Only I know it’s not safe with video-recorders. Damages the “heads”, whatever they are. So is it because I’ve left it on pause that the thing seems to have trouble displaying black properly? It goes all blocky. Only in the black areas, but still…
What kind of player do you have? Most players are designed to shut off after about 5 minutes. Do all your DVD’s get blocky?
It’s a Creative 12-speed. I’m renting DVDs, I don’t own any, so I don’t know if they all do… three in a row have done it noticeably, so far. Family Man, Lost Souls and Gangster No.1.
As far as the movies go, the third is the best, by the way. The other two were pretty forgettable.
With VCR’s it’s practically all analog. There are moving parts and the tape and heads are much much more succeptable to damage if left on pause for extended periods, because the signal is transfered from the tape to the VCR magnetically. With DVD players it’s all light and there are much less moving parts. You could leave it on indefinitely and there would be no discernable damage whatsoever.
So to answer your question, yes, it is safe. Your DVD player will automatically turn off before the moving parts will sustain any damage. What you are experiencing(the black boxes) is a form of digital “stacking”, basically a slight overload. If you press play it should clear up instantaneously. If it does not, there is a problem with that specific player, especially if it happens with all of your DVDs. If it happens with just that DVD, then there may be a scratch on it.
I’ve had a few DVD’s show blocks, but if I “rewind” to the same spot, it rarely happens again. Probably just a programming glitch in the player.
The blocks could just be the nature of DVD-Rom players, as opposed to TV DVD players. My DVD-Rom resolution was very bad on dark spots just because of the inferior method of decompression that DVD-Roms do.
Now I use a proper component player, there have been no noticeable compression artifacts at all (unless you count the NTSC lines on my PAL player)
Is it safe to leave it in pause? Depends on whether it spins down the disc or not. This should be pretty easy to tell in a computer drive, since they aren’t the quietest things in the world. If it leaves the disc spinning, that’s probably not the greatest thing in the world.
To the actual problem: I think the blockiness is due to the rented discs. They probably are incredibly filthy and maybe even scratched, and that can cause the player to miss some info. Without the data, you end up with that blockiness.
Actually, slackergirl and I spoke about the “blocks” when I was at NorCal-SoCal (SLO DopeFest). She is a tech-writer for a digital communications company, so I’m figuring she know of what she speaks (plus, she’s kinda smart.)
Anyhoo, the way MPEG2 (MPEG3, too, I guess) compression works, according to her, is that there is a prediction method used for the images. I’m not going to get this exactly right, but it’s something like: [li]100% full picture frame[]predicted frame, based on previous frame[]50% of the full picture frame[]predicted frame, based on original frame[]repeat[/li]
The longer an image remains stationary, or parts of the background remain static while other things change, the greater teh prediction takes effect for that area. So, if you have a scene where action is only taking place in a small portion of the screen and it goes on for some duration, the prediction for the rest of the frame will be that of the previous scenes. This means that iff there is some movement, the presented picture will be off until the cycle returns to a 100% full picture. The false prediction results in te “blocking” you see, which is why you may not see it if you rewind or slo-mo, the prediciton will be replaced with true images.
I think.