LPCM/AC3 -> AC3/MP2 (5.1ch -> 2ch) during Backup

[Malcolm]

Hi everyone,
in my DVD backups with DVD-Rebuilder, i'd like to convert the audio-streams from AC3 to MP2 (5.1ch -> 2ch) using bitrates like 128 kbit instead of 448 kbit to gain some space for the video-part.
Can this be automated/integrated in DVD Rebuilder?

Thanks,
Malcolm

[jhmac]

That is not a feature I would use, Audio is as important to me as the video quality...

[jdobbs]

Also, if you want to comply with the DVD Spec for NTSC you have to have at least one AC3 track... I'd say the industry is moving away from MPEG audio on DVDs rather than toward it.

What would be the advantage of converting from AC3 to MPEG audio? You can get pretty decent 2 channel audio at 192Kbs with AC3, and most 2 channel MPEG audio is at 224Kbs.

[DDogg]

Has anybody got their fingers on the effect of downcoding AC3, say 448 to 224? It is a way to save a whopping amount of BR, but I have never seen a definitive statement of any negative effects. Maybe I'll ask Kpex to comment. He ought to know.

Jdobbs, I vaguely remember this topic came up before and after further research, the person came back and said an AC3 was not required on a DVD and that MP2's were also within standard. I'm not saying that is correct, just that it may bare further checking.

[insanescape]

I've learned not to bother sacrificing sound, especially since, at most, you'd add what, 1-3% more to the video by making the sound mp2 instead of 5.1 ac3? It's going to be a pathetically small amount. You'd probably be better off running the menus through dvdshrink before you even tried to mess with the audio.

[DDogg]

I've learned not to bother sacrificing sound, ... Quantify please :) Have you done this and you could hear a difference? I would not call adding 200 to 400 megs for video a small amount!

[Malcolm]

as far as i know, MP2 is fine for DVDs. No need to have an AC3 Track.

@jdobbs:
Why i'm using MP2 instead of AC3? Well, i've made no good experience using AC3 as encoding format. I've converted high-bitrate MP2 to low-bitrate AC3 (2ch). the sound was amplified and clipping occured. i guess that's because of built-in dynamic-range compression/decompression.
if you can tell me a way to produce good sounding AC3-encodings, i'll use AC3 instead of MP2 (to gain some more space). i guess i can go to lower bitrates with 2ch-AC3 than 2ch-MP2 while retaining the same quality.

@DDogg:
i totally agree!

@jhmac
Well you don't HAVE to use this feature. But i'd like to! o.k.??? :)
Short explanation why i don't care much for 5.1-sound: there are a lot of DVDs which have 5.1-AC3 sound ONLY for the english audio-track. but my preferred audio language is german and english is only a bonus. so i'd like to have it on my backup, but i dont want to spend 400 MB or more for it! understand?!! ;)
second reason: i don't have a surround equipment. and i'm not interested in it! :)

greetings,
Malcolm

[KpeX]

Disclaimer: everything in this post is somewhat subjective, and the only way to answer these questions for sure is to test with your ears and your equipment.

Regarding bitrates: Although there have been no formal tests, the traditionally accepted minimum bitrate for transcoding AC3 with decent quality was 224 kbps for 5.1. For both MP2 and AC3, 128 kbps is a good minimum for stereo. Although if you have good ears or good equipment, you may notice some sound degradation at these qualities.

Regarding MP2 vs. AC3: The advantage of MP2 is that the free encoders available are quite good quality (toolame, mp2enc, etc.), whereas the only free AC3 encoder (ffmpeg) is not on par quality-wise with commercial encoders. The advantage of AC3 is that it is more universally playable. I haven't found many DVD players here in NTSC land that can handle MP2 audio (regardless of whether it is in spec or not).

All that being said, IMO even transcoding a 5.1 448 kbps AC3 stream to 128 kbps MP2 will not boost your video quality that much when talking about DVD conversions. Some quick math for an example: say you have a video clip you're trying to fit on a DVD-5 with one audio track, and your choice is whether to keep the 448 kbps 5.1 AC3 or transcode to 128 kbps MP2, with total alloted bitrate X. Therefore the percent video bitrate increase achieved by transcoding will be 100*(((X-128)/(X-448))-1).

