Video codec
A video codec (also called video codec ) describes a pair of algorithms for coding and decoding digital videos.
Since the amount of data incurred in videos is relatively large, in the consumer sector , z. B. with DVDs or video platforms , videos are now lossy compressed .
Procedure
During compression, a compressed data stream is generated from the source video with the help of an algorithm, which is then transmitted or stored. This compression must be reversed in order to reproduce the compressed data. The time it takes to compress, transmit, decompress, and play back the video data is known as latency .
A pair of algorithms that belong together is referred to as a video codec ( encoder / decoder , English for encoder / decoder). Different video codecs are usually not compatible with each other; This means that video content that has been compressed with the encoder of one codec cannot be decompressed with the decoder of another codec.
Applications and dissemination
Depending on the area of application, video codecs can be roughly divided into two categories: On the one hand, codecs that should receive the video in the highest possible quality. Such codecs are z. B. MPEG-2 or H.264 and are used in DVD-Videos or digital television , where i. d. Usually a high transmission rate is available. On the other hand, codecs that require the lowest possible data rate or only little energy for decoding, e.g. B. H.263 or VP8 . They are designed for use on mobile devices, such as B. Smartphones, thought that can only receive a low data rate or where only a low computing power or little energy is available.
The progressively increasing computing power leads to ever higher compression rates with simultaneously increasing video quality.
Most devices that are supposed to play videos have special graphics chips built into them that take over or at least support the decoding of the video (see also hardware acceleration ).