CCIR 601 is a standard for digital video. It uses Y'CBCR colour with 4:2:2 chrominance sub-sampling . The data rate is 166Mbits per sec.
Video compression can make use of spatial (intra-frame) and temporal (inter-frame) compression. Spatial compression is still-image compression applied to individual frames. Temporal compression is based on frame differences and key frames .
Motion JPEG applies JPEG compression to each frame. It is usually performed in hardware.
Cinepak , Intel Indeo and Sorenson are popular software codecs used in multimedia. They are based on vector quantization .
MPEG video is an elaborate codec that combines DCT-based compression of key frames ( I-pictures ) with forward and backward prediction of intermediate frames ( P-pictures and B-pictures ) using motion compensation .
QuickTime is a component-based multimedia architecture providing cross-platform support for video, and incorporating many codecs. It has its own file format that is widely used for distributing video in multimedia.
Digital video editing is non-linear (like film editing).
specifies the image format, and coding for digital television signals
Parameter Value YUV encoding 4:2:2 Sampling frequency for Y (MHz) 13.5 Sampling frequency for U and V (MHz) 6.75 No of samples per line 720 No of levels for Y component 220 No of levels for U,V components 225
Perplexing NTSC System 1 2 3 … 480 1 2 3 … 640 Analog to digital Pixels are square 1 2 3 … 480 1 2 3 … 720 CCIR 601 standard Pixels are not square
CCIR 601 Sampling Y samples C B and C R samples 4 : 2 : 2 sampling (co-site) 4 : 2 : 0 sampling (not co-site) 4 : 1 : 1 sampling (co-site)
Code using motion compensated prediction from a past I or P picture
Higher compression rate than I picture
B (bidirectional-predicted) pictures
Code bidirectional interpolation between the I or P picture which preceded & followed them
Highest compression rate
All are compressed using the MPEG version of JPEG compression
I 01 I B P I P B B B B B B B 02 03 04 05 06 11 12 13 14 15 16 21 Group of Pictures (GOP) An MPEG sequence in display order 01 I B P I P I B B B B B B B 04 02 03 11 05 06 14 12 13 21 15 16 An MPEG sequence in bitstream order (decode order)