Does high quality digital cables matter?

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Comments

  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    Me desperate? About audio? Never!

    "Desperate" is a term I would use to describe the following two classes of people:

    1. People who insist that a test appropriate for one type of audio is appropriate for all types of audio.
    2. People who take issue with what other people say they can hear and demand proof.

    "Desperate" is

    People who quote their own paper and think their test is the only appropriate test of equipment as it pertains to stereophonic evaluation.

    "Desperate is"

    Thinking the 50% is a chance at guessing the write answer. If it's one time it sure is. It's also 50% guessing the wrong answer. And I'll agree 100% it's a guess.

    Even in a double blind test people have a 50% chance of guessing the right answer. They can merely "claim" to hear a difference and "validate" that with a correct guess.

    "Desperate" is being scared of the proverbial blind fold.

    "Desperate" is believing they have de-biased oneself to the point that sighted testing is perfectly valid way to make claims of performance and never once offering to prove how calibrated they are by participating in the occasional blind test as a confirmation measure.
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    BlueFox wrote: »
    Well, yes. Did you expect it to mean something else?

    When somebody sticks their hand in a fire, realizes that it burns their hand, and then tells others what they felt, is that not valid information? Or do we need to first understand the human nervous system before we can accept that anecdotal data?

    Human skin blistering at 400f isn't anecdotal. It's a fact. It has a basis in physics and the laws of thermal dynamics.
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    There is no such thing as "anecdotal data". It's an oxymoron.

    Confirmation bias is also a oxymoron.

    A person believes Asians are better at math. They see an Asian in the class get first crack at solving the problem out of a group of great ethnic diversity.

    He solves the problem. The person believes he is now correct in his assumption.

    His assumption is "anecdotal data"

    See how I was able to close the loop on that?
  • WilliamM2
    WilliamM2 Posts: 4,780
    edited June 2014
    Even in a double blind test people have a 50% chance of guessing the right answer. They can merely "claim" to hear a difference and "validate" that with a correct guess.

    It doesn't validate anything unless it's repeatable. And then it's no longer 50%. I thought you would know that.
    There obviously was enough difference for him, and others, to know that the far more expensive RAL cable was the worst performer in his system.

    What difference? They never demonstrated any ability to discern a difference.

    "Desperate" is intentionally trying to mislead people with test results you know are worthless. Not to mention dishonest.
  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2014
    "Desperate" is

    People who quote their own paper and think their test is the only appropriate test of equipment as it pertains to stereophonic evaluation.

    I agree. That is why I do not engage in such behavior. It is common among blind test cultists though. I often quote other people's papers though.
    "Desperate is"

    Thinking the 50% is a chance at guessing the write answer. If it's one time it sure is. It's also 50% guessing the wrong answer. And I'll agree 100% it's a guess.

    "Write answer"? What does that mean?

    It is impossible to guess correctly in multiple trials?
    "Desperate" is being scared of the proverbial blind fold.

    Not using an unnecessary thing is not evidence of being scared of it.
    "Desperate" is believing they have de-biased oneself to the point that sighted testing is perfectly valid way to make claims of performance and never once offering to prove how calibrated they are by participating in the occasional blind test as a confirmation measure.

    Who did this? Certainly not me. I took the blinded Philips Golden Ears Challenge and posted my "Golden Ears" certificate on this forum, in this thread and in a separate thread.

    The part you don't get is that it does not matter what anyone else proves they can hear. Enjoyment of stereo is not based on proving what you can hear to other people.
    WilliamM2 wrote: »
    "Desperate" is intentionally trying to mislead people with test results you know are worthless. Not to mention dishonest.

    How have I intentionally tried to mislead anyone when I posted a link to the thread and a list of posts where results were discussed and anyone can go an read for themselves? They can even join that forum and ask the author for more info if they are inclined.
    Confirmation bias is also a oxymoron.

    Make up your mind. First you said anecdotal data does not exist and now you say it does.
    See how I was able to close the loop on that?

    Great job! However, running in a loop is not the same as closing a loop.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2014
    Confirmation bias is also a oxymoron.

    Let's go to dictionary.com and see:

    oxymoron - a figure of speech by which a locution produces an incongruous, seemingly self-contradictory effect, as in “cruel kindness” or “to make haste slowly.”

    confirmation - something that confirms, as a corroborative statement or piece of evidence.

    bias - a particular tendency or inclination, especially one that prevents unprejudiced consideration of a question; prejudice.

    See how I was able to close the loop on that?

