Hehe... when you said earlier "...share their experience whether there's any difference on sq & pq?" and then you wrote about 4K without saying anything about BD ISO, then this caused the confusion. Anyway, no problem.
Bluray ISO is a one-to-one 100% image copy of the actual bluray disc without any loss of data. Playing the BD ISO has no difference compared to playing than the actual bluray disc itself because the data read by the player is exactly the same.... BUT.... yes, there is a BUT here... somehow there is some difference for me... there are people who can hear the "subtle" difference and there are those that hears no difference! Why do I say that ?
In my personal opinion, eventhough BD ISO has the same data, playing the actual bluray disc sounds better !! Here are the possible reasons that I believe can cause such difference...
1) The longer the path from source played (bluray) to reach the AVR and TV, the more chance there will be that "interference" can interfere with the signal such as EMI. The BD ISO has to be stored in a harddisk which do have moving magnetic discs spinning by an internal motor which can cause interference... and then the USB cable to the player which can also be a problem too. Using a SSD harddisk with any motor will help. The player using laser light to read directly from the disc has the shortest path.
2) When additional hardware is used such as NAS Network Enclosure, Ethernet and WiFi Network is used to "stream" to the player, then quality should also be affected.3) The desktop computer is BIG source of all sorts of "noise" so if a HTPC is used to play the BD ISO, then quality will also suffer!
4) When additional AC/DC Power Adapter is used, it can also cause interference too. Example... adapters for harddisk dock, External NAS Harddisk, NAS Enclosure, WiFi Router etc.
Knowing this, that is why there are people who uses Notebook SSD (Solid-State) harddisk, good quality USB cable, Low-Noise Power Adapter and so forth. I did all this BUT because the signal path (highway) is longer, I somehow still prefer playing the actual bluray disc. Its NOT because of any "lower quality" from the Bluray ISO itself.
Retouched And Remuxed Bluray
This is where the quality CAN suffer when the actual bluray disc data is changed!
A BD50 bluray disc can store a maximum of around 50GB. It doesn't mean that a movie used 50GB. If a movie is originally encoded to 23GB, then a BD25 disc is used so ripping this to 23GB ISO will have the same quality. But... if a movie used 43GB and it is ripped to a 23GB ISO or duplicated to another BD25 disc, then the quality will drop.
A remuxed bluray can mean these things...
(1) When the disc is ripped, all the bluray menus and all "Special Features" and Trailers are removed so that the bluray ISO (BDMV Folder) plays the movie instantly. If they did NOT touch anything to the actual bluray movie file, then the quality will be the same. Whenever the bitrate or filesize is reduced, then quality will drop.
(2) The bluray can be remuxed to a single file such as MKV, MP4, TS, etc. Again, if nothing is touched and transfered to the single file, then quality will be the same BUT most of the time there is shrinking done which also reduces quality. Examples... 35GB bluray remuxed to to 10GB MKV, DTS-HD MA becomes DTS, Video bitrate reduced.
The most important factor whether the "duplicate" has the same quality as the original is actually knowing whether its an "untouched" copy or any "touching" have been done to it. Whether quality will be the same depends on whether anything have be touched on the original... not about ISO itself.
if TCP is used....there will be no drop of "quality" like you say.
Apr 19 2016, 07:07 PM
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