Hello,
Let's put alsa-devel back to the CC...
On Monday 25 January 2010 09:32:45 ext shariff wrote:
Hi Peter,
- As we only have one Main MIC when I am recording in stereo mode by
specifying "-c 2", one channel is silent and one channel is recorded
properly.
As it should. Just as a sidenote, I'm usually using -f dat for the format, which
gives 48KHz, stereo 16LE
- But still the recorded channel is noisy, how can I reduce the noise of
the recorded channel?
Hmm, what kind of noise?
How are you configuring the dai with the snd_soc_dai_set_fmt?
For stereo it should be (if OMAP is slave, TWL is master):
SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBM_CFM;
For TDM mode (four channel):
SND_SOC_DAIFMT_DSP_A | SND_SOC_DAIFMT_IB_NF | SND_SOC_DAIFMT_CBM_CFM;
See omap3beagle.c how it is done.
I have one more question. ( Regarding Audio path)
---> If I want to avoid that one channel silent, do I need to connect "SUB
MIC or AUXR"?( as these are connected right ADC).
If you want audio data there, than yes you need another mic for the right
channel.
----> If I need to record 4 channel audio without any silent channel do I
need to connect digital microphones also?
You can duplicate the channel 1 and 3 to channel 2 and 4, meaning that you route
the ADCL and ADCR to these channels (TX1 and TX2 path are both analog).
You can also hook up a stereo digital mic to the digimic1 interface, but
remember, that the digimic needs 48KHz sampling rate.
--
Péter
>
> Regards,
> Shariff
>
> On Fri, Jan 22, 2010 at 6:29 PM, shariff
> <shariffsinbox@gmail.com
mailto:shariffsinbox@gmail.com> wrote: Hi Peter,
>
> Thank you very much for your suggestions.
>
> Regards,
> Shariff
>
>
> On Fri, Jan 22, 2010 at 6:11 PM, Peter Ujfalusi
> <peter.ujfalusi@nokia.com
mailto:peter.ujfalusi@nokia.com> wrote: Hello,
>
> On Friday 22 January 2010 11:57:23 ext shariff wrote:
> > Hi all,
> >
> > I am working with OMAP3 based custom board that has twl4030 codec
> > & using linux-2.6.29 kernel from opensource.
>
> This is kind of old...
>
> > I have some queries regarding Audio recording.
> >
> > Audio codec is connected to twl4030 as bellow
> >
> > TWL4030
> >
> > |--------------------|
> > |
> > | |------ MAINMIC
> >
> > McBSP2 ------ |i2s/tdm |
> >
> > | ___________|
> >
> > --> One Analog MIC is connected to Main Mic and I am using Audio
> > path not the Voice path.
> >
> > After selecting Main Mic through amixer control.
> >
> > and recording audio using "arecord -c 1 -r 8000 -f S16_LE -t
> > wav -d 20 record-file.wav"
>
> The hardware should have been opened in stereo mode, since it is not
> supporting the mono, you can verify it by appending -v to arecord and see
> how the HW has been opened at the end.
>
> > --> Here record is successful but with lot of noise.
> >
> > 1) Can we record Mono(1 channel) through I2S from TWL4030
> > codec?
>
> The TWL codec "Audio" path is either stereo or 4 channel.
> You need to record stereo/4 channel, and than extract/use the data from the
> valid channel.
> In case of Main mic it is the left channel, or Channel 1 or/and 2
> (depending on the routings) in four channel mode.
>
> > 2) To record stereo(2 channels), do we need two Mic's ? (i.e do
> > I need Sub Mic also).
>
> No you don't need. The right channel will not contain valid data (most
> likely it is going to be silent).
>
> You need to enable the Mic bias 1 for the main mic in your machine driver,
> if you have not done that yet:
>
> static const struct snd_soc_dapm_widget your_widgets[] = {
> ...
> SND_SOC_DAPM_MIC("Your Mic", NULL),
> ...
> };
>
> static const struct snd_soc_dapm_route your_audio_map[] = {
> ...
> {"MAINMIC", NULL, "Mic Bias 1"},
> {"Mic Bias 1", NULL, "Your Mic"},
> ...
> };
>
> I'm not sure about the state of the twl soc codec driver in 2.6.29, but my
> guess is that it should work.
>
> Are there any capture routing option for TX1 path, which selects between
> Analog and Digimic0? If there is than that has to be set to analog as
> well.
>
> > Regards,
> > Shariff
>
> --
> Péter
>
