convert FLAC to ALAC

[CNLiberal]

I have some FLAC files that I'd like to play on my iPod but I don't want to change the firmware on my iPod. My iPod currently connects to the stereo in my SUV through a specialzed iPod connector that Alpine made. Is there a way to convert FLAC files to ALAC (Apple Lossless Audio Codec) so I can transfer the songs to my iPod via gtkpod or Songbird? Thanks!

Jim

[cozmicharlie]

There is a lot of confusion concerning Apple Lossless (ALAC). Many think .m4a is the same but it is not. Part of the confusion lies in the fact that ALAC has a .m4a extension like AAC but it is not AAC. In reality though what you get from the Apple store is really aac. The codec has been reversed engineered and you can get an ALAC decoder through Synaptic. But, I don't know of any transcoders for ALAC. I would recommend aac of which there are a number of good transcoder. aacplusenc is one of the best transcoders for aac (http://ubuntuforums.org/showthread.p...ght=aacplusenc). It is available in Synaptic or via a deb file. PACPL (http://ubuntuforums.org/showthread.p...ighlight=pacpl) is also excellent and uses the aacplusenc transcoder - the advantage of PACPL is you can integrate it in to Amarok. If you want a gui then SoundKonverter (with a k not a c) is the best IMHO - you can install it from Synaptic. These will all transcode your flac files to high quality aac that can be played on your ipod. You will also want to install gtkpod-aac.

Enjoy

[CNLiberal]

Thanks for your reply cozmicharlie!

It's sounding like nobody cares about lossless audio on their iPod using Linux? I'd really like to start using lossless. Anyone else know of an answer? Thanks!

[cozmicharlie]

Actually, I think most do care about lossless. That's why you read a lot of posts in the forums recommending Rockbox (I run Rockbox on my ipod). I would recommend Rockbox also, but you mentioned that do not want to change the native firmware so your options are limited.

Someone else may have a some suggestions though.

Enjoy

[CNLiberal]

Yeah, I only wish that Rockbox worked with my Alpine KCA-420i. I've read the Rockbox forums and they say they can't get it working, mostly because no one has one and is willing to put in the time. I know nothing about programming so I'm relatively worthless.

[cozmicharlie]

Thats too bad. I think the best you can do is use aac (that is really what you get when you buy Apple Lossless from itunes). Use the aacplusenc transcoder (it is better than faac). The quality should be just as good as Apple Lossless.

[jimav]

ALAC is *not* a variant of AAC. They use the same MP4 container (probably why both types of files use the .m4a extension), which causes confusion.

ALAC is a completely different (and lossless) compression algorithm. In contrast, AAC is a lossy compression scheme conceptually similar to MP3.

See http://en.wikipedia.org/wiki/Apple_Lossless

So encoding our FLAC files as AAC will result in loss of quality.

What is needed is a true ALAC encoder for linux. Does anyone have info on such a thing?

[andrew.46]

Hi jimav,

What is needed is a true ALAC encoder for linux. Does anyone have info on such a thing?

Looks like FFmpeg can decode/encode alac:

andrew@skamandros~$ ffmpeg -formats | grep alac
FFmpeg version SVN-r20529, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  built on Nov 13 2009 10:20:28 with gcc 4.3.3
  configuration: --prefix=/usr --mandir=/usr/man --disable-debug 
--enable-shared --disable-static --enable-postproc --enable-avfilter
 --enable-pthreads --enable-libtheora --enable-libvorbis --enable-x11grab
 --enable-libmp3lame --enable-libx264 --enable-libschroedinger 
--enable-libfaac --enable-libfaad --enable-libopencore-amrnb 
--enable-libopencore-amrwb --enable-version3 --enable-libspeex --enable-zlib 
--enable-nonfree --enable-gpl
  libavutil     50. 4. 0 / 50. 4. 0
  libavcodec    52.41. 0 / 52.41. 0
  libavformat   52.39. 2 / 52.39. 2
  libavdevice   52. 2. 0 / 52. 2. 0
  libavfilter    1. 8. 0 /  1. 8. 0
  libswscale     0. 7. 1 /  0. 7. 1
  libpostproc   51. 2. 0 / 51. 2. 0
 DEA    alac            ALAC (Apple Lossless Audio Codec)

But I will admit I have never had the need to experiment with this codec so I cannot suggest specific syntax.

Andrew

[mc4man]

Was actually tring this the other day in response to something, basically just
ffmpeg -i <input> -acodec alac <output>.m4a

Did a number of compares, re-encodes, re-re-encodes, ect. seemed just fine

Otherwise install dBpoweramp in wine (to some extent free for 30 days)

[jimav]

Thanks for the pointer to ffmpeg!

I tried a round-trip encode/decode using ffmpeg + alac-decoder and got back a .wav file of exactly the same length as the original one, but different contents. The diffs start at byte 5, so I suspect the headers differ, maybe because I need some decode options to make the same kind of .wav file (?). However the 'file' command says they are the same format.

Does anyone see why this test fails?

+ ffmpeg -i original.wav -acodec alac new.m4a
+ alac-decoder -f recreated.wav new.m4a
+ file original.wav recreated.wav new.m4a
original.wav:  RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
recreated.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
new.m4a:       ISO Media, MPEG v4 system, iTunes AAC-LC

+ ls -l original.wav recreated.wav new.m4a
-rw-r--r-- 1 jima jima 91673948 2009-11-06 17:49 original.wav
-rw-r--r-- 1 jima jima 91673948 2009-12-29 00:25 recreated.wav
-rw-r--r-- 1 jima jima 60855313 2009-12-29 00:25 new.m4a
+ cmp original.wav recreated.wav
original.wav recreated.wav differ: byte 5, line 1