Originally Posted by lrstevens421
Slimgoodbooty, this is precisely the kind of information I was looking for. I don't wish to derail this thread so can you point me to the source where I can learn more on this topic. I'm so dissapointed in my TimeWarner high-def compared to my BD-P1200 and HD-A20.
Originally Posted by Slim GoodBooty
Uncompressed 1920 x 1080 has a bitrate of 1.5 GB per second. Cable and sat broadcasts can only do 25ish MB per second. So, those HDTV broadcasts have the dookey compressed out of them.
25Mbps HDTV on cable or satellite? I wish that were so!
Most Blu-ray movies average >16Mbps, with peaks of 30Mbps or more on complex scenes. Many Blu-ray disks also use more advanced encoding (AVC, VC-1) on the disk.
By comparison, satellite broadcasts average closer to 9-11Mbps, while cable probably averages 11-15Mbps, with peaks not much higher. Channels require varying levels of bandwidth depending on whether they use a 720p or 1080i carrier and whether they show mostly 24p (film) or 60i (video) content. All broadcast and cable high-definition programming is originally distributed as MPEG-2; no content provider currently uses MPEG-4, AVC, or VC-1 to distribute their feeds.
With Blu-ray disks, you also get the benefit of the post-house's encoding output direct to your screen. With most cable and satellite providers, you almost never see the original broadcast or cable signal on your screen. One or two providers, like Verizon FiOS, pass through the high-definition signal without added compression, but most butcher the signal so that that the resulting picture is very different from the original. Satellite providers like DirecTV and Dish Network, and cable providers like Charter and Time Warner use rate shaping to re-compress the already-highly-compressed
HDTV signals even further to fit more channels on their systems -- i.e. they trade quality for quantity.
In order to compress high-def signals even farther, these providers filter out high-frequency information, such as shadow detail. In some cases, as with satellite, they even downconvert the resolution of their channels. Such excess compression often introduces pixelization and macroblocking that isn't in the source feed. Some people think this pixelization and blocking is normal, when most of it is not -- it's added by the provider.