MPEG-1, defines an audio/video compression standard as proposed by the Motion Picture Experts Group (MPEG). This standard is used for Video CD and mirrors the quality of a standard VHS tape. Originally designed to achieve acceptable quality at 1.5 Mbps at 352x240 pixels resolution with 30 frames per second (NTSC) or 352x288 with 25fps (PAL). As hardware became more powerful the MPEG-2 standard was developed and made popular by DVDs.

MPEG-2, is not optimized for typical VCD bit rates, but excels above 3Mbps. The main advantage of MPEG-2 is that it achieves a greater quality for the same bit rate or put another way, it achieves the same quality using a lower bit rate and hence smaller file size. Basically the same argument for Audio's MP3 vs. the successors WMA & AAC. Commercial DVDs mostly use a bit rate in excess of 7Mbps. Storing this quality for a 2 hour film requires a Dual Layer DVD (DVD-9).

MPEG-4, is the latest compression standard used for audio / video data. Applications include streaming data on the web, video conferencing, PDAs & broadcast TV. The main advantage, once again, is that is achieves a greater quality for a lower bit rate. So powerful in fact that 1 hour of TV can be compressed into less than 400MBs with barely any noticeable loss in quality. Naturally this standard has been adopted for portable Video devices (MP4 players).

Notes:

1. Converting video for a portable device involves recoding to MPEG4 and reducing resolution to fit the device's screen size.
2. Assume Audio is encoded at highest bit rate 384kbps for MPEG1/2 capture & 128kbps for MPEG4 conversion.
3. Actual file sizes and capacities are approximate as they vary by content.

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