My directivo records wads of stuff every day, but they are the same bits that rain down on gazillions of other potential recorders and viewers. Incremental cost to serve one more household, pretty much zero. There are definitely narrowcast applications that don't make sense to broadcast down from a bird, but it also makes no sense at all to claim for capacity planning purposes that every household will need a unicast IP stream of all it's TV viewing capacity... -dorn On Mon, Apr 21, 2008 at 4:25 PM, Ric Messier <kilroy@washere.com> wrote:
On Mon, 21 Apr 2008, Chris Adams wrote:
Nope, ATSC is 19 (more accurately 19.28) megabits per second. That can carry multiple sub-channels, or it can be used for a single channel. Standard definition DVDs can be up to 10 megabits per second. Both only use MPEG2; MPEG4 can be around half that for similar quality. The base Blu-Ray data rate is 36 megabits per second (to allow for high quality MPEG2 at up to 1080p60 resolution).
From wikipedia (see: Appeal to authority :-): The different resolutions can operate in progressive scan or interlaced mode, although the highest 1080-line system cannot display progressive images at the rate of 59.94 or 60 frames per second. (Such technology was seen as too advanced at the time, plus the image quality was deemed to be too poor considering the amount of data that can be transmitted.) A terrestrial (over-the-air) transmission carries 19.39 megabits of data per second, compared to a maximum possible bitrate of 10.08 Mbit/s allowed in the DVD standard.
Ric
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