At 9800 total bitrate: %increase = 100*(((9800-128)/(9800-448))-1) = 3.42% video bitrate increase

At 5500 total bitrate: 100*(((5500-128)/(9800-448))-1) = 6.33 % video bitrate increase

At 2500 total bitrate: 100* (((2500-128)/(2500-448))-1) = 15.6 % video bitrate increase

Would you consider the first two significant increases? I wouldn't, really. So even doing a drastic reduction in audio bitrate will only result in a significant video increase at low bitrates.

Come to think of it, I don't even know what type of bitrates are typical when doing a DVD-RB type conversion. But anyways, that's for you video geeks to work on. This audio geek is going back to finals.

[Malcolm]

@KpeX
Thank you! Your post is very interesting!
good to know what we're talking about here. Means: how much space is possible to gain and the differences between AC3 and MP2!

I would say bitrates between 2500 and 5500 are very common on DVDs. Especially if you shrink them from 9 gig to 5 gig. So a gain between 6% to 15% is a lot (IMHO)!! That's the difference between having unacceptable 60% in DVD-Shrink/ReJig/etc. and having acceptable 75%!!

You also have to consider having multiple audio-tracks on your backup (e.g. german + english). so it's even more important because they add up!

Btw. it makes me wonder that there are DVD-player that can't handle MP2 audio. i live in Europe an i've never heared of such. i mean, all SVCDs have MP2 as audio track. So i thought every DVD-player should be able to handle it. But o.k. maybe that's the case in NTSC-land.

So i would still say it's a good idea to use BeSweet inside DVD Rebuilder to compress also the audio-tracks!

Greetings,
Malcolm

[insanescape]

DDog: in most cases it'll be about 200-225 meg difference going from 448 5.1 to 128 mp2/ac3 (sub-par IMO, but we'll give the benefit of the doubt). When you're talking about almost 3 1/2 gigs of video, does anyone really think adding a mere couple hundred megs spread out over an hour and a half is going to change much? When you're already degrading the video, might as well keep the audio experience intact. Hell, if quality doesn't matter might as well record it to vhs.

Edit: If you're going to get a 15% boost in video from any audio conversion, you're going to be looking at a pretty damn poor video quality to begin with (what's 2500kbps, 3 hours or so?)

[Joergen]

Imho you cant go below 192kbit for MP2 and you need a GOOD encoder like 2lame. Encoders like TMPEGenc give awful results at any bitrate from what I've tried.

192kbit or higher is usually what you find in DVB-transmissions. If a channel is 128kbit you can really hear it with annoying hiss/breakup of the higher frequencies.

[jdobbs]

Originally posted by DDogg
Has anybody got their fingers on the effect of downcoding AC3, say 448 to 224? It is a way to save a whopping amount of BR, but I have never seen a definitive statement of any negative effects. Maybe I'll ask Kpex to comment. He ought to know.

Jdobbs, I vaguely remember this topic came up before and after further research, the person came back and said an AC3 was not required on a DVD and that MP2's were also within standard. I'm not saying that is correct, just that it may bare further checking. If you were going to do that it would make more sense to downcoding from 448 (5 channel) to 192Kbs (2 Channel w/Dolby surround) which is standard. There are several packages that can do that already... for example I used to do it all the time using DVD2AVI's downsampling and SoftEncode to reencode to 192Kbs AC3.

The person who said it wasn't required was wrong for NTSC... it is not required for PAL. There was a disagreement in the committees for the standard. I think PAL is an either/or between AC3 and MPEG audio. For NTSC AC3 is required, even if you have MPEG audio.

[jdobbs]

Originally posted by Joergen
Imho you cant go below 192kbit for MP2 and you need a GOOD encoder like 2lame. Encoders like TMPEGenc give awful results at any bitrate from what I've tried.

192kbit or higher is usually what you find in DVB-transmissions. If a channel is 128kbit you can really hear it with annoying hiss/breakup of the higher frequencies. I agree. You will find that 192Kbs is almost exclusively the bitrate used for 2 channel AC3 audio on commercial DVDs.

[DDogg]

insanescape, I take you point. I guess I was thinking that dvd-rb allows keeping all the different soundtracks and that two or three down-coded could make a big difference.

