WAV-to-AC3

[kenma]

What is the best software for that ?

I want to encode WAV to AC3 and say Encode for PAL and/or NTSC.
How is that possible ?

[arturjose]

You can encode Wav to AC3 with Sonic Foundry Softencode,
but they exist many more programs.
:)

[mikecito]

AC3Machine is free. You feed it a 6 channel wave and it gives back the AC3, or so I hear. I've only used SoftEncode - but I don't think it's purchaseable anymore.

[arturjose]

http://dvd.box.sk/index.php?pid=guid&prj=view&rid=8

[Tonys]

Thanks arturjose


very much for sharing..been looking for long time...:p
Cheers

[mikecito]

That's an interesting guide, but I would substitute BeSweet to decode the ac3 to six wave files. It's MUCH faster, and it even has an option to convert it to 44 KHz. Then just drop them back into Soft Encode. Just a thought. It can be found in the downloads area on doom9.

[kenma]

is it true Sonic Foundry's SoftEncode puts out NTSC-DolbyDigital only ?

[Voltaire]

The absolute best program to do AC3 audio in is the new Vegas Video 4.0. It's the absolute best program to do MP2 or AC3 in. Simply import your WAV, AIFF, MP3 or just about any reasonable sound format and just render as AC3 and that's it. If Maestro accepts these AC3 files then it's really Goof. Soft Encode is good but it's too slow. Vegas does a 11/2 audio stream in 14 minutes. With Vegas Video, CCE 2.66 you really don;t have to do much waiting.

[kenma]

@Voltaire
I installed Vegas 4 Trial, loaded a wav and clicked on RENDER AS but there is no ac3 available, what do I need to do to encode the wav to ac3 with vegas as you wrote ?

[Voltaire]

Forgot to mention that you must install the AC3 Plugin Pack. It came with the non Trial version of Vegas so that can be your problem (http://www.sonicfoundry.com/products/showproduct.asp?PID=808&FeatureID=6893&FeatureTL=6877)

Try to get our hands on it some how and you'll never worry about AC3 again. Keep me posted on your search, I may be able to help you.

[Voltaire]

Did you try 'Render As", I was just thinking.

[kenma]

does this work with vegas:

loading a *.mpa and rendering directly to *.ac3 ? Or does vegas converts only WAVs to AC3 ?

[Voltaire]

You can open an mpa file in vegas.
J

[kenma]

does a plug-in has to be installed ?

[Voltaire]

I don't think so, I did not have to, try the 'Render As" and see if there is the AC3 option there. If not you may need the plugin. I bought the entire package so it may have installed it automatically.

[kenma]

I'll do the same, thanx for your help!

[kenma]

I'm now a proud owner of vegas4+dvdarchitect+sourround-plugin!

I hope it was the right choice.

Now to my question about encoding to AC3.

I have a Stereo-WAV (with surround information in it) which I want to be encoded to AC3.

Question to you all is, what is the right choice to take for the "Dolby Digital Audio coding Mode" ?
Possible are all Coding Modes, i know, but as there is "only" a Stereo WAV with surround information in it, shall I choose:

- 2/0 (L, R)
or
- 2/1 (L, R, Ls)

???

[kenma]

I tested a bit with it and i figured out, that the stereo-wav can't be encoded with 2/1 ! The encoder won't let me encode the file with this setting, so only 2/0 is possible with a normal setereo-wav!
How do I filter out the surround signal to encode it with the 2/1 template ? Is this possible ?

[jansb000]

Originally posted by mikecito
... but I would substitute BeSweet to decode the ac3 to six wave files ...

I have experimented with this in the past, but without success. I guess the BeSweet guides are to difficult for me to understand :confused:

Suppose I ripped a file "music.ac3" from a DVD. What command-line parameters would I feed BeSweet to end up with 6 WAV files?

[Voltaire]

BeSweet I never use, it's not useful to the true sound editor. Sound should always be edited in it's raw form, in the case of windows "wav" is the format of editing. You should never be editing an AC3, by the time it gets to AC3 it's in it's final stages. Just like Postscript is to Desktop Publishing.

