Archive for the ‘Lossless Audio’ Category

Monkey Audio

Sunday, June 10th, 2007

Thanks to Peter Lemenkov who pointed me to this Monkey’s Audio decoder implementation. It has four strong points: GPL, C, small and clean. Oh, it also takes less memory too.

The only drawback is that old APE files are not supported (but nothing can play them on PPC anyway without x86 emulator) so I’m eager see APE support in MPlayer, Xine, VLC (or maybe it’s there already?). Preferably via libavcodec 😉

Why we should have another Monkey’s Audio decoder implementation

Sunday, March 25th, 2007

Why should I bother about Monkey’s Audio? Because many pirates good people offer classical music in this format (FLAC is quite rare and I’ve seen WavPack only once).

What I consider wrong in Monkey’s Audio design:

  • No verson compatibility – each version alters decoding process
  • Huge blocks – some megabytes is huge indeed (WavPack – 64k, FLAC – even less), hence inaccurate seeking and big memory requirements
  • “Insane” profile – if it does not decode in realtime on my CPU that is unusable

What I consider wrong in MA implementation:

  1. There is only one implementation (with two known ports)
  2. It is not endian-safe (both generated WAV headers and < 3.92 decoding)
  3. OO in that case means “Object-Obfuscated” (i.e. too many files where you can’t easily find required code)
  4. Custom license

Maybe during GSoC somebody will write easily understandable portable decoder in Lavc that will allow playback of .APE in FFplay,MPlayer,VLC,Xine,etc. Otherwise I’ll have to do it myself.

Variety of lossless audio codecs

Saturday, September 23rd, 2006

There are currently 14 lossless audio codecs mentioned on MultiMedia Wiki page (look here for further links):

  • Proprietary (Apple Lossless, Meridian Lossless Packing, Real Lossless, WMA Lossless)
  • Closed source (LA, LPAC, LTAC, OptimFROG, RK Audio)
  • Open source (Bonk, FLAC, MPEG-4 ALS, Monkey’s Audio, Shorten, TrueAudio, WavPack)

FFmpeg currently has decoders for Bonk, FLAC, Shorten, TrueAudio and Apple Lossless. So, there are at least MPEG-4 ALS, Monkey’s Audio and WavPack decoders can be added.

I will work on WavPack decoder and ALS (I hope standard will appear soon). What about Monkey’s Audio? Yes, it’s popular but it has following difficulties for implementation:

  1. It has incredibly large  frame sizes (it may be more than one million samples) while competitors stick around 64k or less (hence the compression gain for MA). Current FFmpeg design cannot handle such frames.
  2. Source code is a mess – for almost every action there are at least several if(ver >= …) or if(ver< ...). Format is too unstable for me.

Well, I still hope it will be implemented some day.