All Audio Codecs That Play On Zaurus?

[TonyOlsen]

What are all of the audio codecs that are supported under Zaurus?

So far I know of:

• MP3 (MPEG-Layer 3) - plays on default audio player and most (all?) audio players
• WAV (Uncompressed) - *gag*
• OGG (Ogg Vorbis) - plays on "MediaPlayer" after installing special plugin

OGG is roughly twice as good as MP3, but neither of them are very good at doing what I need.  I have many audio books I want to listen to on my Zaurus.  Previous to my Zaurus I used 5 kbps RealAudio and/or 5 kbps Windows Audio.  MP3s can only go down to 16 kbps (and most encoders can only go down to 32 kbps).  Ogg Vorbis can only go down to 9 kbps (and forces the file to remain stereo), and even this is only possible if I encode the audio file to an 8 KHz uncompressed WAV file and then encode OGG using the lowest audio quality (this is the solution I'm currently using and the quality is fine for audio books... but it is a waste since it requires stereo even though the source is in mono).

Are there other audio codecs that are supported under the Zaurus through any means, hacks, installations, etc?

OR...

Is there a way to encode MONO OGG files (so I can get down to 4-5 kbps?)

[chrget]

What are all of the audio codecs that are supported under Zaurus?

[...]

Are there other audio codecs that are supported under the Zaurus through any means, hacks, installations, etc?

OR...

Is there a way to encode MONO OGG files (so I can get down to 4-5 kbps?)

There are other codecs that can be built for playback on the Zaurus -- as for how/where to incorporate them into existing player programs, I certainly won't touch that

For one, there is FAAD2, which builds just fine on the Z and provides it with AAC decoding abilities. But even AAC doesn't perform all that well when it comes to the bitrates you are shooting for.

As you have noticed, Vorbis is not designed for that kind of operation either. For this, the Xiph.Org people offer Speex (look here for details), which is designed as a low bitrate speech codec which easily goes down to the bitrates you are targeting.

The only other codec that comes to mind with that kind of performance would be AMR -- but not only are there patent issues involved, but the status of the available source code (i.e. the reference implementation) is unclear with regard to licensing. It can be built on the Z though and does work well enough in the appropriate context.

So my recommendation would be to use Speex. The minimum playback application is provided with the source code, and it should quite easily integrate into VLC, MPlayer and who knows which other players that can be built for the Zaurus.

Hope this helps.

Best regards,
Chris.

[TonyOlsen]

Thanks! :-)  So... what's the next step?  Who has the know-how to encorporate this new codec into an existing Zaurus Media Player? ...or a stand-alone player (if that's easier to do).

Also, is the Windows Media Audio (WMA) available to be recompiled for the Zaurus?  WMA appears to have the best audio quality per kpbs which I've seen so far.  (RealAudio would come in second, and OGG third... of the codecs I'm familiar with so far)

[chrget]

So... what's the next step?  Who has the know-how to encorporate this new codec into an existing Zaurus Media Player? ...or a stand-alone player (if that's easier to do).

As I mentioned, the standard Speex distribution includes a minimal (read: command line) player program. Simply building it will provide you (amongst other things) with speexdec, which will decode or play back .spx files.

I'm attaching a speexdec binary with a couple of .spx files for evaluation. For playback, just open a console window and run the speexdec binary from there, giving it the .spx file as an argument, e.g.

Code: [Select]

speexdec ex_6_kbps.spx
This should give you an idea what to expect with Speex at really low bitrates.

Also, is the Windows Media Audio (WMA) available to be recompiled for the Zaurus?  WMA appears to have the best audio quality per kpbs which I've seen so far.  (RealAudio would come in second, and OGG third... of the codecs I'm familiar with so far)

Both WMA and Real are proprietary, closed source frameworks, and while by now both can be licensed, the cost of doing so will probably prohibit even commercial Zaurus developers from doing so, since the critical mass just isn't there. Please also note that both of these are usually not a codec, but rather a collection, with the appropriate one (usually) automatically chosen by the framework based on the source material.

Best regards,
Chris.

[TonyOlsen]

Speex Audio Codec

Awesome!!   I downloaded the attachment above and played the audio samples using the suplied Speex decoder you compiled.

The next step would be to somehow get the codec integrated into some kind of GUI media player with playlists (for an entire book with series' of chapters)

Since Speex is made by the same people who made Ogg Vorbis, I'm assuming that anyone who knows how to integrate Ogg Vorbis could somewhat easily also integrate Speex.

I looked at the Zaurus Software Index (killefiz.de) and found that the latest versions of the following programs support ogg-vorbis:

• mplayer
• NPlayer
• Opie Player 2
• media player vorbis-plugin (this is what I'm currently using)
• X Multimedia System

I'm guessing that any of these could also include the Speex codec.

