eac3to 6ch -> 2ch downmix balance issue

[Blue_MiSfit]

Hey all,

When I try to downmix this 6ch AC3 to a 2ch AC3 in eac3to, the audio is heavily biased to the left side. Listening to the 6ch and having ac3filter handle the downmix works perfectly, as does a manual downmix in avisynth.

Any ideas why eac3to can't handle this?

http://www.mediafire.com/?dtmqekkz2mz

Thx..

~MiSfit

[tebasuna51]

Yes, seems the dpl (I and II) downmix (AviSynth, Azid, ...) make the Left channel loud than Right channel.
The simple stereo downmix works fine.

[Blue_MiSfit]

tebasuna51,

Is there any way to do a simple stereo downmix with eac3to?

~MiSfit

[tebasuna51]

Nope, you can use BeLight/BeSweet-Azid or BeHappy-AviSynth methods.

[b66pak]

Yes, seems the dpl (I and II) downmix (AviSynth, Azid, ...) make the Left channel loud than Right channel.

is this an error or is supposed to be like that? (anyway is very disturbing when you listen with headphones)
_

[tebasuna51]

is this an error or is supposed to be like that? (anyway is very disturbing when you listen with headphones)
_

This isn't a error, maybe the original source isn't DD compliant or is a fault in dpl downmix rules.

The dpl downmix isn't perfect and isn't make to listen with headphones.

[leeperry]

the DPLII coeffs in ffdshow are also wrong...they invert the phase on only one channel, so indeed stereo imbalance occurs.

[nurbs]

Might be related: Does anyone know what exactly -phaseShift does in eac3to. I couldn't find a description anywhere.

edit:
Alright, found it in the changelog:
* "-phaseShift" shifts surround channel phase by 90° for DPL II downmixing
Question is if that does it correctly. (+90° left, -90° right if I read that wikipedia article on DPL correctly)

[tebasuna51]

If the ac3 is Dolby Digital compliant the SL-SR channels must be already phase shifted to avoid this problems in downmix.
If SL-SR channels was created for other method (not DD compliant) the phase shift must be used for the Dolby ProLogic downmix.
And with this sample seems work perfectly.

(Sorry I forget the PhaseShift in my previous comment)

[nurbs]

So generally we wouldn't need -phaseShift for DVD/Blu-Ray if we assume the tracks on them were created correctly, right?

[tebasuna51]

So generally we wouldn't need -phaseShift for DVD/Blu-Ray if we assume the tracks on them were created correctly, right?

Exact, because if is already phase shifted a new phase shift destroy the initial.
Read here for more info. (http://forum.doom9.org/showthread.php?t=112122)

[b66pak]

The dpl downmix isn't perfect and isn't make to listen with headphones.

@tebasuna51 could you be kind and provide a downmix protocol for headphones?
_

[tebasuna51]

With non Dolby compliant sources you can try the -phaseShift parameter with eac3to.

Or always you can use the 'simple Stereo' downmix with BeHappy.

[b66pak]

i am asking because i read this in aften help....

[-dheadphon #] Dolby Headphone mode
This code indicates whether or not the program has been
Dolby Headphone-encoded.
0 = not indicated (default)
1 = Not Dolby Headphone encoded
2 = Dolby Headphone encoded

this implies that dolby have a specific headphone downmix protocol...maybe somebody can help...
_

[Blue_MiSfit]

In cases like my sample - the phaseShift parmeter did not help. I had to do a manual channel mix using avisynth (ugh)

This kills batchability for me

~MiSfit

[b66pak]

i found "Dolby Headphone Wrapper DSP, foo_dsp_dolbyhp" by Chungalin here:

http://www.hydrogenaudio.org/forums/index.php?showtopic=39404

I'd like to introduce a DSP I've been developing these weeks. It's a Dolby Headphone wrapper DSP.
After some research on Lake DOLBYHPH.DLL bundled with software DVD players, I was able to find out its protocol used to interface with the client app. Then, why not make it work for myself?! And that was how foo_dsp_dolbyhp was originated. It wraps the functionality of the original DLL to be used under foobar2000. You just need to configure the plugin pointing out the location of that DLL in your system. Of course I'll NOT give any help about how to get that DLL.

how can i use this to downmix a 5.1 source to stereo?
_

[tebasuna51]

You need DOLBYHPH.DLL installed in your system.

Install Foobar2000, put foo_dsp_dolbyhp.dll in Foobar2000\Components
Open your source file in Foobar2000, rightclick over the source adn select Convert -> ...
Configure the Convert Setup ... (Output format, etc)
In Processing Tab check DSP, select and configure the foo_dsp_dolbyhp component (seems ask for location of DOLBYHPH.DLL)

[b66pak]

@tebasuna51 i have done all of this...
_

L.E. i got it working...the problem was with the .wav header...this is unsupported:

Audio
Format : PCM
Format settings, Endianness : Little
Format settings, Sign : Unsigned
Codec ID : 00001000-0000-0100-8000-00AA00389B71
Codec ID/Hint : Microsoft
Duration : 1mn 33s
Bit rate mode : Constant
Bit rate : 4 608 Kbps
Channel(s) : 6 channels
Channel positions : Front: L, C, R, Middle: L, R, LFE
Sampling rate : 48.0 KHz
Resolution : 16 bits


i used eac3to (-simple switch) to convert to this:

ID : 0
Format : PCM
Codec ID : 1
Codec ID/Hint : Microsoft
Duration : 1mn 33s
Bit rate : 4 608 Kbps
Channel(s) : 6 channels
Sampling rate : 48.0 KHz
Resolution : 16 bits

witch is supported...
_

[tebasuna51]

@tebasuna51 i have done all of this...then i added "convert 5.1 to stereo" and hit OK...
You need add "Dolby HeadPhone" instead "convert 5.1 to stereo" (a simple downmix mode included in Foobar2000) and 'Configure selected', then you put the 'Location' of DOLBYHPH.DLL and select the
'Room model'

Works for me without problems.

[b66pak]

thanks a lot..like you indicated...i got it working...happy new year!
_

[robertcollier4]

Downmixing this way works for me:
eac3to.exe E:\Sourcefile.ac3 E:\Outfile.wav -down2 -mixlfe