Sound cards can implement proprietary compression, and software only video compression is available in products like Microsoft Video for Windows, or for UNIX workstations. While compression can ease the demands on networks and storage media there are several trade-offs. Since some compression techniques remove information considered to be less important a loss in resolution may result. Once material is compressed the algorithms may prevent access to single frames of video for viewing or editing. The cost of complex hardware and software and compression and decompression delay are other factors important to users.
Different uses require different compression methods.
Video conferencing must be done in real time so fast encoding and decoding is needed. This is the aim of the H.261 standard. Video film distribution via cable networks, radio or CD is essentially a playback process, so encoding is not time critical, and decoding should be easy to implement to reduce consumer costs. The MPEG standards address these applications. MIDI encoding of audio notes is not really a compression method, but almost another form of media.