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Audio cassettes still alive

Started by DJ Omnimaga, July 28, 2016, 10:26:48 pm

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DJ Omnimaga

Quote from: c4ooo on October 17, 2016, 07:45:10 pm
As the wikipedia page points out, even if you get a recording in audio format it is likely been digital in some point of its life.
Depends. If you recorded your masters on a magnetic tape then they're definitively analog at that point. However, nowadays I heard that some vinyl records are pressed from a digital source.
Quote from: aeTIos on October 17, 2016, 09:30:39 am
No, CDs are not compressed, they use uncompressed dual channel PCM audio at 44100Hz sample rate. It's just not a continuous signal because well, it's digital.
Well, doesn't using 44KHz instead of 48KHz, 96, or even 128 count as compression, though? I mean, it's less data, right?

p2

it's not actual compression it's just lowering the quality by removing parts of the data
actually non-redundant data... ._.
Anyway war sucks. Just bring us your food instead of missiles  :P ~ DJ Omnimaga (11.10.2016 20:21:48)
if you cant get a jframe set up, draw stuff to it, and receive input, i can only imagine how horrible your game code is _._   ~ c4ooo (14.11.2016 22:44:07)
If they pull a Harambe on me tell my family I love them ~ u/Pwntear37d (AssangeWatch /r/)
make Walrii great again ~ DJ Omnimaga (28.11.2016 23:01:31)
God invented the pc, satan the smartphone I guess ~ p4nix (16.02.2017 22:51:49)

Travis

Well, anything converted to digital has to be quantized (that is, converted from analog to discrete numbers) in some way, and you could argue that no matter how high a sample rate you use, some data technically is lost because it has to be forced to fit into specific value ranges. But this isn't generally called compression, because then you'd have to call everything that's stored digitally "compressed". Normally, compression means applying extra algorithms to remove data that was there after the initial conversion to digital that is considered redundant or unnoticeable by human ears. CD audio is just a raw stream of 16-bit 44.1 kHz samples digitized from the source, though, so it's not considered compression.

Sample rate could be thought of like the resolution in a raw uncompressed image bitmap. The higher the sample rate, the more pixels you have, but scaling down the image to a smaller pixel size isn't usually called compression by itself, even though it results in a loss of detail. But converting the image to PNG, JPEG, GIF, or the like is called compression because the pixels are encoded in a special way that tries to remove either redundancy or detail that people theoretically wouldn't notice (much).

p2

exactly what I wanted to say but much more fancy and much wow O.O  :thumbsup:
Anyway war sucks. Just bring us your food instead of missiles  :P ~ DJ Omnimaga (11.10.2016 20:21:48)
if you cant get a jframe set up, draw stuff to it, and receive input, i can only imagine how horrible your game code is _._   ~ c4ooo (14.11.2016 22:44:07)
If they pull a Harambe on me tell my family I love them ~ u/Pwntear37d (AssangeWatch /r/)
make Walrii great again ~ DJ Omnimaga (28.11.2016 23:01:31)
God invented the pc, satan the smartphone I guess ~ p4nix (16.02.2017 22:51:49)

DJ Omnimaga

So I just learned from a local newspaper article that CD and DVD mediums also suffer from disc rot, like laserdiscs, so after 20-30 years of good storage, some of your CDs might become unreadable apparently D:. This kinda sucks for stuff that isn't available on digital support.

https://en.wikipedia.org/wiki/Disc_rot
http://www.journaldemontreal.com/2017/02/19/les-cd-pourrissent-peu-a-peu

p2

yeah I already experienced loss of data on various old CDs, but rather due to exposure to wifi and other radiation, not pure age...
they were basicaly no longer restorable, data loss was huge >.<
Anyway war sucks. Just bring us your food instead of missiles  :P ~ DJ Omnimaga (11.10.2016 20:21:48)
if you cant get a jframe set up, draw stuff to it, and receive input, i can only imagine how horrible your game code is _._   ~ c4ooo (14.11.2016 22:44:07)
If they pull a Harambe on me tell my family I love them ~ u/Pwntear37d (AssangeWatch /r/)
make Walrii great again ~ DJ Omnimaga (28.11.2016 23:01:31)
God invented the pc, satan the smartphone I guess ~ p4nix (16.02.2017 22:51:49)