IMO, nothing does a better job of recoding the AC3 to Dolby surround MP2 like BeSweet as used by the D2S process. Frankly, Ive never seen a DVD player that can not use MP2s for DVDs. However, if I wanted to do that I would just do XSVCD spec at 704x480 and put it on DVD. That works great. On DVDs I prefer the AC3 as that is why I do DVDs in the first place. I like to hear those bullets whizzing around diagonally :)

So yes, I can see doing a proper down-code to AC3 may not be worth the hassle, especially if it required something like SoftEncode to do it. I thought BeSweet added back this ability via some app, but I remember something about the quality from that app not being to BeSweet standards.

[jdobbs]

Frankly, Ive never seen a DVD player that can not use MP2s for DVDs. Neither have I. But you can bet that the minute I make it possible to build a non-standard NTSC DVD with MPEG audio only, about 800 people will surface who do have players that require it. ;)

I think it is always best to just follow the standard.

[insanescape]

Well, I know for a fact that my Toshiba NTSC player will NOT play Mp2 files in bitstream mode. You can set it to basically analog sound mode over the digital cable, but who wants to do that everytime you put a dvd in (and have to remember to switch back when you put in a 5ch one)?

DDogg: sure if you kept all the audio files downconverting would make a difference, but Only things I keep are the main and commentary tracks. If commentary tracks weren't already small (usually only 192kbps) it might be worth the effort, but they're not :)

[PINOBIRD]

In the help file of DVD-Author I found this:

--------- Audio format for standard DVD-video ---------

There are different specifications for DVD-video disks and for DVD-players.

For commercial DVD-disks:
-In NTSC(television broadcast and video Standard for North America and Japan) region, a commercial DVD-disk having only mp2 audio is non-standard.
A standard DVD-video disk has to include at least Linear PCM audio or AC-3 audio.
-In PAL(television broadcast and video standard for Europe) region, it has to include at least one of those formats, Linear PCM, mp2 or AC-3.

For DVD-players:
-In NTSC region, all DVD players have to support LinearPCM and AC-3 audio.
-In Pal region, all DVD players have to support LPCM, mp2 and AC-3 audio.

[jdobbs]

Originally posted by insanescape
Well, I know for a fact that my Toshiba NTSC player will NOT play Mp2 files in bitstream mode. You can set it to basically analog sound mode over the digital cable, but who wants to do that everytime you put a dvd in (and have to remember to switch back when you put in a 5ch one)?

DDogg: sure if you kept all the audio files downconverting would make a difference, but Only things I keep are the main and commentary tracks. If commentary tracks weren't already small (usually only 192kbps) it might be worth the effort, but they're not :) Ahhh... you just jogged my memory! You're right. The problem happens on a lot of NTSC players when you use the digital (coax or fiber) connection.

[Malcolm]

@jdobbs,
Hi!
i just realized that you are the author of DVD RB!! :) :)
Well i understand your point that it's generally not a good idea to produce non-standard DVDs. a lot of people will complain about DVD RB not working properly, etc. pp.
But this can be avoided:
1. One can use AC3 instead of MP2. DVD RB can refuse MP2 on NTSC-DVDs. Or DVD RB can give warnings.
2. In PAL-region MP2 is totally o.k.!

All i can say is that i would really appreciate having the ability to do this in DVD RB!! (Really!! :) )
I mean, isn't that the point in DVD RB? Compressing with the least amount of visual degradation to get a DVD-9 to DVD-5??
Converting 448 kbit/s audio to 192/128 kbit/s audio helps!! And DVD RB could make this possible for the user!
IMHO everybody should be able to decide using this.

Isn't it a step forward to give the user this freedom of choice?

Greetings,
Malcolm

[jdobbs]

I mean, isn't that the point in DVD RB? Compressing with the least amount of visual degradation to get a DVD-9 to DVD-5?? Well, yes and no. The point is to create a backup that appears and sounds as much like the original as is possible. :)

[Malcolm]

well, i think we don't have to discuss this further. i'm sure you know what i mean and what i'd like to achieve. it's your program and it's 100% up to you what to include and what not.

Greetings,
Malcolm

[jdobbs]

Originally posted by Malcolm
well, i think we don't have to discuss this further. i'm sure you know what i mean and what i'd like to achieve. it's your program and it's 100% up to you what to include and what not.

Greetings,
Malcolm Don't write it off yet... I'm always open to suggestions.

[insanescape]

Well, you could always have the program compliment us on our movie choices. I sometimes wonder why I bought some of them, but if a program made me feel more secure in my purchase I'd get through the day a little easier.

