The bitrate of an MPEG1 and MPEG2 file

[Maciek]

How does MPEG1 file bitrate compare to the bitrate of this file converted to MPEG2?

I have some VCD files on several CDs and I want to put them all on one DVD disk. I know that one of the resolutions supported by DVD format is 352x240 (VCD resolution) so I won't have to change the resolution of my VCD files. But what should I do with bitrate? Should I make an MPEG2 file with exactly the same bitrate, should I lower it or maybe it has to have a higher bitrate?

[chickenmonger]

The Wikipedia (http://en.wikipedia.org/wiki/Mpeg2) article on MPEG-2 says:

The Video section, part 2 of MPEG-2, is similar to the previous MPEG-1 standard, but also provides support for interlaced video, the format used by analog broadcast TV systems. MPEG-2 video is not optimized for low bit-rates, especially less than 1 Mbit/s at standard definition resolutions. However, it outperforms MPEG-1 at 3 Mbit/s and above. All standards-compliant MPEG-2 Video decoders are fully capable of playing back MPEG-1 Video streams. MPEG-2/Video is formally known as ISO/IEC 13818-2 and as ITU-T Rec. H.262.

Since they're VCDs, the video bitrate would be 1,150 kbits/sec. I'd increase the bitrate for two reasons: The non-optimization at that bitrate, and also that you're going to be taking these videos through another lossy compression scheme (MPEG-2).

You may even be able to author DVDs with MPEG-1 video. I'm not sure about that, though.

[evilclive]

I have some VCD files on several CDs and I want to put them all on one DVD disk. I know that one of the resolutions supported by DVD format is 352x240 (VCD resolution) so I won't have to change the resolution of my VCD files. But what should I do with bitrate? Should I make an MPEG2 file with exactly the same bitrate, should I lower it or maybe it has to have a higher bitrate?

Every time you recompress a recording with a lossy codec, you will lose quality. You can never hope to get something of better quality than the original, because the "perfect" data is not there in your lossily-encoded source MPEG.

(Exception: if you use filters to remove snow, ghosting or other similar artifacts, you'll be throwing away more of the unwanted noise than the desired signal, so the recording will appear better than it was.)

It turns out that MPEG-1 video files do fall within the DVD spec, so your best bet may be to transfer the files without recoding them at all, thereby avoiding any loss of picture and sound quality.

You can author the disk with IfoEdit, which is free.

First, copy the .DAT files from the MPEGAV folder on your VCD, to your hard disk.

Then join them into one file with MPEG Tools in TMPGEnc 2.5 (which is freeware for MPEG-1), because IfoEdit only works with a single source file. You will also need to demultiplex the resulting file with TMPGEnc, for the same reason.

The sound will need to be converted from 44.1kHz (the standard used for VCD) to 48kHz (as used by DVDs). IfoEdit simply assumes the sound data is at 48kHz; when it isn't, the synchronisation goes haywire. Given that the audio source is coded at 224kbps, use 256kbps for the target file.

All I can say is, try it. Running the files through the "Merge and Cut" tool in TMPGEnc often seems to be helpful in stopping the sound wandering out of synch.