Any way to convert an ac3 5.1 into a smaller audio file and still 5.1?

[jp80]

As I would like to encode movies with dual 5.1 language sounds, I'm searching for a codec to convert ac3 into an much smaller audio file, but which would keep the surround multi-channels. I've already tried ogg 5.1 at quality level 3, but it only converted me a 300mb ac3 into a 250mb ogg, and moreover the channel order was messed, as I could hear the center and right channel inverted when playing the ogg file...

[KpeX]

Options:

1. See the AC3 faq #9.

2. Ogg vorbis or AAC are your other main transcoding options. As you mentioned, if you want a low bitrate with ogg, you'll have to use less than q 3. I'd recommend using Nero HE-AAC for low bitrates. There are many threads on this issue, please use search.

hth,

[Tuning]

You can go for AAC, It supports all of your requirements. DSPGuru's new GUI makes encoding ac3->AAC very easy. Look tutorial here (http://www.doom9.org/oagmachine.htm). You can use either LC AAC or HE AAC, the latter is bound to use at lower bitrates.

Note: You need nero burning rom for creating AAC with this tool. This audio format will not work in standalone players at the moment.

Hope that helps....

Edit:
KpeX, You are fast...:D

[jp80]

I tried to follow the aac tuto, but after setting the right plugin path and checking the Show config dialog, I couldnt get this dialog to show at all...

[Tuning]

Originally posted by jp80
I tried to follow the aac tuto, but after setting the right plugin path and checking the Show config dialog, I couldnt get this dialog to show at all...
Instead put aac.dll, NeroIPP.dll and aacenc32.dll to your BeSweet folder and check show config dialoge.

Btw, you have to set BeSweet path too.

[jp80]

Well I did all of this but the dialog stil doesnt show.

[Tuning]

Originally posted by jp80
Well I did all of this but the dialog stil doesnt show.

Post BeSweet CLI. Then we could analyse your problem.

[Stux]

Originally posted by jp80
As I would like to encode movies with dual 5.1 language sounds, I'm searching for a codec to convert ac3 into an much smaller audio file, but which would keep the surround multi-channels. I've already tried ogg 5.1 at quality level 3, but it only converted me a 300mb ac3 into a 250mb ogg, and moreover the channel order was messed, as I could hear the center and right channel inverted when playing the ogg file...

You can use the 3ivx Filter Suite to do this

Basically you use a graphedit graph like this

ac3->ac3 parser->ac3 decoder->3ivx aac encoder->3ivx mp4 muxer->mp4

you can mux multiple audio tracks into the mp4

[Sirber]

RealAudio can do 5.1 also, from 96kbps to 260kbps.

[jp80]

Tuning: I dont understand what do you mean by posting Besweet CLI?

Stux and Sirber: Can the mp4 and real audio be cut in virtualdubMod, as I plan tu mux my video+audios by cutting them in 2 at the same time ?

[Tuning]

Originally posted by jp80
Tuning: I dont understand what do you mean by posting Besweet CLI?
Stux and Sirber: Can the mp4 and real audio be cut in virtualdubMod, as I plan tu mux my video+audios by cutting them in 2 at the same time ?
Sorry Jp80, you may read as CL(Command line or Script used in Oagmachine :) )

Btw, BeSweet/Bsn also creates MP4(aac inside) files which yo cannot cut directly with virtual dub mod. And it also doesn't support avi. You have to use mkv or OGM for that. So what you need to cut is first mux video and audio to mkv in mkvtoolnix and then open that mkv in VDM for cutting. (Bcoz audio is now mka, supported by VDM ):)

[jp80]

Sirber tx for the info, but I dont think I can edit real audio for a 2 parts mkv/ogm, which is what I plan to use as container...

Stux, after having installed latest 3ivx filter suite and even ac3filter 0.70b, in graphedit list of filter to insert, I could find ac3->ac3 parser, but I couldn't find any other matching the exact names of the rest fo your list. Could you help me by telling me the exact path for those filters pliz?

Tuning, sorry to be such a dummy but I dont know or even understand how exactly to post my beswet CLI?

[Tuning]

Originally posted by jp80
Tuning, sorry to be such a dummy but I dont know or even understand how exactly to post my beswet CLI?

Don't feel dumb, everyone here( especially me :p)learns by his own experience and from others comments.:)

There is a button lower left corner in Oagmachine called " Copy command to clip board". Click this and paste your command(CL) in a text or directly post to form.
This can also be aquired from log produced by BeSweet, if you forgot whatever settings were used.
which can be found at :-logfile "C:\Program Files\BeSweet\BeSweet.log" as shown in you command.
Hope that helps... :)

[jp80]

hey tuning, I found this tuto to do directly ac3 to aac here: http://doom9.free.fr/index.html?/AacMachine.htm , and its simplicity suits me perfectly, however I dont understand why I cant uncheck at all the splitting options in AAcmachine gui???

