YouTube - Not Afraid, Eminem (link to youtube page)
(360p@570Kbps, 480p@1Mbps, 720p@2.1Mbps, 1080p@3.5Mbps)

Same video optimized (choose bitrate)
(576p@570Kbps, 720p@1Mbps, 1080p@1.7Mbps)
 

Instructions for comparison :

This is a comparison page between the standard encoding of Youtube and an optimized technique. More info in this Blog Article.
It's difficult to visually compare two 720p or 1080p videos. The best could be to have two identical HD monitors and playback both videos at full screen, side by side (use the link to the original youtube page to open video in the secondary monitor).

With only one monitor it is still possible to playback both videos at the same time and switch from one full screen to the other using, for example, Alt-TAB on Windows.
Obviously you need a fast Computer to decode both videos and/or a good GPU. You may also use two separate computers or laptops side by side and synchronize playback using the pause button of any player.

As an alternative you can use a software like AVIdemux to extract exactly the same frame from both video to compare them but some encoding techniques use psyco-visual approaches that provide an improved perception of quality only during playback. I have used this technique in the article.

The aim of this PoC is to demostrate that it is possible to optimize accurately the encoding of an important subset of a huge library to save considerable amount of bandwidth and thus money improving at the same time the overall QoS and the average quality delivered to user. Differently from older PoCs, in this one no enhancement filters are applied during playback. All is obtained by user-guided optimizations. More info here.

Compare for example:

Youtube 1080p@3.5Mbps vs optimized 1080p@1.7Mbps = half bitrate at virtually the same quality. Money savings + higher quality than Youtube 720p at the same bitrate.
Youtube 720p@2Mbps vs opt. 1080p@1.7M or 720p@1M = higher quality at -15% bitrate or almost the same at half the bitrate. More users reached with HD contents.
Youtube 480p@1Mbps vs opt. 720p@1Mbit/s or 576@570Kbit/s = higher quality at same bitrate or same quality at half the bitrate. HQ to everyone.
Youtube 360p@570Kbit/s vs optimized 576p@570Kbit/s = much higher quality at the same bitrate. Even the entry level bitrate can offer an HQ quality at fullscreen.


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