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#41
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
On Tue, 17 Feb 2004 06:11:03 -0000, Rich Andrews
wrote: Randy Yates wrote in : (Svante) writes: Randy Yates wrote in message news: ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. Svante, by all means, I appreciate your response. This is good information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. That it is lossy compression, and therefore *measurably* diffferent, does not mean that it's *audibly* different. Only *listening* tests, under controlled conditions, can determine audibility. General repoirts seem to indiucate that 128kbs is audible, but 192 may be adequate for all but the most critical applications. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#42
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"citronzx" wrote in message link.net...
Svante, what do you teach? Mainly electroacoustics at the Royal Institute of Technology, Sweden. But this is another course that is actually about project control, and I supply them with the task of determining the audibility of mp3s. "Svante" wrote in message om... Randy Yates wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. |
#43
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"citronzx" wrote in message link.net...
Svante, what do you teach? Mainly electroacoustics at the Royal Institute of Technology, Sweden. But this is another course that is actually about project control, and I supply them with the task of determining the audibility of mp3s. "Svante" wrote in message om... Randy Yates wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. |
#44
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"citronzx" wrote in message link.net...
Svante, what do you teach? Mainly electroacoustics at the Royal Institute of Technology, Sweden. But this is another course that is actually about project control, and I supply them with the task of determining the audibility of mp3s. "Svante" wrote in message om... Randy Yates wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. |
#45
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"citronzx" wrote in message link.net...
Svante, what do you teach? Mainly electroacoustics at the Royal Institute of Technology, Sweden. But this is another course that is actually about project control, and I supply them with the task of determining the audibility of mp3s. "Svante" wrote in message om... Randy Yates wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. |
#46
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
Rich Andrews writes:
Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. Thanks for your input, Rich. -- % Randy Yates % "Watching all the days go by... %% Fuquay-Varina, NC % Who are you and who am I?" %%% 919-577-9882 % 'Mission (A World Record)', %%%% % *A New World Record*, ELO http://home.earthlink.net/~yatescr |
#47
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
Rich Andrews writes:
Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. Thanks for your input, Rich. -- % Randy Yates % "Watching all the days go by... %% Fuquay-Varina, NC % Who are you and who am I?" %%% 919-577-9882 % 'Mission (A World Record)', %%%% % *A New World Record*, ELO http://home.earthlink.net/~yatescr |
#48
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
Rich Andrews writes:
Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. Thanks for your input, Rich. -- % Randy Yates % "Watching all the days go by... %% Fuquay-Varina, NC % Who are you and who am I?" %%% 919-577-9882 % 'Mission (A World Record)', %%%% % *A New World Record*, ELO http://home.earthlink.net/~yatescr |
#49
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
Rich Andrews writes:
Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. Thanks for your input, Rich. -- % Randy Yates % "Watching all the days go by... %% Fuquay-Varina, NC % Who are you and who am I?" %%% 919-577-9882 % 'Mission (A World Record)', %%%% % *A New World Record*, ELO http://home.earthlink.net/~yatescr |
#50
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
"Charles Tomaras" writes:
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. I think it's more like the difference between Smirnoff versus Absolut. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Are you pompous enough to maintain that your subjective impressions are the reference by which we should all compare? What incredible stupidity. -- % Randy Yates % "And all that I can do %% Fuquay-Varina, NC % is say I'm sorry, %%% 919-577-9882 % that's the way it goes..." %%%% % Getting To The Point', *Balance of Power*, ELO http://home.earthlink.net/~yatescr |
#51
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
"Charles Tomaras" writes:
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. I think it's more like the difference between Smirnoff versus Absolut. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Are you pompous enough to maintain that your subjective impressions are the reference by which we should all compare? What incredible stupidity. -- % Randy Yates % "And all that I can do %% Fuquay-Varina, NC % is say I'm sorry, %%% 919-577-9882 % that's the way it goes..." %%%% % Getting To The Point', *Balance of Power*, ELO http://home.earthlink.net/~yatescr |
#52
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
"Charles Tomaras" writes:
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. I think it's more like the difference between Smirnoff versus Absolut. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Are you pompous enough to maintain that your subjective impressions are the reference by which we should all compare? What incredible stupidity. -- % Randy Yates % "And all that I can do %% Fuquay-Varina, NC % is say I'm sorry, %%% 919-577-9882 % that's the way it goes..." %%%% % Getting To The Point', *Balance of Power*, ELO http://home.earthlink.net/~yatescr |
#53
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is TheDifference Audible?
