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Cafe Sceptico: The Objectivist Cafe - Page 19  

post #271 of 498
Quote:
Originally Posted by gnarlsagan View Post

 

Thanks, might I ask your reasoning behind that? I've read different answers about it, but I forget where. There was a great ars technica (?) piece about it, but maybe it was over my head since I came away without a definite conclusion. I'm pretty sure someone who frequents this cafe knows for sure. 


No worries. Data compression does not concern itself with dynamic range. It concerns itself with file size and attempts to preserve the fidelity as much as possible. In the case of lossless compression, full fidelity is preserved. Most of the lossless approaches use some sort of entropy coding. One of the best known ones is Huffman. A more advanced one is Arithmetic. All of these methods (lossless) look at data statistics to compress BITS. I'm fairly familiar with lossless data compression. Lossy uses filter banks, transforms (cosine for example), and quantizers (such as vector ones.) These will lose some information though. Lossy compression is many times used combined with lossless compression.

 

I'm not as familiar with audio dynamic range compression, but my understanding is that it applies a gain mapping where the instantaneous gain is mapped to a different gain using a linear (or quasi-linear) function. My yamaha receiver calls this silent cinema I think. This does not necessarily translate into a smaller file. We are talking dynamic range compression vs. file size compression.


Edited by ultrabike - 12/4/12 at 6:36pm
post #272 of 498
Quote:
Originally Posted by ultrabike View Post


No worries. Data compression does not concern itself with dynamic range. It concerns itself with file size and attempts to preserve the fidelity as much as possible. In the case of lossless compression, full fidelity is preserved. Most of the lossless approaches use some sort of entropy coding. One of the best known ones is Huffman. A more advanced one is Arithmetic. All of these methods look at data statistics to compress BITS. I'm fairly familiar with data compression.

 

I'm not as familiar with audio dynamic range compression, but my understanding is that it applies a gain mapping where the instantaneous gain is mapped to a different gain using a linear (or quasi-linear) function. My yamaha receiver calls this silent cinema I think. This does not necessarily translate into a smaller file. We are talking dynamic range compression vs. file size compression.

 

Awesome thanks for that. I think that was the gist of the ars article. 

post #273 of 498

Let me know if you have any questions. It's been a while and I may be forgetting stuff, but FWIW I wrote my thesis about lossess data compression biggrin.gif

post #274 of 498

@gnarlsagan You might want to read this thread over at hydrogenaudio:

http://www.hydrogenaudio.org/forums/index.php?showtopic=55336

 

The short answer is, mp3s are theoretically capable of encoding even more dynamic range than CDs.  Their quality loss lies in other areas

post #275 of 498

Quote:
Originally Posted by Joe Bloggs View Post

@gnarlsagan You might want to read this thread over at hydrogenaudio:

http://www.hydrogenaudio.org/forums/index.php?showtopic=55336

 

The short answer is, mp3s are theoretically capable of encoding even more dynamic range than CDs.  Their quality loss lies in other areas

 

Thanks! 

post #276 of 498

When I worked in compression it was mostly images and did not cover all there is to it. MP3? I need to read on that redface.gif

 

That said, another thing that comes to mind when discussing compression is that when we are talking dynamic range compression, many times the goal is to affect loudness. When compressing the dynamic range of a signal, one can amplify it without clipping.

 

When compressing the file size, dynamic range may be affected if using a lossy algorithm, but my understanding is that this may be an unintentional byproduct and possibly not dramatic. If using a data lossless compression algorithm, dynamic range does not change.


Edited by ultrabike - 12/5/12 at 3:30pm
post #277 of 498
Thread Starter 
Quote:
Originally Posted by ultrabike View Post

When compressing the file size, dynamic range may be affected if using a lossy algorithm, but my understanding is that this may be an unintentional byproduct and possibly not dramatic.

 

Where did you hear that? I've never read that lossy compression affects dynamics.

post #278 of 498
Quote:
Originally Posted by bigshot View Post

 

Where did you hear that? I've never read that lossy compression affects dynamics.


I don't think it would do much to it. However, when applying lossy compression, two files will not be exactly the same after decompression. Therefore, I could see there might be a slight difference in dynamic range depending on the compression algorithm and the level of compression. We are probably taking of small fractions of a bit (EDIT: best to say LSBs), but I'm not certain. Someone more familiar with the mp3 standards, or other lossy audio formats might chime in.


Edited by ultrabike - 12/6/12 at 9:29am
post #279 of 498
post #280 of 498
Quote:
Originally Posted by Marvin7 View Post

REVIEW: Deltasound ZP30 Clarifying Stands


Nice review. Makes me want to drink wine for some reason.

On another note we have people claiming to hear the difference between 320 mp3 and lossless again. Sigh...
Edited by gnarlsagan - 12/7/12 at 9:07pm
post #281 of 498
Thread Starter 
There's one born every minute
post #282 of 498
Quote:
Originally Posted by gnarlsagan View Post


Nice review. Makes me want to drink wine for some reason.
On another note we have people claiming to hear the difference between 320 mp3 and lossless again. Sigh...

Not me guys! There are files differences due to the lossy nature of mp3s, but that's as far as I go...

 

BTW... Got my iPad mini biggrin.gif


Edited by ultrabike - 12/7/12 at 10:37pm
post #283 of 498
Quote:
Originally Posted by gnarlsagan View Post

Nice review. Makes me want to drink wine for some reason.
On another note we have people claiming to hear the difference between 320 mp3 and lossless again. Sigh...

Back in August, someone in another thread mentioned they only rip to AIFF and that they were re-ripping some of their files that were ALAC to AIFF. I asked if they can really hear a difference between two lossless formats and i apparently hit a nerve i didnt know was exposed. After a brief discussion about lossless files, this person blocked me redface.gif
post #284 of 498
Quote:
Originally Posted by palmfish View Post

Back in August, someone in another thread mentioned they only rip to AIFF and that they were re-ripping some of their files that were ALAC to AIFF. I asked if they can really hear a difference between two lossless formats and i apparently hit a nerve i didnt know was exposed. After a brief discussion about lossless files, this person blocked me redface.gif

I totally read that thread. Mind blowing. I don't see what's offensive about asking for a few more descriptors when claims like that are made. If it's true there shouldn't be any reason why I couldn't hear then same thing knowing what to listen for. And if a description is made then 99% of the time it's sound stage.

I don't understand what people expect when making those mp3/lossless claims and then not adding concrete descriptions. It helps nobody, and comes off as self aggrandizing. I don't even ask for a blind test ever, which is really what should be happening given the likely bogusness of the claim.
post #285 of 498
Quote:
Originally Posted by Marvin7 View Post

REVIEW: Deltasound ZP30 Clarifying Stands


That's hysterical.
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