[speex-dev] RE: [speex-dev] Difference in Encoding of files on Pocket PCvis-?-vis desktop

[Conrad Parker]

Dude,

what jean-marc was getting at is that it sounds like you've got a symmetric
bug in both your encoder and decoder.

To be a valid speex decoder, your decoder *must* be able to play files that
were encoded with speexenc on your desktop. There's no such thing as
different files on different platforms -- the same files work everywhere,
that's the whole point of a standard file format.

So, what's probably happening is that your encoder is doing something wrong,
and producing an incorrect file; and your decoder is also making exactly
the same mistake, but in reverse, which means that as it decodes, it
ends up producing the original audio. So, it appears to you that you can
encode and decode, but in fact the files that you are creating are bad.

Jean-Marc pointed to typical sources of this kind of problem -- endianness
(eg. you're not defining the endianness of your Pocket PC platform properly
when building libspeex), and word size (ie. you're assuming an incorrect
word size during both encode and decode).

You have bugs in your encoder and decoder, probably due to your build
process.

The speex files you create on your desktop are correct, and your Pocket PC
decoder is buggy if it cannot play them.

Conrad.

On Tue, May 25, 2004 at 01:20:26PM +0530, Asheesh Vashishtha wrote:
> Hello Jean-Marc,
> 
> I encoded a 143 kb file on both the desktop as well as the Pocket PC using the default settings/
> Here are the results.
> 
> Size : Desktop - 17.6 Kb, Pocket PC -17.1 kb (not much difference in size)
> 
> Now when I try to decode the file encoded on the Pocket PC, I get a message
> "This doesn't look like a Speex file". However, when I decode the Pocket PC encoded file on Pocket PC, it plays fine.
> 
> Same applies for the file encoded on the desktop. If I decode the desktop encoded file on Pocket PC, I get a completely
> broken sound that is totally indecipherable, but it plays fine when decoded on the desktop.
> 
> Isn't it possible to decode a desktop encoded file on Pocket PC? 
> Do I have to make change some settings?
> 
> Thanks a lot for your help.
> 
> Thanks & regards,
> Asheesh
> 
> 
> 
> -----Original Message-----
> From: Jean-Marc Valin [mailto:Jean-Marc.Valin at USherbrooke.ca]
> Sent: Monday, May 24, 2004 10:06 PM
> To: speex; Asheesh Vashishtha
> Subject: Re: [speex-dev] Difference in Encoding of files on Pocket
> PCvis-?-vis desktop
> 
> 
> Hi,
> 
> I suspect something related to endianness or word size here. Can you
> check that the encoded files end up the same size? Also, what if you
> encode on the Pocket PC and decode on a desktop? Maybe if you encode a
> small wav file on both pocket PC and desktop using default options and
> send me the results.
> 
> 	Jean-Marc
> 
> Le lun 24/05/2004 ? 09:52, Asheesh Vashishtha a ?crit :
> > Hi all,
> > 
> > I've  created a Speex decoder for Pocket PC so that I can play Speex
> > files from within my .NET CF app. 
> > But there has been a problem while playing the files on my Pocket PC. 
> > 
> > I encode a wav file on the desktop using Speexenc.exe (Speex- 1.1.5)
> > and then copy this file to my Pocket PC where
> > I playback using my decoder library. But the sound quality is
> > extremely poor and completely broken. 
> > 
> > I can't make a word out of the encoded speex file. However, if I
> > encode the Speex file using the code 
> > on my iPAQ and playback the same file using the decoder library, I get
> > a pretty decent sound.
> > 
> > My approach is to simply bundle the encoded speex files with my
> > application since I only need to use
> > the decoding part, and play back the output to the device but somehow
> > the 2 files sound so different.
> > 
> > Is there some difference with a wav file encoded on the desktop to
> > that on the Pocket PC? 
> > Can't I use the wav file encoded on the desktop directly with my
> > Pocket PC decoder?
> > 
> > I'd really appreciate if anyone could shed some light on this. 
> > 
> > Thanks & regards,
> > Asheesh
> > 
> -- 
> Jean-Marc Valin
> http://www.xiph.org/~jm/
> LABORIUS
> Universit? de Sherbrooke, Qu?bec, Canada
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