"Charles Tomaras" writes:
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. I think it's more like the difference between Smirnoff versus Absolut. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Are you pompous enough to maintain that your subjective impressions are the reference by which we should all compare? What incredible stupidity. -- % Randy Yates % "And all that I can do %% Fuquay-Varina, NC % is say I'm sorry, %%% 919-577-9882 % that's the way it goes..." %%%% % Getting To The Point', *Balance of Power*, ELO http://home.earthlink.net/~yatescr |
#54
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Randy Yates" wrote in message
"Arny Krueger" writes: "Randy Yates" wrote in message Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? As a rule, its possible to hear at last slight differences, especially if you pick the music to exploit the failings of the coder. Thanks Arny. I cannot, even with the proported "difficult" jangling keys passage - I suppose I'm just getting old. Or you've got a coder that does well with keys jangling. I know for sure that people have diddled coders that failed miserably with my test files, until they ran clean. Say, Microsoft... The people on the Hydrogen Audio forum like to sift CDs looking for stuff that breaks coders. They're good people to get the latest-greatest tips from. http://www.hydrogenaudio.org/ |
#55
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Randy Yates" wrote in message
"Arny Krueger" writes: "Randy Yates" wrote in message Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? As a rule, its possible to hear at last slight differences, especially if you pick the music to exploit the failings of the coder. Thanks Arny. I cannot, even with the proported "difficult" jangling keys passage - I suppose I'm just getting old. Or you've got a coder that does well with keys jangling. I know for sure that people have diddled coders that failed miserably with my test files, until they ran clean. Say, Microsoft... The people on the Hydrogen Audio forum like to sift CDs looking for stuff that breaks coders. They're good people to get the latest-greatest tips from. http://www.hydrogenaudio.org/ |
#56
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Randy Yates" wrote in message
"Arny Krueger" writes: "Randy Yates" wrote in message Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? As a rule, its possible to hear at last slight differences, especially if you pick the music to exploit the failings of the coder. Thanks Arny. I cannot, even with the proported "difficult" jangling keys passage - I suppose I'm just getting old. Or you've got a coder that does well with keys jangling. I know for sure that people have diddled coders that failed miserably with my test files, until they ran clean. Say, Microsoft... The people on the Hydrogen Audio forum like to sift CDs looking for stuff that breaks coders. They're good people to get the latest-greatest tips from. http://www.hydrogenaudio.org/ |
#57
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Randy Yates" wrote in message
"Arny Krueger" writes: "Randy Yates" wrote in message Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? As a rule, its possible to hear at last slight differences, especially if you pick the music to exploit the failings of the coder. Thanks Arny. I cannot, even with the proported "difficult" jangling keys passage - I suppose I'm just getting old. Or you've got a coder that does well with keys jangling. I know for sure that people have diddled coders that failed miserably with my test files, until they ran clean. Say, Microsoft... The people on the Hydrogen Audio forum like to sift CDs looking for stuff that breaks coders. They're good people to get the latest-greatest tips from. http://www.hydrogenaudio.org/ |
#58
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Rich Andrews" wrote in message
. 44 Randy Yates wrote in : information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. A form of lossy compression called "14/32 Linear PCM" is generally known to be unconditionally transparent. Failing that, kick the numbers up a bit. The point is that it is humanly possible to lose data in a fashion that is inaudible. The only questions remaining are how much and how to. |
#59
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Rich Andrews" wrote in message
. 44 Randy Yates wrote in : information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. A form of lossy compression called "14/32 Linear PCM" is generally known to be unconditionally transparent. Failing that, kick the numbers up a bit. The point is that it is humanly possible to lose data in a fashion that is inaudible. The only questions remaining are how much and how to. |
#60
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Rich Andrews" wrote in message
. 44 Randy Yates wrote in : information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. A form of lossy compression called "14/32 Linear PCM" is generally known to be unconditionally transparent. Failing that, kick the numbers up a bit. The point is that it is humanly possible to lose data in a fashion that is inaudible. The only questions remaining are how much and how to. |
#61
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Rich Andrews" wrote in message
. 44 Randy Yates wrote in : information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. A form of lossy compression called "14/32 Linear PCM" is generally known to be unconditionally transparent. Failing that, kick the numbers up a bit. The point is that it is humanly possible to lose data in a fashion that is inaudible. The only questions remaining are how much and how to. |
#62
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
Stewart Pinkerton wrote in message . ..
