2000-5-24

Haven't you always dreamed of it? The perfect DivX picture combined together with cristal clear Dolby Digital soundtrack? It's now possible and even easier than you tought.

First of all go the credits: VULTURE suggested this method to me and provided a nice software package that contains every software you need for it to work. Many thanks to him. If you have any questions please post them to Olegs Forum - in General Discussions there's a thread called DivX AVIs with AC3 - package available. 

IMPORTANT: Convert the video to AVI first. You don't need to do the audio conversion, so skip the ac3dec/graphedit/totalrecorder stuff, and you can select Direct Stream Copy in the FlaskMpeg audio options instead of Decode Audio. Using that flag in flask will already give you the necessary ac3 file so you can skip step1. 

You also need to download this package, unzip it to the same directory as your current virtualdub resides - to keep processing settings and stuff - and then run registerfilters-98.bat if you're running Windows98 or registerfilters-2k.cmd if you're running Windows2000. Then follow the instructions on this page. 

Step 1: Extract the ac3 soundtrack from a DVD.

Of course you'll need the vob files already on your hardisk. If you haven't do so, read a guide on how to do it. Then start up the mpeg2avi gui:

Select the path of vstrip.exe, the input file and the Ouput file in section 1. For those who still don't know what a stream list is I suggest you read the FAQ. ALWAYS USE A STREAMLIST. I can't tell you that enough. Too many times I see people extract soundtracks and split files with Mpegutils. Nothing against it but it's just not fully capable of the tasks at hand. You'll lose a couple of kilobytes every time you start working on a new vob, whereas vstrip - only when you use a streamlist - will work perfectly. For all you command line freaks, note the command line in the gui, that's how it's supposed to look. Select your language and leave the rest. Make sure you've marked Enable Demux Mode, Audio,Strip Everything and Process Input List, uncheck the rest.

When you press Strip My VOB a dos box will pop up and it'll take 10-20 minutes till the process is complete. After the process is complete, you'll have the soundtrack in dolby digital format on your harddisk.

If you came here when following the Graphedit method, it's time to get back there. 

Step 2: Multiplex Avi and AC3

Start the modified version of VirtualDub and load the avi you've created. Then set video to direct stream copy:

Then Set Audio to Direct Stream Copy and Select Wav Audio

Make sure you select All files as filetypes, then chose the ac3 soundtrack.

After selecting the soundtrack the following dialog window will pop up telling you everything about the ac3 file in question.

After that you have to selec the Interleaving options. Note that since this is an ac3 track, no compression and conversion is needed and it wouldn't probably work anyways. Remember, you want ac3 soundtrack, nothing else. 

Make sure you don't go over these settings, especially the Interleave audio every XX ms, since otherwise playback will be choppy. You can of course experiment with these settings, and if the audio is not synch, use the usual procedures. However you can't add silence to an ac3 file, that would take a lot of additional steps and is too much to discuss in this guide. You'd need ac3 capable software which is not freely available to modify an ac3 file.

If your ac3 file has a bitrate higher than 383kb/s you should lower the interleave values to 120. For 192kb/s tracks you can go higher than 160.

Last but not least you have to save the Avi.

After some minutes we're done. The new DivX/AC3 avi can be played in any DivX capable player. For those who want to split their movies on several CDs, that should be possible, too. I didn't notice any problems when I tried it.

Here's some help for those who need the AC3 signals on their SPDIF digital outputs. However it only works in Windows98 for the moment. The Soundlbaster Live drivers for Windows 2000 won't support SPDIF out at the moment.

The problem is that when the media player builds the graph to render the file it inserts a "DirectSound" rendering device at the end which appears incapable of outputing to the SPDIF. To fix this:

Open Graphedit, select Open - Render media file and then your avi/ac3 file.

Delete Default DirectSound Devide from the graph - click on it and press the delete button. Then select Graph - Insert filters:

Select Default WaveOut Device and connect the filter to the XFrom Out of the InterVideo Audio Decoder.

In the end it shoud look like this:

Then save the graph and open it in Media Player by either creating a shortcut or specify the graph in the command line - mplayer2 graph.grf. 

Now press Stop in Media player, right click in the picture, select Properties, then select the advanced tab, click on the Intervideo Audio Filter and chose properties. Finally you should be able to set SPDIF output. 4 Channel output won't work on most copies of WinDVD and it's filters due to licensing issues with Dolby Labs.