[tiki4]

@jp80:

Please don't use AACMachine for transcoding AC3 to 5.1 AAC. You end up with the wrong channel order and the used aacenc has a matrixing bug with multichannel that won't be fixed anymore. Stay with Oagmachine and follow the guide to the word. Install Nero 6 if available and put aac.dll, aacenc32.dll and NeroIPP.dll into your BeSweet directory. Tick the config option and your options dialogue should show up.

tiki4

[bobsc]

@jp80
You could also use BeSweetGUI 0.7b2 and BeSweetv1.5b24, but use the DD-Profiles that come with BeSweetv1.5b24.

[jp80]

Ouch, it seems like the more I manage to go on, the more there are pblms... As actually with the guide I managed in Oagmachine to bypass the aac config menu which still doesnt show up, and to transcode my 300mb 48Khz .ac3 to a 150mb 44Khz aac in .mp4, by specifying the path to Nero aac dlls in its ahead common files folder... however here are the new pblms I bumped into:

-When I play the output aac file in media player classic, wmp 9 or 6, and if I try to choose a certain point at random in the playing bar, then my cpu reaches a peak of 100%, freezing completely all my other applications, for a period between 30s and 2mn, until the play resumes at the chosen point... So I suppose if the aac is muxed w video, it would keep the same effect, and I wonder how to avoid this very inconvenient pblm?

-When I try to add my aac .mp4 file to the stream list in VDMod to mux it with the video, VDMod can't open it by showing the warning msg that my .mp4 doesnt seem to be a valid Mpeg audio file. Then how can I mux my mp4 audio (I dont think its possible with mkvmerger?), with all the options of VDmod like stream title, and cut for a 2 parts movie?

[tiki4]

First, I guess that your seeking problem is related to DirectShow decoding by the Nero DirectShow filters. Try to decode your file with a decent decoder like the 3ivx DirectShow filters or even better: listen to it in foobar2000.

Second, in order to mux your AAC in MP4 container with your video into Matroska container you need to use mkvmerge. VirtualDubMod can't do this (yet?). Mkvmerge comes with a nice GUI called mmg.exe, you have to read the docs though. Once inside Matroska container, please install CoreAAC from Rarewares or the new Matroska Pack 1.0.1 to hear your AAC.

tiki4

[jp80]

You were right tiki4, as the seeking is made instantly now that I installed the 3ivx filter, but now I have another pblm: if U just play the aac with wmp 6, it takes as much cpu resources as a divx/xvid playing, more exactly at least 60% of my Athlon 2200+!

And one thing I dont understand is that the channels orders seems to be messed by the filter, as though my speakers and sound card is well configured for 5.1 surround, the my aac plays only the fx but no voice!

Any solution to come around those?

[tiki4]

O.K., here we go again:

I'd guess that your file has a messed up channel order! I don't know exactly how you created your file now, but please remember the following things:

1. Do not use AACMachine with BeSweet and Psytel AACenc for 5.1, this messes up your channel ordering for sure.

2. If you use OagMachine you have to know which version of Nero Burning ROM you have installed.

a. If your Nero is 6.0.0.11 or older you have to use the '6chold' configuration (command line window should show '-bsn( -6chold )').

b. If you use Nero 6.0.0.19 or later (.23 and new 6.3.0.0) you have to use '6chnew' and your command line says '-bsn( -6chnew )'.

3. Use a reasonable bitrate: For example for 5.1 AC3 to HE-AAC use something like 'streaming' or 'internet' preset. CBR encoding will result in LC-AAC most likely, there's something broken ATM. Example: 'streaming' HE-AAC should result in something like ~200 kBit/s.

4. Resample to 44.1 kHz if you use OagMachine (there's a button in the Shibatch setup part of the GUI). Anything else might give you unexpected results.

5. Finally, if you want to do us a favour, try the following on the command line:

besweet -core( -input in.ac3 -output x:\out.mp4 -logfile BeSweet.log ) -azid( -c normal --maximize ) -shibatch( --rate 44100 ) -bsn( -6chnew -config )

in.ac3 is your input AC3, out.mp4 is your output file, don't forget to give a full path, otherwise you get nothing. The '-config' switch in the -bsn() section opens the configuration window of Nero AAC encoder. This should give you a working MP4 with the right channel order, if not post your logfile, please.

6. Really finally: For Oagmachine to work you need a full install of latest BeSweet 1.5. Then copy aac.dll and aacenc32.dll to your BeSweet directory (should be somewhere like "c:\program files\common files\ahead\audio plugins"). Finally if you use a Nero version < 6.0.0.28 copy NeroIPP.dll to your BeSweet dir, too. If you have a newer version than do not copy it. Aac.dll will check for it in the registry, so make sure that you have only one on your hard drive.

