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Old 17th July 2003, 09:44   #1  |  Link
bleo
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Guide: 2- to 5-channel upmix using Dolby Pro Logic II

This procedure is similar in purpose to GUIDE: Stereo to 5-Channel Surround but uses Dolby Pro Logic II upmixing.

You can upmix any 2-channel audio format as long as you have the appropriate DirectShow decoder filter installed.

Software required:
- InterVideo WinDVD (http://www.intervideo.com/)
- GraphEdit (http://www.doom9.org/Soft21/Audio/graphedit.rar)
- A hex editor e.g. XVI32 (http://www.chmaas.handshake.de/delph...vi32/xvi32.htm)

Procedure:
- In GraphEdit go to File > Render Media File... > Open your 2-channel audio file
- Delete the Default DirectSound Device filter
- Go to Graph > Insert Filters... > DirectShow Filters > InterVideo Audio Processor Fx > Insert Filter
- Also insert the WAV Dest filter and File writer filter with an output filename e.g. output.wav
- Connect the audio decoder to InterVideo Audio Processor Fx, then WAV Dest, then the File writer filter
- Right click the InterVideo Audio Processor Fx filter > Filter Properties... > 6 SPEAKER
- Go to InterVideo Container DMO > InterVideo EXP DMO > Append <---
- Click Play and then immediately click Stop to 'initialise' the filter
- Go back to Filter Properties > InterVideo EXP DMO tab > ProLogic2
- Click Play and wait until the button reactivates
- The output file has an incorrect 2-channel WaveFormatEx header!
- Use a hex editor to change:
- nChannels at 16 from 02 to 06
- nAvgBytesPerSec at 1C from 00 EE 02 to 00 CA 08 if your audio is 48 KHz, or from 10 B1 02 to 30 13 08 if it is 44.1 KHz
- nBlockAlign at 20 from 04 to 0C
- You now have a Dolby Pro Logic II upmixed 6-channel WAV file! (empty .1 channel)
- You can reencode it to AC3, AAC, Ogg Vorbis, RealAudio, DTS, WMA9Pro, et al, multi-channel formats using the appropriate programs

Let me know your feedback/problems! Good luck!

BeSplit:
- The demuxed mono output files also have incorrect WAV headers. Use your handy hex editor to change nBlockAlign at 20 from 06 to 02.
- The channel ordering is FL FR C LFE BL BR

WMA9Pro:
Requires WaveFormatExtensible header for direct loading of 6-channel WAV. Use your hex editor to change:
- riffSIZE at 4, add 0x16 to the DWORD here (note little-endian byte order)
- fmtSIZE at 10 from 12 to 28
- wFormatTag at 14 from 01 00 to FE FF
- cbSize at 24 from 00 to 16
- insert at 26, 10 00 3F 00 00 00 01 00 00 00 00 00 10 00 80 00 00 AA 00 38 9B 71

Notes:
- Feel free to tweak the settings on the InterVideo EXP DMO tab to your liking! In general, use Movie mode for DPL(2) encoded material and Music mode if not.
- InterVideo's filter seems to silence the first second of audio...
- Has anyone got a better solution to the WAV header hacking e.g. an automatic program or a better WAV wrapper?

Edit: argh! On closer inspection, there appears to be a bug in the CyberLink filter where it only does DPL ONE upmixing i.e., the surround channels are identical. Is there a registry/filter hack to invoke DPL2?

I have changed the guide to use InterVideo's filter

Last edited by bleo; 27th July 2003 at 11:47.
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Old 17th July 2003, 19:49   #2  |  Link
Sycho
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wouldn't it be better if it was in movie mode
music mode is meant for music, not very presice localization

movie mode is very presice, and the surround left is the information between the left and surround, the right surround in the information between the right and surround
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Old 18th July 2003, 01:31   #3  |  Link
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@bleo

What are you using to split the 6 chan wav?

I tried besplit and wav2wav6 and got 6 mono files, but there's no volume in them.
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Old 18th July 2003, 04:09   #4  |  Link
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@sycho
From Roger Dressler. Dolby Surround Pro Logic II Decoder Principles of Operation. http://www.dolby.com/tech/l.wh.0007.PLIIops.html

The Movie mode uses sufficient delay in the surround channels to ensure the sounds from the front speakers arrive at least 10 ms before the sounds from the surround speakers. This creates the Haas precedence effect, which helps ensure dialogue and other frontal sounds intended to relate with the on-screen action are actually perceived as originating there.

The goal for music playback is to have the sounds from all the speakers arrive at the listener at the same time, which is known as coincident arrival. This helps prevent any smearing or combing of the sounds as they combine from the various speakers.

There is a mild high-frequency shelf filter provided in the surround channels for the Music mode. It results in a more natural, believable soundfield, since ambient sounds normally have a high-frequency rolloff induced by room reflections and absorption.

Lastly, the autobalance is turned off in Music mode, considering vocalists are sometimes deliberately placed off center in the mix.


