using plug for sample format conversion

using plug for sample format conversion

[Adam Rosenberg]

>> I am trying to use plug to play audio files that are S16_LE but my
>> hardware only supports S32_LE.  It is not working.  Here is an example
>> of the problem using speaker-test.  First I use S32_LE and it works as
>> expected.  I then try S16_LE but it fails.  Does this mean the plug
>> plugin cannot convert between these sample formats?
>>
>> Thanks,
>> Adam
>>
>
>Please use latest version of speaker-test and alsa-lib.
>
>and post struct  snd_pcm_hardware of you driver
>

I am using the latest release of uClinux for Blackfin BF537 and do not
know how to configure and install the latest version of alsa-lib and
alsa-utils.  I am starting to understand how struct snd_pcm_hardware
is used by the ALSA PCM code but you are correct to assume I may have
something wrong.  Here is the struct:

static struct snd_pcm_hardware ourCS42448PcmHw =
{
	.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER ),
	.formats = SNDRV_PCM_FMTBIT_S32_LE,
	.rates = SNDRV_PCM_RATE_48000,
	.rate_min = 48000,
	.rate_max = 48000,
	.buffer_bytes_max = 32768,
	.channels_min = 1,
	.channels_max = 2,
	.period_bytes_max = 32768,
	.periods_min = 1,
	.period_bytes_min = 8,
	.periods_max = 4096,
};

Can you tell me how to configure and install the latest ALSA and
whether the snd_pcm_hardware is correct?

Thanks,
Adam


Adam Rosenberg
Software Engineer

Alcorn McBride Inc.
3300 South Hiawassee
Building 105
Orlando, FL 32835

(407) 296 - 5800 ext. 5490

Re: using plug for sample format conversion

[Raymond Yau]

2010/7/29 Adam Rosenberg <adam@alcorn.com>

> >> I am trying to use plug to play audio files that are S16_LE but my
> >> hardware only supports S32_LE.  It is not working.  Here is an example
> >> of the problem using speaker-test.  First I use S32_LE and it works as
> >> expected.  I then try S16_LE but it fails.  Does this mean the plug
> >> plugin cannot convert between these sample formats?
> >>
> >> Thanks,
> >> Adam
> >>
> >
> >Please use latest version of speaker-test and alsa-lib.
> >
> >and post struct  snd_pcm_hardware of you driver
> >
>
> I am using the latest release of uClinux for Blackfin BF537 and do not
> know how to configure and install the latest version of alsa-lib and
> alsa-utils.  I am starting to understand how struct snd_pcm_hardware
> is used by the ALSA PCM code but you are correct to assume I may have
> something wrong.  Here is the struct:
>
> static struct snd_pcm_hardware ourCS42448PcmHw =
> {
>        .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
> ),
>        .formats = SNDRV_PCM_FMTBIT_S32_LE,
>        .rates = SNDRV_PCM_RATE_48000,
>        .rate_min = 48000,
>        .rate_max = 48000,
>        .buffer_bytes_max = 32768,
>        .channels_min = 1,
>        .channels_max = 2,
>        .period_bytes_max = 32768,
>        .periods_min = 1,
>        .period_bytes_min = 8,
>        .periods_max = 4096,
> };
>

Unable to set hw params for playback: Invalid argument
Setting of hwparams failed: Invalid argument


This will tell you which argument is invalid

export LIB_LIBASOUND_DEBUG=1
speaker-test -l 1 -r 48000 -c 2 -F S16_LE -Dplughw:0,0,0



If the above still cannot help you find out the problem

you will need to enable RULES_DEBUG in core/pcm_native.c and check the
system log to find out how those hw parameters are refined

if you cannot use latest version of speaker-test , read the history of
speaker-test

http://git.alsa-project.org/?p=alsa-utils.git;a=history;f=speaker-test/speaker-test.c

Re: using plug for sample format conversion

[Adam Rosenberg]

I have a few other things going on at the office but here is a month
late status to close out this thread:

I see now that it fails with S16_LE because of this:

ACCESS = 0000000000000007 -> 0000000000000000

when it works using S32_LE is shows this:

ACCESS = 0000000000000008 -> 0000000000000008

because of this issue I decided to implement S16_LE support in my
driver directly.  This turned out to just be a workaround though as
the real problem seems to be in the organization of the actual driver.
 I will send a separate message to alsa-devel about this.

Thanks,
Adam

Re: using plug for sample format conversion

[Niels Mayer]

On Wed, Jul 28, 2010 at 9:55 AM, Adam Rosenberg <adam@alcorn.com> wrote:
> I am trying to use plug to play audio files that are S16_LE but my
> hardware only supports S32_LE.  It is not working.  Here is an example
> of the problem using speaker-test.  First I use S32_LE and it works as
> expected.  I then try S16_LE but it fails.  Does this mean the plug
> plugin cannot convert between these sample formats?

