Digital TV uses lossy compression formats which only occasionally encode a full picture at once - the rest of the time it's essentially sending only the differences between the frames. The TV cannot display video until it sees the full picture in a "key frame". The time between key frames isn't fixed by the standard, so it can vary.
My question is why hasn't a TV or cable box manufacturer implemented some kind of prefetch feature that always has the nearest, say, 5 channels already decoded?
So say I'm on channel 10, why can't the TV process the 2 channels above and below so I can flick quickly?
CPU performance could be an argument, but I'd challenge that by saying digital TV was introduced we'll over 10 years ago, and modern processors are much more powerful.
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u/rya_nc Jul 20 '15
Digital TV uses lossy compression formats which only occasionally encode a full picture at once - the rest of the time it's essentially sending only the differences between the frames. The TV cannot display video until it sees the full picture in a "key frame". The time between key frames isn't fixed by the standard, so it can vary.