    No, I see where you went around in circles. I don't see where the terms "confirmation" and "bias" are self-contradictory.

    One can confirm something and have a bias for or against it. One can have a bias toward expensive audio gear, simply due to aesthetics, and still confirm that a lower priced component sonically outperforms a more aesthetically pleasing and higher priced component.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    You are reaching. Again.

    Anecdotal Data is about as valid as someones confirmation of ones bias. Anecdotal data isn't meaningful data to the marketplace.

    Both in and of themselves they are events that will not pass without thorough testing protocols and significant N in place. It's simply not useful.

    So my question is: What event's would I likely be able to go to, setup a testing scenario for 3-4 people an hour at a time and get that #?

    I'll await suggestions.
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    I took the blinded Philips Golden Ears Challenge and posted my "Golden Ears" certificate on this forum, in this thread and in a separate thread.

    And since you passed the Golden Ears Challenge, and I'm doing all the labor and setup of the SBT, all you need to do is show up.

    We now know you are good for it. I hope to see you at an event.
  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2014
    You are reaching. Again.

    You are the one claiming that certain words and meanings do not exist and seeing oxymorons were none exist. Obviously you do not always know the definitions of the words you attempt to use. In those regards, it appears that you are the one reaching.
    Anecdotal Data is about as valid as someones confirmation of ones bias. Anecdotal data isn't meaningful data to the marketplace.

    But you didn't say anecdotal data has limited validity or that it wasn't meaningful to the marketplace. You said:
    There is no such thing as anecdotal data.

    Anecdotal data is data not collected under scientifically controlled conditions. Therefore, the data may or may not be scientifically valid and may or may not be truthful. One way that anecdotal data is meaningful to the marketplace, and in criminal investigations, is that it can lead to more controlled studies if the sources are believed to be credible.

    For example, some Pass Labs preamp owners claim to hear an improvement in stereophonic performance after upgrading the DB25 power cable between the power supply chassis and the signal control chassis. None of them have my particular model of Pass preamp (XP-30), but my preamp uses the same generic DB25 cable as theirs. Pass Labs said they never heard "much of a difference" between DB25 cables.

    This anecdotal data piqued my interest enough to do a more detailed listening and quantitative study comparing the stock DB25 to two different audio grade DB25 cables. One cable is priced at $154 for a 3 foot length and is a highly regarded, well-shielded cable designed for recording studio applications. The other cable is designed for high end stereo equipment and is made of much better materials and has extensive electrical and mechanical noise abatement. It is priced at $699 per meter.

    On the outside, it may seem that a $154 or $699 power cord is outrageous, but within the context of a $16,500 preamp, the price of these accessories is negligible.
    And since you passed the Golden Ears Challenge, and I'm doing all the labor and setup of the SBT, all you need to do is show up.

    Why do I "need" to show up? I thought the only place I "needed" to show up was work.

    By the way, some blind test for stereo proponents insist that SBTs are not rigorous enough and that only a DBT should be considered scientifically valid. What is your opinion?
    Proud and loyal citizen of the Digital Domain and Solid State Country!
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    This anecdotal data piqued my interest enough to do a more detailed listening and quantitative study comparing the stock DB25 to two different audio grade DB25 cables. One cable is priced at $154 for a 3 foot length and is a highly regarded, well-shielded cable designed for recording studio applications. The other cable is designed for high end stereo equipment and is made of much better materials and has extensive electrical and mechanical noise abatement. It is priced at $699 per meter.

    I don't have an any current interest in DB25 cables.
    On the outside, it may seem that a $154 or $699 power cord is outrageous, but within the context of a $16,500 preamp, the price of these accessories is negligible.

    No argument from me there. Spend what you want to spend.
    Why do I "need" to show up? I thought the only place I "needed" to show up was work.

    By the way, some blind test for stereo proponents insist that SBTs are not rigorous enough and that only a DBT should be considered scientifically valid. What is your opinion?

    You may want to think about it's usage in a bit different context. All I think I will need to significant N is ~50 to start teasing out some data. I am going to check to see if there is a Psych student that would want to co-author a paper on this.

    If you ever wanted to participate you would certainly be welcome.

    I am 100% going to take up your point that you made pages ago about my intent in all this. I'm not beyond constructive feedback and will say I have genuinely appreciated some of posts that were absolutely even handed.

    My opinion about doing this in a SBT is: I believe when well designed it will stand up to peer scrutiny. I will work with someone on developing it to stand up to a more rigorous review process.

