Intra-frame

For other meanings, see IFrame (disambiguation).

Intra-frame coding is used in video coding (compression). It is part of an intra-frame codec like ProRes: a group of pictures codec with inter frames.

The term intra-frame coding refers to the fact that the various lossless and lossy compression techniques are performed relative to information that is contained only within the current frame, and not relative to any other frame in the video sequence. In other words, no temporal processing is performed outside of the current picture or frame. Non-intra coding techniques are extensions to these basics. It turns out that this block diagram is very similar to that of a JPEG still image video encoder, with only slight implementation detail differences.

Inter frame has been specified by the CCITT in 1988-1990 by H.261 for the first time. H.261 was meant for teleconferencing and ISDN telephoning.

Coding process

Data is usually read from a video camera or a video card in the YCbCr data format (often informally called YUV for brevity). The coding process varies greatly depending on which type of encoder is used (e.g., JPEG or H.264), but the most common steps usually include: partitioning into macroblocks, transformation (e.g., using a DCT or wavelet), quantization and entropy encoding.

See also

• Video compression
• Inter frame
• Group of pictures application of frame types

http://www.cs.cf.ac.uk/Dave/Multimedia/node248.html