Advanced Linux Sound Architecture

On Tue, 26 Oct 2010 00:00:07 +0100
Wojciech Bober <wojciech.bober@...> wrote:

> Hi all,
> 
> I'm trying to build mp3 jukebox out of Efika, which is an embedded
> MPC5200 based board. I got to the stage where I'm able to play a wav
> file using aplay. But when I try to play an mp3 using mpg123 it
> freezes after decoding a few frames. I spent a few hours trying to get
> this work, but I'm slowly running out of ideas.   I'm running crux 2.6
>

[snip]

I think you should "slower your pace". I.e. being in your shoes I would
first try to verify that mpg123 _decoder_ works, leaving ALSA out of the
picture for a time being.

To do the verification I would try to convert MP3 file into WAV file, then
I would try to check how the WAV files plays/sounds - the latter maybe (also
in a different computer.

If/when it's verified the decoding part work, then the ALSA issues can be
dealt with.

Regards,
  Sergei.

Hi Sergei,

Thanks for your reply.

I already did this kind of verification. I used the WAV output of
mpg123 to create a WAV file. It works fine. I can play that file using
aplay. I also have another WAV file created with Audacity and this one
works fine too.

I also tried cmus and alsaplayer to play both WAV and MP3 files
without success. I tried to use oss emulation with them and it didn't
work either.

I'm quite convinced that it is ALSA configuration issue. Is there a
way to debug the driver, so I can see why the output freezes?

--
Wojtek



2010/10/26 Sergei Steshenko <steshenko_sergei@...>:
> On Tue, 26 Oct 2010 00:00:07 +0100
> Wojciech Bober <wojciech.bober@...> wrote:
>
>> Hi all,
>>
>> I'm trying to build mp3 jukebox out of Efika, which is an embedded
>> MPC5200 based board. I got to the stage where I'm able to play a wav
>> file using aplay. But when I try to play an mp3 using mpg123 it
>> freezes after decoding a few frames. I spent a few hours trying to get
>> this work, but I'm slowly running out of ideas.   I'm running crux 2.6
>>
>
> [snip]
>
> I think you should "slower your pace". I.e. being in your shoes I would
> first try to verify that mpg123 _decoder_ works, leaving ALSA out of the
> picture for a time being.
>
> To do the verification I would try to convert MP3 file into WAV file, then
> I would try to check how the WAV files plays/sounds - the latter maybe (also
> in a different computer.
>
> If/when it's verified the decoding part work, then the ALSA issues can be
> dealt with.
>
> Regards,
>  Sergei.
>

On Tue, 26 Oct 2010 11:17:31 +0100
Wojciech Bober <wojciech.bober@...> wrote:

> Hi Sergei,
> 
[snip]
> 
> I'm quite convinced that it is ALSA configuration issue. Is there a
> way to debug the driver, so I can see why the output freezes?
> 
> --
> Wojtek
> 
> 

IIRC ("I got to the stage where I'm able to play a wav file using aplay"), you did manage to play WAV file(s) using 'aplay', so if 'aplay' works, ALSA is
clean/kosher, and the issue(s) are with other applications, with their ALSA 
interface.

According to my

~/AFSWD/install/mpg123-1.12.5/binsh/mpg123 --help

"-a d  set audio device", so which devices did you try to set ?

If you did try, were devices the same as the ones you've used with
'aplay' ?

Regards,
  Sergei.

2010/10/26 Sergei Steshenko <steshenko_sergei@...>:
> IIRC ("I got to the stage where I'm able to play a wav file using aplay"), you did manage to play WAV file(s) using 'aplay', so if 'aplay' works, ALSA is
> clean/kosher, and the issue(s) are with other applications, with their ALSA
> interface.
>
> According to my
>
> ~/AFSWD/install/mpg123-1.12.5/binsh/mpg123 --help
>
> "-a d  set audio device", so which devices did you try to set ?

The device was the same:

mpg123 -vvv -a plughw:0,0 -o alsa Take_Five.mp3
aplay -v -d plughw:0,0 take_file.wav

I also suspected that it's a problem of mp3 decoding, so I tried to
use mplayer to play a wav file:
mplayer -ao alsa:device=plughw=0.0 take_file.wav

But mplayer stops at 0.0 seconds.

I cannot use hw:0.0 directly, because the sound card seems to accept
samples only in S32_BE format. The question is what is aplay doing
that mplayer/cmus/alsaplayer etc isn't?

Wojtek

On Tue, 26 Oct 2010 12:04:25 +0100
Wojciech Bober <wojciech.bober@...> wrote:

> 2010/10/26 Sergei Steshenko <steshenko_sergei@...>:
> > IIRC ("I got to the stage where I'm able to play a wav file using aplay"), you did manage to play WAV file(s) using 'aplay', so if 'aplay' works, ALSA is
> > clean/kosher, and the issue(s) are with other applications, with their ALSA
> > interface.
> >
> > According to my
> >
> > ~/AFSWD/install/mpg123-1.12.5/binsh/mpg123 --help
> >
> > "-a d  set audio device", so which devices did you try to set ?
> 
> The device was the same:
> 
> mpg123 -vvv -a plughw:0,0 -o alsa Take_Five.mp3
> aplay -v -d plughw:0,0 take_file.wav
> 
> I also suspected that it's a problem of mp3 decoding, so I tried to
> use mplayer to play a wav file:
> mplayer -ao alsa:device=plughw=0.0 take_file.wav
> 
> But mplayer stops at 0.0 seconds.
> 
> I cannot use hw:0.0 directly, because the sound card seems to accept
> samples only in S32_BE format. The question is what is aplay doing
> that mplayer/cmus/alsaplayer etc isn't?
> 
> Wojtek
> 

If your

aplay -v -d plughw:0,0 

works, then the WAV file number of bits is compatible with with your
card.