[jdobbs]

Originally posted by insanescape
Well, you could always have the program compliment us on our movie choices. I sometimes wonder why I bought some of them, but if a program made me feel more secure in my purchase I'd get through the day a little easier. LOL. Kind of like the waiter who says "Excellent choice sir" in front of your date? :p

[MedicineMan]

Now that we're at it, isn't it the right time to talk about converting those really huge LPCM tracks. It's a bit off-topic, but I think it's worth to think about it. I know that i only have then in Music DVDs (and I agree that in those kinds of DVDs sound is maybe more worthy than video), but in those cases the gain we could have from converting (to AC3 or MP2) would be big. And properly done (BeSweet) I'm sure we wouldn't tell the difference (at least the average user that wants to do backups of his DVD won't; if he really wants to keep top quality he can buy 2 copies of the same DVD).


Sincerely


MM

[Malcolm]

@jdobbs
bump :)

[burnout]

just thought i would add that people with SoftEncode will want to use that instead of BeSweet, and probably similar with other commercial programs. so what would be better would be a replace track feature with an external file (otherwise u would have to set it up for different audio encoding programs), but then this external track would have to be cut into the cellID chunks that DVDReBuilder authors with right? (probably not too easy) :p

another way to look at it, if you had a 448kbit 5.1 track and encoded it to 192kbit 2.0 track you could increase the main films video bitrate by 256kbit, and also the 'kbit per track' would be quite similar (448/5 = 89.6kbit, 192/2 = 96kbit). and with multiple streams you could increase the video bitrate more than 256kbit.

well i would also like this feature in DVD ReBuilder, then i could use it all the time :D otherwise maybe sum1 could help me in making a program to do this before using DVD ReBuilder (or other DVD9 to DVD5 tool)

[Malcolm]

Originally posted by burnout
well i would also like this feature in DVD ReBuilder, then i could use it all the time :D otherwise maybe sum1 could help me in making a program to do this before using DVD ReBuilder (or other DVD9 to DVD5 tool) If it's inside DVD-RB then it would be a very simple point&click thing for the user. -> just as DVD-RB wants to be (for compressing the video). The final DVD-structure would have to be built only once. But you're bound to DVD-RB.
As a standalone tool that works on the ripped DVD, it would be more flexible (different audio-encoders, different DVD backup tools afterwards), but also more complicated. Also it would take some more time, as the DVD structure (VOBs) would have to be created twice.
Like this we end up calling 3 different programs (manually):
1. any existing demuxer we like to get the wanted audio-streams out of the VOBs
2. any existing audio-encoder we like (BeSweet, SoftEncode, ffmpegGUI)
3. some tool that can rebuild the original DVD structure, but with the newly created audio-tracks. Maybe there are already tools that can do this (VOBEdit?). But they are not well suited for this specific task. Also you still have to know some details and you have to do a lot manually!

Greetings,
Malcolm

[MixMaker]

Pleeeaase.......!! Add LPCM to AC3 conversion. It would be really great.

[ChickenMan]

I really see no point in going from AC3 to MP2. An audio track converted to AC3 or to MP2 at the same bitrate have EXACTLY the same size file. MP2 has absolutely no advantage over AC3 using same bitrates, but as said many times above, makes it non-standard for NTSC dvd specs. I live in a PAL world and I've seen MANY dvd players that can NOT play mp2 only containing movies. Dont assume if a dvd players plays SVCD w/ MP2 audio that it can play a dvd with MP2 audio. Its the same as most dvd players can play MP3 files burnt to a CDR, but will NOT play them burnt to DVDR !

A conversion of WAV/LPCM to 2ch AC3 would be FANTASTIC :) :) :) though. A conversion of 5.1ch AC3 to 2ch AC3 could be useful also IMHO.

The AC3Enc.dll (in latest BeSweet) and ffMPEG have both originated from the same source code. Sonic SoftEncode is no longer commercially available and Sonic AC3Enc.exe (included in Scenarist) is to darn expensive. I'm not aware of any other alternatives.

[Malcolm]

quote:
Originally posted by ChickenMan
I really see no point in going from AC3 to MP2.

