AC3 or not AC3?

[mb571]

I just reviewed one of the guides on AC3 conversion. It said the file information displayed
Channels: 2
Compression: Unkown (tag 2000)

The one I am trying to convert is
Channels: 5
Compression: Unkown (tag 2000)

I have tried many times without sucess to convert these things to SVCD. They all end up with audio sync problems. I have followed the guides to a tee. I have tried HeadAC3, and BeSweet to no avail. Have others experienced this. Now when I aquire a file of this nature, I just give up before starting. These files seem to be kicking around more than ever now.

Any help would be appreciated,
Mark

[puertorican138]

It sounds like you have an AC3-audio file.

[puertorican138]

You could download the Nimo's Codec Package as it contains an AC3 audio decompressor (codec). :P

[mb571]

Bin der dun dat many moons ago. I can play the files out of media player no problem. Extract the audio direct stream with VD. Convert the file named .ac3 with Headac3 or BeSweet. Encode with TMPGEnc to SVCD.
I have made more than two dozen Svcd's in the last six months but I have never had success converting AC3.

Mark

[Q101]

Im having the same problem.I open the file in Vdub and check the file information.I get

Frequency 48,000khz
Channels :2(stereo)
Compression: Unkown (tag 2000)
I then save to WAV and put it through Headache to get AC-3 sound as following the Headache guide on here.I then open the latest version of TMPGEnc to make an svcd and put the Original file in the video and the file that was created by Headache in the audio part.What is puzzling me is that if you look in the expert part of TMPGEnc then in the audio section of it,the audio bitrate cant go up any higher than 224kb/s and you get the choice of Stereo,Joint Stereo and Dual Channel.If Im not mistaken then Dolby Digital 5.1 Sound is 384kb/s or 448kb/s.So Can I change the audio bitrate any higher on Tmpgenc or does it just sample the 5.1 sound down too 224kb/s.Ive got the ac-3 codec loaded onto the pc as well but Im wanting to play them on my dvd player.When I play the disc the decoder shows inputigital/Surroundolby Pro-logic.The sound is very good and comes out of all 5 speakers but I dont know whether Im am actually getting 5.1 Dolby Digital as it doesnt show up on the Decoder.Is it possible to get Dolby Digital 5.1 on Svcd or is Pro-logic going to be the best I can hope for?Am I actually Getting 5.1 DD but it is showing as Pro-logic?

Any Help would be Appreciated.If I just make an svcd without seperating the audio 1st,what sound would I get just by Tmpgenc the file into an svcd if there is ac-3 sound as detailed above in the file information section.

Cheers

[mb571]

You are probably using Headac3 to convert your ac3 file to a 2 channel wav file. At this point your 5.1 sound is gone. That is likely why you get the choice of Stereo etc. in TMPGEnc.

Mark

[trillium]

does anyone know where Nimo's Codec Package is available? I tried the link listed in Tools and it appears to be no longer valid. A Google search didn't turn up much luck either.


Thanks
-trilli

[Dobbs2010]

When you save the audio to a wav file in virtualdub, you need to rename the file .AC3 instead of .WAV. Once you have renamed the file to .AC3 you need to run the file through a program called AC3Fix, because virtualdub creates errors in an ac3 audio stream. Once you encode the fixed audio stream you should not have any sync problems.

Hope this helps

Dobbs

[mb571]

Dobbs, Yes I do rename the file .ac3 . It is the only way Besweet or HeadAC3 will accept it. Your answer was interesting but incomplete. Do you run it through this AC3fix and then transcode to wav with BeSweet or HeadAc3 before mpeg 2 encoding??

Mark

PS:trillium, start a new topic instead of changing the subject in one.

[Dobbs2010]

Yes you run the .ac3 file through AC3Fix before you encode it. One thing I noticed in you last post was you said ' before transcoding to wav'. If you are making a SVCD you should be encoding the audio to .MP2 not .WAV.

Dobbs

[banjazzer]

If you are making a SVCD you should be encoding the audio to .MP2 not .WAV.

Which you can also do very nicely with HeadAC3he, and at the same time resample to 44.1kHz.

[mikeweb]

How do you run AC3Fix? i double click the exe file but it apears for a sec then disapears.

[ZippyP.]