What does

file take_file.wav

show ?

...

How about

"--reopen           force close/open on audiodevice"

in mpg123 ?

Regards,
  Sergei.

--
Wojtek




---------- Forwarded message ----------
From: Wojciech Bober <wojciech.bober@...>
Date: 2010/10/26
Subject: Re: [Alsa-user] Can't play mp3 with mpg123, but wav with aplay works
To: Sergei Steshenko <steshenko_sergei@...>


2010/10/26 Sergei Steshenko <steshenko_sergei@...>:
> aplay -v -d plughw:0,0
>
> works, then the WAV file number of bits is compatible with with your
> card.

Correct me if I'm wrong, but from the output of aplay it looks like it
isn't compatible. See below.

The wave file is S16_LE, then the plug comes in and converts it from
S16_LE to S32_BE in order to play it on the slave device (hw:0,0)
which is S32_BE.

aplay -v -d plughw:0,0 take_file.wav
Code:
Playing WAVE 'take_file.wav' : Signed 16 bit Little Endian, Rate 44100
Hz, Stereo
Plug PCM: Linear conversion PCM (S32_BE)
Its setup is:
 stream       : PLAYBACK
 access       : RW_INTERLEAVED
 format       : S16_LE
 subformat    : STD
 channels     : 2
 rate         : 44100
 exact rate   : 44100 (44100/1)
 msbits       : 16
 buffer_size  : 22052
 period_size  : 5513
 period_time  : 125011
 tstamp_mode  : NONE
 period_step  : 1
 avail_min    : 5513
 period_event : 0
 start_threshold  : 22052
 stop_threshold   : 22052
 silence_threshold: 0
 silence_size : 0
 boundary     : 1445199872
Slave: Hardware PCM card 0 'Efika' device 0 subdevice 0
Its setup is:
 stream       : PLAYBACK
 access       : MMAP_INTERLEAVED
 format       : S32_BE
 subformat    : STD
 channels     : 2
 rate         : 44100
 exact rate   : 44100 (44100/1)
 msbits       : 32
 buffer_size  : 22052
 period_size  : 5513
 period_time  : 125011
 tstamp_mode  : NONE
 period_step  : 1
 avail_min    : 5513
 period_event : 0
 start_threshold  : 22052
 stop_threshold   : 22052
 silence_threshold: 0
 silence_size : 0
 boundary     : 1445199872
 appl_ptr     : 0
 hw_ptr       : 0

>
> What does
>
> file take_file.wav
>
> show ?
>
> ...
>
> How about
>
> "--reopen           force close/open on audiodevice"
>
> in mpg123 ?

I'll try that later on today, and let you know.

--
Wojtek

On Tue, 26 Oct 2010 12:26:28 +0100
Wojciech Bober <wojciech.bober@...> wrote:

[snip]
> Correct me if I'm wrong, but from the output of aplay it looks like it
> isn't compatible. See below.
[snip]

You appear to be correct.

Then I would try the following try to use 'SoX' (sox.sf.net) - it has
built-in format conversions, so it can work out of the box, or you can
force it to use the needed format.


Regards,
  Sergei.

The problem was solved by updating the kernel to 2.6.36.

--
Wojtek



2010/10/26 Wojciech Bober <wojciech.bober@...>:
> 2010/10/26 Sergei Steshenko <steshenko_sergei@...>:
>> aplay -v -d plughw:0,0
>>
>> works, then the WAV file number of bits is compatible with with your
>> card.
>
> Correct me if I'm wrong, but from the output of aplay it looks like it
> isn't compatible. See below.
>
> The wave file is S16_LE, then the plug comes in and converts it from
> S16_LE to S32_BE in order to play it on the slave device (hw:0,0)
> which is S32_BE.
>
> aplay -v -d plughw:0,0 take_file.wav
> Code:
> Playing WAVE 'take_file.wav' : Signed 16 bit Little Endian, Rate 44100
> Hz, Stereo
> Plug PCM: Linear conversion PCM (S32_BE)
> Its setup is:
>  stream       : PLAYBACK
>  access       : RW_INTERLEAVED
>  format       : S16_LE
>  subformat    : STD
>  channels     : 2
>  rate         : 44100
>  exact rate   : 44100 (44100/1)
>  msbits       : 16
>  buffer_size  : 22052
>  period_size  : 5513
>  period_time  : 125011
>  tstamp_mode  : NONE
>  period_step  : 1
>  avail_min    : 5513
>  period_event : 0
>  start_threshold  : 22052
>  stop_threshold   : 22052
>  silence_threshold: 0
>  silence_size : 0
>  boundary     : 1445199872
> Slave: Hardware PCM card 0 'Efika' device 0 subdevice 0
> Its setup is:
>  stream       : PLAYBACK
>  access       : MMAP_INTERLEAVED
>  format       : S32_BE
>  subformat    : STD
>  channels     : 2
>  rate         : 44100
>  exact rate   : 44100 (44100/1)
>  msbits       : 32
>  buffer_size  : 22052
>  period_size  : 5513
>  period_time  : 125011
>  tstamp_mode  : NONE
>  period_step  : 1
>  avail_min    : 5513
>  period_event : 0
>  start_threshold  : 22052
>  stop_threshold   : 22052
>  silence_threshold: 0
>  silence_size : 0
>  boundary     : 1445199872
>  appl_ptr     : 0
>  hw_ptr       : 0
>
>>
>> What does
>>
>> file take_file.wav
>>
>> show ?
>>
>> ...
>>
>> How about
>>
>> "--reopen           force close/open on audiodevice"
>>
>> in mpg123 ?
>
> I'll try that later on today, and let you know.
>
> --
> Wojtek
>