Can I reencode a divx movie?

[watdahel]

I have a divx movie that was encoded using one of the audio codec provided in the 3.11 alpha divx codec. In order for me to play the movie WITH sound with a different computer, I have to install the 3.11 alpha codec in that computer.

My question is is it possible to reencode this movie so that it uses the lame mp3 audio codec? How would I go about doing this? Is there a way to separate the audio from the video and just recompress the audio and then join the video and audio back together?

 

[vss1980]

Yes you can re-encode the audio (transcode) without touching the video quality.

Using VirtualDub, all you have to do is change a setting under the Video tab under the main title bar.
By default, 'Full processing mode' is on. Select 'Direct Stream Copy' and each video frame will be copied over to the output file without any processing, hence no time wastage or video re-compression which can lower quality further.
Then make any changes under the audio tab that you want (making sure 'Full processing' is on for the audio tab).

When you save the video it will re-encode and copy the video-frames into one new file.

 

[watdahel]

Is it possible to just extract the audio and compress it to mp3? If I do the way you told me it will take the length of the movie.

 

[imgod2u]

You can use Premiere, import the file, make the cuts (if any) to the audio portion, then export an audio file. I think version 6 of Premiere allows you to export in mp3 instead of wav.

 

[vss1980]

Yeah, but if you cant afford Premiere 6, the same VirtualDub will do the same thing.

Load up the movie, then select File->Save WAV , and voila, you have the movie soundtrack in WAV format.

Also, I dont see how the method I suggested earlier can be so slow. If your rig in your sig is correct, it should be quite fast. A Duron is more than able to decode audio and then re-encode it into MP3 faster than real-time (remember, no processing takes place on the video). In fact, for most films (~1 hour, 30 mins) it should take less than 30 minutes to do (as long as your hard-drive is up to it also).

As far as I know though, you cant actually combine the audio frames compressed with mp3 into a video file (program limitations - maybe it can be done).

If you have the DivX 3.11 codec installed, you should also have the hacked Radium MP3 codec and this is perfectly acceptable for audio quality (Fraunhofer CBR of this codec is similar quality to LAME CBR).

 

[watdahel]

The audio was being reencoded as the movie was playing. That is slow!

 

[vss1980]

Sorry (dont usually say this) but you must be doing something wrong in VirtualDub or your computer is seriously under-performing. Even on a P2-400, selecting direct stream copy for video, and only doing processing on audio resulted in considerably faster than real-time processing.

You are (if you want to transcode in one step) opening the file, selecting direct stream copy for the video, and full processing for the audio (and making selection settings for the codec to use, etc. under the title audio tab)? Once you've done that, just select file->save avi and it should zip through. The speed may jump up and down a bit, but it should be done relatively quickly (definitely not the length of time of the film).

As for just getting the audio out of a video, open the file and then just select file->save wav. That should complete quite fast also.