from the V1 or from the V4 codebook. When coding from the V1 codebook, one codebook index per 4×4 block is written to the bitstream, and the corresponding 2×2 codebook entry is upscaled to 4×4 pixels. When coding from the V4 codebook, four codebook indices per 4×4 block are written to the bitstream, one for each 2×2 subblock. Alternatively to coding from the V1 or the V4 codebook, a 4×4 block in an inter-coded image can be skipped. A skipped block is copied unchanged from the previous frame in a conditional replenishment fashion. The data rate can be controlled by adjusting the rate of key frames and by adjusting the permitted error in each block. References External links Technical Description of the Cinepak Codec Cinepak - MultimediaWiki Cinepak Official Website Cinepak Decoder - FFmpeg Video codecs