Travis

I've heard of "laser" rot (oxidation) from poorly-manufactured discs, and I've had various recordable discs go bad just by sitting there (I've come across some really crappy CD-Rs manufactured by some companies back in the day), so it's sadly not news to me. These days it's safest to rip everything valuable and save it to a variety of types of storage media (and then be prepared to do it again before those fail or become obsolete).

On the other hand, I've burned a few hundred DVD-R and DVD+R discs over the last several years, and those mostly seem to be holding up still. There were a couple in that entire batch that inexplicably started turning yellow and becoming unreadable, and one was completely unrecoverable. I'm not sure how that happened; my best theory is that because they were stored next to a window for a few years, certain discs got exposed to too much sunlight and got degraded and discolored. (I had some pens and pencils stored in the same area whose erasers got hard and bad, even though the same ones stored in my dresser for the same number of years didn't; maybe due to sunlight/UV as well?)

I hadn't yet heard of WiFi killing discs, though. I wouldn't have expected the amount of microwave energy from a typical WiFi device (which is almost a million times weaker than that in a microwave oven, and diffused in all directions rather than concentrated in a small metal box) to be anywhere high enough to do any harm. I would be more worried about intense visible light exposure, especially from sources like the sun. After all, they're designed to be written to using nothing more than a powerful enough source of red/IR light. ;) So it's not a bad idea to store -R/RW discs away from sources of bright light when not in use.

I used to use a program on Linux called DVDisaster, which allows you to create extra recovery ECC data files for recordable data CD/DVDs. I often used it to recover discs that started developing bad sectors. As long as you still had the ECC data, you could recover data from discs with a surprising amount of damage. The ECC data takes up maybe 1/6 or so of the space of the original disc, so it saves a lot of space over making a full copy, but the downside is that it's entirely useless if you aren't able to recover at least some of the data from the original copy (e.g., if you have the ECC but the whole disc goes bad or gets lost and have no other copies, you're still screwed). You also have to store the ECC data somewhere and separately protect it from damage, and keep it up to date if you modified the original discs, so it was bit of a hassle. More recently, I've been moving away from optical discs, and I don't miss them (they suck in reliability and compatibility and are as slow as molasses). I mostly use HDDs/SSDs or flash media now and only use optical discs when I have to.

DJ Omnimaga

I didn't know that radiation or wi-fi could make CDs deteriorate. I knew that putting a cassette or floppy disk next to a magnet was a very bad idea for that reason but I thought that physical mediums such as CDs didn't have this problem. All I knew is that laserdiscs from certain companies had the tendency to rot after just a few years, same for some HD-DVDs. For CDs the only bad thing I usually noticed is that the label on some of my CD-R's became very yellow after just 2 years. I haven't tried reading them again afterwards, though.

p2

to be honest im not 100% sure about that. All I know is that it pretty much kills VHS casettes and that some people could swear the same happens to CDs...
interestingly for us it was two CDs - one is like 70-80% gone and was next to wifi, the other one is still pretty good, and it was in a closet in a room further off the wifi...
Anyway war sucks. Just bring us your food instead of missiles  :P ~ DJ Omnimaga (11.10.2016 20:21:48)
if you cant get a jframe set up, draw stuff to it, and receive input, i can only imagine how horrible your game code is _._   ~ c4ooo (14.11.2016 22:44:07)
If they pull a Harambe on me tell my family I love them ~ u/Pwntear37d (AssangeWatch /r/)
make Walrii great again ~ DJ Omnimaga (28.11.2016 23:01:31)
God invented the pc, satan the smartphone I guess ~ p4nix (16.02.2017 22:51:49)

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