Since my DVD player has started acting up when trying to play a particular dual-layer disc, I decided it was high time to make a backup. The film itself wasn't quite enough though, as I found the director's commentary track very enlightening. I'd made several SVCDs before, and thought it would be a nice challenge to incorporate both audio tracks into a SVCD.

The only tool I found that allowed multiplexing more than one audio stream with a video stream, was Missing Mpeg Tools. Ffmpegx seems to allow it on the surface, but I haven't gotten it to work. I ripped a test chapter from the movie, encoded the video and audio streams separately, multiplexed them into a MPEG, used VCDToolsX to pack it into a .bin, burned the .bin (using Toast) on a CD-RW and plopped it in my stand-alone Denver DVD-311. No problem whatsoever; both audio files were accounted for and in perfect sync.

But don't stop there. Keep reading, if you don't want to repeat my mistakes.

Since the streams need to be encoded separately, I decided to rip the entire movie to Elementary streams. I got ffmpegx working on the video stream (making very sure to check the box "Keep elementary streams" since no audio would be forthcoming - it's no fun seeing your computer delete the video stream a nano-second after finishing the encode... major, why not make "Keep elementary streams" a default and have people turn it off if they want?), and left for work. When I got back, I checked the newly encoded .m2v, only to find the 16:9 footage crammed into a 4:3 container. It never occured to me that using an elementary stream as source, I needed to be extra careful when instructing ffmpegx how to treat the material - a VOB contains a lot more useful input than a raw video stream.

I restarted the encode, this time making sure to select 16:9 aspect ratio in the video section. (Another 8 hours pass...) Previewing it in both QuickTime and VLC, I was very pleased. The audio streams were encoded next (bitrates 224 for the proper one, and 160 for the commentary track btw), and Missing Mpeg Tools muxed it all into a big hefty MPEG. Back into ffmpegx (Tools) to cut the MPEG into 3 parts (I have had better luck with that tool than the JAW Mpeg-2 splitter), and VCDToolsX made .bins out of the three segments. Burned CD 1 onto a CD-RW, and went into the living-room to test. Again I was greeted by a 4:3 image, that jeered left-right-left-right 25 times a second... Although my video was now 16:9, it was by no means letterboxed...

Lesson learned - back to VOB I go. At least as far as the video is concerned - the audio files are done, after all. Another 8 hours of encoding later, I once again mux, .bin and burn. Finally, the video looks great, the audio is in sync - both of them - and I breathe a sigh of relief.

Being a cautious kind of guy, I decided to check all three of the discs before calling it a day. Some movie files don't survive the segmentation process without audio sync issues. But imagine my surprise when CD 2 and 3 turned out to have - only one audio stream. Puzzled, I went back to the computer and inspected the streams in VLC. (You can't use QuickTime with multiple audio streams - that program puts the audio streams one after another, so in effect the lengthof your movie is doubled... when the film/first audio is over, the final frame freezes and stays on throughout the second audios runtime...) and indeed there *was* a second soundtrack there - but also a third, that was completely silent. Wonderfully weird, isn't it?

I won't bore you with detailing my tests after this, but judging by experience it boils down to this: you can not split a MPEG-2 file with multiple audio streams on the Mac. At least, not if you want any other part than the first one to have selectable audio on a DVD player. Which means (yes, you've got it) that I had to go back again and re-do the whole thing, treating it as three separate projects (one per disc) instead of 1.

So that's what I did. Thankfully, the title was divided up into 30 chapters of roughly equal length, so it was quite easy to automate the process. Rip 10 chapters of video as VOB, rip the same 10 chapters of 2 audio as elementary streams, re-encode, mux, .bin, burn... I'll spare you the tirade I swore at the screen when it dawned on me that I'd accidentally misnamed one of the video files and thrown out the actual 2nd part... Thank God a third of a movie is so much faster to re-encode than the whole thing There were times when I wasn't sure I'd get through it all in one piece, or at least not without becoming a physical threat to my immediate family.

Anyway, there you have it. Now you know what (and what *NOT*) to do when making a SVCD with multiple audio streams on the Mac. Don't ask me about adding more streams, because I don't have the faintest idea on how it's done. And I think it's sad that there is no subtitle-ripper for the Mac, too.

/Wizeman

P.S.
Yes, I know there are easier ways of making SVCDs in general and the video tracks in particular, but I'm talking about "proper" SVCDs here - 480x480/576 . and not the XSVCDs 720x480/576 that have become all the rage lately... not that I mind that format though, as I am fortunate enough to have a player that deals with pretty much anything/everything I throw at it... oh well, it's 3:38AM and I should try and get some sleep...