MixAudio() produces stitches

[keytouch]

MixAudio() produces stitches.
When using MeGUI's downmix function

function c6_stereo(clip a)
{
fl = GetChannel(a, 1)
fr = GetChannel(a, 2)
fc = GetChannel(a, 3)
lf = GetChannel(a, 4)
sl = GetChannel(a, 5)
sr = GetChannel(a, 6)
fl_sl = MixAudio(fl, sl, 0.2929, 0.2929)
fr_sr = MixAudio(fr, sr, 0.2929, 0.2929)
fc_lf = MixAudio(fc, lf, 0.2071, 0.2071)
l = MixAudio(fl_sl, fc_lf, 1.0, 1.0)
r = MixAudio(fr_sr, fc_lf, 1.0, 1.0)
return MergeChannels(l, r)
}

It produces stitches. Additionally, the process speed is much lower than using official avs2.6 when MixAudio() is engaged.
Here's the file that can reproduce the issue without difficulty.
test.zip
When using official avs2.6, I tried to find anything wrong, but it works well.

[keytouch]

Besides, Output using megui's wrapper produces much more stitches than using avs2pipemod

[pinterf]

Hi, x86 or x64?

[keytouch]

It was on x86, I will have a test on x64 now.

[keytouch]

It's the same behaviour on x64.

[pinterf]

-what is the speed difference you encounter (cacheing - if any - I suppose is totally different between classic and avs+)
-what's your avspipemod commandline (to test similarly)
My script now:
function c6_stereo(clip a)
{
fl = GetChannel(a, 1)
fr = GetChannel(a, 2)
fc = GetChannel(a, 3)
lf = GetChannel(a, 4)
sl = GetChannel(a, 5)
sr = GetChannel(a, 6)
fl_sl = MixAudio(fl, sl, 0.2929, 0.2929)
fr_sr = MixAudio(fr, sr, 0.2929, 0.2929)
fc_lf = MixAudio(fc, lf, 0.2071, 0.2071)
l = MixAudio(fl_sl, fc_lf, 1.0, 1.0)
r = MixAudio(fr_sr, fc_lf, 1.0, 1.0)
return MergeChannels(l, r)
}

a=FFAudioSource("original_dts-hd.dts")
v=BlankClip(length=10000000)
AudioDub(v,c6_stereo(a))#.Info()

[keytouch]

Weirder now, with,

function c6_stereo(clip a)
{
fl = GetChannel(a, 1)
fr = GetChannel(a, 2)
fc = GetChannel(a, 3)
lf = GetChannel(a, 4)
sl = GetChannel(a, 5)
sr = GetChannel(a, 6)
fl_sl = MixAudio(fl, sl, 0.2929, 0.2929)
fr_sr = MixAudio(fr, sr, 0.2929, 0.2929)
fc_lf = MixAudio(fc, lf, 0.2071, 0.2071)
l = MixAudio(fl_sl, fc_lf, 1.0, 1.0)
r = MixAudio(fr_sr, fc_lf, 1.0, 1.0)
return MergeChannels(l, r)
}
a=FFAudioSource("original_dts-hd.dts")
v=BlankClip(length=10000000)
AudioDub(v,c6_stereo(a))#.Info()

It's good, AND speed is normal.
HOWEVER, with,

function c6_stereo(clip a)
{
fl = GetChannel(a, 1)
fr = GetChannel(a, 2)
fc = GetChannel(a, 3)
lf = GetChannel(a, 4)
sl = GetChannel(a, 5)
sr = GetChannel(a, 6)
fl_sl = MixAudio(fl, sl, 0.2929, 0.2929)
fr_sr = MixAudio(fr, sr, 0.2929, 0.2929)
fc_lf = MixAudio(fc, lf, 0.2071, 0.2071)
l = MixAudio(fl_sl, fc_lf, 1.0, 1.0)
r = MixAudio(fr_sr, fc_lf, 1.0, 1.0)
return MergeChannels(l, r)
}
a=LWLibavAudioSource("original_dts-hd.dts")
v=BlankClip(length=10000000)
AudioDub(v,c6_stereo(a))#.Info()

It comes again, with slow speed.

[keytouch]

I will first investigate a bit into bit comparison of ff and lsmash alone for sake of consistency.

[keytouch]

All tracks decoded fine, no differences found.

Comparing:
"C:\Users\\Desktop\test_alone_ff.flac"
"C:\Users\\Desktop\test_alone_lm.flac"
Compared 3081216 samples.
No differences in decoded data found.
Channel peaks: 0.0781555 0.1070557 0.2019653 0.0453491 0.0375061 0.0741272

Total duration processed: 1:04.192
Time elapsed: 0:00.698
91.98x realtime

[keytouch]

The above result is performed without any mixdown or process other than source filter.

[keytouch]

avs2pipemod.exe -wav test.avs > testout.wav
same behaviour as directly inputting avs in megui.

FFAudioSource() == LWLibavAudioSource() == GOOD
FFAudioSource() + c6_stereo() != LWLibavAudioSource() + c6_stereo()
FFAudioSource() + c6_stereo() == GOOD

[keytouch]

avs2pipemod test batch
test1.zip
ff_stereo.wav and lw_stereo.wav won't match.
ff.wav and lw.wav match.