So which mode you choose depends on your source and preference!
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Old 18th July 2003, 05:40   #5  |  Link
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@SallyDog
...well the truth is I never tried splitting it... but I did try BeSplit just then and got some strange mono WaveFormatEx files that played like chipmunks... Can anyone else help? Perhaps something along the lines of stripping the header and writing a new mono WaveFormatPCM header?...
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Old 21st July 2003, 03:32   #6  |  Link
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I found that using Wav2wav6 on the resultent intervideo file splits okay. (just don't use the -44 option as it seems to screw up the file sizes, and surcode complains)

Remap the resultent files from
FR to C
FL to FL
C to FR
SL to sub (the blank file BTW)
SR to SR
Sub to SL

If these are wrong let me know (I,m working on best guess here)


The files play fine as are.
Also you can use cool edit pro 2 to add a perfct subwoofer channel into the mix.

Take the original stero wave and open it in CE.
Then Edit -> Convert Sample Type -> Mono,50%, 50%, 16bit, 44100.
This creates mono file to work with.
Then Effects -> Filters -> FFT Filter -> Preset to only the subwoofer.
You now have a sub channel - be warned that you may need to de-amplify this file as it can override the sub by being to high in volume.

Hope this helps
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Old 21st July 2003, 06:23   #7  |  Link
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Is this really that much better than just takin AC3 audio with 2 channels and enabling Pro Logic or DSP so all 5 speakers create the effect?
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Old 21st July 2003, 12:53   #8  |  Link
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@Hello
This is the SAME as what you suggested, BUT allows you to output the 5 channels to a WAV file and process it!
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Old 22nd July 2003, 07:44   #9  |  Link
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Yeah, but I don't know if it's making true, 5 channels and not some effect that I can enable without this.
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Old 23rd July 2003, 06:41   #10  |  Link
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@Hello
hmm... I'm not sure I understand what you mean... The procedure will give you the same 5 channels as if you went into WinDVD and played a 2-channel file straight to your 5 speakers using 'Dolby PLII', BUT it writes the audio to a WAV file. I suggest you try WinDVD first and see if you like the output.

The procedure makes 'true' 5 channels, as in, they are all different. BUT, the contents of those 5 channels depends on your source. If it was Dolby Surround 2 encoded, then it will decode to 5 channels as the producer intended. If it wasn't, then DPL2 will attempt to use the phase information present in the audio to create two surround channels. Obviously, the results will vary greatly!
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Old 23rd July 2003, 23:26   #11  |  Link
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how exactaly do you change the wav header?
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Old 24th July 2003, 06:17   #12  |  Link
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@sycho
Use the hex editor XVI32 to load up your WAV file. Go to the byte addresses (shown in the lower left corner as 'Adr. hex') that I have specified and change the bytes to the correct values. Note, the actual field names, e.g. nChannels, are not seen in the WAV header.
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Old 24th July 2003, 22:54   #13  |  Link
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thanx, i was a little confused at first but now i got it

Last edited by Sycho; 24th July 2003 at 22:57.
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Old 24th July 2003, 23:22   #14  |  Link
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what would you change in the headed if it decoded 3/0?
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Old 25th July 2003, 01:55   #15  |  Link
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For 3/0:
nChannels = 03
nAvgBytesPerSec (nBlockAlign x samples per second) = 00 65 04 (48 KHz) or 98 09 04 (44.1 KHz)
nBlockAlign (bytes per sample x nChannels) = 06
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Old 16th April 2004, 18:26   #16  |  Link
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My first post (what's up with the damn 5-day waiting period?)

I'm currently capturing the SW LDs with my Sony digital camcorder (video pass-through), and there's definitely pro-logic steering going on (I have the Logitech Z640 5.1 speaker system)

What I would like to do, however, is capture the LPCM soundtrack directly off the laserdisc and steer the soundtrack into 4 .wav's (L,C,R,S - possibly an LFE as well) so that I can make and remix a DD 5.1 soundtrack (i.e. better surround effects.)

Will Besweet do this? If I want to use Pro-Logic II, is there a program that will do this.

BTW, please don't tell me to run it through my receiver. I want to avoid unnecessary A/D conversions, and my reciever is nowhere next to my computer. Additionally, I don't want to record 2 channels at a time and have to re-sync the files on the computer. I'd like to do all this in the computer as much as possible.

Similarly, I don't want a 2.0 soundtrack, because these usually sound better in Pro-logic mode anyways. I'd rather just have a 5.1 soundtrack, so I don't have to switch modes.
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Old 16th April 2004, 20:41   #17  |  Link
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You will find a Dolby Pro-Logic VST encoder here

http://multiphonie.free.fr/index_nouveau.htm

Use it in Bidule or other VST 'Enabled' program. EG Nuendo
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Old 16th April 2004, 22:06   #18  |  Link
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Will this decode as well? I need to split the file, not encode it.

(My firewall at work won't let me see the site - I'll have to wait until I get home.)
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Old 16th April 2004, 22:38   #19  |  Link
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There is also a decoder as well.

The site is in French. The files you want are towards the bottom of the page.
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Old 16th April 2004, 23:43   #20  |  Link
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can you just link to the plugins please?
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