On Tue, 17 Feb 2004 06:11:03 -0000, Rich Andrews wrote: Randy Yates wrote in : (Svante) writes: Randy Yates wrote in message news: ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. Svante, by all means, I appreciate your response. This is good information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. That it is lossy compression, and therefore *measurably* diffferent, does not mean that it's *audibly* different. Only *listening* tests, under controlled conditions, can determine audibility. General repoirts seem to indiucate that 128kbs is audible, but 192 may be adequate for all but the most critical applications. I agree, with the additional condition that the encoder is good. There certainly are encoders out there that are audible even at 320 kbit/s (I just see that I wrote "mbit/s" in my previous post, milli-bit/s, oops...). This encoder difference is one of the things that usually comes out of the students' tests. |
#63
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
Stewart Pinkerton wrote in message . ..
On Tue, 17 Feb 2004 06:11:03 -0000, Rich Andrews wrote: Randy Yates wrote in : (Svante) writes: Randy Yates wrote in message news: ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. Svante, by all means, I appreciate your response. This is good information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. That it is lossy compression, and therefore *measurably* diffferent, does not mean that it's *audibly* different. Only *listening* tests, under controlled conditions, can determine audibility. General repoirts seem to indiucate that 128kbs is audible, but 192 may be adequate for all but the most critical applications. I agree, with the additional condition that the encoder is good. There certainly are encoders out there that are audible even at 320 kbit/s (I just see that I wrote "mbit/s" in my previous post, milli-bit/s, oops...). This encoder difference is one of the things that usually comes out of the students' tests. |
#64
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
Stewart Pinkerton wrote in message . ..
On Tue, 17 Feb 2004 06:11:03 -0000, Rich Andrews wrote: Randy Yates wrote in : (Svante) writes: Randy Yates wrote in message news: ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. Svante, by all means, I appreciate your response. This is good information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. That it is lossy compression, and therefore *measurably* diffferent, does not mean that it's *audibly* different. Only *listening* tests, under controlled conditions, can determine audibility. General repoirts seem to indiucate that 128kbs is audible, but 192 may be adequate for all but the most critical applications. I agree, with the additional condition that the encoder is good. There certainly are encoders out there that are audible even at 320 kbit/s (I just see that I wrote "mbit/s" in my previous post, milli-bit/s, oops...). This encoder difference is one of the things that usually comes out of the students' tests. |
#65
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
Stewart Pinkerton wrote in message . ..
