Is the exact same laser used to read both Blu-ray and 4k discs?

[mdhaus]

I tried searching for this and got some conflicting information.

Do 4K UHD players use the exact same "blue" laser to read both 4K discs and Blu-ray discs? Even though the data on 4K discs is much more compacted, does the player use the same laser it uses for Blu-ray discs? Or are there two "blue" lasers in the player - one for standard Blu-ray discs and another for the much more dense 4K discs?

I know they carry a "red" laser for DVDs and CDs...but I wasn't sure if anything extra was needed for the "step-up" to 4K playback from regular Blu-ray playback.

[David M]

Yes, same laser.

[teddyballgame]

Originally Posted by David M

Yes, same laser.

Hey David, do you know why a 4k disc would be "unreadable" in the ub820 but playback just fine in a ub420? I always assumed those two players were like brother&sister with parts and software. I'm sending the disc back for a replacement but thought it was strange it worked on one player but not the other. Any idea what goes on after you insert the disc and how a disc is determined to be unreadable? Does it just start trying to read data straight away or is there some kind of basic health check that takes place first?

[Yogi6807]

If your new 820 is having problems reading a disc you should return it and get a new one.

[PUsokrJosh305]

Originally Posted by teddyballgame

Hey David, do you know why a 4k disc would be "unreadable" in the ub820 but playback just fine in a ub420? I always assumed those two players were like brother&sister with parts and software. I'm sending the disc back for a replacement but thought it was strange it worked on one player but not the other. Any idea what goes on after you insert the disc and how a disc is determined to be unreadable? Does it just start trying to read data straight away or is there some kind of basic health check that takes place first?

Do you get that message when playing a regular blu-ray or a DVD in your Panny 820?

[David M]

Originally Posted by teddyballgame

Hey David, do you know why a 4k disc would be "unreadable" in the ub820 but playback just fine in a ub420? I always assumed those two players were like brother&sister with parts and software. I'm sending the disc back for a replacement but thought it was strange it worked on one player but not the other. Any idea what goes on after you insert the disc and how a disc is determined to be unreadable? Does it just start trying to read data straight away or is there some kind of basic health check that takes place first?

That's probably a pretty good assumption. I would bet at least that the drive has similar parts. It's probably just a defective 820.

[teddyballgame]

Originally Posted by Yogi6807

If your new 820 is having problems reading a disc you should return it and get a new one.

Thanks but I've had this player for over 3 years now and this is the first time it said unreadable. So I'm thinking there's just something weird about this disc.

Originally Posted by PUsokrJosh305

Do you get that message when playing a regular blu-ray or a DVD in your Panny 820?

Nope it's really just The Princess Bride 4k criterion disc that has given me a problem. There's some light scratching on the outer edge so maybe the UB820 is more fussy with tolerances for that sort of thing. Like I said the 420 doesn't seem to care.

Watched the new Matilda 4k just fine tonight on the 820 and also tested about 5 other discs with no problems. So I think the player is mostly fine it just doesn't like that one disc

[BXR 1138]

Originally Posted by teddyballgame

Thanks but I've had this player for over 3 years now and this is the first time it said unreadable. So I'm thinking there's just something weird about this disc.



Nope it's really just The Princess Bride 4k criterion disc that has given me a problem. There's some light scratching on the outer edge so maybe the UB820 is more fussy with tolerances for that sort of thing. Like I said the 420 doesn't seem to care.

Watched the new Matilda 4k just fine tonight on the 820 and also tested about 5 other discs with no problems. So I think the player is mostly fine it just doesn't like that one disc

If you go to the thread for The Princess Bride 4K you'll see posts by other people who bought it saying they're also experiencing issues with that disc.

[mdhaus]

Does the Princess Bride disc not even boot up in your 820? As mentioned, it appears that particular release has been problematic for a lot of people.

I do wonder if some of the errors we see are simply manufacturer-based. For example, this weekend I was watching "Marnie" for the first time in 4K on my Panasonic 9000. Forty-three minutes into it, I got a crap-ton of pixelation and the screen froze. I took the disc out, wiped it down, went back to that spot and the same thing happened again. The player eventually moved forward a few seconds, but the error knocked out all of the sound.

So out of curiosity, I put it into my Panasonic 820, which is hooked up to another TV in another room. This time, the glitch was off and on - On some playbacks, I would get a quick smatter of the error, and sometimes it was fine. But an error did show up at times, which proves that there was something there that the drive didn't like very well.

Later on after I had finished the movie, I tried the disc in my Xbox Series X. This time, there was no error to be found...no matter how many times I rewound and replayed the section. It played fine. My PS5 never had any issues with that section, either.

I have another disc on the way, since I'm assuming it's a disc-based problem - The fact that it happens all of the time on the 9000 and occasionally on the 820 means that there is something off with the disc. It's just weird how some drives can blow through that kind of stuff and not get bothered...and others totally freak out.