    There are other testing methods that may also yield valid results with a smaller N or a testing method that may well be better vetted for this type of testing. It's going to be a lot of work.
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    DSkip wrote: »
    What exactly do you expect to gain from this Monk? I'm not talking about the test with members, but about an intensive research paper that seems to already be covered by other sources. Seems like a lot of work for little to gain.

    A few things. 1st I haven't seen anything remotely in a well disciplined study presented that passes anything coming close to scientific muster.

    2nd I'm curious.

    3rd I would welcome the learning process of doing this.

    4th I think a well ran, vetted, with enough N, test would yield data driven results that can speak for itself. I'm willing to let data speak for itself.

    What are the other sources you are speaking of? Gain is in the eye of the beholder :smile:
    DSkip wrote: »
    In the end though, those who have had multiple cable 'discoveries' will not be satisfied with your research, regardless of how it turns out. I just don't see the point.

    You currently can not convince the climate change skeptics either. I think most rational people appreciate well thought out models and testing.
    DSkip wrote: »
    Question for you Monk - if all this boils down to networking, how does the software play into it? Should they all sound the same? I know another forum member started using the Oppo software instead of Jriver because he states he can hear a difference. If the same files are being sent with each program and being decoded by the DAC, where is the difference coming from? I can't offer any experience with this question - sincere curiosity.

    That is a question the deserves further scrutiny. If there are demonstrable differences then I would think sussing them out would be in order. Better understanding benefits all.

    I would want to see his/her JRiver configuration first hand. I would want to see the Oppo setup / configuration first hand. I would want to know if they volume matched the speaker output. Maybe they had an output plug-in mis-configured. Questions, questions, questions.
  • villian
    villian Posts: 412
    edited June 2014
    DSkip wrote: »
    Question for you Monk - if all this boils down to networking, how does the software play into it? Should they all sound the same? I know another forum member started using the Oppo software instead of Jriver because he states he can hear a difference. If the same files are being sent with each program and being decoded by the DAC, where is the difference coming from? I can't offer any experience with this question - sincere curiosity.

    Could be something as simple as what type of digital bitstream is being sent to the DAC from the software. There's so many different formats that could be used, that it's impossible to think that two programs would use the same (Or the best) formats straight from the box. Then, even if it's bitstreamed, is it relatable to the original file or a bitstream that has been decoded and re-encoded into something like PCM from FLAC, or even WAV?
    Too many good quotes to list..waiting for some fresh ammo. :)
  • villian
    villian Posts: 412
    edited June 2014
    DSkip wrote: »
    Villain, you've turned the debate into a personal vendetta against BlueFox. I have no dog in this fight, but you constantly calling him out puts you in the wrong camp on this forum.

    Calling someone out for an erroneous claim that they're unwilling to back up? Sure, I'll do that all day long.
    There are still, up to this post, questions asked that Darque Knight and Bluefox have either tried deflection of (a paper discussing running Ethernet along with high voltage power on Navy ships) or outright just non-responsive.

    I agree. You'll be hard pressed to find a question asked of myself or Habanero that we haven't tried to answer. Yet, I have asked the following questions in direct response to claims made by other posters (Most notably Bluefox and DK) numerous times (I think this makes 8 times now..) with NO response, and even a refusal. Remember, my questions are not being asked rhetorically, they are in direct response to claims made by other members. Nothing wrong with pushing these questions..

    Q: Where does jitter (Or any audio distortion as you call it..that varies from the original recording) exist in a digital music file? Can you provide an example of a binary code showing this?

    Q: Where does jitter exist (Other than the original recording jitter) in a digital file with a CRC matching the original file?

    Q: Does jitter exist within a file in RAM or in a buffer?

    Q: Does jitter exist in a file within any computer storage device (Storage medium)?
    DSkip wrote: »
    He's (Villian) made his point, and its getting to the point of harassment.

    Well, if only somebody had mentioned that before. Here I was thinking that the entire forum was a bunch of fools who were still drinking the koolade and seeing things the Bluefox way..hence the reinteriating of my point. I take it that most here have now realized that 1:1 bit perfect transfers do occur, and are the norm when it comes to digital signal transmission over ethernet?
    xcapri79 wrote: »
    That said with digital communications, wire quality and media type can definitely make a difference in certain high performance applications. For example, in the networking communications industry, fiber optic cables are used to improve bandwidth and minimize signal attenuation and bit errors in high speed digital communications. The transmission of information using photons in glass is better than transmitting electrons in a copper wire. Here the media used makes a difference.

