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Apple Lossless Audio Codec is now open source (Apache license)
adamgibbo
post Oct 28 2011, 00:47
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QUOTE
The Apple Lossless Audio Codec (ALAC) is an audio codec developed by Apple and supported on iPhone, iPad, most iPods, Mac and iTunes. ALAC is a data compression method which reduces the size of audio files with no loss of information. A decoded ALAC stream is bit-for-bit identical to the original uncompressed audio file.



The Apple Lossless Audio Codec project contains the sources for the ALAC encoder and decoder. Also included is an example command line utility, called alacconvert, to read and write audio data to/from Core Audio Format (CAF) and WAVE files. A description of a 'magic cookie' for use with files based on the ISO base media file format (e.g. MP4 and M4A) is included as well.



The Apple Lossless Audio Codec sources are available under the Apache license. Details can be found here http://www.apache.org/licenses/LICENSE-2.0.


http://alac.macosforge.org/
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googlebot
post Oct 28 2011, 20:07
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QUOTE
The Apple Lossless Format
3 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
4
5 Apple Lossless supports the following features. Not all of these are implemented in alacconvert, though they are in the codec code provided.
6
7 1. Bit depths 16, 20, 24 and 32 bits.
8 2. Any arbitrary integer sample rate from 1 to 384,000 Hz. In theory rates up to 4,294,967,295 (2^32 - 1) Hz could be supported.
9 3. From one to eight channels are supported. Channel orders for the supported formats are described as:
10 Num Chan Order
11 1 mono
12 2 stereo (Left, Right)
13 3 MPEG 3.0 B (Center, Left, Right)
14 4 MPEG 4.0 B (Center, Left, Right, Center Surround)
15 5 MPEG 5.0 D (Center, Left, Right, Left Surround, Right Surround)
16 6 MPEG 5.1 D (Center, Left, Right, Left Surround, Right Surround, Low Frequency Effects)
17 7 Apple AAC 6.1 (Center, Left, Right, Left Surround, Right Surround, Center Surround, Low Frequency Effects)
18 8 MPEG 7.1 B (Center, Left Center, Right Center, Left, Right, Left Surround, Right Surround, Low Frequency Effects)
19 4. Packet size defaults to 4096 sample frames of audio per packet. Other packet sizes are certainly possible. However, non-default packet sizes are not guaranteed to work properly on all hardware devices that support Apple Lossless. Packets above 16,384 sample frames are not supported.


QUOTE
Within the audio domain, there are many possible subdomains. For example: low bitrate speech, high-bitrate multi-channel music, etc. FLAC itself does not target a specific subdomain but many of the default parameters of the reference encoder are tuned to CD-quality music data (i.e. 44.1kHz, 2 channel, 16 bits per sample). The effect of the encoding parameters on different kinds of audio data will be examined later. (Official FLAC FAQ)


Which one looks better?

QUOTE
The FLAC and Ogg FLAC formats themselves, and their specifications, are fully open to the public to be used for any purpose (the FLAC project reserves the right to set the FLAC specification and certify compliance).


FLAC is no industry standard. There is no committee, where interested parties could participate according to an open, defined protocol. It's just a bunch of guys who created a (good) format, gave it into the public domain, and now reserve the right to certify and shape the future of the standard.

Why should Apple accept the sovereignty of outside community developers to decide whether Apple products are FLAC compliant or not? Why should they let them decide how and when they want to support multichannel and additional bitrates and whether this breaks existing Apple compatibility. What about Apple users trying to use embedded cue-sheets with meta data, there is no unambiguous definition available.

Apple wants this to just work, without users having to think about the details. And I don't see them doing a bad job concerning ALAC.

