[alsa-devel] Rates/formats available upstream from the plug plugin

[Jaroslav Kysela]

On Tue, 3 Aug 2010, Pavel Hofman wrote:

> Jaroslav Kysela napsal(a):
>> On Tue, 3 Aug 2010, Pavel Hofman wrote:
>>
>>> Hi,
>>>
>>> mplayer checks hw_params for availability of the current format
>>> http://mplayer-ww.git.sourceforge.net/git/gitweb.cgi?p=mplayer-ww/mplayer-ww;a=blob;f=libao2/ao_alsa.c;h=57f0bd07cb5ec300d327682a0b5209ba9dc10e30;hb=09ab9f6346aaf15d20792ca3df761a45fe46d83d#l514
>>>
>>> . If the check fails, it uses 16bits as fixed default.
>>>
>>> Now if we define the card to be plughw:0, the check still fails for
>>> formats unsupported directly by the card. Which in fact is incorrect
>>> since the plug plugin takes care of most formats known. The same holds
>>> for sample rates.
>>
>> It works for me:
>>
>> perex at eeebox2:~/alsa/alsa-lib/test> ./pcm
>> Playback device is plughw:0,0
>> Stream parameters are 44100Hz, S16_LE, 1 channels
>> Sine wave rate is 440.0000Hz
>> Using transfer method: write
>> test format float_le: 0
>> test format mpeg: -22
>>
>> Using modified alsa-lib/test/pcm.c code:
>>
>> diff --git a/test/pcm.c b/test/pcm.c
>> index abb83e4..0582891 100644
>> --- a/test/pcm.c
>> +++ b/test/pcm.c
>> @@ -106,6 +106,8 @@ static int set_hwparams(snd_pcm_t *handle,
>>          printf("Broken configuration for playback: no configurations
>> available: %s\n", snd_strerror(err));
>>          return err;
>>      }
>> +    printf("test format float_le: %i\n",
>> snd_pcm_hw_params_test_format(handle, params, SND_PCM_FORMAT_FLOAT_LE));
>> +    printf("test format mpeg: %i\n",
>> snd_pcm_hw_params_test_format(handle, params, SND_PCM_FORMAT_MPEG));
>>      /* set hardware resampling */
>>      err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);
>>      if (err < 0) {
>>
>>
>> Could you describe you hw configuration or can you reproduce this issue
>> with the snd-dummy module?
>>
>
> Thanks for your reply. How do you compile the test directory? Neither
> gitcompile nor make in the test dir did the trick. Thanks,

cd alsa-lib/test
make pcm

 				Jaroslav

-----
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.