AC3FIX needs to be run from the command line (Dos). Shell to Dos then the command is: AC3FIX <input filename> <output filename>
Of course you must specify proper paths in all of the file names. Don't ask me for a Dos tutorial but if you have trouble maybe others can help...

I use AZID when headac3he will refuse to process some files. It also must be run from the command line as above:
AZID <input filename> <output filename>

Good luck!

[mikeweb]

Ok, I will 8)

Does anyone know what commands to use?

[mb571]

Mike, read before asking dumb questions. What part of ZiggyP's post did you not read?

"then the command is: ac3fix <input filename> <output filename>"

[mb571]

Okay guys, The advice given was working. I extract the audio direct stream with VD, naming it .ac3, run it through AC3FIX, convert to mp2 with BeSweet, and then encode the avi and mp2 with TMPGEnc. At least I have accomplished good audio sync now, but a new problem has arisen.

After two good encodes I turned out two where the audio cuts out 30 secs into the disc. Last night I did a three disc SVCD batch encode. The first two worked but the audio in the third one cut out.

Any ideas or advice now?

Mark

[banjazzer]

You don't encode the .mp2 with TMPG. You encode the .avi, and then mux the .mpg/.m2v file with the .mp2.

And before you mux, check that audio and video are the same length.

[Puggsley456]

I tried following the directions that were listed but this is what it says " Ac3fix is not recognized as an internal or external comand, operable program or batch file.

I tried using it in the comand prompt in XP. But thats all it says.

[ZippyP.]

I tried following the directions that were listed but this is what it says " Ac3fix is not recognized as an internal or external comand, operable program or batch file.

I tried using it in the comand prompt in XP. But thats all it says.

You have entered an incomplete pathname for the file you are trying to execute. The operating system doesn't know where to find it (it's dumb).Rather than turn this into a Dos-command line tutorial (I was trying to avoid this) and giving long explanations about changing directories and pathnames, here's a simple method:
1. Find the name of the directory that you go to when a Dos window is open (either the root directory c:\ or some other i.e. c:\?????\????).
2. Using Windows Explorer, temporarily move AC3fix and the file to be processed into that directory.
3. Open the dos window and run AC3fix .
4. Exit dos (enter <exit>) and move your files back where you want.

The above can be used for any similar command line program.

[Dutch Coder]

Use Cillers's Ac3 Tool, it does the job very well. Were Headac3eh failed, this tool worked for me. D.C 8)

[banjazzer]

If AC3FIX was in the C:\temp directory, together with an ac3 called sample.ac3, the command line would be:

C:\temp\AC3FIX sample.ac3 fixed.ac3

If you wanted a challenge, you could put AC3FIX in a separate directory to your AC3 file, and specify the path to each. However, for an easy life I recommend not, as also I do not recommend giving your files hard-to-spell names.

[mb571]

You don't encode the .mp2 with TMPG. You encode the .avi, and then mux the .mpg/.m2v file with the .mp2.

And before you mux, check that audio and video are the same length.

I did write "convert to mp2 with BeSweet". I was not trying to encode to mp2 with TMPGenc. I guess I didn't use the word "mux" so you had trouble understanding what I meant.
Anyways the audio cut out problem may have went away after increasing the direct draw priority in TMPGEnc.

Mark

[Puggsley456]

Ive done just as you said but when I open up the command prompt the line already has "C:\Documents and Settings\Sean>" on it.
When I try to enter the propper path way in I always get a "Impropper pathway" return. I've even trried to enter the ac3fix folder into that directory but it makes no difference.

Sorry guys this is my first time tring this.

[banjazzer]

I was not trying to encode to mp2 with TMPGenc. I guess I didn't use the word "mux" so you had trouble understanding what I meant.

So, are you saying you muxed a working audio stream and working video stream of the same length, and the audio cuts out after 30 secs? It's just that I have never heard of sound cutting out like this during the muxing. Usually it happens during the encoding.

When I try to enter the propper path way in I always get a "Impropper pathway"

There is evidently a small syntax error. What I wrote was for Win98. For XP I think someone said you needed the quotation marks. Did you try editing the path it gave to reflect the actual path?

[KingJohn]

For those who asked about Nimo, you dont need it, and will be better off without it.
KingJohns Guide to Codecs V2

For those with .ac3 saves
KingJohns Guide AVI Audio

And for everyone else
Baldrick helper