This post has been edited by googlebot: Oct 28 2011, 20:09
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Posts in this topic
- adamgibbo   Apple Lossless Audio Codec is now open source (Apache license)   Oct 28 2011, 00:47
- - slothropean   So does this mean Apple is finally going to start ...   Oct 28 2011, 01:03
|- - kornchild2002   QUOTE (slothropean @ Oct 27 2011, 17:03) ...   Oct 29 2011, 01:37
- - kwanbis   Excellent news!   Oct 28 2011, 03:26
- - Ron Jones   This won't greatly affect Mac users, but this ...   Oct 28 2011, 05:56
|- - _mē_   Is it Apple code or something independent? QUOTE (...   Oct 28 2011, 07:41
||- - soulsearchingsun   QUOTE (_mē_ @ Oct 28 2011, 08:41) Is it A...   Oct 28 2011, 08:30
|- - Garf   QUOTE (Ron Jones @ Oct 28 2011, 06:56) Th...   Oct 28 2011, 10:37
|- - Justin Ruggles   QUOTE (Garf @ Oct 28 2011, 05:37) QUOTE (...   Oct 28 2011, 13:12
- - Larson   http://alac.macosforge.org/ the news has also bee...   Oct 28 2011, 07:55
|- - lameboy   QUOTE (Larson @ Oct 28 2011, 08:55) http:...   Oct 28 2011, 14:26
|- - tuffy   QUOTE (lameboy @ Oct 28 2011, 08:26) Some...   Oct 28 2011, 15:03
|- - Kohlrabi   QUOTE (lameboy @ Oct 28 2011, 15:26) Some...   Oct 28 2011, 15:04
|- - saratoga   QUOTE (lameboy @ Oct 28 2011, 09:26) Some...   Oct 28 2011, 18:51
|- - tuffy   QUOTE (saratoga @ Oct 28 2011, 12:51) QUO...   Oct 28 2011, 19:27
|- - Justin Ruggles   QUOTE (saratoga @ Oct 28 2011, 13:51) QUO...   Oct 28 2011, 19:36
|- - saratoga   No I mean a source for files that the current deco...   Oct 28 2011, 19:42
|- - Justin Ruggles   QUOTE (saratoga @ Oct 28 2011, 14:42) QUO...   Oct 28 2011, 20:21
|- - benski   QUOTE (saratoga @ Oct 28 2011, 14:42) No ...   Oct 28 2011, 20:42
- - spoon   Apple is trying to position ALAC as the dominant l...   Oct 28 2011, 09:34
- - Brand   This looks like nothing but a business move from A...   Oct 28 2011, 10:47
- - Agent69   Personally, I appreciate Apple doing this, regardl...   Oct 28 2011, 11:19
- - bubbleguuum   This is good news but whatever the motive of Apple...   Oct 28 2011, 13:43
- - Brand   QUOTE (bubbleguuum @ Oct 28 2011, 14:43) ...   Oct 28 2011, 14:30
- - Elbart   Next step: AirPlay. Then we're talking.   Oct 28 2011, 15:12
- - kwanbis   Come on guys, stop complaining. Whatever the reaso...   Oct 28 2011, 19:13
|- - [JAZ]   QUOTE (kwanbis @ Oct 28 2011, 20:13) Come...   Oct 28 2011, 20:17
|- - googlebot   Webkit was a BSD and LGPL project. So Apple did no...   Oct 28 2011, 21:25
|- - Garf   QUOTE (googlebot @ Oct 28 2011, 22:25) We...   Oct 29 2011, 12:08
- - googlebot   QUOTE The Apple Lossless Format 3 - - - - - - - - ...   Oct 28 2011, 20:07
- - kwanbis   Ok, then, so, what harm does it makes?   Oct 28 2011, 21:31
- - funkyblue   I'd presume if any hardware or software that h...   Oct 29 2011, 04:55
- - galad   Yes, Apple needed to publish their changes, but th...   Oct 29 2011, 13:04
|- - Garf   QUOTE (galad @ Oct 29 2011, 14:04) Yes, A...   Nov 1 2011, 15:37
- - nu774   It seems Apple's reference implementation give...   Oct 29 2011, 16:43
|- - Justin Ruggles   QUOTE (nu774 @ Oct 29 2011, 11:43) It see...   Oct 29 2011, 17:44
||- - nu774   Hi, In fact, I registered and tried it, only to se...   Oct 29 2011, 17:51
||- - Justin Ruggles   QUOTE (nu774 @ Oct 29 2011, 12:51) In fac...   Oct 29 2011, 18:33
|- - jfb   QUOTE (nu774 @ Oct 29 2011, 16:43) It see...   Nov 4 2011, 00:13
- - Aramys   Great news, I trully hope this move from Apple mea...   Nov 1 2011, 10:00
|- - Garf   QUOTE (Aramys @ Nov 1 2011, 11:00) Great ...   Nov 1 2011, 15:29
|- - Aramys   QUOTE (Garf @ Nov 1 2011, 15:29) QUOTE (A...   Nov 1 2011, 15:57
- - LosMintos   QUOTE (kwanbis @ Oct 28 2011, 20:13) A LO...   Nov 1 2011, 13:40
|- - kwanbis   QUOTE (LosMintos @ Nov 1 2011, 13:40) It ...   Nov 1 2011, 19:51
|- - saratoga   QUOTE (kwanbis @ Nov 1 2011, 14:51) QUOTE...   Nov 1 2011, 19:57
|- - kwanbis   QUOTE (saratoga @ Nov 1 2011, 19:57) You...   Nov 1 2011, 20:07
|- - saratoga   QUOTE (kwanbis @ Nov 1 2011, 15:07) QUOTE...   Nov 1 2011, 20:11