One of the VOIP programs LinPhone already recognizes Speex, but it doesn't look like it could simply play files directly.

Are any of the developers of any of the applications listed above (or any others I failed to mention) reading this who could add Speex to the next version of their software (or as an upgrade patch)?

That would be awesome!

4 kpbs audio books on the Zaurus!  Now THAT's what I'm talking about!      

[chrget]

Awesome!!   I downloaded the attachment above and played the audio samples using the suplied Speex decoder you compiled.

Glad to see it worked for you. The executable is just taken from a straightforward cross-compile of the standard speex-1.1.6 distribution, statically linked together with a regular libogg-1.1 library built the very same way using the good(?) old Embedix crosscompiler provided by Sharp

The quality of the samples may not be the best, though, since ( a ) I was too lazy to build 1.1.6 for my Desktop and used my existing speex 1.0.3 installation and ( b ) used some old 16 kBps RealAudio source as input, since it was the only thing that I had lying around that was pure speech without some sort of music mixed in. My guess is that using a better quality source the result might even be better.

[...] found that the latest versions of the following programs support ogg-vorbis:

• mplayer
  
• NPlayer
  
• Opie Player 2
  
• media player vorbis-plugin (this is what I'm currently using)
  
• X Multimedia System

AFAIK MPlayer does not integrate speex yet, but my guess is that it eventually will, since people are asking for it on the mailing lists. There is a speex plugin available for XMMS, so it should be a simple task to build it for someone who has an XMMS development environment set up for the Z.

Since I've decided to tinker with VLC, I can only say that speex does integrate nicely there (actually I did build myself a speex-capable version of VLC just yesterday, hence my quick response with the binary  ) -- unfortunately there still seems to be an issue with VLC playing back 8kHz audio on the Z (dropouts on playback, seemingly independant from the codec used; I'll have to look into that and/or pester some of the VLC people about that when I get the time to do so  ).

4 kpbs audio books on the Zaurus!  Now THAT's what I'm talking about!     

Well, hopefully you'll find someone who shares your enthusiasm

Best regards,
Chris.

[TonyOlsen]

One thing I noticed on the Version 1.0.3 binary posted above is that it cuts off the last 1-3 seconds of each audio file.  I compared this with the x86 Version 1.0.4 executable I downloaded from the speex website and it correctly palyed the last 1-3 seconds.  I suspect it could be a audio buffer type of bug in version 1.0.3.

How stable is 1.0.16?

[chrget]

One thing I noticed on the Version 1.0.3 binary posted above is that it cuts off the last 1-3 seconds of each audio file.  I compared this with the x86 Version 1.0.4 executable I downloaded from the speex website and it correctly palyed the last 1-3 seconds.  I suspect it could be a audio buffer type of bug in version 1.0.3.

How stable is 1.0.16?

Uhm, slight misunderstanding here: the executable attached above is in fact built from 1.1.6 (see speexdec -v); the encoder I used to create the samples was the 1.0.3 version that I still had on my desktop.

I haven't noticed anything amiss with that version so far, but then again I am just an occasional user -- my main focus is on MP4 and 3GP playback, and I just looked into Speex to compare it to AMR and played around with it a bit. So I can't as of yet make any statements w/regard to stability or bugs.

I'll re-check as soon as I get a chance to do so.

Best regards,
Chris.

[TonyOlsen]

Ah... got it.  Sorry for not catching that.

The spx files I was testing I created using SpeexEnc Version 1.0.4.

What are the pro's and con's of the MP4, 3GP, and AMR codecs?  Which one is the best for what?

Thanks again!

[chrget]

What are the pro's and con's of the MP4, 3GP, and AMR codecs?  Which one is the best for what?

MP4 and 3GP are not codecs but rather containers (with 3GP being a restricted subset of MP4 for use on mobile phones). Both belong to the MPEG-4 framework and can contain Audio, Video and who knows what else

The elementary streams within can be encoded using a variety of codecs (MP4V, H.261, H.263 or H.264 aka AVC for video and MP3, AAC-LC, -HE or AMR for audio), depending on the playback device one is targetting.

AMR is the (kinda) new kid on the block when it comes to speech compression especially with mobile phones, whereas AAC-LC is more or less the MPEG-4 successor of MP3, i.e. a general purpose audio codec. AAC-HE is the low bitrate variant of AAC, using SBR to achieve better sound quality at lower bitrates (so technically speaking it would me MPEG-4's equivalent of MP3pro).

Best regards,
Chris.

[steliosx]

tony for such advanced audio encoding information you could consider a specialists' resource site, the one I'm using regularly is: www.hydrogenaudio.org , which is really a huge resource; dont take my word for it, just try a search on the subjects you are interested in