Video Files Question

[jason69uk]

People say theres no degradion in digital media.

When i get bad sectors and corrupted data will it still not be degraded (the video playback) but i will get freezes and easily noticeably blocky screens..

Thats not really degradion though isit becuase degradion is something wearing out but when data is corrupted its not worn out i suppose isit..

Am i right here?

[mats.hogberg]

You're still at this? Yes, you're right.

/Mats

[jason69uk]

cheers for your help

Ive seen these vids i got, and theres blotches of green on some bits, its XviD i then got it on another compouter from the internet and its exactly the same playback, there are blotches of green and some bits go really pixelated as if it were a bad drive.. This must have been a bad encode, right or something the other persons end damaged them??

[mats.hogberg]

AVIs "found" on Internet, and specially on P2P networks, where IMO KaZaA stands out as the worst example, are to a very high degree ridden with data errors, some to the point where (parts of) the video won't play at all. If the source you DL from is equally bad, or bits&bytes get damaged/mixed up in the transfer, you'll never know, until you can compare the file data side by side.

/Mats

[jason69uk]

Well we all know kazaa is a pile of poop lol i stopped using that at 13..

So these downloads i get will they corrupt on their own or will something make them corrupt llike a hard drive corruption??

Also i put something on cd ages ago, watched it on the tv and pc from the cd and it was jumpy, copied it back, watchedit once it had been copied back and it wasnt jumpy at all, why was it jumpy??

where u said 'some to the point where (parts of) the video won't play at all'
did u mean they will eventually be so errored that they wont play at all??

[redwudz]

Generally, once the downloaded file is on a HD or DVD, there will be no more deterioration. You will just have to deal with the screw ups that came through poor original encoding and transfer defects. You can't recover lost data.

You can cut it out, but you usually can't fix it. An old CD file may have been put on poor quality media, which can deteriorate. Had that problem myself. Don't use crap media and you will have less problems. You probably use different codecs now than you had then, that makes a difference also.

[mats.hogberg]

where u said 'some to the point where (parts of) the video won't play at all'
did u mean they will eventually be so errored that they wont play at all??

Yes, not at all. If vital bits of the AVI has the wrong value or are mising altogether, the player (and/or codec) can't decode it at all.
Or "bad frames" present in the AVI which makes it unreencodable (but probably still watchable).

/Mats

[jason69uk]

Cheers.

What can cuase movies to go out of sync, name me all the things.

If i have a corrupted hard drive can that make sound go out of sync on videos on it but wld i always get a freeze or wld i sometimes not get a freeze and sound wld be out of sync..??

where u said 'You will just have to deal with the screw ups that came through poor original encoding and transfer defects' does that mean if i DO download an errory type file over time this file will get worse well i suppose it wont actually cos its on the hard drive and cant deteriorate am i right yeah?

[jason69uk]

AAh right, so if i do get a dodgy download its defoinate after time it will get worse for no reaosn what so ever?

So i get a download with say 4 blocky bits on it.
The drive has been kept in good health with same codecs and i have it on there for about 1 year ru saying that out of the blue the film will randomly get more errors on it as time goes on??

[mats.hogberg]

Jason, Listen closely: Data don't go bad. Media (what the data is stored on/in) might.

What can cuase movies to go out of sync, name me all the things.

Bad encoding.

If i have a corrupted hard drive can that make sound go out of sync

No. No, like in "Will you be hit by lightning the next time you ask a question about digital video file degradation?" I guess it could happen in theory, but the probability is so low, we don't have to take it into account, even as a academic question.

/Mats

[jason69uk]

lol no worries man i juss get so stewed up about nothing lol its kinda an obsession with me i suppose honestly you lott have been really helpful n irespect u all 4 this, ive learnt so much being on these forums now.

where u said this
'Yes, not at all. If vital bits of the AVI has the wrong value or are mising altogether, the player (and/or codec) can't decode it at all.
Or "bad frames" present in the AVI which makes it unreencodable (but probably still watchable)'

So these issues wld be as soon as the download completes on the hard drive caused from a dodgy transfer??

[mats.hogberg]

AAh right, so if i do get a dodgy download its defoinate after time it will get worse for no reaosn what so ever?

So i get a download with say 4 blocky bits on it.
The drive has been kept in good health with same codecs and i have it on there for about 1 year ru saying that out of the blue the film will randomly get more errors on it as time goes on??

NO! it will be exactly the same until what it's stored on/in starts losing bits and bytes.

/Mats

[jason69uk]

And how could it start losing bits and bytes what would be the cause of this mate?

sorry

[mats.hogberg]

So these issues wld be as soon as the download completes on the hard drive caused from a dodgy transfer??

Yes. And the day after. And year. And decade. And century.

/Mats

[jason69uk]

so youre saying that if a transfer goes wrong and i have corrupted data from it it wont get better it wont get worse it will stay like it on the drive forever with no degradion.

Obviously bad sectors wld damage it more but all being a healthy drive the corrupted download will stay how it is for ever n ever..lol

[mats.hogberg]

And how could it start losing bits and bytes what would be the cause of this mate?sorry

Aww geesh! Why did I eve... Ah, well, writable media like CD-R and DVD-R and stuff do have a live span. They are simply not resistant to the tooth of time.
Hard drives store the bits and bytes on a magnetic surface - hold it near a magnet, things start to happen with the data stored on it. If a velocitron, emitted from the Sun, hits the wrong electron in your HDD and brings it along on its voyage to eternity, a "1" in a byte somewhere in your AVI encode of Lost In Translation turns into a 0, and Voila! At frame 23456 there's a green pixel where before, the glint in Bill Murrays Whiskey glass was.
Things go bad over time. Data doesn't. Now, this is starting to get more of a philosophical question - what is data without its storage medium? I suggest you start reading some of our great Cyber Punk writers if you've not done so already - like (early) Neal Stephenson and William Gibson. If nothing else, it will keep you absorbed for a while...

/Mats

[mats.hogberg]

so youre saying that if a transfer goes wrong and i have corrupted data from it it wont get better it wont get worse it will stay like it on the drive forever with no degradion.

Obviously bad sectors wld damage it more but all being a healthy drive the corrupted download will stay how it is for ever n ever..lol

100% correct. There is still hope!

/Mats

[jason69uk]

sorted then thanks very much for your help..