|- - kwanbis   QUOTE (saratoga @ Nov 1 2011, 20:11) Yes,...   Nov 1 2011, 20:32
|- - saratoga   QUOTE (kwanbis @ Nov 1 2011, 15:32) QUOTE...   Nov 1 2011, 20:48
||- - kwanbis   QUOTE (saratoga @ Nov 1 2011, 20:48) Well...   Nov 1 2011, 20:57
||- - saratoga   Err, you never know for sure that any code is bug ...   Nov 1 2011, 21:28
|- - marc2003   QUOTE (kwanbis @ Nov 1 2011, 19:32) Au co...   Nov 1 2011, 21:38
|- - Xenion   QUOTE (marc2003 @ Nov 1 2011, 21:38) QUOT...   Nov 4 2011, 13:26
- - googlebot   I'm pretty sure that Apple has something comin...   Nov 1 2011, 18:36
|- - Aramys   All Apple devices or whatever other brand devices ...   Nov 1 2011, 19:47
- - Elbart   QUOTE (googlebot @ Nov 1 2011, 19:36) I...   Nov 1 2011, 22:38
- - Phixion   Can anyone point me in the direction of the new op...   Nov 1 2011, 22:55
- - Gregory S. Chudov   Well, i did compile it, but the command line utili...   Nov 1 2011, 23:49
|- - kode54   QUOTE (Gregory S. Chudov @ Nov 1 2011, 15...   Nov 2 2011, 00:10
- - Gregory S. Chudov   You can check it out with SVN from here: http://sv...   Nov 2 2011, 00:25
- - Ron Jones   QUOTE (Garf @ Oct 28 2011, 02:37) This do...   Nov 4 2011, 04:28
- - spoon   Cue Microsoft in 3..2..1?   Nov 4 2011, 20:19
|- - hellokeith   QUOTE (spoon @ Nov 4 2011, 14:19) Cue Mic...   Nov 5 2011, 04:47
- - JunkieXL   You need to read this thread more closely. We are...   Nov 5 2011, 00:38
|- - saratoga   QUOTE (JunkieXL @ Nov 4 2011, 19:38) We a...   Nov 5 2011, 19:44
- - spoon   Not MS supporting alac rather to release wmal as o...   Nov 5 2011, 08:54
- - Destroid   Well, of course everything Apple is lame and Steve...   Nov 8 2011, 01:21
|- - jukkap   QUOTE (Destroid @ Nov 8 2011, 02:21) prob...   Nov 9 2011, 08:05
- - Wombat   QUOTE (Destroid @ Nov 8 2011, 02:21) Ok, ...   Nov 8 2011, 02:06
- - spoon   QUOTE Either way you look at it, there is little r...   Nov 9 2011, 10:51
- - Wombat   QUOTE (jukkap @ Nov 9 2011, 09:05) QUOTE ...   Nov 9 2011, 15:12
|- - tuffy   QUOTE (Wombat @ Nov 9 2011, 09:12) QUOTE ...   Nov 9 2011, 17:09
- - Destroid   So now the capsule summary of ALAC appears to be f...   Nov 10 2011, 09:55
- - lvqcl   Some time ago I tested several lossless encoders: ...   Nov 10 2011, 16:57
|- - Destroid   @lvqcl - I saw your post in the FB2K 1.1.10 beta t...   Nov 21 2011, 10:21
- - Wombat   QUOTE (Destroid @ Nov 10 2011, 10:55) So ...   Nov 10 2011, 17:09
- - lvqcl   Results of my lossless encoding tests: Encoding sp...   Nov 10 2011, 18:06
- - Wombat   Nice graph, thanks. To be really complete and fair...   Nov 10 2011, 19:31
- - googlebot   So about how much difference in storage costs are ...   Nov 10 2011, 22:27
- - Wombat   QUOTE (googlebot @ Nov 10 2011, 23:27) So...   Nov 10 2011, 22:37
- - bennie   Hi all, First post after lurking for a while Tha...   Nov 16 2011, 18:20
- - lvqcl   BTW, refalac 0.12 decoding speed: 198x realtime.   Nov 21 2011, 15:56
- - Peter   Sadly this new decoder has multiple security issue...   Nov 22 2011, 09:19
|- - Justin Ruggles   Concerning what Apple had to gain from open sourci...   Nov 22 2011, 13:54
- - neovibe   Hi all, I am a big user of CUETools + libalac (to...   Dec 9 2011, 13:59
|- - tuffy   QUOTE (neovibe @ Dec 9 2011, 06:59) I am ...   Dec 9 2011, 14:36
- - Wombat   QUOTE (neovibe @ Dec 9 2011, 14:59) Hi al...   Dec 9 2011, 14:58
|- - neovibe   QUOTE (Wombat @ Dec 9 2011, 13:58) I may ...   Dec 9 2011, 15:59
- - Wombat   QUOTE (neovibe @ Dec 9 2011, 16:59) QUOTE...   Dec 9 2011, 16:34
- - Peter   I've published my bug-fixed version of Apple...   Dec 10 2011, 15:36
|- - nu774   QUOTE (Peter @ Dec 10 2011, 23:36) I...   Dec 10 2011, 16:26
||- - Peter   QUOTE (nu774 @ Dec 10 2011, 16:26) By the...   Dec 10 2011, 16:29
|- - jukkap   QUOTE (Peter @ Dec 10 2011, 16:36) I...   Dec 21 2011, 11:41
- - kode54   To save 5 seconds of Googling, here's a refere...   Dec 10 2011, 21:21
- - nu774   Have found another bug in Apple implementation. ht...   Dec 21 2011, 06:34
- - k.eight.a   I've read the whole thread. I thought I'd ...   Sep 30 2012, 16:21
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