QuickTime Animation format (also known as QuickTime RLE) is a video compression format and codec created by Apple Computer to enable playback of RGB video in real time without expensive hardware.[1][2] It is generally found in the QuickTimecontainer with the FourCC 'rle '.[note 1] It can perform either lossless or lossy compression and is one of the few video codecs that supports an alpha channel. Supported color depths are 1-bit (monochrome), 15-bit RGB, 24-bit RGB, 32-bit ARGB, as well as palettized RGB. As a result of reverse-engineering of the format, a decoder is implemented in XAnim as well as an encoder and decoder in libavcodec.[3][4]
QuickTime Animation uses run-length encoding and conditional replenishment for compression.[2] When encoding, the input frame is scanned pixel-wise in raster-scan order and processed line-wise.[2] Within a line, pixels are segmented into runs, the length of which is variable and signaled in the bitstream. For each run, one of three coding modes is used: same color, skip, or PCM.[2] In same color mode, a run of pixels is represented by a single color in a run-length encoding fashion. If pixels with different colors are joined into a run (of a single color) by the encoder, the coding process is lossy, otherwise it is lossless. The lossless mode is used at the 100% quality level. In skip mode, the run of pixels is left unchanged from the previous frame (conditional replenishment). In PCM mode, the color of each pixel is written to the bitstream, without any compression.[2]
Run-length encoding works well on content with large areas of constant color. Conditional replenishment works well if only small areas change from frame to frame. QuickTime Animation works well on content with both these properties, such as traditional 2-D animation and screencast content.[5] For natural video and complex 3D rendered scenes, in which runs of constant color rarely occur, only low compression ratios can be achieved in lossless mode, and the merging of runs becomes visible as noise in lossy mode.
^(PDF). Inside QuickTime: The QuickTime Technical Reference Library. Apple Inc. 2000. Archived from the original (PDF) on March 7, 2000. Retrieved 5 April 2013.
^ abcde"Apple QuickTime RLE". MultimediaWiki. 24 May 2011. Retrieved 9 April 2013.
^Mark Podlipec (10 December 1997). "xanim.2.70.6.4.2 README". XAnim. Retrieved 4 April 2013.
^"FFmpeg Documentation". FFmpeg. Retrieved 4 April 2013.
^Peter Hosey (8 December 2013). "Screencast codec showdown: The codecs: Animation". Archived from the original on 3 July 2013. Retrieved 9 April 2013.
External links
QuickTime Animation (RLE) Video Decoder - FFmpeg
Quicktime Animation (RLE) Video Encoder - FFmpeg
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quicktime, animation, topic, this, article, meet, wikipedia, general, notability, guideline, please, help, demonstrate, notability, topic, citing, reliable, secondary, sources, that, independent, topic, provide, significant, coverage, beyond, mere, trivial, me. The topic of this article may not meet Wikipedia s general notability guideline Please help to demonstrate the notability of the topic by citing reliable secondary sources that are independent of the topic and provide significant coverage of it beyond a mere trivial mention If notability cannot be shown the article is likely to be merged redirected or deleted Find sources QuickTime Animation news newspapers books scholar JSTOR September 2011 Learn how and when to remove this template message QuickTime Animation format also known as QuickTime RLE is a video compression format and codec created by Apple Computer to enable playback of RGB video in real time without expensive hardware 1 2 It is generally found in the QuickTime container with the FourCC rle note 1 It can perform either lossless or lossy compression and is one of the few video codecs that supports an alpha channel Supported color depths are 1 bit monochrome 15 bit RGB 24 bit RGB 32 bit ARGB as well as palettized RGB As a result of reverse engineering of the format a decoder is implemented in XAnim as well as an encoder and decoder in libavcodec 3 4 Contents 1 Technical Details 2 See also 3 Notes 4 References 5 External linksTechnical Details EditQuickTime Animation uses run length encoding and conditional replenishment for compression 2 When encoding the input frame is scanned pixel wise in raster scan order and processed line wise 2 Within a line pixels are segmented into runs the length of which is variable and signaled in the bitstream For each run one of three coding modes is used same color skip or PCM 2 In same color mode a run of pixels is represented by a single color in a run length encoding fashion If pixels with different colors are joined into a run of a single color by the encoder the coding process is lossy otherwise it is lossless The lossless mode is used at the 100 quality level In skip mode the run of pixels is left unchanged from the previous frame conditional replenishment In PCM mode the color of each pixel is written to the bitstream without any compression 2 Run length encoding works well on content with large areas of constant color Conditional replenishment works well if only small areas change from frame to frame QuickTime Animation works well on content with both these properties such as traditional 2 D animation and screencast content 5 For natural video and complex 3D rendered scenes in which runs of constant color rarely occur only low compression ratios can be achieved in lossless mode and the merging of runs becomes visible as noise in lossy mode See also EditList of lossless video codecsNotes Edit Three letters followed by a space References Edit QuickTime File Format PDF Inside QuickTime The QuickTime Technical Reference Library Apple Inc 2000 Archived from the original PDF on March 7 2000 Retrieved 5 April 2013 a b c d e Apple QuickTime RLE MultimediaWiki 24 May 2011 Retrieved 9 April 2013 Mark Podlipec 10 December 1997 xanim 2 70 6 4 2 README XAnim Retrieved 4 April 2013 FFmpeg Documentation FFmpeg Retrieved 4 April 2013 Peter Hosey 8 December 2013 Screencast codec showdown The codecs Animation Archived from the original on 3 July 2013 Retrieved 9 April 2013 External links EditQuickTime Animation RLE Video Decoder FFmpeg Quicktime Animation RLE Video Encoder FFmpeg This multimedia software related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title QuickTime Animation amp oldid 1061826692, wikipedia, wiki, book, books, library,
