dm8168 dvr3.50 32bit audio capture

bingyi cheng

Intellectual 900 points

platform dm8168+dvr3.50

We can use mca0 to capture 16bit audio data.But can not capture 32bit audio data(HDMI audio data).

if we set 32bit catpre as below:

if ((err = snd_pcm_hw_params_set_format (capture_handle, hw_params, SND_PCM_FORMAT_S32_LE)) < 0) {

it will show "Segmentation fault"。

Could some one give some help.

thanks.

over 12 years ago

0 bingyi cheng over 12 years ago

Intellectual 900 points

Could some one capture 32bit audio data?

0 bingyi cheng over 12 years ago in reply to bingyi cheng

Intellectual 900 points

Has any Ti engineer test 32bit audio input?

0 Sivagamy Govindasamy over 12 years ago in reply to bingyi cheng

TI__Expert 6950 points

32 bit capture might not be supported in hdmi - alsa driver.

0 bingyi cheng over 12 years ago in reply to Sivagamy Govindasamy

Intellectual 900 points

Hi Sivagamy Govindasamy

thanks for you replay.

In our past product development, we have capture 32bit audio data through ALSA successful under DM6467T platform.

The data format set to ALSA is SND_PCM_FORMAT_S32_LE; we think the DM6467T audio port will capture 32bit audio data then through DMA discard low 16bit data,

So APP can get 16bit audio data.

Now we want to capture the same audio signal through ALSA API under DM8168 +dvr3.50 platform, our ALSA cfg is according to DM6467 ALSA cfg, but if we set the format to SND_PCM_FORMAT_S32_LE, segment fault will occurs.

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I am not sure whether we can capture 32bit audio data in DM8168 according to DM6467, can you give me some suggestion?

0 bingyi cheng over 12 years ago in reply to bingyi cheng

Intellectual 900 points

Is there existing special hdmi-alsa in DVR3.50 ?

0 bingyi cheng over 12 years ago in reply to bingyi cheng

Intellectual 900 points

http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/p/191507/881469.aspx#881469

Ramappa,

The HDMI hardware only supports 16 and 24bit word size. You will not be able to support the same directly .

Alternatively you can use the ASLA "plughw:" options to convert any stream in software based on the support available on the hardware and achieve this.

Ex:

aplay -plughw:0,1 -r3200 -fS31_LE <sample file>

where plughw:0,1 is ur HDMI device (normal usage is -Dhw:0,1)

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It seems able to play 32bit audio.Can We capture 32bit audio but save 16bit audio like this ?

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dm8168 dvr3.50 32bit audio capture