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Cafe Sceptico: The Objectivist Cafe
Dec 4, 2012 at 9:34 PM Post #271 of 497
Quote:
ultrabike said:
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.
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Awesome thanks for that. I think that was the gist of the ars article. 
 
Dec 4, 2012 at 9:39 PM Post #272 of 497
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
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Dec 5, 2012 at 12:53 PM Post #273 of 497
@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
 
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Dec 5, 2012 at 2:46 PM Post #274 of 497

Quote:
joe bloggs said:
@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
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Thanks! 
 
Dec 5, 2012 at 6:22 PM Post #275 of 497
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
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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.
 
Dec 5, 2012 at 6:45 PM Post #276 of 497
Quote:
ultrabike said:
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.
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Where did you hear that? I've never read that lossy compression affects dynamics.
 
Dec 5, 2012 at 7:02 PM Post #277 of 497
Quote:
bigshot said:
 
Where did you hear that? I've never read that lossy compression affects dynamics.
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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.
 
Dec 8, 2012 at 12:58 AM Post #280 of 497
There's one born every minute
 
Dec 8, 2012 at 5:13 PM Post #282 of 497
gnarlsagan said:
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...
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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 :xf_eek:
 
Dec 8, 2012 at 6:54 PM Post #283 of 497
palmfish said:
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 :xf_eek:
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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.
 
Dec 9, 2012 at 2:10 AM Post #285 of 497
Quote:
palmfish said:
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
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Some people have a difficult time dealing with facts that put their worldview into question. 
 
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