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Old 18th December 2019, 20:41   #3293  |  Link
manolito
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Join Date: Sep 2003
Location: Berlin, Germany
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Quote:
Originally Posted by Mike-uk View Post
Found PCM audio: 8 channels, 48000 Hz, 32 bits, 80.040000 seconds.

it seems any file with 8 channels/6 channels is not liked, just tried a file with 2 channels and its fine
Since the DVD specs do not allow for more than 6 audio channels, A2D always automatically downmixes 8-ch source audio to 6-ch. Which obviously does not work for your source audio.

I spent some time testing clips with different 8-ch audio formats this afternoon, and the result was that A2D is not well suited for 8-ch audio sources.

I used clips from here for my tests:
https://www.demo-world.eu/2d-demo-trailers-hd/

One problem is that there are many different 7.1 audio formats, and depending on the format MediaInfo spits out very different results. Which oftentimes leads to A2D making wrong downmix decisions.

One example is 8-ch EAC3 audio. This format is always detected as 6-ch, I have no idea how the other 2 channels are embedded in the format, but since LAV audio sees it as 6-ch there is no other way than treating it as 6-ch for the conversion.

For other formats MediaInfo reports 8-ch/6-ch audio, and A2D will probably pick the wrong format. Other 8-ch formats like DTS or Dolby Atmos may even cause A2D to detect 0 audio channels. So currently if you have 8-ch source audio you will need to apply some manual workarounds to convert such audio correctly.

The only way to reliably detect the number of audio channels is to check how many channels your audio source filter recognizes. For LAV audio there is a "Status" tab in the configuration window. Play the file in a DirectShow based player and open the LAV audio configuration to get the real number of channels.

Then in A2D right-click on the source title and click "Edit Source Title Info". Under "Audio Channels" enter the correct number of channels.

If you have 8 audio channels then make sure that your AVS script has the command "Audio = Audio.Dmix86()" in it. This will execute a function from "Downmix.avsi" which is located in your "AVStoDVD\Lib" folder.


So my conclusion is that right now there is no automatic way to treat 8-ch audio sources correctly. It would be a major undertaking to detect all possible 8-ch formats reliably, and I have my doubts if MrC has the time to do this in the near future. He has not posted here for almost 6 months, I sure hope that he is doing well...


BTW you may be interested in using an improved version of the "Downmix.avsi" script. Have a look here:
https://forum.doom9.org/showthread.p...17#post1882617


Cheers
manolito

Last edited by manolito; 18th December 2019 at 20:48.
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