGrounded.wav
       original WAV file size: 46,673,132 bytes
Jai-2008-06-08 compresses to: 41,669,860 bytes
         iTunes compresses to: 29,451,331 bytes

So, clearly, the compression factor is a work in progress. That's 
understood. For the interoperability report:

works in Windows/QT Player 7.4.5 (latest)
works in Windows/iTunes 7.6.2.9 (latest)
*doesn't work* on my iPod Touch

Methodology:

   ffmpeg -i <source.wav> -acodec alac dest.mov

Problem: Specifying either dest.mp4 or dest.m4a does not work. It 
should. ALAC is supposed to be encapsulated in these formats and not in 
.mov, although that obviously works for iTunes and QT Player. I don't 
think the iPod firmware understands ALAC in MOV (although iTunes 
cheerfully transferred it).

Great start. The rest of you: Let the group know when your stuff is 
ready to get pounded on.

-- 
	-Mike Melanson