* First 50 milliseconds of audio clipping with dmix
@ 2010-05-19 17:05 Tyler Conant
2010-05-20 4:04 ` Raymond Yau
0 siblings, 1 reply; 3+ messages in thread
From: Tyler Conant @ 2010-05-19 17:05 UTC (permalink / raw)
To: alsa-devel@alsa-project.org
I'm trying to use dmix on an OMAP processor. I'm experiencing the first 50 ms of the sample getting clipped. When I aplay directly to the hw:0 I don't get the clipping. The difference I see between the alsa configuration between dmix and hw:0 is the start_threshold, stop_threshold and silence_size. When it's direct to hw:0 the start and stop threshold are equal to the buffer size. For dmix the start threshold is 1 and the stop threshold is 1445199872. Is this dmix which is setting the start and stop or is this aplay. I'm only guessing this is the reason why the first part is clipping. The only bug which seem similar is http://bugs.gentoo.org/show_bug.cgi?id=218641 and it's already been closed out. I'm using alsa lib 1.0.23
with hw:0
Audio_Prompts # aplay -v -D hw:0 Click03.wav
Playing WAVE 'Click03.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Mono
Hardware PCM card 0 'TWL4030' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 1
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
appl_ptr : 0
hw_ptr : 0
/opt/axonapp/Audio_Prompts #
With dmix:
/Audio_Prompts # aplay -v Click03.wav
Playing WAVE 'Click03.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Mono
Plug PCM: Direct Stream Mixing PCM
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 1
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
Hardware PCM card 0 'TWL4030' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : MMAP_INTERLEAVED
format : S16_LE
subformat : STD
channels : 1
rate : 44100
exact rate : 44100 (44100/1)
msbits : 16
buffer_size : 22052
period_size : 5513
period_time : 125011
tstamp_mode : ENABLE
period_step : 1
avail_min : 5513
period_event : 0
start_threshold : 1
stop_threshold : 1445199872
silence_threshold: 0
silence_size : 1445199872
boundary : 1445199872
appl_ptr : 0
hw_ptr : 0
/opt/axonapp/Audio_Prompts #
asound.conf:
pcm.dmixer {
type dmix
ipc_key 2048
ipc_key_add_uid true
slave {
channels 1
pcm hw:0
rate 44100
period_time 125011
period_size 5513
buffer_size 22052
}
}
pcm.asymed {
type asym
playback.pcm "dmixer"
capture.pcm "hw:0,0"
}
pcm.!default {
type plug
slave.pcm "asymed"
}
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: First 50 milliseconds of audio clipping with dmix
2010-05-19 17:05 First 50 milliseconds of audio clipping with dmix Tyler Conant
@ 2010-05-20 4:04 ` Raymond Yau
2010-05-20 5:55 ` Jarkko Nikula
0 siblings, 1 reply; 3+ messages in thread
From: Raymond Yau @ 2010-05-20 4:04 UTC (permalink / raw)
To: ALSA Development Mailing List
2010/5/20 Tyler Conant <tconant@taser.com>
> I'm trying to use dmix on an OMAP processor. I'm experiencing the first 50
> ms of the sample getting clipped. When I aplay directly to the hw:0 I don't
> get the clipping. The difference I see between the alsa configuration
> between dmix and hw:0 is the start_threshold, stop_threshold and
> silence_size. When it's direct to hw:0 the start and stop threshold are
> equal to the buffer size. For dmix the start threshold is 1 and the stop
> threshold is 1445199872. Is this dmix which is setting the start and stop or
> is this aplay. I'm only guessing this is the reason why the first part is
> clipping. The only bug which seem similar is
> http://bugs.gentoo.org/show_bug.cgi?id=218641 and it's already been closed
> out. I'm using alsa lib 1.0.23
>
>
> with hw:0
>
> Audio_Prompts # aplay -v -D hw:0 Click03.wav
