How important is Blu-ray bitrate to image quality?
Just how important is the video bitrate of a Blu-ray disc to image quality? While doing some research recently, I found something that intrigued me. for example, the film Avatar came to Blu-ray in its original, single-disc version and, shortly thereafter, as 3-disc Extended Collector's edition set. Now, here's what intrigued me: the original release has an average video bitrate of around 28 Mbps, while the 3-disc version, where they had to fit 16 additional minutes on a single disc, has a video bitrate of around 22-23 Mbps. Likewise, I found similar differences with Django Unchained. The US Blu-ray release of that film has a bitrate of 28 Mbps, compared to the European version's 23 Mbps. And I'm sure these are not the only 2 such cases.
But my question is: does this necessarily mean that those lower-bitrate versions have slightly worse image quality? What can technically be done to keep image quality the same, while reducing the bitrate by 5 Mbps (when, as far as I know, Blu-ray already pushes codecs to their limits)?
P.S.: I don't have both versions of the above mentioned films to do a comparison myself.
Last edited by marko7; 08-27-2015 at 06:41 AM.