    Difference in bandwidth and thoroughput, but not in the sound of the digitally transferred and reproduced music (If it was able to be sucessfully transferred.
    Too many good quotes to list..waiting for some fresh ammo. :)
  • bikezappa
    bikezappa Posts: 2,463
    edited June 2014
    http://www.wimp.com/explainedscience/

    Where is the experimental data to prove/disprove the theory?
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    Here is a good technical paper from TI:

    AN-1862 Reducing Radiated Emissions in Ethernet 10/100
    LAN Applications

    http://www.ti.com/lit/an/snla107a/snla107a.pdf

    Most has to do with designing a PCB (NIC's and Switches/Routers etc). But there are a few take aways outside of that.
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    Here is another TI article on their DP83640 PHY 1588 Precision Time Protocol Transceiver.

    http://www.ti.com/lit/an/snla091b/snla091b.pdf


    Table 2 and 3 are interesting as to how well their PHY performs when it comes to induced jitter. Keep in mind they are testing 150 Meters (492 feet). WAY beyond the 328 foot spec for Ethernet Data.

    The papers protocol could certainly be a basis outside of certification devices from the likes of Fluke, Wavetek, Ideal etc...
  • villian
    villian Posts: 412
    edited June 2014
    For Bluefox and DK
    (Note: I'm not asking any new questions, so please...quit avoiding giving an answer. It can be as simple as yes or no. I think myself and Habanero deserve it after all the ridicule and answering of your questions we've done.)

    Q: Where does jitter (Or any audio distortion as you call it..that varies from the original recording) exist in a digital music file? Can you provide an example of a binary code showing this?

    Q: Where does jitter exist (Other than the original recording jitter) in a digital file with a CRC matching the original file?

    Q: Does jitter exist within a file in RAM or in a buffer?

    Q: Does jitter exist in a file within any computer storage device (Storage medium)?
    Too many good quotes to list..waiting for some fresh ammo. :)
  • villian
    villian Posts: 412
    edited June 2014
    This one's for you Headrott..

    I'll remove your post from my sig if you can explain to me how digital transmissions are not "Perfect".

    The way I would define perfect would be an output that matches the input 1:1.
    Too many good quotes to list..waiting for some fresh ammo. :)
  • polrbehr
    polrbehr Posts: 2,834
    edited June 2014
    villian wrote: »
    I'll remove your post from my sig if you can explain to me how digital transmissions are not "Perfect".

    That was my read-between-the-lines advice to you a few days ago, but I guess you feel it's more important to make enemies rather than friends?

    So be it, no skin off my apple either way.
    So, are you willing to put forth a little effort or are you happy sitting in your skeptical poo pile?


    http://audiomilitia.proboards.com/
  • villian
    villian Posts: 412
    edited June 2014
    polrbehr wrote: »
    That was my read-between-the-lines advice to you a few days ago, but I guess you feel it's more important to make enemies rather than friends?

    So be it, no skin off my apple either way.

    I'm not here for the beauty contest, I could care less. You say something idiotic and I'll gladly quote it. If that quote of your idiotic post deters you or anyone else from being my "Friend" at that point, I could care less. I don't want to be friends with someone who's stuck in a fantasy world where they're right after being proven wrong anyways.
    Too many good quotes to list..waiting for some fresh ammo. :)
  • pretzelfisch
    pretzelfisch Posts: 160
    edited June 2014
    well I was not expecting to find this. (Increasing the sound quality of your music, by switching from Cat 5 networking to Cat 7)http://www.extremetech.com/tag/audiophile
  • polrbehr
    polrbehr Posts: 2,834
    edited June 2014
    villian wrote: »
    I'm not here for the beauty contest, I could care less. You say something idiotic and I'll gladly quote it. If that quote of your idiotic post deters you or anyone else from being my "Friend" at that point, I could care less. I don't want to be friends with someone who's stuck in a fantasy world where they're right after being proven wrong anyways.

    Color me unsurprised.
    So, are you willing to put forth a little effort or are you happy sitting in your skeptical poo pile?


    http://audiomilitia.proboards.com/
  • villian
    villian Posts: 412
    edited June 2014
    well I was not expecting to find this. (Increasing the sound quality of your music, by switching from Cat 5 networking to Cat 7)http://www.extremetech.com/tag/audiophile

    You should read the whole article. It clearly states "we’re not sure if his claims hold up". It's one man making a claim, without any factual evidence to bat. Not like we've seen this before..yawn..
    Too many good quotes to list..waiting for some fresh ammo. :)
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    well I was not expecting to find this. (Increasing the sound quality of your music, by switching from Cat 5 networking to Cat 7)http://www.extremetech.com/tag/audiophile

    I find the review dubious at best and hardly data driven.

