DVD bitrate

[ShadowDweller]

Alright, I ripped the .vob files from the DVD I wanted to backup. Since the vob's will on one 4.7 gig DVD-R, I know I need to downsample the movie. I was wondering if anyone can help me do this. I've done it to make SVCD's but do I have to downsample the audio also? What bitrate do I use to downsample the movie. To make SVCD's I always used VBR passes 4 and the bitrate of 2kbits. Could anyone help me out or point me in the direction of where I can get some help.. thanks

[Baldrick]

you can check one dvd to dvdr ripping method here to the left...it uses rempeg.

[alkieman]

You don't have to downsample the audio, just the video. If the audio you ripped is in AC3 or MPA/MP2 format then it will already be fairly small. You can of course, drop the encoding rate to squeeze a little more space but generally I leave the audio alone. However, be aware that MyDVD 2.3 and earlier (I don't know about MyDVD 3.0) create PCM audio files when creating your final disc. They will re encode your compressed audio file to an uncompressed PCM format which takes up a lot more room so you need to experiment a little more with the video encoding rates. Better authoring packages don't do this, they leave your audio file intact.

I usually split the audio/video, use ReMPEG to reencode the video file to a lower bitrate and use the demuxed files in my authoring software. Spruce UP, DVD Virtuoso, DVDit and others accept demuxed files. There is also another problem, most budget and midrange authoring packages create MPEG compressed audio when muxing the VOB files. Many US DVD video players and the Playstation 2 can't handle MPEG audio. You get video, but no audio. The PS2 handles uncompressed PCM and compressed Dolby Digital or DTS output but not MPEG Audio. With Spruce UP and DVD Virtuoso you will need to re encode your audio files to either AC3 or PCM formats before importing if your intended audience doesn't support MPEG audio. MyDVD creates PCM audio anyway so it's fine, but of course, this means less video on a blank disc. DVDit can re encode the audio to DD/AC3 stereo I believe although I've never used it myself.

There is generally a quick way to tell if your DVD player can handle MPEG audio. If it can play VCDs then it should play DVDs with MPEG audio quite happily.

If you are using one of the cheap packages like MyDVD or the offerings from Ulead or MGI then you will need to work with multiplexed files so don't demultiplex the audio first.

To fit aroud 2 hours on one blank DVD with audio, encode at around 4-5MB/sec. ReMPEG doesn't actually have too detrimental an effect on picture quality as you are starting with such a high quality source, but don't expect the end result to be quite as good as the source DVD. It should however, be perfectly acceptable.

Buy a couple of DVD-RW discs to experiment with though and to ensure you can fit everything, including created menus, on one blank disc. Also be aware that the DVD spec of 4.7Gb is not the same as the PC specs of 4.7Gb. In DVD terms 1Gb = 1000Mb, in PC terms 1Gb = 1024Mb. This means that a 4.7Gb blank actually only really holds around 4.3Gb of data. Your DVD authoring software should report available space in DVD terms so use that to judge how much will fit on one blank, not Windows Explorer. That has caught a few people out, they create a disc image of 4.65Gb on their PC but find it wont fit on a blank DVD-R disc. Some authoring software designed for data and video work wont warn you about this but thankfully, those designed purely for DVD Video authoring all seem to.