@ChickenMan:
O.k. i'm pretty tired to explain why i want to do this. if you would have read my above posts then you would have seen this:
quote:
Originally posted by Malcolm
Why i'm using MP2 instead of AC3? Well, i've made no good experience using AC3 as encoding format. (...) the sound was amplified and clipping occured. i guess that's because of built-in dynamic-range compression/decompression. if you can tell me a way to produce good sounding AC3-encodings, i'll use AC3 instead of MP2.

quote:
Originally posted by ChickenMan
An audio track converted to AC3 or to MP2 at the same bitrate have EXACTLY the same size file.

@ChickenMan:
I KNOW THAT!

quote:
Originally posted by ChickenMan
MP2 has absolutely no advantage over AC3 using same bitrates

@ChickenMan:
As KpeX has stated above, but what you didn't read as it seems - mp2 has advantages:
quote:
Originally posted by KpeX
Regarding MP2 vs. AC3: The advantage of MP2 is that the free encoders available are quite good quality (toolame, mp2enc, etc.), whereas the only free AC3 encoder (ffmpeg) is not on par quality-wise with commercial encoders.

quote:
Originally posted by ChickenMan
but as said many times above, makes it non-standard for NTSC dvd specs.

@ChickenMan:
O.k. :rolleyes: That's what i've already written above:
quote:
Originally posted by Malcolm
Well i understand your point that it's generally not a good idea to produce non-standard DVDs. (...)
But this can be avoided:
1. One can use AC3 instead of MP2. DVD RB can refuse MP2 on NTSC-DVDs. Or DVD RB can give warnings.
2. In PAL-region MP2 is totally o.k.!

@ChickenMan:
If my PAL DVDs play fine in my PAL player, then why should i care if they play in any NTSC player???
Why do you want to hinder PAL people in producing PAL DVDs with MP2 which completely comply to the standard???

[ChickenMan]

Malcolm, I have fully read this thread and 100% understand why you need to reduce the size of the audio. I fully suport what your trying to achieve. However, I say again I see no reason to go to MP2 when you can go to AC3. I'm talking generally for the ReBuilder audience, not just yourself. You say you have had problems converting to AC3 but I'm not sure what software you have used/tried for such conversions. There are quality commercial software availble that does these conversions, I use AC3Enc thats included with Scenarist with great success, have you tried that? If not, then maybe you can understand why I say there is no need for mp2 conversion IMHO. However, I doubt jdobbs would include such a conversion using that tool because of the cost involved. Latest BeSweet or ffMPEG seam to be the only viable alternatives.

Your dvd player obvioulsy plays MP2 audio fine, but as I said above, there are a number of PAL dvd players that in theory are compelled to play mp2 audio but in practice do not. I have never seen or heard of any dvd player that cannot play movie with a compliant AC3 audio track. So why convert to a format that many players can have problems with, while AC3 has no problems.

EDIT: Sorry I did not answer - "Originally posted by Malcolm
Why i'm using MP2 instead of AC3? Well, i've made no good experience using AC3 as encoding format. (...) the sound was amplified and clipping occured. i guess that's because of built-in dynamic-range compression/decompression. if you can tell me a way to produce good sounding AC3-encodings, i'll use AC3 instead of MP2."

I down mix the 5.1 ac3 to WAV using BeSweet set to Stereo Surround2 mode, then convert to AC3 2ch with Sonics AC3Enc (comes with Scenarist) with Dolby Surround Mode set to "Dolby Surround Encoded" and bitrate set to 192. On final playback via Prologic II, I get very good surrond sound. Not possible with MP2.

[Michi27]

Hi,

I like DVD-Rebuilder :-) and the only thing I miss a LPCM/WAVE to AC3 conversion. This could save a lot of space for the video.

On some DVD's the LPCM space is more than 1,5GB and in some cases it is 'only' a comedy-show. A reduction to 0,5GB in AC3 helps to get much better video.

Please Jdobbs, add a feature for this in your ultimate tool.

With best regards,

Michi

[Malcolm]

@ChickenMan:
o.k. fine :) so we both want the same! ;)
to answer your questions:
i have used BeSweet and ffmpeg for my (quick) tests. I have never used Scenarist.
I really don't care if it's mp2 or ac3. i go for the one with the better quality. Although: i clearly prefer a solution where everything can be done with free software!

