![]() MPEG-1 supports only progressive scan video. However, it is an antiquated format that has been surpassed in terms of quality and file size by many others. MPEG-1 offers high compatibility, in that almost any computer can play back MPEG-1 files, and many DVD players also support the VCD format. If the source video quality is good and the bit rate is high enough, VCD can look better than VHS, but VCD requires high bit rates for this. The quality is roughly comparable to that of VHS. This is used for video CDs (VCD) and also sometimes for online video. H.261 supported only progressive scan video. It included such well-established concepts as YCbCr color representation, the 4:2:0 sampling format, 8-bit sample precision, 16 by 16 macroblocks, block-wise motion compensation, 8 by 8 block-wise discrete cosine transformation, zigzag coefficient scanning, scalar quantization, run+value symbol mapping, and variable length coding. Essentially all subsequent standard video codec designs are based on it. Used primarily in older videoconferencing and video telephony products, H.261, developed by the ITU-T, was the first practical digital video compression standard. Many codecs have such similar names that it.s easy to get them confused. Although you may not use or need many of these in your work, it.s good to know the names and backgrounds of what.s available. Some are older versions of the popular standards others are geared toward specific uses so may not be as well known. Its use will decline as a delivery format as more efficient codecs such as AVC and VC-1 are adopted for HD video. MPEG-2 is now considered an aged codec, but it has tremendous market acceptance and a very large installed base, and even the relatively new high-definition video acquisition format, HDV, is based on MPEG-2. ![]() In terms of technical design, the most significant enhancement in MPEG-2 over its predecessor, MPEG-1 (see the next section), was the addition of support for interlaced video. When used on a standard DVD, it offers good picture quality and supports wide-screen. Used on DVD, on SVCD, and in most digital video broadcasting and cable distribution systems, MPEG-2.s sweet spot in the market is the quality of video it provides for standard-definition video. Like MPEG-4 part 10, VC-1 uses the concept of profiles to differentiate different uses and data settings it will support though its configurations are more straightforward than MPEG-4 part 10/AVC/H.264. It is commonly found on the Web, in portable devices, and on computers that support the WMV format. ![]() It is also one of the three mandatory video codecs in Blu-ray high-definition optical disc standards (MPEG-2 and H.264 are the others). This is an SMPTE standardized video compression standard (SMPTE 421M) based on Microsoft.s WMV 9 video codec. This is a proprietary video codec developed by On2 Technologies and used in Adobe Flash Player 8 and newer. Though it has impressive quality at bit rates lower than older codecs like MPEG-2, it is very processor-intensive to edit, encode, and play back, and older computers or low-powered portable devices may have difficulty playing it back or may drain their batteries faster than normal when using it. It contains a number of significant advances in compression capability, and it has recently been adopted into a number of company products, including the Xbox 360, PlayStation Portable, iPod, the Nero Digital product suite, and Mac OS X 10.4, as well as high-definition Blu-ray Disc. It uses different profiles and levels to identify different configurations and uses. This new standard is the current state of the art of ITU-T and MPEG standardized compression technology, and it is rapidly gaining adoption into a wide variety of applications. MPEG-4 part 10 is a standard technically aligned with the ITU-T.s H.264 and often also referred to as AVC. The following sections cover some widely used video codecs, starting with the ones that are currently most popular, followed by a chronological-order list of the ones specified in international standards. In the end, it seems unlikely that one codec will ever supplant all others. It’s therefore possible for multiple codecs to be available in the same product, avoiding the need to choose a single dominant codec for compatibility reasons. Some popular codecs for computer video include MPEG, Indeo and Cinepak.Ī variety of codecs can be implemented with relative ease on PCs and in consumer electronics equipment. Codecs can be implemented in software, hardware or a combination of both. Codec: (1) Short for compressor/decompressor, a codec is any technology for compressing and decompressing data.
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