HDMI to speaker

Discussion in 'General Electronics Chat' started by JerryNa, Aug 25, 2014.

  1. JerryNa

    Thread Starter Member

    Feb 15, 2010
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    Hi

    I got beaglebone black which is connected to an internal HDMI IC (TDA19988).

    The HDMI IC is connected to a HDMI connector.

    Is it possible to use the HDMI IC to produce audio signal to a speaker?

    meaning:

    1. The processor will send digital signals to the HDMI IC (the digital signals represent a song)

    2. the HDMI IC will convert the digital signal to analog signal and will send them to the speaker which will be connected to the HDMI connector.

    Can it be done like that?

    Thank you mates.
     
  2. wayneh

    Expert

    Sep 9, 2010
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    The short answer to point 2 is no. Driving a speaker requires an audio amplifier and that is not part of HDMI. I believe the HDMI interface will deliver only digital audio at its output. You would need separate conversion to analog and then to a signal with enough power to drive the speaker.

    I believe point 1 can be done. The chip will accept a proper digital audio signal and send it over HDMI.
     
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  3. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Most likely yes, the question is how affordable it is to get it done. I found some chips from analog, but they are in BGA package, which basically means at least 6 layer board and generally no hand soldering. And they cost $15 a pop. NXP seems to make tda19971, but I cannot find a datasheet for it.
    You sure you need to go this way? It seems like a pretty tough job to pull of for such a simple thing as getting audio.
     
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  4. JerryNa

    Thread Starter Member

    Feb 15, 2010
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    Hi
    Thank you very much.

    I learned a lot from your comments.

    My main goal is to produce audio from the Beaglebone Black using as less HW as possible, therefore I thought I could use the already integrated HDMI IC for that.

    How would you then get Audio produced by the Beaglebone Black, with being as less as possible involved with HW?

    Thank you again friends.
     
  5. wayneh

    Expert

    Sep 9, 2010
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    [responding to #3] Yes of course audio can be extracted from an HDMI signal, and there are many commercial devices fro doing this. I understand the OP's question to about the named IC, which cannot do the extraction itself, as far as I see.

    I suppose the BeagleBone already contains the hardware to extract HDMI audio.

    What exactly are you trying to do? What do you want to do with the audio that is not already possible with the BeagleBone? Are your questions about the necessary software? (I didn't realize until just now that BeagleBone is a computer, not an audio system.)
     
    Last edited: Aug 25, 2014
  6. JerryNa

    Thread Starter Member

    Feb 15, 2010
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    Hi Wayneh,

    Thank you.

    What I want to do is play an audio file on the Beaglebone black and produce Audio of that audio file.

    I hoped to get involved with as less HW as possible, as I'm a SW guy, that was why I thought of using the already existing external components of the Beaglebone black processor.

    How would you suggest to do with with as less additional HW as possible?
     
  7. wayneh

    Expert

    Sep 9, 2010
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    I've just been reading here about the HDMI capabilities. It looks to me like the BB Black HDMI port is really just for monitor connections. There is no mention whatsoever of it passing an audio signal, and that makes me think it is not possible. It's not proof, just a hint.

    Oops, dead wrong. Audio is an option with some resolutions.
    See here, here, and here.
     
    Last edited: Aug 25, 2014
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  8. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Looking at the BBB schematic, the audio data is present on expansion port P9 as SPI1_D0,SPI1_CS0 and SPI1_SCLK and is in the I2S data format. You should be able to hook an I2S DAC to that and get your analog audio.
    Frankly I dont have much experience with this bus, but there seem to be some expansion cards for raspberry in existence, so you might try those.
     
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  9. kubeek

    AAC Fanatic!

    Sep 20, 2005
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  10. JerryNa

    Thread Starter Member

    Feb 15, 2010
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    I thank you very much guys

    You've given me a lot of information!

    I read the articles you attached.

    It seems that I have no way to avoid attaching additional HW for getting Audio from the BeagleBone Black
     
  11. BobTPH

    Active Member

    Jun 5, 2013
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