On a similar note, someone please explain the following behavior that occurs in
playing an S16_LE stream on an M-Audio Delta 66 (...kernel/sound/pci/ice1712).

The following mplayer invocation sends  a "bit mangled" version of the
original source stream to the outputs of the soundcard, where "66ch34"
is a dshare'd device, defined per
http://nielsmayer.com/npm/dot-asoundrc.txt .

///////  /////////  ////////  ////////  //////////
$ mplayer -quiet http://media.kcrw.com/live/kcrwlive.pls -ao alsa:device=66ch34
[...]
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 44100 Hz, 2 ch, s16le, 112.0 kbit/7.94% (ratio: 14000->176400)
[...]
AO: [alsa] 44100Hz 2ch s16le (2 bytes per sample)
[...]
Starting playback...
///////  /////////  ////////  ////////  //////////

Playing the exact same stream using  http://space.twc.de/~stefan/gst123.php
$ gst123 -a alsa=66ch34 http://64.12.61.1:80/stream/1046
uses the correct format and so the playback sounds as intended.

And whereas mplayer has no problem talking directly to snd_hda_intel
device, e.g.:
$ mplayer -quiet http://media.kcrw.com/live/kcrwlive.pls -ao alsa:device=hw=SB

Doing the same with the delta-66 gives:

///////  /////////  ////////  ////////  //////////
[AO_ALSA] Format s16le is not supported by hardware, trying default.
[AO_ALSA] Unable to set format: Invalid argument
Failed to initialize audio driver 'alsa:device=hw=M66'
///////  /////////  ////////  ////////  //////////

So where exactly is gst123 succeeding and how is the application able
to find out form ALSA that the format isn't supported, and then
correctly goes off and uses plughw (presumably) to get the correct bit
depth/order/complement matching?

Alternately, why do different applications behave differently based on
the sound card they're talking to. Is this an mplayer bug (in not
handling/preventing ALSA failure "Unable to set format: Invalid
argument"). How is gst123 and its http://www.gstreamer.net/
infrastructure handling this, and shouldn't this capability be an
underlying part of ALSA that is automatically invoked?

In programming, those working in dynamic languages have long enjoyed
the benefits of "self-identifying data" (
http://www.cs.rice.edu/~javaplt/311/Notes/09/05.supp.html ).
What about self-identifying devices?? Which is perhaps what gstreamer
and facilities like http://live.gnome.org/GObjectIntrospection  help
enable,  the fruits of which can be automatically enjoyed by apps like
gst123 ?

Is there a Vala-based "gstreamer toolkit" ?? Seems like that would be
the easiest way to gain well-integrated, and properly introspected
access all the way down to the ALSA level. Although I guess this would
require Glib-wrappers for ALSA to help describe what's actually there,
so as to allow the framework to delegate to the appropriate ALSA level
in a data-driven fashion.

Niels
http://nielsmayer.com
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel

Re: using plug for sample format conversion

[Raymond Yau]

2010/7/28 Adam Rosenberg <adam@alcorn.com>

> I am trying to use plug to play audio files that are S16_LE but my
> hardware only supports S32_LE.  It is not working.  Here is an example
> of the problem using speaker-test.  First I use S32_LE and it works as
> expected.  I then try S16_LE but it fails.  Does this mean the plug
> plugin cannot convert between these sample formats?
>
> Thanks,
> Adam
>

Please use latest version of speaker-test and alsa-lib

and post struct  snd_pcm_hardware of you driver

using plug for sample format conversion

[Adam Rosenberg]

I am trying to use plug to play audio files that are S16_LE but my
hardware only supports S32_LE.  It is not working.  Here is an example
of the problem using speaker-test.  First I use S32_LE and it works as
expected.  I then try S16_LE but it fails.  Does this mean the plug
plugin cannot convert between these sample formats?

Thanks,
Adam

root:/> speaker-test -l 1 -r 48000 -c 2 -F S32_LE -Dplughw:0,0,0

speaker-test 1.0.12

Playback device is plughw:0,0,0
Stream parameters are 48000Hz, S32_LE, 2 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 1 to 4096
Period size range from 1 to 4096
Using max buffer size 4096
Periods = 4
was set period_size = 1024
was set buffer_size = 4096
 0 - Front Left
 1 - Front Right
Time per period = 5.844000

root:/> speaker-test -l 1 -r 48000 -c 2 -F S16_LE -Dplughw:0,0,0

speaker-test 1.0.12

Playback device is plughw:0,0,0
Stream parameters are 48000Hz, S16_LE, 2 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 1 to 4096
Period size range from 1 to 4096
Using max buffer size 4096
Periods = 4
was set period_size = 1024
was set buffer_size = 4096
Unable to set hw params for playback: Invalid argument
Setting of hwparams failed: Invalid argument