Editing AC3 is a bottomless pit and there is a good reason why there are no editors. Look at it always as Edit\Master. A good film editor never touches his masters if he or she has to do further editing. When I hear people talking about AC3 editing, it bothers me.
Simply edit doen your wav to 48MHZ and dolby AC3 would do the rest. Surround sound is only possible with 4 speakers so if you have twp speakers don;t worry too much about the settings.

[mikecito]

That's absolutely not true at all. There are many reasons a person would want to edit AC3. A photograph is a final product of a camera, and yet people manipulate pictures all the time by scanning them in, even though they "lose quality."

I edit ac3 all the time. I edit movies, and since I start with a dvd, I end up with 6 wave files decoded using BeSweet. I dump the files into Premiere along with the video, make all the changes, reencode the video, export the audio to 6 wave files, and reencode with Soft Encode. The video loses a "tiny bit" of quality - hardly noticeable to the trained eye, and invisible to the rest.

The audio sounds just as good as the original. Although AC3 is a compressed "final ouput", it is still exceptional quality. It's not like compressing to a 96kbit mp3 or something. I can't tell the difference, and I'm guessing 1 in 1000 people could.

My final product is a movie that a family can enjoy together without all the swearing, violence, and sex. People love my work, and always thank me for it. And they always comment on the "high quality" of my dvds.

Before attacking an idea, find out the reasons someone might want to accomplish the task. Not everyone just makes direct copies of dvds, and very few here have the "original master" copies of the wave files to work with.

As an answer to the question on the command line to decode the ac3 - use the gui, select decode to six wave files. Much easier than typing in all the parameters. :)

[jansb000]

In my case, decomposing AC3 into wav files serves the purpose of showing how the pro's have mixed certain soundeffects - I want to be able to reproduce similar results in my own AC3 sounds in a computer game.

Example: From "Saving private Ryan" I would like to see and explore how the effect of a whizzing bullet can be achieved. How is the volume mixed from front to rear and what time delay do they use.

[kenma]

is it possible to use the 5.1-plug-in from Vegas4 with SoundForge 6.0 ? Or is there a limitations when using the demo version ? Just wanted to know if it's possible to use this plug-in with SoundForge to produce AC3-Material from WAVs directly and to edit the audio first with SoundForge and re-import it into vegas4 to let it encode to AC3/DolbyDigital.

[kenma]

is there a tool which converts pal-to-ntsc/ntsc-to-pal AC3-Material with the correct time-stretching ? AC3Machine/BeSweet is just playing the file faster/slower, where the mickey-mouse-effect can be heard.

[mikecito]

I believe it would be possible, but I just used Vegas's AC3 encoder for the first time, and I find it very user-unfriendly. I would do all your editing, produce 6 wave files, and then import them to the encoder of your choice. Soft Encode makes it really easy, but I hear it's slower than the other options. I use it because I know it's not messing with me on anything, and with a fast processor, it doesn't take long anyway. Vegas will accept 6 wave files, but you have to change the project settings first to plan for 5.1 surround.

To stretch your audio, use Cool Edit. It does the best job I've seen out there, and you can create batch scripts that will stretch multiple files for you, for example, 6 channels in seperate waves from a decoded ac3. There is a percentage stretch option that should work for you. You can probably find the right percentage change online with a search. I never deal with PAL, so I can't tell you what it is.

[kenma]

I don't use CoolEdit generally, I'm wondering how to use the Time-Stretch-Option in Cool-Edit with 6 waves, is there a guide or quick guide about the time-stretch function ?

[mikecito]

Cool Edit 2000 accepts scripts.

By changing the option 1) and 2) in the following script to a different number, it will automatically stretch all the waves in the batch by that percent(times one hundred). In other words, if it's ten minutes long, and you type "1.10" (without quotes) in place of 1.00017 then your output wave file will be stretched to 11 minutes, with no pitch change.