    But let's take this tidbit from the 2nd T.I. article I posted:

    Table 3. Transmit Jitter and RX Errors as Functions of Peak-to-Peak Long-Term Jitter (250 cycles,
    150 m)
    Reference Clock Jitter (ns) | Transmit Jitter (ns)| DUT RX Errors |Partner RX Errors
    0.14 | 0.35 | 0| 0
    0.60 | 0.77 | 0 | 0
    1.10 |1.25 | 0 | 0
    1.62 |1.75 | 0 | 0
    2.12 | 2.27 | 0 | 0
    2.63 | 2.79 | 0 | 0
    3.16 | 3.30 | 0 | 4 CRC
    3.66 |3.81 | 0 | 33 CRC
    4.19 | 4.31 | 1 CRC | 277 CRC


    A few items of note:

    The cable distance was 492 feet. This is 164 feet or 50% over the maximum IEEE spec of 328 feet for Ethernet 5/5e/6 runs at 100Mhz MLT-3.

    The Jitter threshold for IEEE spec is 1.4ns

    So for a TI particular implementation, even at injected jitter of 2.63ns at 492 feet, there is ZERO, NUNCA, ZILCH, NADA, DUT(device under test) and it's Partner Errors.

    A question I find myself asking: What box of 500 ft cable where they using? What was the cost per foot? Certainly food for thought.

    I'll take a paper from T.I. over Ren
  • ZLTFUL
    ZLTFUL Posts: 5,652
    edited June 2014
    Digital generation loss

    Used correctly, digital technology can eliminate generation loss. Copying a digital file gives an exact copy if the equipment is operating properly. This trait of digital technology has given rise to awareness of the risk of unauthorized copying. Before digital technology was widespread, a record label, for example, could be confident knowing that unauthorized copies of their music tracks were never as good as the originals.

    Processing a lossily compressed file rather than an original usually results in more loss of quality than generating the same output from an uncompressed original. For example, a low-resolution digital image for a web page is better if generated from an uncompressed raw image than from an already-compressed JPEG file of higher quality.

    Techniques that cause generation loss in digital systems
    In digital systems, several techniques, used because of other advantages, may introduce generation loss and must be used with caution. However, copying a digital file itself incurs no generation loss--the copied file is identical to the original, provided a perfect copying channel is used.

    Some digital transforms are reversible, while some are not. Lossless compression is, by definition, fully reversible, while lossy compression throws away some data which cannot be restored. Similarly, many DSP processes are not reversible.

    Thus careful planning of an audio or video signal chain from beginning to end and rearranging to minimize multiple conversions is important to avoid generation loss. Often, arbitrary choices of numbers of pixels and sampling rates for source, destination, and intermediates can seriously degrade digital signals in spite of the potential of digital technology for eliminating generation loss completely.

    Similarly, when using lossy compression, it will ideally only be done once, at the end of the workflow involving the file, after all required changes have been made.

    Transcoding
    Converting between lossy formats – be it decoding and re-encoding to the same format, between different formats, or between different bitrates or parameters of the same format – causes generation loss.

    Repeated applications of lossy compression and decompression can cause generation loss, particularly if the parameters used are not consistent across generations. Ideally an algorithm will be both idempotent, meaning that if the signal is decoded and then re-encoded with identical settings, there is no loss, and scalable, meaning that if it is re-encoded with lower quality settings, the result will be the same as if it had been encoded from the original signal – see Scalable Video Coding. More generally, transcoding between different parameters of a particular encoding will ideally yield the greatest common shared quality – for instance, converting from an image with 4 bits of red and 8 bits of green to one with 8 bits of red and 4 bits of green would ideally yield simply an image with 4 bits of red color depth and 4 bits of green color depth without further degradation.

    Some lossy compression algorithms are much worse than others in this regard, being neither idempotent nor scalable, and introducing further degradation if parameters are changed.

