Originally Posted by Sonyboy
Wanted to get some opinions on 4k bluray featuring Dolby Vision. I recently purchased a 77C9 and have thoroughly enjoyed it so far. I have a sony x800 4k blu ray player which works fine but doesn't have Dolby Vision playback. I currently let the dynamic tone mapping on the Lg do it's thing for 4k blu rays. Is dolby vision on blu ray a noticeable difference vs using the tone mapping on the LG? I'd rather hang on to my player if I can for a while longer.
So your actual question is whether HDR10 with DTM is comparable with Dolby Vision.
The difference between LG's DTM and Dolby Vision should theoretically always be visible, but in practice this is not necessarily the case.
LG's DTM algorithm tries to do on the fly what is done in the mastering process with Dolby Vision. This means that with Dolby Vision content, after the automatic tone mapping is applied, someone looks at the movie again and manually corrects the tone mapping values. Not only are the overall values for the movie corrected, but also those of scenes or even frames that don't look the way they should.
LG's automatic algorithm for dynamic tone mapping, on the other hand, can be more or less off in reality and depending on the content.
A badly mastered Dolby Vision film won't necessarily look better than an HDR10 film with DTM. With a well mastered film, however, the difference should be quite visible. How much you perceive is subjective and depends other factors as well (the content itself, your environment etc.)
Finally, it should be mentioned that Dolby Vision works with up to 12 bits, while HDR10 uses only 10 bits. Theoretically, you lose a bit of quality here, but in practice, very little of it should be visible - especially with a 10 bit panel.