FYI, my script is 1.00017 because I use it to stretch my wave files after exporting from the CCE pluging because the video is 29.976, but the premiere plugin(actually I think it's premiere that limits it) only encodes to 29.98, which causes a 2 second difference or so after a two hours movie. This stretch gets it right in synch again.

Open notepad, type in the following(or copy this and paste... much easier) (take out tildes)

~~~~~~~~~

Collection: New Collection
Title: Stretch Audio
Description:
Mode: 2

Selected: none at 0 scaled 380553216 SR 48000
cmd: Channel Both

Selected: 0 to 380553215 scaled 380553216 SR 48000
cmd: Time/Pitch\Stretch
1: 1.00017
2: 1.00017
3: 0
4: 0
5: 25
6: 0
7: 0.8
8: 2
9: 2
10: 0
11: 0

End:

~~~~~~~~


(without the tildes)


Then save it as something.scp. I used "stretchaudio.scp". In Cooledit, click on Options ---> Scripts and Batch Processing. Then click open/new collection. Then open the file you just created. Then click on the description of the file in the left pane. Uncheck pause at dialogs if it is checked. Then click on batch Run.

Add all the sound files you want to stretch, choose a destination directory, check the "disable undo" box so that it doesn't waste time on that, and then click begin. An hour later or probably 5 minutes on your computer you'll have them all stretched without the misery of clicking continue every 5 minutes.

[Voltaire]

mikecito, you could be right, I am told by these audio guys here at Culver City that you should never edit AC3. I am a Scenarist Pro and here in the Home Video Section we get the naked film to transfer to digital and boy let me tell you, you shouls see the kinds of delay correction those poor guys have to make. we've got audio sync machines that sometimes create delays if the frame are out.

For example we are learning how to handle sound and video for HDTV which is going oto be mastered on the Blue Light DVD (28 Gig). and AC3 is way to fickle. So are the old classics and TV series that we master.

No argument from me but When an AC3 file here at Sony need editing, we go back to the source and that is usually raw audio file.

[mikecito]

You have my dream job, Voltaire. I've always wanted to learn how to transfer film to dvd/video. I think it would be fun to go through the process... but I could see how that could be a major headache, too. :) How did you get a job like that? I'm stuck doing this as a hobby, I guess, until the day comes that I own my own studio. So pretty much, it's a hobby for life. :)

The only reason I didn't go into film editing was because I didn't want to deal with all the crap in movies that make me less human... is it a pain to deal with? I guess some people might enjoy all the sex and violence, huh? Anyway - I'll stop rambling.

[Voltaire]

First thanks a lot for the compliment on the job, I came here first as a Web guy, doing Java, PHP etc. I wanted to do more so I got them to sent me to Platt for a Multimedia class (3 months). I took Director and was blown away by it's capabilities. I was so bored and uninspired with web pages that I asked to go to multimedia and was given that chance for about 3 years now. It was there that I learned how to rip DVDs and because a lot of front ends on DVD are done in directorI was moved again to Home Entertainment to do graphics and Lingo for the front ends. I was again sent off to learn DVD authoring, I learned Sonic Fusion at first but there was about 12 commands so it was real easy. They switched to Scenarist and that was a bit more intense as we would do "Easter Eggs" like "Programming little animations if the user pressed "Play" in a 15 minute span of the movie. Seeing that I was now deep into lingo and some C++ DVD programming was a breeze. The real fun comes in the planning stages of the DVD, I'll design 4 or 5 treatments for the opening in photoshop then do the programming. There is a department here that produces the digital files on real expensive machines. We are not even nallowed in without a special suit. The film is tramsferred to a Hardware encoder then the audio and video is split, put back together then synced on yet another machine. After this, the "Dolby" is put in and this is where the headache comes in for the audio guys. The syncing is usually off and these guys do all sorts of things at this point like different audio streams, Angles even working files that areusually a second blank audio track. Don;t ask me, I don;t know why. After that, when it gets to me, I have two m2v files and sometimes up to 6 AC3 or PCM files. PCM is uncompressed so there is usually an english track only. I create my "Scenarios" and program away. This could take about a week by the time it goes through "QC (Quality Control)" and the big boys up stairs. The disc is sent to a house in the Valley and in your stores shortly. So when you get the DVD, you'll notice that there is usually a delay. That's because silent Audio track that acts like a padding is touched and it's always at the head of the audio file. The video is never a problem, it's always the audio. That's why I would tell every on not to mess with the Audio. It's a pain for my friends in Audio always and ripping is a perfect way to go down this bottomless pit. Alll in all it's a very rewarding job especially when you have to digitize the entire "Honeymooners" set by christmas. It's a good job and the pay ain't bad to.

