Multichannel 5.1 speed up + pitch adjustment

[FranceBB]

Hi there,
I have a 24p movie that I'm trying to speed up by 4% and pitch adjust so that it's gonna be 25p.
This is not something new as I've been doing it other times for stereo contents by using TimeStretch().

For stereo contents, to avoid having the left and right channels go out of phase and generate flanger effect (i.e the audio oscillating constantly from left to right) I use MergeChannels() before calling TimeStretch() so that both channels are processed together and timestretch is aware of it so that it doesn't make them out of phase.

In other words:

#Indexing 24p video & audio
video=LWLibavVideoSource("M11340.m2v")
Left=WAVSource("M11340_Left.wav")
Right=WAVSource("M11340_Right.wav")
audio=MergeChannels(Left, Right)
AudioDub(video, audio)

#Speed up + pitch adjustment 4% 48000Hz
ConvertAudioToFloat()
AssumeFPS(25, 1, false)
TimeStretch(tempo=100.0*25.0/(24000.0/1000.0))
SSRC(48000)
ConvertAudioTo24bit()

So far so good, but the question is: what happens with 5.1?
Can I just do:

#Indexing 24p video & audio
video=LWLibavVideoSource("M11340.m2v")
FL=WAVSource("M11340_01.wav")
FR=WAVSource("M11340_02.wav")
CC=WAVSource("M11340_03.wav")
LFE=WAVSource("M11340_04.wav")
LS=WAVSource("M11340_05.wav")
RS=WAVSource("M11340_06.wav")
audio=MergeChannels(FL, FR, CC, LFE, LS, RS)
AudioDub(video, audio)

#Speed up + pitch adjustment 4% 48000Hz
ConvertAudioToFloat()
AssumeFPS(25, 1, false)
TimeStretch(tempo=100.0*25.0/(24000.0/1000.0))
SSRC(48000)
ConvertAudioTo24bit()

and call it a day?
And if so, what is TimeStretch() actually doing with the 5.1? Do I have to specify the audio layout in the frame properties? Is it gonna know that it's a 5.1 or is it only gonna process the stream as 3 stereo pairs (i.e FL FR // CC, LFE // LS, RS)?

Last but not least, given that the output PCM 24bit 48000Hz audio file muxed as RF64 .wav is gonna be fed to a DolbyE encoder (Dolby DP600) which needs the 5.1+2.0, do I have to filter them separately 'cause otherwise TimeStretch() is gonna make a boo boo or can I just do something like:

#Indexing 24p video & audio
video=LWLibavVideoSource("M11340.m2v")
FL=WAVSource("M11340_01.wav")
FR=WAVSource("M11340_02.wav")
CC=WAVSource("M11340_03.wav")
LFE=WAVSource("M11340_04.wav")
LS=WAVSource("M11340_05.wav")
RS=WAVSource("M11340_06.wav")
Left=WAVSource("M11340_Left.wav")
Right=WAVSource("M11340_Right.wav")
audio=MergeChannels(FL, FR, CC, LFE, LS, RS, Left, Right)
AudioDub(video, audio)

#Speed up + pitch adjustment 4% 48000Hz
ConvertAudioToFloat()
AssumeFPS(25, 1, false)
TimeStretch(tempo=100.0*25.0/(24000.0/1000.0))
SSRC(48000)
ConvertAudioTo24bit()

Thank you in advance.
I'm currently trying to test stuff but I don't really trust my ears, you know...

[coolgit]

Try Audacity as other people have said it will speed up properly without pitch blah blah.

[FranceBB]

To be fair, the point isn't to try other things manually but rather to know whether I should correct my AVS Script or not, 'cause most of the time those would be part of a completely automatized workflow in FFAStrans, so... yeah... I kinda need to know.
Also, I'm extremely curious about the inner working of TimeStretch() and the SoundTouch library.

[hello_hello]

I thought the TimeStretch multichannel issues had been fixed. Is there still a phasing problem?
https://forum.doom9.org/showpost.php...2&postcount=20

The SoundTouch changelog says multichannel support was added to version 1.8.0, which was a fair while ago.
http://www.surina.net/soundtouch/README.html

[tebasuna51]

In the readme of Avs+:
- Updated: TimeStretch plugin with SoundTouch 2.1.3 (as of 07.Jan 2019)

But I don't know if work fine with 5.1+2.0