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Filter out HDMI audio

post #1 of 8
7/9/07 at 12:37pm
Thread Starter 
Is it possible to filter or block the HDMI audio stream from a DVD player to a TV? The situation is that I have a Sony KDF-37H1000 that does not accept bitstream audio signals and a Samsung DVD HD-960 that can not selectively send PCM audio over HDMI and bitstream over optical to my receiver. This causes the TV to constantly pop up an error message about unsupported audio.

Therefore, if I could filter out the HDMI audio I think I could continue sending the audio via optical to my receiver bitstream and avoid the annoying error on my TV.

Thank you.
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post #2 of 8
7/18/07 at 11:14pm
You could use a HDMI to DVI and a DVI to HMDI connector at the end of the cable. Not the best setup but switching to DVI should loose the audio part on the channel. especially the cheap connectors are usefull for this purpose.
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post #3 of 8
7/19/07 at 6:11am
Thread Starter 
Thank you, however I gave this a shot and the audio still passed through. I got a pair of Monster F -> M and F <- M HDMI to DVI adapters and plugged the DVI ends together. I couldn't believe it but no joy. I can only assume that all the HDMI pins are mapped to DVI pins so whatever pins carry the audio had continuity through the whole mess.

Another idea...I was looking at the HDMI 1.1 pinout. It looks like there are 3 data paths over 9 pins. Data 0, 1 and 2. Could one carry audio, one video and one aux/DRM crap? Do you think it might be possible to get a custom cable that didn't have the audio pins (if such pins exist)? What might happen if there was no signal on one of the data paths?

Thank you.
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post #4 of 8
7/19/07 at 11:09am
In the dvd player audio settings...switch hdmi audio to Off?
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post #5 of 8
7/20/07 at 6:34am
Thread Starter 
That's the problem, the Samsung DVD HD-960 that can not selectively send LPCM audio over HDMI. If I set the audio to LPCM then I lose raw bitstream over the optical connection to my receiver.

I considered replacing it with one that can, but I like the HD-960, Faroudja deinterlacer and all. I had hoped there would be a reasonable cabling solution.
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post #6 of 8
8/1/07 at 3:52pm
First off, the DVI to HDMI dongles do nothing in terms of filtering out any signals. They are literally mechanical adapters, but the pins for the signals are all transferred through. That is why a dongle will not have any effect in this matter.

It appears that your goal is to use a non-HDMI receiver with your HDMI DVD player and HDMI TV. If so, then using SPDIF for the audio to your AVR would indeed be the best way. From your description, it appears your DVD player does not support the ability to simultaneously output audio on HDMI and the other audio connectors (this is not a common limitation on HDMI sources actually).

The only work arounds I can think of are ones that you probably won't like:
1) use a different DVD player
2) use a different AVR with HDMI input and audio processing capabilities (they're down to less than $300 now)

Sorry, I nothing cheap & easy comes to mind at the moment.
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post #7 of 8
8/2/07 at 11:59am
Thread Starter 
Your assessment is accurate. With the exception of one thing. My DVD player does output audio on HDMI and the other audio connectors. The problem is that the audio is the same over SPDIF and HDMI. The DVD player will send raw audio over both or LPCM over both. I can not PCM down convert over HDMI, selectively, while still sending raw bitstream over SPDIF.

Since the TV can not accept bitstream audio (causes a persistent annoying pop-up on the TV), I can not be connected HDMI to the TV while using bitstream audio to the AVR over SPDIF.

Your option 1, would work best for me but I like my DVD player. It would be nice if there was a way to strip the audio data out of the HDMI connection. I think I just hoped there were specific pins in HDMI that carried audio, then I could disable them.

Thank you.
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post #8 of 8
10/22/07 at 3:48pm
Unfortunately, HDMI transmits audio and video on the same pins. It has an optimizing encoder that figures out how best to send the signal at any given time (not as much audio info as video, so it sends packets of audio in between packets of video). This means that pins 1, 3, 4, 6, 7, and 9 could at any point be transmitting video, audio, or auxiliary data (for error correction between source and display). Pins 2, 5, and 8 transmit control data so that the display (or receiver, if you use one) can tell what data it's receiving at any given point.

Can't tell you how sad I was to discover this... I've got an Xbox 360 that is displayed on a DVI monitor, and I can't splice the audio out of my HDMI to DVI adapter.... which means I'm deaf while playing 360 .
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