Hi
Been fiddling a bit with a soundtrack in 5.1 surround from a dvd. It's a film and has an extra DVD with extra features and also full soundtrack of film in 5.1.
Both a Sony DVD player, Panasonic BD player play severely distorted surround as it mixes to stereo, I assume. Don't have surround system.
On PC VLC player the same as those above.
Kind of digital clipping type of unclean, but really low level and a bit like bassy mostly.
There is some audio of LF channel in parts.
But on PC MPC-HC player play it beautyfully and no distortion whatever I do.
It says AC3 48k 16bit 6 channels audio.
Kudos to the guys that made MPC-HC I must say.
On MPC HC I tried turn off all volume compensation and clipping adjustments.
Tried turn off one by one of the 6 channels, mapping them to each other just stereo.
But not distortion to hear, and no overs either - most of it is rather low level, but still distorts on those other devices.
MPC HC also has matrix mapping, which also I believe are some volume adjustments of channels - and tried Dolby Pro Logic and Dolby Pro Logic II - but still no distortion.
So what possibly make these devices that fail to play nicely to fail?
I played loads of DVD music concerts and films for 11 years on the Sony and two years on the Panasonic - and it never sound bad on playing the regular films. Even the main film for this box play just fine, which has the soundtrack included but guess very different levels with video I suppose.
Any ideas?
Failed decoding somehow or just strange volume mapping that does not fit this particular material?
But MPC HC - how did they do it?
I'd like to dive in and possibly learn something.
Thanks.
Strange surround 5.1 distortion on DVD, BD and VLC players but MPC-HC is fine?
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- KVRAF
- 16840 posts since 8 Mar, 2005 from Utrecht, Holland
Idea: record the s/pdif outputs of the HW players, and inspect the raw waveforms. Or easier: record the output of VLC to WAV. Use a simple audio editor and compare them with the raw tracks on MPC-HC. Same volume, same 5.1 -> stereo mixing matrix?
We are the KVR collective. Resistance is futile. You will be assimilated. 
My MusicCalc is served over https!!
My MusicCalc is served over https!!
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- KVRAF
- Topic Starter
- 7104 posts since 22 Jan, 2005 from Sweden
Thanks, seems like good ideas.
First I come to think of - if instead setting hw output to bitstream, so you get 6 channels right out - are there any recording software that can handle that from an optical?
To just experiment a bit and set different mixes for surround to stereo and compare with how other players do it?
Since distorting already at -30dB levels on peak meters it's something about how they are mixed and not attenuating enough what they mix.
Look at some controls in MPC-HC that I never got a function from - mixing of main two channels, surround channels and LF channel - the LF channel is set really far left to give just 70% mix. The two main and surround become 70% at maybe 80% of sliders to the right. Putting LF slider same position you got 250% level or something instead of 70%.
So currently I suspect something funny with LF channel and level in how this is mixed to stereo - and MPC-HC folks were experienced in sensing how to handle LF channel.
I get functionality from various checkboxes in that Mix tab of Audio, but notice nothing from sliders changing levels. Just on first tab there - I can disable certain channels and here how levels go up the fewer are active.
I have RME internal cards - and there are various checkboxes to set if raw data, or how they put it - and if this might be a way to extract it?
I succeded over the years to extract audio directly from vob files with AnyVideoConverter, will make that as a test as well and see if I get surround as well.
EDIT: Did not go well, it stopped at 4 min but vob is 37 min.
Found this AC3Filter www.ac3filter.net which seems to have options to convert to stream over spdif and other things.
EDIT2: It seems this soundtrack is horribly mixed. Got the separate channels out and they distort really bad from something that probably should be left in LFE channel, earthquake kind of rumble bass in there that f**ks up strings and everything else. Broken speaker kind of trashed sound.
VLC was just worse on PC, with the layers it goes through before audio interface. MPC HC was that much better, but best were FooBar2000 with proper ASIO driver there.
Trying in Cubase now to see if I can HP channels to get this out, but conversions from AC3 has probably degraded quality itself possibly.
This was the Soundtrack of Hans Zimmer for the film Inception which is cool. But this soundtrack they provided separately as a feature on second DVD was not up to par, I think.
So that was that.
First I come to think of - if instead setting hw output to bitstream, so you get 6 channels right out - are there any recording software that can handle that from an optical?
To just experiment a bit and set different mixes for surround to stereo and compare with how other players do it?
Since distorting already at -30dB levels on peak meters it's something about how they are mixed and not attenuating enough what they mix.
Look at some controls in MPC-HC that I never got a function from - mixing of main two channels, surround channels and LF channel - the LF channel is set really far left to give just 70% mix. The two main and surround become 70% at maybe 80% of sliders to the right. Putting LF slider same position you got 250% level or something instead of 70%.
So currently I suspect something funny with LF channel and level in how this is mixed to stereo - and MPC-HC folks were experienced in sensing how to handle LF channel.
I get functionality from various checkboxes in that Mix tab of Audio, but notice nothing from sliders changing levels. Just on first tab there - I can disable certain channels and here how levels go up the fewer are active.
I have RME internal cards - and there are various checkboxes to set if raw data, or how they put it - and if this might be a way to extract it?
I succeded over the years to extract audio directly from vob files with AnyVideoConverter, will make that as a test as well and see if I get surround as well.
EDIT: Did not go well, it stopped at 4 min but vob is 37 min.
Found this AC3Filter www.ac3filter.net which seems to have options to convert to stream over spdif and other things.
EDIT2: It seems this soundtrack is horribly mixed. Got the separate channels out and they distort really bad from something that probably should be left in LFE channel, earthquake kind of rumble bass in there that f**ks up strings and everything else. Broken speaker kind of trashed sound.
VLC was just worse on PC, with the layers it goes through before audio interface. MPC HC was that much better, but best were FooBar2000 with proper ASIO driver there.
Trying in Cubase now to see if I can HP channels to get this out, but conversions from AC3 has probably degraded quality itself possibly.
This was the Soundtrack of Hans Zimmer for the film Inception which is cool. But this soundtrack they provided separately as a feature on second DVD was not up to par, I think.
So that was that.