Home audio & video: Can someone explain Lossless
Can someone explain Lossless
by Rollbar - 1/24/08 11:20 AMIt comes up all the time and I know it's important to Jostenmeat.
What the heck is it?
Gary
well, my understanding is that
by jostenmeat - 1/24/08 11:42 AM In reply to: Can someone explain Lossless by Rollbaryou "lose" nothing from what is mastered in the studio. That's right, you are supposedly getting 100% of the effect as the guy who is creating the soundtrack in the studio.
For lossy algorithms, they take a LOT of information out to squeeze the audio on to a puny format (mp3, er, even a DVD).
See, they figured they could do this because a lot of the removed audio-info is not perceivable by humans anyways. Saves a lot of space without compromise, in theory. The problem is they still are taking away a lot of which we can hear.
Lossless does not mean uncompressed. You can have a compressed yet lossless audio track.
Just think of it as the best audio you can possibly get.
Well...
by froasier - 1/27/08 8:34 AM In reply to: well, my understanding is that by jostenmeatyou probably won't get "100% of the effect as the guy who is creating the soundtrack in the studio" because his studio is probably better than your living room, and he may be working at better than CD quality.
What you will get is 100% of the effect as if you had played the uncompressed version, i.e. the original audio CD.
Most people, however, cannot tell the difference between a well-encoded mp3 and the original (especially on lower end equipment), so lossless may or may not be for you.
Lossless compression is a myth
by mjd420nova - 1/25/08 8:08 PM In reply to: Can someone explain Lossless by RollbarI've tested many compression schemes in a laboratory and found none to be lossless. The idea that what is removed by the mathematical formulas is not percieved by the human ear and thereby not needed is wrong. Much of what the human ear percieves is not determined by the actual content but the contents effect on the ear drum. This includes the subharmonics created by many notes beating against each other, creating content that is not present in the original recordings nor recreated by their translation from sound waves to electrical signals by microphones or other pickup devices. Again, this content is retranslated back to sound waves by amplifiers and speakers. Subtracting any amount of this content however small does affect the eventual output of the content and its perception by the human ear.
Compression vs. digitisation
by genotypewriter - 1/26/08 6:31 AM In reply to: Lossless compression is a myth by mjd420novaI don't know why you needed a lab to answer this question as you only need a PC. Compress something like a text file in ZIP or RAR formats and uncompress it. Use whatever tool you like to do this but just compare the two files to see if they're any different... and they shouldn't be because they're lossless.
With images, TIFF, PNG, BMP are lossless formats. With sound there's PCM .WAV.
It seems to me that you're talking about the loss of information in the digitisation process. This is not related to lossy or lossless concepts as the latter relate to compression. Digitisation does quantise information and this theoretically causes a loss of detail (how much depends on the sampling amounts)... that's why for example some people prefer vinyl over CDs and film photos over digital photos.
hold on
by froasier - 1/27/08 8:47 AM In reply to: Compression vs. digitisation by genotypewriterTIFF is a container that can hold uncompressed, losslessly compressed, or lossily compressed data. BMP is not compressed. WAV files are also uncompressed. PNG however, is a good example of lossless compression, as would be FLAC for audio.
Was referring to lossless TIFF
by genotypewriter - 2/1/08 1:54 AM In reply to: hold on by froasierHold on to what?
Lossless compression
by mjd420nova - 1/28/08 10:59 AM In reply to: Compression vs. digitisation by genotypewriterI work in a standards lab and had access to very accurate equipment and did the testing just to satisify my own questions. As an example, I started with just a single tone, a 1000 cycle signal, compressed it, decompressed it using a number of different formats and then measured the result. Even with just a single tone, i was amazed to find that the output was not 1000 cycles anymore, but anywhere from 990 to 998 cycles. Now grated most users would never notice the difference, but we're talking about a very complex signal input when it comes to music. Now this is a completely different problem when dealing with photos as no one will notice anything whena few pixels are missing or might be the wrong color. Data is very, very different, as the loss of even a single bit can mean diaster for an accounting program or a trajectory program for a satelite. Music is quite complex and compression will not be noticed by 90 percent of the users.
it sounds like
by froasier - 1/27/08 8:53 AM In reply to: Lossless compression is a myth by mjd420novayou are testing lossy compression methods; therefore it is unsurprising that they are... lossy.
If you tested actual "lossless" formats like FLAC (were you aware these existed?) you would find that nothing is removed from the original digital recording.
the nature of losslessness
by jbelck - 1/25/08 8:59 PM In reply to: Can someone explain Lossless by RollbarTo impress you, at absolute zero, wire of any kind offers no resistance to the flow of electricity.
To inform you, a recording of any kind would be lossless only if what you heard was absolutely the same to your ears as a live performance.
In othe words, lossless is hype.
Compression artifacts
by genotypewriter - 1/26/08 6:41 AM In reply to: the nature of losslessness by jbelckWith lossy compression, you get compression artifacts. Maybe, the devices you use now can't resolve enough detail for these to be a problem but think about in a couple of years time you might wish you had the uncompressed/lossless compressed originals. This is why MiniDV is still preferred over HDD camcorders and
Lossless in general is definitely not hype. Lossy saves a lot more space and is easier to transfer. But why do you think all studio work is done in uncompressed/lossless formats if they're really just hype? Plus if you're zipping or rar'ing your files, you'll corrupt the files if they're not lossless.
As an aside....
by forkboy - 1/26/08 4:37 PM In reply to: Compression artifacts by genotypewriterAs an aside...thanks for bringing forward a very good reason to stick with MiniDV-based camcorders, which I have been putting forth on forums, etc. It's also a better long-term storage medium than home-burned CDs or DVDs.
what?
by froasier - 1/27/08 8:26 AM In reply to: Compression artifacts by genotypewriterAs zip and rar are lossless algorithms themselves, they should not "corrupt" any file, regardless of previous compression. I don't know where you pulled that one from.
Read more carefully
by genotypewriter - 2/1/08 1:52 AM In reply to: what? by froasier"Plus if you're zipping or rar'ing your files, you'll corrupt the files if they're not lossless."
Not lossless == lossy
Of course, if rar and zip are not lossless, you files are going to get corrupted!
Read more carefully
by genotypewriter - 2/1/08 1:54 AM In reply to: what? by froasier"Plus if you're zipping or rar'ing your files, you'll corrupt the files if they're not lossless."
Not lossless == lossy
Of course, if rar and zip are not lossless, you files are going to get corrupted!
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