    For example, with JPEG, changing the quality setting will cause different quantization constants to be used, causing additional loss. Further, as JPEG is divided into 16
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • Toolfan66
    Toolfan66 Posts: 17,300
    edited June 2014
    WOW!!! 30 pages of Yawn... {:-O
    Polk Audio SDA 2.3tl Fully Hot Rodded. 😎

    SVS SB16 X2

    Cary SLP-05/Ultimate Upgrade.
    Cary SA-500.1 ES Amps
    Cary DMS 800PV Network
    OPPO UDP 205/ModWright Modification
    VPI Scout TT / Dynavector 20x2
    Jolida JD9 Fully Modified

    VPI MW-1 Cyclone RCM

    MIT Shotgun 3 cables throughout / Except TT, and PC’s
  • WilliamM2
    WilliamM2 Posts: 4,780
    edited June 2014
    ZLTFUL wrote: »
    Generation loss applies to digital files, period. To claim that all digital files are the same in the digital domain as was postulated earlier in this thread supports this claim. That all digital files can be effected by this so it stands to reason that digital files can inherit or develop artifacts (including jitter) from any of the techniques discussed above.

    You must have missed this:
    However, copying a digital file itself incurs no generation loss--the copied file is identical to the original, provided a perfect copying channel is used.

    A "perfect copying channel" is trivial, and accomplished by even the cheapest of computers.

    I think everyone knows that editing, or transcoding a file to a lossy format will not be an exact copy.
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    ZLTFUL wrote: »
    Digital generation loss

    Used correctly, digital technology can eliminate generation loss. Copying a digital file gives an exact copy if the equipment is operating properly. This trait of digital technology has given rise to awareness of the risk of unauthorized copying. Before digital technology was widespread, a record label, for example, could be confident knowing that unauthorized copies of their music tracks were never as good as the originals.

    Processing a lossily compressed file rather than an original usually results in more loss of quality than generating the same output from an uncompressed original. For example, a low-resolution digital image for a web page is better if generated from an uncompressed raw image than from an already-compressed JPEG file of higher quality.

    Techniques that cause generation loss in digital systems
    In digital systems, several techniques, used because of other advantages, may introduce generation loss and must be used with caution. However, copying a digital file itself incurs no generation loss--the copied file is identical to the original, provided a perfect copying channel is used.

    Some digital transforms are reversible, while some are not. Lossless compression is, by definition, fully reversible, while lossy compression throws away some data which cannot be restored. Similarly, many DSP processes are not reversible.

    Thus careful planning of an audio or video signal chain from beginning to end and rearranging to minimize multiple conversions is important to avoid generation loss. Often, arbitrary choices of numbers of pixels and sampling rates for source, destination, and intermediates can seriously degrade digital signals in spite of the potential of digital technology for eliminating generation loss completely.

    Similarly, when using lossy compression, it will ideally only be done once, at the end of the workflow involving the file, after all required changes have been made.

    Transcoding
    Converting between lossy formats – be it decoding and re-encoding to the same format, between different formats, or between different bitrates or parameters of the same format – causes generation loss.

    Repeated applications of lossy compression and decompression can cause generation loss, particularly if the parameters used are not consistent across generations. Ideally an algorithm will be both idempotent, meaning that if the signal is decoded and then re-encoded with identical settings, there is no loss, and scalable, meaning that if it is re-encoded with lower quality settings, the result will be the same as if it had been encoded from the original signal – see Scalable Video Coding. More generally, transcoding between different parameters of a particular encoding will ideally yield the greatest common shared quality – for instance, converting from an image with 4 bits of red and 8 bits of green to one with 8 bits of red and 4 bits of green would ideally yield simply an image with 4 bits of red color depth and 4 bits of green color depth without further degradation.

    Some lossy compression algorithms are much worse than others in this regard, being neither idempotent nor scalable, and introducing further degradation if parameters are changed.

    For example, with JPEG, changing the quality setting will cause different quantization constants to be used, causing additional loss. Further, as JPEG is divided into 16
  • ZLTFUL
    ZLTFUL Posts: 5,652
    edited June 2014
    I didn't miss anything. Unlike others in this debate, I choose to read the entire articles instead of picking and choosing what I want to fixate on. Case in point, villain chooses only to acknowledge, in the Audiophile article posted by pretzelfisch, that there may or may not be any measurable differences. In fact, you folks only seem to like to focus on parts that support your claims instead of the other parts that go against them.

    As for "perfect copying channel"...yeah...I have seen "perfect" networks produce errors. I have seen "perfect" OSes spew forth errors constantly and still work well within their established margin of error. Let me ask you this, in all seriousness...if a packetized data network is perfect, why the need for error checking/error correction? Exactly.
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • Habanero Monk
    Habanero Monk Posts: 715
    edited June 2014
    duplicate post
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