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The quality the codec can achieve is heavily based on the compression format the codec uses. A codec is not a format, and there may be multiple codecs that implement the same compression specification – for example, MPEG-1 codecs typically do not achieve quality/size ratio comparable to codecs that implement the more modern H.264 specification.
Thus, a representation that compresses the storage size of a file from 10 MB to 2 MB yields a space saving of 1 - 2/10 = 0.8, often notated as a percentage, 80%. For signals of indefinite size, such as streaming audio and video, the compression ratio is defined in terms of uncompressed and compressed data rates instead of data sizes:
C The MaxDpbSize, maximum number of pictures in the decoded picture buffer, for the maximum luma picture size of that level is 6 for all levels. [1] [2] The MaxDpbSize can increase to a maximum of 16 frames, if the luma picture size of the video is smaller than the maximum luma picture size of that level, in incremental steps of 4/3×, 2×, or 4×.
Video compression schemes for Web and DVD make use of a 4:2:1 color sampling pattern, and the DV standard uses 4:1:1 sampling ratios. Professional video codecs designed to function at much higher bitrates and to record a greater amount of color information for post-production manipulation sample in 4:2:2 and 4:4:4 ratios.
A video coding format [a] (or sometimes video compression format) is a content representation format of digital video content, such as in a data file or bitstream. It typically uses a standardized video compression algorithm, most commonly based on discrete cosine transform (DCT) coding and motion compensation .
The video encoding was done for entertainment applications and twelve different bitrates were made for the nine video test sequences with a HM-8.0 HEVC encoder being used. Of the nine video test sequences, five were at HD resolution, while four were at WVGA (800×480) resolution. The bit rate reductions for HEVC were determined based on PSNR ...
The DCT, which is fundamental to modern video compression, [74] was introduced by Nasir Ahmed, T. Natarajan and K. R. Rao in 1974. [17] [75] H.261, which debuted in 1988, commercially introduced the prevalent basic architecture of video compression technology. [76] It was the first video coding format based on DCT compression. [74]
Video compression is used to greatly reduce the bit rate while having little effect on quality. [35] Bits per pixel (BPP) is a measure of the efficiency of compression. A true-color video with no compression at all may have a BPP of 24 bits/pixel. Chroma subsampling can reduce the BPP to 16 or 12 bits/pixel.