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Author Topic: HDMI audio  (Read 2375 times)

bob

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HDMI audio
« on: April 18, 2014, 02:38:05 pm »

I'm seeing this with a 3.14 kernel
Any idea why there are two HDMI ports with different sample rate ranges?
There is only one HDMI port that I can see.


alsacap
*** Scanning for playback devices ***
Card 0, ID `PCH', name `HDA Intel PCH'
  Device 0, ID `ALC283 Analog', name `ALC283 Analog', 1 subdevices (1 available)
    2 channels, sampling rate 44100..192000 Hz
    Sample formats: S16_LE, S32_LE
      Subdevice 0, name `subdevice #0'
  Device 3, ID `HDMI 0', name `HDMI 0', 1 subdevices (1 available)
    2..6 channels, sampling rate 32000..48000 Hz
    Sample formats: S16_LE, S32_LE
      Subdevice 0, name `subdevice #0'
  Device 7, ID `HDMI 1', name `HDMI 1', 1 subdevices (1 available)
    2..8 channels, sampling rate 32000..192000 Hz
    Sample formats: S16_LE, S32_LE, IEC958_SUBFRAME_LE
      Subdevice 0, name `subdevice #0'
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JimH

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Re: HDMI audio
« Reply #1 on: April 18, 2014, 02:39:50 pm »

Are there pins for a second one on the board?
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JimH

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InflatableMouse

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Re: HDMI audio
« Reply #3 on: April 19, 2014, 03:24:39 am »

I think DVI-D is listed as HDMI too. Which is weird because it doesn't support audio.

My card has 2 DVI-D and 2 HDMI, it lists 4 HDMI devices:

card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 7: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 8: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 9: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
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Hendrik

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Re: HDMI audio
« Reply #4 on: April 19, 2014, 03:31:17 am »

For NVIDIA its quite common to list a number of HDMI devices, it does this on Windows too, although most show up as "not plugged in".

Also, who said DVI doesn't do Audio? :)
You can plug a DVI->HDMI adapter on those ports and usually get audio out of them just fine.
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InflatableMouse

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Re: HDMI audio
« Reply #5 on: April 19, 2014, 04:03:07 am »

Also, who said DVI doesn't do Audio? :)
You can plug a DVI->HDMI adapter on those ports and usually get audio out of them just fine.

https://en.wikipedia.org/wiki/Digital_Visual_Interface

I know you're usually right and you problably are now so as well, yet on that page there is no mention of the word audio or sound in relation to DVI. If you look at the pin outs of the specification, there are only TMDS +/- pins for red, blue and green. So, where would audio come from?

Could it be some manufacturers implement their own way for audio over DVI? I see no mention on MSI or Asus product pages?

Any reference for this?
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Hendrik

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Re: HDMI audio
« Reply #6 on: April 19, 2014, 04:14:29 am »

From the page you linked:

Quote
So, DVI-D devices output HDMI signals, many including audio, (examples: ATI 3000-series and NVIDIA GTX 200-series video cards),[9] and some multimedia displays input that HDMI signal, including audio, by using a DVI to HDMI adapter. Exact capabilities vary by video card specifications.

Technically its not that DVI supports audio, its just that DVI and HDMI are so extremely similar that the video cards drive them the same way, including the audio transport.
On an electrical level, DVI and HDMI are the same, its just a matter of protocol support what can go through the link - which allows DVI->HDMI adapters to carry audio as well on most GPUs (on AMD you need one of the AMD-proprietary adapters for this to work, on NVIDIA/Intel any DVI->HDMI adapter works)
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InflatableMouse

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Re: HDMI audio
« Reply #7 on: April 19, 2014, 06:42:23 am »

Wow ... I must have been reading very selectively. I even searched the page for audio and sound and still missed that.

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