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The disadvantages of transcoding are that there is quality loss when transcoding between lossy compression formats, and that the process is highly CPU-intensive. This article compares video converters that have their own articles on Wikipedia.
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.
No No No No Planned No VP9: Lossy or lossless: June 2013 Patent claims Yes Yes No Yes Yes No No No VP8: Lossy or lossless: September 2008 Patent claims Yes Yes No Yes Yes No No No Dirac: Lossy or lossless: March 2008 Patent-free [61] VCM [d] No Yes No Needs Dirac [62] No Private No MVC: Stereoscopic: May 2009 Patent encumbered Yes [41] No No No ...
Most lossless compression programs do two things in sequence: the first step generates a statistical model for the input data, and the second step uses this model to map input data to bit sequences in such a way that "probable" (i.e. frequently encountered) data will produce shorter output than "improbable" data.
In contrast to that, some very general-purpose container types like AVI (.avi) and QuickTime (.mov) can contain video and audio in almost any format, and have file extensions named after the container type, making it very hard for the end user to use the file extension to derive which codec or program to use to play the files.
Linear pulse-code modulation (LPCM, generally only described as PCM) is the format for uncompressed audio in media files and it is also the standard for CD-DA; note that in computers, LPCM is usually stored in container formats such as WAV, AIFF, or AU, or as raw audio format, although not technically necessary.
The only filename extension for MPEG-4 Part 14 files as defined by the specification is .mp4. MPEG-4 Part 14 (formally ISO / IEC 14496-14:2003 ) is a standard specified as a part of MPEG-4 . Portable media players are sometimes advertised as " MP4 players ", although some are simply MP3 players that also play AMV video or some other video ...
Classification of objective video quality models into Full-Reference, Reduced-Reference and No-Reference. No-reference image and video quality assessment methods. Objective models can be classified by the amount of information available about the original signal, the received signal, or whether there is a signal present at all: [5]