MPEG-1(.mpg, .dat) is the predecessor to MPEG-2 used for DVDs. MPG files are a lower quality/bitrate format usually at half of the resolution of DVD VOB files. They encompass CD quality 2 channel audio, as opposed to the 5.1 channels found in some DVD VOB files. Quality depends on the encoder used, and can be quite good if done properly.
VideoCDs (VCDs) are simply MPEG-1 data (at a specific resolution/data rate - ie. VCD compliant) burned onto CDs using a special CD writing format. You don't need special CD-Rs to make a VCD (any blank CD-R will do), but you'll need a CD writer tool that supports VCD burning. The .mpg files will then appear as .dat files on the VCD. VCDs can also feature limited interaction (VCD version 2.0), and one popular use for VCDs is for Karaoke. The best thing about VCDs is that they are playable in almost all standalone DVD players (that supports CD-R or CD-R/W reading). A usual 2 hour movie will usually require 2 CDs.
Below are some useful statistics :
Format : .mpg
Resolution : PAL - 352x288 @ 25 FPS ; NTSC -352x240 @ 23.976 or 29.97 FPS
Bitrate : 650 MB stores around 50-60 minutes
Quality : VIDEO - Similar to VHS ; AUDIO - CD Quality (44kHz, stereo)
Encoding time : 1-2 frames per second on a PII-350
Below are some usage guides and download links for the conversion process :
You'll need a suitable VCD burning software like Nero Burning ROM, you can download a fully working 30 day trial version here. These VCD burning tools will usually check to see if your MPEG-1 file is VCD compliant and will give you a warning if the file isn't compliant. In most cases, if you convertd the MPEG-1 file using the "Resolution" information listed in the "STATS" section above, and you shouldn't get an error, and even if you do get an error, the file may still play as a VCD, but you may encounter display problems (eg. not full screen, frame skipping, distortions ...).
HOW TO PLAYBACK MPEG-1/VCD
Below are some players for VCDs
DVD Decoders Cards
Most DVD decoder cards also support MPEG-1 playback, and hence VCDs