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I am wondering how much bandwith is required to stream a 1080p movie from for example Youtube. I am aware that there may be things such as compression that come in play here, but can anyone provide a good answer for this anyways?

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Compression makes such a huge difference, uncompressed its about 10Gbs compress for youtube 1-5mbit ( rough numbers ) – Lamar B Apr 18 '12 at 16:31
Assuming 16/9 aspect, 8 bit/channel/pixel, 4:2:0 chroma subsampling and 60 fps; an uncompressed 1020p stream should be 1492992000 b/s or just under 1.5 Gb/s.(math'd it) Bluray lets video transfer be 40 Mb/s (wpedia). – Eroen Apr 18 '12 at 16:49
up vote 9 down vote accepted

Compressing using x264, a "typical" file ends up somewhere around 8GB for 100 minutes of movie. To stream this without problems, you need a speed of 8GB/100 minutes ~= 1.3MB/s ~= 10Mb/s.

It is directly dependent on compression rate (and more correctly: bitrate), though. Youtube compresses material quite strongly. Try downloading a 1080p Youtube video with some of the (many) available services and divide by length to get an average bitrate (or check the bitrate directly with some tool - your connection simply needs to be able to handle the audio+video bitrate).

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Ah, the pain of uploading a 1080p video to YouTube without the automatic compression completely killing the quality... – Bob Apr 18 '12 at 16:45
Where did you find this "typical" bitrate/qf/crf for x264 that gives these figures? – Eroen Apr 18 '12 at 16:53
@Eroen: The "typical" quality was from a check on some movie content I had on my drive that was compressed with standard settings with common compression tools (e.g. Handbrake/Avidemux). It can be said that it differed with a factor of more than 2 upwards, but if I were to give any "typical" value, this seemed the most reasonable. – Daniel Andersson Apr 18 '12 at 16:55
@DanielAndersson, but were those movies you sampled varied enough? That is, were some animated, some drama, some action, some sci-fi, some horror, etc? All of these types have very different visual characteristics (smooth, detailed, slow, fast, bright, dark, etc.) that make them compress quite differently. If your sample did not have enough variety, then those are only typical of your movies. One way to get a pretty accurate average is to examine lists of ripped movies from torrent sites; those should have a good variety source material. – Synetech Nov 12 '12 at 18:38
@Synetech: As you point out, it is impossible to give one "good" value. It will be able to differ by a factor 2 up or down no matter what. All one can give is a ballpark figure with such a general question, which is what I meant by "typical" (within quotes to begin with :-) ). In real situations, animated movies often can be compressed more than a factor 2 more than live-action, but it depends on the exact animated content, and there are a ton of variables, but this goes beyond the scope of the question, and the scope of my answer. – Daniel Andersson Nov 13 '12 at 7:18

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