Film-Tech Forum ARCHIVE: Uncompressed Audio OutpuT!

This is topic Uncompressed Audio OutpuT! in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Lucas Iaccarino (Member # 8762) on 08-10-2015, 07:28 PM:

Hello! Thanks for letting me ask this here
I'm working designing special Cinema Projections in non prepared places. We are going to project a DCP using easydcp player and a PC. I'm getting crazy trying to think a way to output 6 uncompressed channels PCM (like the DCP use to) to send them to a Christie SKA 3D processor. Anyone has any idea or some device that can work? Optical is only 2 channels and HDMI is only outputting 2 also.
Thanks!

Posted by Carsten Kurz (Member # 5396) on 08-11-2015, 05:26 AM:

Current HDMI graphics cards have no problem to output up to 8 channels of LPCM, thats usually the easiest way to output multiple channels of audio, even when using a notebook. The question is not so much the audio hardware, but what the DCP-Player supports. You have to look into the DCP-Player documentation to find out which drivers are supported.

Basically, when the HDMI audio is configured to 5.1 in windows sound preferences, you should be able to configure easyDCP player to use this output device (plus, disable 'Automatic stereo downmix' in audio options).

As an alternative, you may want to look into NeoDCP Player. This will also output to BlackMagicDesign HD-SDI cards, etc., and it offers more presentation options than easyDCP.

- Carsten

Posted by Lucas Iaccarino (Member # 8762) on 08-19-2015, 10:43 PM:

Thanks for the answer! what kind of driver or graphic card are you using? where you receive the 8 PCM channels so you can check there is information? I´m making experiments with a Christie 3D Ska but no success.
thanks!

Posted by Carsten Kurz (Member # 5396) on 08-20-2015, 05:01 AM:

Every current graphics card with HDMI output supports multichannel LPCM. Even a cheap 20US$ ATI or NVIDIA or some chipset-graphics. This HDMI audio device shows up in windows audio preferences once you connect the card to a suitable HDMI audio sink. If the sink only offers stereo decoding, it will only offer a stereo config. If it offers 5.1 or 7.1, you can configure it accordingly, but it still defaults to stereo initially. The system on my desk uses a cheap Radeon 4350. For the SKA-3D, I don't know, but the specs/FAQ lists multichannel embedded audio over HDMI.
I may be that only some HDMI/DVI inputs of the SKA-3D support embedded audio, or that you have to set them up for various channel modes.

For mobile testing, I use this multichannel HDMI audio de-embedder. You can set it to signal various HDMI audio modes to the HDMI output device. You can connect a simple headphone to it's analog outputs for channel testing during setup.

http://atlona.com/product/at-hd570/

Windows 7 and Windows 8 have a basic surround sound setup assistant in system control panels -> sound. You can set the audio device to surround mode and play test sounds over each channel. Try this first.

What graphics card is installed in your playout system?

- Carsten