Improved H.264 Compression Holds Down File Sizes on 1080p iTunes Store Content

ars technica takes look @ new 1080p content available on itunes store, showing how "high" compression profile h.264-encoded content on iphone 4s , new ipad , apple tv minimizing increase in file size needed move 720p 1080p.

comparison of 720p (left) , 1080p (right) video quality in itunes store content​

in survey of several titles available in 1080p on itunes store, report found file sizes increased 15-25% on respective 720p versions, despite number of pixels more doubling reach higher standard.

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the reason 1080p versions of itunes store videos can deal better without doubling file size--or worse--can found in tech specs of new appletv , new ipad. appletv supports h.264 compression 1920x1080 resolution video @ 30 frames per second using high or main profile level 4.0, ipad , iphone 4s same level 4.1. profile indicates kind of decompression algorithms h.264 decoder has on board--the "high" profile has tricks sleeve "main" or "baseline" profiles known previous devices don't support. level value indicates how many blocks or bits per second device can handle.

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the report offers comparison of video quality between 720p , 1080p formats on itunes store, noting increase in image quality 1080p content minor in many cases, more significant in brighter scenes.

article link: improved h.264 compression holds down file sizes on 1080p itunes store content

 

howaaaarrrd!!!

 

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