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Comment fair comparison (Score 1) 594

Has anyone noticed that the "5.5" Mbps stream has a maximum rate of 8.6 Mbps, and the "6.9" Mbps stream has a maximum rate of 10.7 Mbps?

ATSC HDTV MPEG-2 streams are broadcast at a maximum rate of 19.39 Mbps (in practice, they average less, just like Microsoft's streams; VBR encoding is thrifty). ATSC includes 18 formats, including 1920x1080@24p, which is the preferred format for HD films.

In contrast, these demo clips are encoded from only a 1280x720@24p source. (Codec reports 30fps presumably due to film pulldown conversion.)

So, the Microsoft clips have only 44% of the resolution that a HD-DVD might have. Now, I certainly hope that a WM9 codec is powerful enough to not require 1/0.44=2.25 times the bitrate for a full resolution HDTV stream (as would be encoded on an HD-DVD), otherwise the 10.7 Mbps max rate demo stream would require 24 Mbps!!! That's more than the existing ATSC MPEG-2 standard!

Hey, I'm not dismissing Media 9; it's a very powerful codec, and it's more efficient than MPEG-2 and the earlier versions of MPEG-4. But let's compare apples to apples here!

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