[mythtv-users] PCM type noise when HDMI cable is connected

Richard Woelk richardwoelk at yahoo.ca
Sun Feb 7 17:46:37 UTC 2010

Rafael Moslin wrote:
> On 7 February 2010 04:01, RALPH KEMP <4romany at gmail.com> wrote:
>> Friend of mine build a mythbuntu system - got everything working in this
>> "lab" - using a 23in LCD with external speakers (connected to the computer
>> sound card).  All well and good...disconnects the computer - takes and hooks
>> it to a HDTV - essentially the same way HDMI to DVI for video and analog out
>> of the sound card to the audio L/R of the TV - and all he gets is what to my
>> ears sounds like digital poping noise.  I sold him this TV and on my myth
>> box - using the same type of connections - it worked fine.    From what I
>> read DVI interface does not carry sound so I would not think there is a
>> setup issue on the computer causing the noise.   From what he tells me the
>> video plays fine from myth - but only the poping sounds are heard.Possible
>> bad cable I suppose.   Anyone have any insights on this?   I hope to swing
>> by and look at it tomorrow.....
> Only thing I can do is agree with you that DVI-D does not do sound so
> that the HDMI cable is unlikely to be the source of the problem. In
> saying that should the TV audio source be set to get sound from the
> HDMI input rather than its RCA's then there is perhaps the chance of
> crosstalk causing the odd spurious 'pop' sound. Either way it seems to
> me that the audio source is incorrectly set either on the PC output or
> TV input.
> Not a particularly useful response I grant you but hey, its a slow
> Sunday morning!
> _______________________

Some TVs, like my Samsung, don't have a manual switch between HDMI and 
analog audio. If the video card is capable of HDMI audio, and it 
recognizes the TV can receive HDMI audio, it will be enabled.
The only way to fix this is to save and edit his tv's EDID information 
and remove the HDMI audio portion. Then tell the X server to use that 
EDID instead of reading from the tv. There have been a few threads on 
this situation.

Ahh, its even on the wiki

- Richard

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