Search results
Results from the WOW.Com Content Network
Apple ProRes is a high quality, "visually lossless" lossy video compression format developed by Apple Inc. for use in post-production that supports video resolution up to 8K.It is the successor of the Apple Intermediate Codec and was introduced in 2007 with Final Cut Studio 2. [1]
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:
VBR is commonly used for video CD/DVD creation and video in programs. Bit rate control is suited to video streaming. For offline storage and viewing, it is typically preferable to encode at constant quality (usually defined by quantization) rather than using bit rate control. [1] [2]
In the second pass, the collected data from the first pass is used to achieve the best encoding quality. In a video encoding, two-pass encoding is usually controlled by the average bitrate setting or by the bitrate range setting (minimal and maximal allowed bitrate) or by the target video file size setting. [5] [6]
For example, an image may have areas of color that do not change over several pixels; instead of coding "red pixel, red pixel, ..." the data may be encoded as "279 red pixels". This is a basic example of run-length encoding; there are many schemes to reduce file size by eliminating redundancy.
In a PSNR based performance comparison released in April 2013 the Main 10 profile was compared to the Main profile using a set of 3840×2160 10-bit video sequences. The 10-bit video sequences were converted to 8 bits for the Main profile and remained at 10 bits for the Main 10 profile. The reference PSNR was based on the original 10-bit video ...
In April 2015 Google released a significant update to its libvpx library, with version 1.4.0 adding support for 10-bit and 12-bit bit depth, 4:2:2 and 4:4:4 chroma subsampling, and VP9 multithreaded decoding/encoding.
Some earlier systems placed three 10-bit channels in a 32-bit word, with 2 bits unused (or used as a 4-level alpha channel); the Cineon file format, for example, used this. Some SGI systems had 10- (or more) bit digital-to-analog converters for the video signal and could be set up to interpret data stored this way for display.