said by TitusTroy:
can anyone explain why the Video On Demand feeds always look better then the network feeds of the same programming (sometimes a lot better)?...do they use a much higher bit rate for VOD?...for example the AMC HD broadcast feed of Walking Dead looks soft and grainy but the VOD looks a lot better (I know the grain is intentional with this particular show but my point is that the VOD looks much better)
same goes for HBO HD and pretty much all other network feeds versus their VOD counterparts...I thought they would be similiar in quality but the differences are quite noticable...why does VOD look so much better?
VOD shows use two-pass encoding, whereas network broadcast feeds use one-pass encoding.
Two-pass encoding involves having the encoder conduct an "analysis" pass first, to determine which portions of the video could benefit from various optimizations. These optimizations are applied during the encoding pass, resulting in significantly better picture quality at any given bitrate.
With a broadcast stream, two-pass encoding is impossible; it has to be real-time. Without the benefit of the analysis pass, the encoder cannot perform much in the way of optimization, so the picture winds up looking a lot worse.