Greetings,
Malcolm

[Malcolm]

Meanwhile i asked jsoto, the author of VobBlanker to add the needed demux/remux functionality for audio tracks. I think VobBlanker would be the right place for this. (It already can strip off audio-tracks and other unwanted stuff).
Unfortunately jsoto says that it's out of his knowledge and possibilities to add this functionality. Maybe someone else is skilled enough to help him out?
Here is the thread to jsoto & VobBlanker (http://forum.doom9.org/showthread.php?s=&threadid=73145&perpage=20&pagenumber=6)
Alternatively a standalone tool for demuxing/remuxing audio tracks would do the job!

[Malcolm]

@jdobbs,
over the last 2 weeks, i was talking with several software authors:
- DVD-Shrink
- VobBlanker
- TitleSetBlanker
- ImagoMPEG-Muxer

What i know now: Removing/exchanging audio-streams from/inside VOBs makes it necessary to reauthor the DVD-structure (update navigation packs, IFO-files).
With the exception of DVD-Shrink, none of the tools has the ability to do the reauthoring - although they change different things inside VOBs.
DVD-Shrink is no option, because the only thing that the author is working on is the transcoder engine to get a better output quality. He doesn't want/has the time to add other enhancements & features.
AFAIK, DVD-Rebuilder already rebuilds the DVD-structure. (Who would have thought this ;) :D). This is necessary because the original video track is replaced by a low-bitrate version, right? I guess replacing one audio stream in the same step would be easy to add!
So you really are my last hope!

Meanwhile several other people has asked for this feature too. Having it would put DVD-Rebuilder a big step ahead!
I really hope to create your interest. :)
How do you think about it?

Thanks and greetings,
Malcolm

[wmansir]

Rebuilder isn't really your last hope because (AFAIK) you can do this already with Big3. It is a more complex process and requires Scenarist, but it is an option.

[Michi27]

Hi,

@wmansir : But the only "One Click Tool" is DVD-Rebuilder. I can only hope that jdobbs make it possible in a later version of his great tool.

But Pinnacle seems to work also on a LPCM transformer (this I could read in a some months old german magazine) for Instant Copy.


With best regards,


Michi

[Malcolm]

Originally posted by Michi27
@wmansir : But the only "One Click Tool" is DVD-Rebuilder.
That's just the point! Also, i do not own Scenarist. :) But thanks for the tip!
Actually i know of another method (using DVD2SVCD + VobBlanker). I can imagine it's similiar to the Big3 method. But it's so complicated plus time & space consuming, i doubt anyone will ever use it!

Greetings,
Malcolm

[Shalimar]

Well after reading through this thread I agree with alot of it.

However I would say the most valueable conversion by far and away would be LPCM to AC3 since the size difference is massive.. And I've seen more than one DVD here that has LPCM. Such a massive waste of space.

A standalone tool for this would be seriously kicass (I'm workin on finding a fairly easy manual way to do so in the meantime). If such could be added to DVDRB as well as an option that would rule. :)

I would have to agree as well though that AC3 to MP2 wouldn't be of as great a benefit since the savings if any would be minimal. LPCM is a whore and a half for space though.

I've also seen cases where LPCM is used for the main menu but not the for the main programming of a dvd.. seems rather stupid to me to have yet another waste of space.

Honestly I'm suprised no one has come up with a simple tool for this conversion by now!

Regards,

Shalimar
icq# 7790581

[mikegun]

I think it depends on the movie what kind of audio bitrate/format I
would prefer. I definately will miss 5.1 sound in movies with a lot of action sequences. If the movie is very "talky" I could go down.
So I can see changeing the auio format/bitrate as an useful option - unless I do not have to write to code for it ;-)

Regards,

M.

[VamPYR]

i got a few 'p' movie which the audio was LPCM (not only main movie, but all the bonus stuff), it take up alot of space and making reencoding imposibble (40%).
i use TMPGEnc DVD Author 1.5 to import the dvd using the button 'add DVD Video' (Each Title Set) and enable the options 'Re-encode LPCM audio to AC-3(2.0)' in Environmental Setting. Create Menu > no menu; Output > VIDEO_TS.
Use dvdremake pro 2.2 to replace the original LPCM vob with the one created by TMPGEnc DVD Author (AC-3 2.0), and using DVD-RB (have try with RB0.56,0.57,0.64a) to do the encoding. the project was successfull and they all play without problem in my standalone.
cheers.

[Malcolm]

Finally i have found a solution to change the audio! the method is fairly easy.
I have made a guide. You can find it here: http://forum.doom9.org/showthread.php?s=&threadid=84887

greetings,
Malcolm