Passthrough mpeg4 video but re-encode mp3 audio to AAC?

[live4ever]

I would like to make some .avis, previously ripped with Handbrake to XviD with mp3 audio, iPod video capable by passing through the mp4 video and only re-encoding the audio to AAC and putting it in a .mp4 or .mov container.

I can't seem to get ffmpegX to choose video passthrough along with a mov or mp4 container - once I choose video passthrough the container changes to avi.

[macr0t0r]

Yep. It's been requested, but it's not supported yet. I tried doing it using the command-line (frame copy into MP4 container), but Quicktime wouldn't recognize the file afterwards.

Sadly, Quicktime Pro doesn't support passthru when going from AVI to MP4 either.

DIVX DOctor will convert to a Quicktim MOV format with MP3, and THEN you can use Quicktime Pro to copy the video into an MP4 container and convert the audio, but this is...beyond tedious.

major has a feature-request list as long as Santa's Naughty List, so you might have to be patient on this one.

[Jacke]

What you could try is using the advanced output-mode in VLC to convert it. I just tried it and it seems to work fine. (I'm guessing the video needs to be in Simple Profile for Quicktime/iPod.)

In VLC you choose 'Open' (not 'Quick open'), select your file and check the 'Advanced output'-checkbox, fix the settings and press 'open'.

[live4ever]

I forgot about VLC's transcoding abilities - it's weird the file I got with play in QT preview in column view in the Finder (QT 7 on 10.3.9) but not in the standalone QT.app.

Also when I get info on file in VLC it says the frame rate is like 12 fps and the AAC audio (which I encoded to 96 kbps) is displaying as 1500 kbps - the file plays back fine in VLC though (not at 12 fps).

[macr0t0r]

Jacke, you get a cookie!

Turns out that VLC is an excellent 1-stop shop for converting a DIVX/XVID AVI to MP4 with video Pass-Thru!

1. Go to File: Streaming/Exporting Wizard
2. Select "Transcode/Save to File," then "Next"
3. Select a Stream or just highlight a currently open file.
4a. Here's the key part: Make sure "Transcode Video" is NOT selected. Then make sure "Transcode Audio" IS selected.
4b. Set Audi Codec to "MPEG 4 Audio" (which is a fancy term for AAC) and set your bitrate.
5. Set Encapsulation to "MPEG 4/MP4"
6. Specify the destination file and let 'er rip!

This is beautiful! No quality is lost in the video (there is slight quality-loss in the audio since you have to encode from one lossy format to another). It's a bit slow, but at least it does it in one shot. Now I have a way to convert my favorite XVID/DIVX movies to something iPod-compatible. Sweet!

@live4ever: I have often gotten "wonky" values from VLC's info window. I have better luck dragging files to FFMPEGX and getting info from that instead. What does it say?

EDIT:
Well, the VLC passthru does NOT always work. For XVID movies, its pretty reliable, but DIVX sames to use a modified varient of the MPEG4 in the video-encoding which my iPod chokes on. This article references that:
http://forums.3ivx.com/index.php?showtopic=84030&pid=416721&st=0&#entry416721

So, it looks like most of my DIVX stuff will need full transcoding anyway. Oh well.

[live4ever]

Any updates on how to do this better or any other program recommendations. I sort of forgot about doing this because I never did get an iPod video back then but I do have one coming next week.