data compression

I recommend you watch this video, it gives a good and easy to understand introduction:


After that you can find more detailed videos on the same channel.

Rattenhirn

the video doesn't has a clear definition and is a mess too explaining data compression

and that's my point with this post

if information cannot be destroyed nor created then what does really means data compression?

Is there a philosophical background in this question? With respect to data compression, information can be destroyed simply by leaving it out, so that the receiver cannot reconstruct it. Creating information is meaningless when assuming that the original information was sufficient and complete. Creating more information from a given fixed knowledge base means to generate redundancy what is meaningless to the amount of information.

Lossless compression means to encode information in a way that needs less data in the space dimension to represent the information as before. It just reduces redundancy. Lossy compression accepts the loss of information that is deemed to be unimportant.

haegarr

"information can be destroyed simply by leaving it out"

you can't prove that, was there information before you were born, is there going to be information after you die?

I will expand:

data compression means to move data from the space dimension to the time dimension...

So how do you move data from space dimension to the time dimension?

You can't...

what can be done is take various different data that is already in time dimension, then combine it in space dimension to get the time data representation of the data in the space dimension, like this

or I could use another clock that has a default 111011

what do you think?

haegarr

"information can be destroyed simply by leaving it out"

you can't prove that, was there information before you were born, is there going to be information after you die?

Hence my question whether there is a philosophical background in your question! My post states that the given answer belongs to data compression (as found in computer science), and that is done on a defined set of information give to a consumer. The consumer is then the instance that assess the received information.

JPEG compression destroys data because it is a lossy compression algorithm

"destroy"

I don't think that's a good word, it should be "replace"

replaced by a repetition

Information exists on some kind of storage (being it brain memory, a piece of paper, a hard disk, …). Data as I understand it here is a representation of information. Data compression is a way to choose another (comparable) representation with less amount of space. If the compression is lossy, then some of the information isn't stored in the result compared to the original data. But the original data may still be stored elsewhere and hence not globally lost. However, the instance that has the compressed data as the only source of information about the given topic simply knows not so much as the instance having the original data did. From its point of view some information is lost if it is aware that lossy compression has occurred. At the end, if all storages with the original data are erased (the person is dead, the paper burned, the hard disk demagnetized, …), some information is lost definitely.

I do not discuss esoteric things like time traveling here. Information is something that can be retrieved, or else it has no meaning.

I'm confused... is this a philosophical or technical question?

Doesn't matter whether we mean physics or CS, information always exists in both spatial and time dimensions and changes over time. Information changes over time and a process of compression is just another form of this change, some types of which can render the original information unretrievable except by guesswork and context (one time pad encryption for example is "uncrackable" in the sense that without the pad, you can never prove mathematically that you have cracked the code, only demonstrate it probabilistically based on some kind of meaningful output).

Unretrieveable does not mean destroyed in physics sense, but it does in any context regarding decompression.

So no, I don't see how compression can be seen as moving information from spatial to time dimension. Information already exists in both and compression is just another form of change over time.

data compression means to move data from the space dimension to the time dimension...

From Wikipedia:
"Lossless compression reduces bits by identifying and eliminating statistical redundancy."

So nothing is moved between dimensions, whatever that might even mean in this case.

Maybe you try to space/time trade offs that are often the case with CS algorithms, including compression. For instance, a better compression rate will typically take a longer time. So by spending more time working on the data one can save space or, vice versa, by using more space, one can cut down the processing time.

Is this what you mean by any chance?

Well you need bits from the future (or past) to analyse the statistics so I guess you do need the time dimension.

I don't think the OP terminology is helping to clear up confusion though.

Applying 'philosphy' to the topic of data compression is somewhat nought...As most others have already pointed out, data compression from a CS perspective have nothing to do with space and time, no in the general sense of space-time that is. Data compression as we know from a CS perspective exist and work pretty well. Data compression is use extensively in modern electronic devices ( digital cameras, set-top boxes etc..), information transmission, you name it...So it works, whether or not its lossy or lossless is a matter of choice. Lossless compression is as it says lossless, the original compressed information can be recreated in its full entirety from the original source..again from a CS/ Digital Signal Processing perspective..no time/space involvement, unless space refers to the amount of storage required to store the information.

"destroy"

I don't think that's a good word, it should be "replace"

replaced by a repetition

If that was in response to what I said, then no. JPEG compression does destroy data, because it makes approximations in such a way that it is impossible to fully reconstruct the original data.

My take on what OP is trying to say is that it takes time to decompress data, but in return you can reduce the amount of data.

"abcabcabc" --> "3|abc"

Time component: it took some cpu cycles to compress it

Space component: it requires less space after compression

But you didnt move information from one dimension to another. You rather changed information in the same domain - you densed it up, in a way. There are different methods for compressing, all of which are very interesting to read up on.

You shouldnt think in such a roundabout way, keep it simple (and stupid).

Hence my question whether there is a philosophical background in your question! My post states that the given answer belongs to data compression (as found in computer science), and that is done on a defined set of information give to a consumer. The consumer is then the instance that assess the received information.

There is a pseudo-scientific background to that which assumes a Newtonian universe and the theoretical ability to compute every state from the universe's previous (or future) state.

The followers of that theory come up with all kinds of amusing examples how you can't destroy information when you quite obviously can. Such as when I tell you a secret and shoot you the next moment, they'd say that the sound waves when I told you the secret caused atmospheric disturbations which contribute to weather changes and can in theory be measured at the next weather station, etc etc.

Or when you type on a typewriter without looking, and burn the paper afterwards, your fingers leave measurable heat and impressions on the keyboard.

Of course, the entire approach means that for example Heisenberg didn't have much of a clue how the universe works, and that there exist no black holes, and it neglects small details such as a storm having chaotic pressure differences that are like 50 orders of magnitude greater than those produced by my voice.

There is a pseudo-scientific background to that which assumes a Newtonian universe and the theoretical ability to compute every state from the universe's previous (or future) state.

Seriously?

Data compression means finding an alternate, smaller representation of data.

"abcabcabc" --> "3|abc"

This is all there is to explain about the principle of data compression: if you have strings of lowercase letters you can write out repeated substrings longhand (not compressed) or write them once with a repeat count (compressed). Of course you need to know whether Aphton encoding is being used and have an implementation available; the cost is usually amortized over the savings of compressing a lot of data.