MP4 player
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The name MP4 player is a marketing term for portable media players that comply with certain standards and formats.[3] The name itself is a technical misnomer, since most MP4 players are incompatible with the MPEG-4 Part 14 or the .mp4 container format. Instead, the term symbolizes their status as successors of MP3 players. [4]
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[edit] Technical information
[edit] Rockchip
Fuzhou Rockchip Electronics's video processing Rockchip has been incorporated into many MP4 players, supporting AVI with no B frames in MPEG-4 Part 2 (not Part 14), while MP2 audio compression is used.[5] The clip must be padded out, if necessary, to fit the resolution of the display. Any slight deviation from the supported format results in a Format Not Supported error message.
[edit] Other chipsets
Some players, like the Onda VX979+, have started to use chipsets from Ingenic, which are capable of supporting RealNetworks's video formats.[6] Also, players with SigmaTel-based technology are compatible with SMV (SigmaTel Video).
[edit] AMV
The image compression algorithm of this format[7] is inefficient by modern standards (about 4 pixels per byte, compared with over 10 pixels per byte for MPEG-2 / DVD video). There are a fixed range of resolutions (96 × 96 to 208 × 176 pixels) and frame-rates (12 or 16 frame/s) available. A 30-minute video would have a filesize of approximately 100 MB at a 160 × 120 resolution.[8]
[edit] MTV
The MTV video format (no relation to the cable network) consists of a 512-byte file header that operates by displaying a series of raw image frames during MP3 playback.[8] During this process, audio frames are passed to the chipset's decoder, while the memory pointer of the display's hardware is adjusted to the next image within the video stream. This method does not require additional hardware for decoding, though it will lead to a higher amount of memory consumption. For that reason, the storage capacity of an MP4 player is effectively less than that of a player that decompresses files on the fly.
[edit] Instruction manuals
The instruction manuals usually contain the basic information to operate and use the devices, but sometimes lack further detail. They are often translated into pidgin English.
[edit] See also
[edit] Notes and references
- ^ "“MP4教父” 爱可视全球总裁访华力拓中国市场". NetEase. http://tech.163.com/05/0603/14/1LB2B7TO000915BD.html.
- ^ "爱可视VS苹果：从MP3到MP4". 致信网. http://www.mie168.com/marketing/2007-06/209707.htm.
- ^ "MP3≠MP4！区别和认识MP3与MP4的不同！". Beareyes. http://bj.beareyes.com.cn/2/lib/200510/26/20051026011.htm.
- ^ "走出MP4误区：跟视频沾一边的播放器就是MP4". 西北IT网. http://www.cps365.com/news/200608/06/0712_0000021657.shtml.
- ^ "Leading Chinese MP4 IC Design Houses' R&D and Product Strategies Research Report # MIC1324". Electronics.ca Publications. http://www.electronics.ca/reports/multimedia/mic_mp4chips_design.html.
- ^ "Teclast announces the M series". haomp. 2007-11-28. http://www.haomp.com/page/2/. Retrieved on 2008-03-18.
- ^ Israelsen, Paul D. (1993-09-21). "United States Patent 5247357". http://www.freepatentsonline.com/5247357.html. Retrieved on 2007-12-07.
- ^ a b voroshil (2007-10-15). "AmvDocumentation". Google Code. http://code.google.com/p/amv-codec-tools/wiki/AmvDocumentation. Retrieved on 2008-04-06.
[edit] External links
- MPEG-4 Software at the Open Directory Project
- MyMPxPlayer.org is aimed at providing owners of unbranded or ’not so well known’ branded MP3/MP4 players with more information on their players and resources to help make them get the most out of their MP3/MP4 players.
