Speex dev - Jul 2008 - Noise problem while encoding and decoding

Hi, everyone!

I'm a newbie of speex develog. I tried to encode and decode with the
sample program in the speex manual. I compile those program with

    gcc sampleenc.c -o enc -lspeex
    gcc sampledec.c -o dec -lspeex

I run these two program in this way and then speak loudly:
    ./enc /dev/dsp ? ./dec /dev/dsp

I thought I would hear my voice. However, what i heard was a lot of
noise. I can hardly recognize my voice.

Then I tried in another way.

cat /dev/dsp > from
./enc from ? ./dec to
cat to > /dev/dsp

But still the same.

However, the voice  is very clear if I run the following command:
cat from > /dev/dsp

I am really confused. Would you please help me? My OS is Fedora8.
Speex Version is speex-1.2beta3.

Thanks a lot!

Oov

On Sat, Jul 19, 2008 at 12:29 PM, ???? <oovoov008 at gmail.com>
wrote:
> Hi, everyone!
>
> I'm a newbie of speex develog. I tried to encode and decode with the
> sample program in the speex manual. I compile those program with
>
>    gcc sampleenc.c -o enc -lspeex
>    gcc sampledec.c -o dec -lspeex
>
> I run these two program in this way and then speak loudly:
>    ./enc /dev/dsp ? ./dec /dev/dsp
/dev/dsp is a raw device that does not include any format headers.
There's no way for the encoder to guess reliably the format of the
incoming data, and the defaults assumed by the two don't match.  Very
likely the same for playback; the playback device simply assumes some
input format and if you pipe data to it, there's no format setup at
all.

All the settings have to agree, and you have to declare them
explicitly because you're using raw devices.  Or use actual programs
for record and playback that properly header their data.
> However, the voice  is very clear if I run the following command:
> cat from > /dev/dsp
Sure, because the input and output defaults from the raw devices
match.  If, however, you try to import that data in any audio editor
or manipulation program, it would say 'huh?'.

My guess: The default is 8000Hz mono no idea is 8 or 16 bit.

Monty

Thank you for your reply! But the problem has not been solved yet.

I thought these two programs are designed for raw devices. In Page36
of "TheSpeexCodecManual Version1.2Beta3", it sais:
"
This section shows sample code for encoding and decoding speech using
the Speex API. The commands can be used to encode
    and decode a file by calling:
    % sampleenc in_file.sw | sampledec out_file.sw
    where both files are raw (no header) files encoded at 16 bits per
sample (in the machine natural endianness).
"
Because the programs don't work, so I modify part of the code. I
change the type of "in " and "out" from "short" to
"char". The reason
i make this modify is that i found /dev/dsp encoded at 8 bits per
sample. I also modify relevant file operation. But the problem is
still there. I also tried "unsigned char", but still the same.



2008/7/20, xiphmont at xiph.org <xiphmont at
xiph.org>:
> On Sat, Jul 19, 2008 at 12:29 PM, ???? <oovoov008 at gmail.com>
wrote:
> > Hi, everyone!
> >
> > I'm a newbie of speex develog. I tried to encode and decode with
the
> > sample program in the speex manual. I compile those program with
> >
> >    gcc sampleenc.c -o enc -lspeex
> >    gcc sampledec.c -o dec -lspeex
> >
> > I run these two program in this way and then speak loudly:
> >    ./enc /dev/dsp ? ./dec /dev/dsp
>
> /dev/dsp is a raw device that does not include any format headers.
> There's no way for the encoder to guess reliably the format of the
> incoming data, and the defaults assumed by the two don't match.  Very
> likely the same for playback; the playback device simply assumes some
> input format and if you pipe data to it, there's no format setup at
> all.
>
> All the settings have to agree, and you have to declare them
> explicitly because you're using raw devices.  Or use actual programs
> for record and playback that properly header their data.
>
> > However, the voice  is very clear if I run the following command:
> > cat from > /dev/dsp
>
> Sure, because the input and output defaults from the raw devices
> match.  If, however, you try to import that data in any audio editor
> or manipulation program, it would say 'huh?'.
>
> My guess: The default is 8000Hz mono no idea is 8 or 16 bit.
>
> Monty
>