Doom9's Forum - View Single Post - eac3to

Rodeo · 4th October 2011, 02:06

So, I was making sure that channel assignments and/or downmixing worked well, and tested eac3to on a bunch of channel checks I had available.

The FFmpeg TrueHD decoder was swapping the side and back surround channels. That was fixed recently: http://git.videolan.org/?p=ffmpeg.gi...diff;h=6daf513

Given that eac3to 3.24 is much older than that fix, it should have been affected by the bug - but to my surprise, it wasn't.

I used a TrueHD 7.1 channel check available on demo-world.eu

I tested it this way:

Code:

eac3to.exe input.mkv 2: output.wavs

and all the channels seemed to be in the correct file, in particular:

output.SL.wav -> left side surround
output.SR.wav -> right side surround
output.BL.wav -> left back surround
output.BR.wav -> right back surround

So I tested it on a DTS-HD MA 7.1 channel check from the Disney World of Wonder Blu-ray, and got incorrect results:

output.SL.wav -> left back surround
output.SR.wav -> right back surround
output.BL.wav -> left side surround
output.BR.wav -> right side surround

Code:

eac3to.exe -test

eac3to (v3.24) is up to date                                                   
Nero Audio Decoder (Nero 6 or older) doesn't seem to be installed              
  http://www.nero.com/eng/store-blu-ray.html                                   
  CAUTION: You need Nero 7. Nero 8 won't work with eac3to.                     
ArcSoft DTS Decoder (1.1.0.0) works fine                                       
Sonic Audio Decoder (3.24.0.0) doesn't seem to be installed                    
Haali Matroska Muxer (2011-03-03) is up to date                                
Nero AAC Encoder could not be located                                          
  http://www.nero.com/eng/nero-aac-codec.html                                  
  Copy NeroAacEnc.exe to the eac3to or to the Windows folder.                  
Surcode DTS Encoder doesn't seem to be installed                               
  http://www.surcode.com                                                       
MkvToolnix (5.0.0.0, release version) is up to date

There are a couple possibilities:

1)
- the FFmpeg TrueHD decoder is patched in eac3to to fix the channel swap bug, and either:
- - a. the Arcsoft DTS decoder is swapping channels
- - b. eac3to is remapping channels incorrectly from DTS-HD MA 7.1 sources

2)
- the side and back surround channels are swapped internally in eac3to, affecting all 7.1 sources
- the FFmpeg and eac3to bugs cancel each other out

In the latter case, remapping should always be used when dealing with 7.1 sources, whether downmixing or not:

Code:

-0,1,2,3,6,7,4,5

…except when using the FFmpeg decoder and the source is TrueHD 7.1.

Here are the WAV files output by eac3to:

no remapping: http://www.mediafire.com/?3r35vr7gpg3v008

-0,1,2,3,6,7,4,5: http://www.mediafire.com/?68q021d69doy8va

4th October 2011, 02:06	#11336 \| Link
Rodeo Registered User Join Date: Jul 2011 Posts: 13	So, I was making sure that channel assignments and/or downmixing worked well, and tested eac3to on a bunch of channel checks I had available. The FFmpeg TrueHD decoder was swapping the side and back surround channels. That was fixed recently: http://git.videolan.org/?p=ffmpeg.gi...diff;h=6daf513 Given that eac3to 3.24 is much older than that fix, it should have been affected by the bug - but to my surprise, it wasn't. I used a TrueHD 7.1 channel check available on demo-world.eu I tested it this way: Code: eac3to.exe input.mkv 2: output.wavs and all the channels seemed to be in the correct file, in particular: output.SL.wav -> left side surround output.SR.wav -> right side surround output.BL.wav -> left back surround output.BR.wav -> right back surround So I tested it on a DTS-HD MA 7.1 channel check from the Disney World of Wonder Blu-ray, and got incorrect results: output.SL.wav -> left back surround output.SR.wav -> right back surround output.BL.wav -> left side surround output.BR.wav -> right side surround Code: eac3to.exe -test eac3to (v3.24) is up to date Nero Audio Decoder (Nero 6 or older) doesn't seem to be installed http://www.nero.com/eng/store-blu-ray.html CAUTION: You need Nero 7. Nero 8 won't work with eac3to. ArcSoft DTS Decoder (1.1.0.0) works fine Sonic Audio Decoder (3.24.0.0) doesn't seem to be installed Haali Matroska Muxer (2011-03-03) is up to date Nero AAC Encoder could not be located http://www.nero.com/eng/nero-aac-codec.html Copy NeroAacEnc.exe to the eac3to or to the Windows folder. Surcode DTS Encoder doesn't seem to be installed http://www.surcode.com MkvToolnix (5.0.0.0, release version) is up to date There are a couple possibilities: 1) - the FFmpeg TrueHD decoder is patched in eac3to to fix the channel swap bug, and either: - - a. the Arcsoft DTS decoder is swapping channels - - b. eac3to is remapping channels incorrectly from DTS-HD MA 7.1 sources 2) - the side and back surround channels are swapped internally in eac3to, affecting all 7.1 sources - the FFmpeg and eac3to bugs cancel each other out In the latter case, remapping should always be used when dealing with 7.1 sources, whether downmixing or not: Code: -0,1,2,3,6,7,4,5 …except when using the FFmpeg decoder and the source is TrueHD 7.1. Here are the WAV files output by eac3to: no remapping: http://www.mediafire.com/?3r35vr7gpg3v008 -0,1,2,3,6,7,4,5: http://www.mediafire.com/?68q021d69doy8va Last edited by Rodeo; 4th October 2011 at 02:13.