> Playing WAVE 'Click03.wav' : Signed 16 bit Little Endian, Rate 44100 Hz,
> Mono
> Hardware PCM card 0 'TWL4030' device 0 subdevice 0
> Its setup is:
> stream : PLAYBACK
> access : RW_INTERLEAVED
> format : S16_LE
> subformat : STD
> channels : 1
> 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
> appl_ptr : 0
> hw_ptr : 0
> /opt/axonapp/Audio_Prompts #
>
>
> With dmix:
>
> /Audio_Prompts # aplay -v Click03.wav
> Playing WAVE 'Click03.wav' : Signed 16 bit Little Endian, Rate 44100 Hz,
> Mono
> Plug PCM: Direct Stream Mixing PCM
> Its setup is:
> stream : PLAYBACK
> access : RW_INTERLEAVED
> format : S16_LE
> subformat : STD
> channels : 1
> 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
> Hardware PCM card 0 'TWL4030' device 0 subdevice 0
> Its setup is:
> stream : PLAYBACK
> access : MMAP_INTERLEAVED
> format : S16_LE
> subformat : STD
> channels : 1
> rate : 44100
> exact rate : 44100 (44100/1)
> msbits : 16
> buffer_size : 22052
> period_size : 5513
> period_time : 125011
> tstamp_mode : ENABLE
> period_step : 1
> avail_min : 5513
> period_event : 0
> start_threshold : 1
> stop_threshold : 1445199872
> silence_threshold: 0
> silence_size : 1445199872
> boundary : 1445199872
> appl_ptr : 0
> hw_ptr : 0
> /opt/axonapp/Audio_Prompts #
>
>
> asound.conf:
> pcm.dmixer {
> type dmix
> ipc_key 2048
> ipc_key_add_uid true
> slave {
>
> channels 1
> pcm hw:0
> rate 44100
> period_time 125011
> period_size 5513
> buffer_size 22052
> }
> }
>
> pcm.asymed {
> type asym
> playback.pcm "dmixer"
> capture.pcm "hw:0,0"
> }
>
> pcm.!default {
> type plug
> slave.pcm "asymed"
> }
>
>
>
The major difference is access : MMAP_INTERLEAVED
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: First 50 milliseconds of audio clipping with dmix
2010-05-20 4:04 ` Raymond Yau
@ 2010-05-20 5:55 ` Jarkko Nikula
0 siblings, 0 replies; 3+ messages in thread
From: Jarkko Nikula @ 2010-05-20 5:55 UTC (permalink / raw)
To: Raymond Yau; +Cc: ALSA Development Mailing List
On Thu, 20 May 2010 12:04:06 +0800
Raymond Yau <superquad.vortex2@gmail.com> wrote:
> 2010/5/20 Tyler Conant <tconant@taser.com>
>
> > I'm trying to use dmix on an OMAP processor. I'm experiencing the first 50
> > ms of the sample getting clipped. When I aplay directly to the hw:0 I don't
> > get the clipping. The difference I see between the alsa configuration
> > between dmix and hw:0 is the start_threshold, stop_threshold and
> > silence_size. When it's direct to hw:0 the start and stop threshold are
> > equal to the buffer size. For dmix the start threshold is 1 and the stop
> > threshold is 1445199872. Is this dmix which is setting the start and stop or
> > is this aplay. I'm only guessing this is the reason why the first part is
> > clipping. The only bug which seem similar is
> > http://bugs.gentoo.org/show_bug.cgi?id=218641 and it's already been closed
> > out. I'm using alsa lib 1.0.23
> >
...
> >
> The major difference is access : MMAP_INTERLEAVED
>
I think I hear the same problem with OMAP3 BeagleBoard. These play fine:
aplay -D hw:0 48k_1kHz0dB100ms.wav
aplay -D hw:0 -M 48k_1kHz0dB100ms.wav
But with this there is some crack etc. if played after playing directly
to HW device:
aplay -D dmix 48k_1kHz0dB100ms.wav
But I don't hear this crack sound if repeating the command above.
Problem appears only when playing to dmix after playing to HW device.
And no, ASoC DAPM is not explaining this. Time between the commands
doesn't have any other effect than power up/-down pops.
--
Jarkko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-05-20 4:04 ` Raymond Yau
2010-05-20 5:55 ` Jarkko Nikula
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