MeGUI downmix question

[MatzeXXX]

Hi,

I am new to MeGUI, after having used AutoGK for many years. So that's why I kinda compare MeGUI to AutoGK.

The question I'm having right now concerns audio: I always downmix my DVD source material to stereo, because I don't need more. AutoGK is doing quite some work to achieve best results: For example the LFE channel is reduced in it's volume, etc.

Is MeGUI doing stuff like that too? Because in the settings for Vorbis (that's what I'm using in MeGUI) there aren't that many options - and nothing to specify the way the channels are downmixed.

And also: If I was fine with Lame MP3 128kbit ABR, I should be fine with OGG Quality 2, right? It sounds ok to me so far...

Thanks!

Matthias

[tebasuna51]

With MeGUI you have the 3 standard downmix: stereo, Dolby ProLogic and Dolby ProLogic II
If you need other downmix you can use BeHappy or make your own avs downmix file.

[MatzeXXX]

With MeGUI you have the 3 standard downmix: stereo, Dolby ProLogic and Dolby ProLogic II
If you need other downmix you can use BeHappy or make your own avs downmix file.

Hi! Thanks for the quick reply.

I am only interested in the Downmix to Stereo, and my question would be how MeGUI (or Vorbis?) combines the channels?

Matthias

[tebasuna51]

You have the log:
--[NoImage] Avisynth script
---[NoImage] NicAc3Source("D:\Test\AudioD\Samples\ac3\6a321.ac3")
---[NoImage] 6<=Audiochannels(last)?x_stereoc4ccf21cf7254473ac1e98873fdd1f6f(ConvertAudioToFloat(last)):last
---[NoImage] Normalize()
---[NoImage] 32==Audiobits(last)?ConvertAudioTo16bit(last):last
---[NoImage] return last
---[NoImage] function x_stereoc4ccf21cf7254473ac1e98873fdd1f6f(clip a)
---[NoImage] {
---[NoImage] fl = GetChannel(a, 1)
---[NoImage] fr = GetChannel(a, 2)
---[NoImage] c = GetChannel(a, 3)
---[NoImage] lfe = GetChannel(a, 4)
---[NoImage] sl = GetChannel(a, 5)
---[NoImage] sr = GetChannel(a, 6)
---[NoImage] l_sl = MixAudio(fl, sl, 0.2929, 0.2929)
---[NoImage] c_lfe = MixAudio(lfe, c, 0.2071, 0.2071)
---[NoImage] r_sr = MixAudio(fr, sr, 0.2929, 0.2929)
---[NoImage] l = MixAudio(l_sl, c_lfe, 1.0, 1.0)
---[NoImage] r = MixAudio(r_sr, c_lfe, 1.0, 1.0)
---[NoImage] return MergeChannels(l, r)
---[NoImage] }
--[NoImage] Commandline used: -b 128 --cbr -h - "{0}"
The stereo mix is:

FL' = 0.2929 x FL + 0.2071 x FC + 0.2071 x LF + 0.2929 x SL
FR' = 0.2929 x FR + 0.2071 x FC + 0.2071 x LF + 0.2929 x SR

[MatzeXXX]

The stereo mix is:

FL' = 0.2929 x FL + 0.2071 x FC + 0.2071 x LF + 0.2929 x SL
FR' = 0.2929 x FR + 0.2071 x FC + 0.2071 x LF + 0.2929 x SR

sounds complicated enough for me ;)

thanks!

matthias