Burning mixed/split mono VCDs

ministry88 · Member Joined: 18 Dec 2008 Location: United States

Well, I've been trying to copy a few of my Hong Kong VCDs to DVD and the copying goes fine but unfortunately when I play the DVD back it plays IN STEREO (or mixed mono, I don't know the difference). Now, this would NORMALLY be a good thing, but with many HK VCDs, they assign the left channel to a specific dialect (like Mandarin) and the right channel to another (Cantonese). So when you play the VCD you must select either left channel playback or right channel playback or else it will play in stereo and you get overlapping dialogue (that is, both channels playing back simultaneously, in Cantonese and Mandarin).

I use Isobuster to extract the files and Nero 3.1.0.25 to burn the VCDs. I could not find an option on either software to enable me to record just ONE channel (that is, one language). The closest I find is in the Nero software where it allows me to record in Dolby Digital AC-3 2.0 or LPCM. Is it possible to isolate the audio channels or is the audio just packaged this way on the VCD and not changeable? When I watch the original VCD my DVD player menu allows me to select either the right or left channel, but when I watch the burned DVD, it just says "AC3 2CH unknown" with no option to isolate the audio channels.

Thanks for any help!

tomlee59 · Posted: Jan 18, 2009 23:17

This is very straightforward. You only need three (maybe four) tools, all free.

1) Use VCDEasy to extract the mpg file from the .dat file on the VCD. (You can also use VCDGear, if you happen to have it.)
2) Use TMPGEnc's MPEG tools to demux the stream into separate video and audio.
3) Use Audacity to eliminate the undesired audio channel. Duplicate (by cutting and pasting) the desired channel and copy it back to the other (now empty) channel, to produce glorious two-channel mono. Export the combination as MP2, 224kb/s (assuming that this is a standard VCD; otherwise, export using whatever bitrate your original stream had).
4) Again use TMPGEnc's tools to remux the new audio with the original video. Choose "VCD, non-standard" if the bitrates deviate at all from the spec (eg, for XVCDs).
5) If you want to burn a disc, as opposed to playing the files from the computer, use VCDEasy again to convert the mpg into bin/cue images.
6) Burn the images created in step 5 onto the CD-R of your liking. For best results, burn no faster than 8x. VCD data is stored with very little error correction compared to audio CDs, and so is very sensitive to media and burn quality.

If you don't have a suitable burning tool, burnatonce works well with bin/cue files, and is also free.

tomlee59 · Posted: Jan 18, 2009 23:36

Oh, by the way, is there a particular reason that you need to convert the VCDs into DVDs? Almost all DVD players (except bluray) will play VCDs directly. And a great many DVD players have an option to play only the left channel or only the right channel to accommodate precisely the language choice issue that you are struggling with.

If you must convert VCD into DVD for some reason, leave the video untouched -- the DVD specification already supports VCD's video resolution and bitrates. Any additional conversion would serve only to consume time and degrade image quality (which isn't all that great to begin with). The only issue is with the audio, but it's no biggie: Take the audio stream and simply perform a sampling-rate change (from VCD's 44.1kHz, to DVD's 48kHz) with a tool like Audacity. Remux, and then use your favorite DVD authoring tool to make a burnable DVD from the resulting mpg.

Because of the larger capacity of a DVD, you can actually put 5 VCDs onto a single-layer disk, and 10 on a dual-layer. You can author the DVD with each VCD as a separate title, if you so desire, with menus, etc. if you want to put in the work. If you use, e.g., Nero to convert into DVD, you'll just eat up all that space, consume a lot of time to do the conversion, and end up with a degraded result.

redwudz · Mod Neophyte Joined: 07 Sep 2002 Location: AZ, USA

You might have to use the latest version of Audacity with FFmpeg support as the older versions won't accept MPEG-1 Layer2 audio. (Or AC3) I think the new one might. Or you could demux the audio to WAV and that should be no problem for Audacity.

tomlee59 · Posted: Jan 19, 2009 01:44

AFAIK, Audacity has supported importing of mp2 since the very first version. However, exporting has been a different matter. Luckily, MP2 export has been supported in Audacity for quite some time now (although with different methods in the different versions), so there shouldn't be a problem unless he downloads it from some retro-time server.