[kenma]

There seems to be no direct-ac3-converter for the pal/ntsc-conversion!
Is that true ?
So we have to go back to 6-wavs and converting these with our favourite Sample-Editor or by ProSoniq's TimeFactory and reencode to AC3 ?
Isn't there a loss of quality in that process ?
Which Tool to use for the AC3-WAV-Conversion, BeSweet, AC3-Machine or another program ? Tips for that ?

Thanx again to all participating in this thread!

[mikecito]

besweet will do it, use the gui.

Any conversion of ac3 to any other format(even another ac3) will require de/recompression.

[Infinity]

Originally posted by mikecito
That's an interesting guide, but I would substitute BeSweet to decode the ac3 to six wave files. It's MUCH faster, and it even has an option to convert it to 44 KHz. Then just drop them back into Soft Encode. Just a thought. It can be found in the downloads area on doom9.

Hi! I've been trying to work with soft encode but didn't have much success. Can you explain or point me a manual please?
Thanks

[mikecito]

What is it you don't understand in the program? Which part do you need explained?

Importing Waves
Choosing channels
Encode Options
Encoding

Mike

[FreQi]

Every time I make an AC3 with Soft Encode (or BeSweet actually) the encoded audio is very quiet. I've tried unlocking the stream and boosting the dB a bit, but even then the resulting AC3 is at a lower volume than the source WAV's or source AC3. Is there something in the Encode Settings that causes this?

[mikecito]

There are numerous threads that address this issue - do a search and I'm sure you'll find a lot of answers in this forum. I've never had this problem personally, but I hear a lot of complaints about it.

[FreQi]

I have read about the negative-gain problem a lot too, and that's kind of the problem... no one seems to have a solution or work around. All I've been able to gather is it is a known problem that DSPGuru planned on fixing, but he's on hiatus atm, so who knows...

Right now I am considering using MP2 audio instead, but I am not sure on the compatability and compliance with the NTSC DVD-Video spec. And that only does me good for 2Ch audio. With 5.1 I am at the mercy of something like 3 programs for AC3.

[Eye of Horus]

Originally posted by kenma
I tested a bit with it and i figured out, that the stereo-wav can't be encoded with 2/1 ! The encoder won't let me encode the file with this setting, so only 2/0 is possible with a normal setereo-wav!
How do I filter out the surround signal to encode it with the 2/1 template ? Is this possible ?

I know this thread is rather old, but I was reading it in the hope to find an answer to a question I have.... but it doesn't :-)

Anyway, here is my method of handling stereo files with an AC3 encoder...
Use these settings :

2/0 , but.... select Dolby surround encoded and LFE on !
90 degrees phase shift and 3 db attentuation to the rears...

Ac3's this way sound excellent........

EoH

[kenma]

@EoH
thank's for your suggestion!

[kenma]

how to get 6 wavs back to ac3 ? without BeSweet...

[Eye of Horus]

Originally posted by kenma
how to get 6 wavs back to ac3 ?

Use an AC3 encoder and fill in one wav for the front left speaker, one for the center speaker, one for the front right, one for the rear left, one for the rear right and one for the LFE :-))

EoH

[kenma]

this was funny, haha