HDMI Audio Setting

[#1]

• 1. Set up HDMI
• 2. Test raw audio
• 3. Make HDMI audio the default output
• 4. Encoded audio

1. Set up HDMI

Set up your kernel to use HDMI adding the following code to bootargs on u-boot:

video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24

2. Test raw audio

In order to test only raw audio, use the following command:

aplay -D hw:1,0 Kaleidoscope.wav

3. Make HDMI audio the default output

In order to configure audio output over HDMI, please, replace content of file ~/.asoundrc to the following one

pcm.dmix_48000{

     type dmix

     ipc_key 5678293

     ipc_key_add_uid yes

     slave{

          pcm "hw:1,0"

          period_time 0

          period_size 2048

          buffer_size 24576

          format S16_LE

          rate 48000

     }

}

pcm.!dsnoop_44100{

     type dsnoop

     ipc_key 5778293

     ipc_key_add_uid yes

     slave{

          pcm "hw:0,0"

          period_time 0

          period_size 2048

          buffer_size 24576

          format S16_LE

          rate 44100

     }

}

pcm.!dsnoop_48000{

     type dsnoop

     ipc_key 5778293

     ipc_key_add_uid yes

     slave{

          pcm "hw:1,0"

          period_time 0

          period_size 2048

          buffer_size 24576

          format S16_LE

          rate 48000

     }

}

pcm.asymed{

     type asym

     playback.pcm "dmix_48000"

     capture.pcm "dsnoop_44100"

}

pcm.dsp0{

     type plug

     slave.pcm "asymed"

}

pcm.!default{

     type plug

     route_policy "average"

     slave.pcm "asymed"

}

ctl.mixer0{

     type hw

     card 0

}

This will configure alsa to use sound card hw:1,0. Please, pay attention to use the proper audio card name for your device.

In order to see available sound cards on board:

root@imx53qsb:~# aplay -l

**** List of PLAYBACK Hardware Devices ****

card 0: imx3stack [imx-3stack], device 0: SGTL5000 SGTL5000-0 []

  Subdevices: 1/1

  Subdevice #0: subdevice #0

card 1: imx3stackspdif [imx-3stack-spdif], device 0: IMX SPDIF mxc spdif-0 []

  Subdevices: 1/1

  Subdevice #0: subdevice #0

For detail on how to create asound.conf, please see alsa-lib configuration introduction.

4. Encoded audio

For encoded (i.e. AC3, DTS) audio, you can use, for example, ac3dec, an utility provided by alsa-tools with the following command line:

ac3dec -D hw:1,0 -C test.ac3

This would work for both HDMI audio and SPDIF audio. Double check your hardware and/or schematic in order to know which one to use.

[phuongdangminh]

Hello,

Very beautiful guide, how to set default SPDIF audio card on Android ?

Thanks

[jojorong]

good, it really works if i use the native app to play audio in IMX6QSD :smileyhappy:

but there is no audio output from HDMI with the pulse audio server.

the output of audio just is from the "wm8962audio" as bellow in my IMX6QSD, any advices about this ?

i want to use pulse audio server to output in HDMI interface.

root@imx6qsabresd:~# aplay -l

**** List of PLAYBACK Hardware Devices ****

card 0: wm8962audio [wm8962-audio], device 0: HiFi wm8962-0 []

  Subdevices: 1/1

  Subdevice #0: subdevice #0

card 1: imxhdmisoc [imx-hdmi-soc], device 0: IMX HDMI TX mxc-hdmi-soc-0 []

  Subdevices: 0/1

  Subdevice #0: subdevice #0

[daiane_angolini]

ohhhhhhhhhhhh you´re right! the way to configure pulseaudio is different....

From my old emails, I got this command line:

pacmd set-default-sink 1

Could you, please, give it a try and let us know the results?

[jojorong]

Hi,

     There is not the command "pacmd", just "pactl".

BTW, i use the YOCTO project of FSL community to build all, what is my next step about for your ask ?

[daiane_angolini]

Well, I think you make it work (by your comment on meta-freescale)

[jojorong]

it looks like bad, i also stat up the daemon like what i said in mail list,

i restart again with command "pulseaudio -D", the output of audio is not from HDMI except the "card 0: wm8962audio [wm8962-audio], device 0: HiFi wm8962-0 []"

it's really strange, help...

[jojorong]

i think the pulseaduio detect the output of audio, sometime is HDMI and sometime is the other, so i need to specify the HDMI as the default output, how to do ?

[daiane_angolini]

look for some pulseaudio conf file. Create a bbappend on your meta layer in order to add this by default on your image.

(sorry, i don't know pulseaudio :smileysad:)

[eric_kang]

Dear Daiane Angolini,

I want to know how to configure the HDMI Audio as 24bit in i.MX6Q / Linux 3.14.52.

Please let me know how to do that.

It's very helpful to me if you tell me how to confirm that in i.MX6Q Evaluation board.

Actually I could confirm the below contents in the some documents.
- HDMI Audio 24bit is supported in the i.MX6Q Reaference Manual
  . Table 33-6. Data Arrangement in System Memory for L-PCM (24 bits) in Chapter 33
  .
- HDMI Audio 24bit is NOT supported in the i.MX6 Linux Reference Manual for Linux 3.14.52
  . Chapter 15 On-Chip High Definition Multimedia Interface (HDMI) Driver
  .

Best Regards,
Eric.

[daiane_angolini]

Could you, please, create a new ticket? Otherwise it might get off the radar

[eric_kang]

Dear Daiane Angolini,

I created a new ticket through SR.

Please check the below case from SR.

[Case:00198948] How to configure the HDMI Audio as 24bit in i.MX6Q / Linux 3.14.52

Best Regards,

Eric.