Merry christmas,

tiki4

[jp80]

Thanks for your long answer, though before it I think I almost already did everything right, like choosing 6chnew in Oagmachine with Nero 6.3 dlls, and resample in 44.1khz; I'll try it once again with your new instructions, and give u news about my try. Merry Christmas to you too!

BTW for those wondering where are the latest mkv packs, they're here: http://packs.matroska.org/, along with nice mkv samples of MAtrix Reloaded mixing RV9 and AAC!: http://matroska.free.fr/samples/

[jp80]

YYYYYYEEEESSS, VICTORY, I finally made it!!!

Ok here is how I managed to get my results:

-First of all, I kept the same first aac file I got, and I realized by playing the ac3 that it was also missing the voice, becoz... an audio cable was disconnected from my sound card, silly of me!!!

-The aac config menu showed at last, as I misunderstood the guideby thinking the menu would show as soon as I checked the box, not as right way!

-Then I tried to mux the aac with the video in mkvmerger gui, and guess what happened when I played the output mkv? The cpu was only at 30% just like a normal divx/xvid, so yes my assumption that it would require a lot of cpu was wrong, though I dunno why the standalone aac still does!!!

So at last I got the way to my high quality divx/xvid with dual audio 5.1! Thats a nice present christmas may have given me just today!
I wonder why many ppl r still stuck into divx/xvid movies with only a single 5.1 ac3 track while they could have 2 language for the same surround quality with aac! Surely they dunno about it, then I hope word will be spread quickly worldwidely about this revolution in 5.1 audio compression for movies!

Now I'd like to find the way to play 5.1 aac with low cpu, as the future of stereo music which we know now as CDs compressed into mp3, lies in 5.1... You can already test a windows media sample of surround music at andy hunter's homepage (I wonder too how to encode wav/ac3 to wma/realaudio 5.1): http://www.andyhunter.com

And anyone knows how could use a batch list with Oagmachine?

[jp80]

I also searched but couldnt find info on faqs and the forum about those questions:

-In Oagmachine gui, does Dynamic Compression means the same than dynamic range compression by applying to hte output volume?
-What exactly is the difference between HybridGain and MaxGain?

[tiki4]

Hi,

happy that you made it.

Dynamic compression is a form of restricting dynamic range of your AC3 audio. It is a function of azid the most widely used freeware AC3 decoder. BeSweet uses azid in form of azid.dll. If you set dynamic range to 'normal' you get approx. the sound you'd get from your standalone or your DVD player software. I think 'light' allows more dynamics and 'heavy' equals out dynamics much more (I always use 'normal'). Please check the 'AC3 FAQ' as I'm no expert in this.

MaxGain and HybridGain are to different options to normalize your audio. If I'm not mistaken it in-/decreases the amplitude of your wave form to the level that can be described without clipping (cutting off the tops of it).
MaxGain is the older form of two-pass normalize. In the first pass azid logs the maximal loudness and increases the volume in the second pass by a constant gain so that you get 0db at the loudest parts of your sound track.
Hybridgain works differently in a one-pass mode. For a stereo source it sets the azid options -azid( -L -3db ) [downmix into the stereo channels] and applies a gain value in the end. This works differently for MP3/MP2/Ogg Vorbis/AAC MP4. For a 6 channel source the hybridgain switch sets -azid( -n1 -g 10db -L -3db ) which corresponds to 'dialogue normalization reduction' and a constant gain of 10 db. The rest of the gain is again applied by changing the final file (= postgain, thus the name hybridgain).

Now if you encode to AAC the final file is modified by only a tag (just like Ogg Vorbis). While this gain value is supported by Ogg Vorbis decoders it isn't yet supported by AAC encoders and thus pretty useless at the moment. So you better stick with MaxGain for the moment.

Cheers,

tiki4

[KpeX]

@jp80

Good to see your problem solved.

@tiki4
Many thanks for your patient and eloquent assistance in this thread and elsewhere. :goodpost:

[jp80]

Yup, now I noticed something that looks like a major mistake in the Oagmachine guide to encode ac3 to aac, it's the step in "the downmix options" telling to "set LFE to LR Channels to -3db".

I realized this by a comparison at playing between the original ac3 of my movie and the AAC, with my 5.1 speakers setup. And it showed me the AAC had less bass, especially during scenes with bass sound fx. Then during the aac playing, I checked the Matrix Mixer included in the Matroska Pack, and I could see indeed the LFE (if I'm right, i.e Low Frequency Effect, the 6th channel for dolby surround sound played by the subwoofer) had no sound at all, logically the effect of the LFE downmix option checked in the Oagmachine process.

But if it would make sense to do this downmix in order to play the sound for a stereo 2.0 speakers setup, I really don't see what's the use for a 5.1, as its front left and right speakers are not made at all for playing low frequency sounds?

[bobsc]

For 5.1 output do not set LFE to LR Channels -3db.