On Tue, 17 Feb 2004 06:11:03 -0000, Rich Andrews wrote: Randy Yates wrote in : (Svante) writes: Randy Yates wrote in message news: ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Pardon me for responding to a question not directed to me, but I think I have some input to this. I have a group of undergraduate students every year that perform A/B testing on mp3 compression. Their task is to find compressors on the web, rip a few CDs of their choice and to run A/B testing with a software supplied by me. The software randomises the testing, so they can do it without too big risk of errors. I am not present during the tests, however. 99% confidence is required (7 correct responses of 7 tries or equivalent). Last year the students tested three encoders. According to their report they tested Lame, bladeenc and mpegenc. They tested 8 CDs. At 128 mbit/s and with the lame encoder they managed to detect 3 of these 8. Same number for the other two encoders was 7 of 8. At 160 mbit/s they still got 99% confidence for 1 of 8 with lame, 2 of 8 with bladeenc, and 5 of 8 for mpegenc. Now, this is a student report, so I would not take it as 100% certainly true, but the blinded A/B procedure makes the test reasonably well controlled. Svante, by all means, I appreciate your response. This is good information. Even at 320kc the MP3 is audibly different. It cannot help but be different. It is a lossy compression. That it is lossy compression, and therefore *measurably* diffferent, does not mean that it's *audibly* different. Only *listening* tests, under controlled conditions, can determine audibility. General repoirts seem to indiucate that 128kbs is audible, but 192 may be adequate for all but the most critical applications. I agree, with the additional condition that the encoder is good. There certainly are encoders out there that are audible even at 320 kbit/s (I just see that I wrote "mbit/s" in my previous post, milli-bit/s, oops...). This encoder difference is one of the things that usually comes out of the students' tests. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Well, if someone says that it is impossible to differentiate between vodka and water, the way to *prove* him/her wrong is to do a blind test. For sure it will succeed. Without the test the difference might be obvious, but not proven. Anyone who states that a difference is obvious should not be afrait to prove it with an A/B test, IMO. Also, the choice of encoder is important, and while 128 kbit/s appears to be audible in A/B tests even for the good encoder, it also appears as if many can live with it. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Well, if someone says that it is impossible to differentiate between vodka and water, the way to *prove* him/her wrong is to do a blind test. For sure it will succeed. Without the test the difference might be obvious, but not proven. Anyone who states that a difference is obvious should not be afrait to prove it with an A/B test, IMO. Also, the choice of encoder is important, and while 128 kbit/s appears to be audible in A/B tests even for the good encoder, it also appears as if many can live with it. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Well, if someone says that it is impossible to differentiate between vodka and water, the way to *prove* him/her wrong is to do a blind test. For sure it will succeed. Without the test the difference might be obvious, but not proven. Anyone who states that a difference is obvious should not be afrait to prove it with an A/B test, IMO. Also, the choice of encoder is important, and while 128 kbit/s appears to be audible in A/B tests even for the good encoder, it also appears as if many can live with it. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. Well, if someone says that it is impossible to differentiate between vodka and water, the way to *prove* him/her wrong is to do a blind test. For sure it will succeed. Without the test the difference might be obvious, but not proven. Anyone who states that a difference is obvious should not be afrait to prove it with an A/B test, IMO. Also, the choice of encoder is important, and while 128 kbit/s appears to be audible in A/B tests even for the good encoder, it also appears as if many can live with it. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. As long as someone states that water and vodka taste the same, the way to prove he/she is wrong is to do the test. The test will obviously succed, but until it's done, the difference isn't proven. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. As long as someone states that water and vodka taste the same, the way to prove he/she is wrong is to do the test. The test will obviously succed, but until it's done, the difference isn't proven. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. As long as someone states that water and vodka taste the same, the way to prove he/she is wrong is to do the test. The test will obviously succed, but until it's done, the difference isn't proven. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
"Charles Tomaras" wrote in message ...
"Randy Yates" wrote in message ... "Charles Tomaras" writes: "Randy Yates" wrote in message ... Arny, Given a relatively good MP3 encoder, has any of your ABX testing been able to quantify whether or not people can reliable detect the difference between a CD recording and 128 kbps MP3? Doesn't take special tests to hear the difference at 128kbps for any of the codecs that I have heard. The differences are pretty obvious to most astute listeners even on moderately priced equipment. As a jazz fan I really hear it on the high end of cymbals with swirly sort of phase issues. This is exactly the sort of unscientific assertion I wanted to circumvent by my ABX-qualified question. While I can appreciate the accuracy of blind testing, I recently heard someone post on a newsgroup that you don't need a blind comparison test to tell the difference between vodka and water. I'm sorry if one cannot hear the difference between Redbook CD and 128kbps material compressed with the popular codecs.....I think it's as obvious as the water and vodka analogy. When you get up to 192kbps and above the differences are much less pronounced but at 128kpbs it's not even close. As long as someone states that water and vodka taste the same, the way to prove he/she is wrong is to do the test. The test will obviously succed, but until it's done, the difference isn't proven. |
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
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Question to Arny Krueger: 128 kbps MP3 Vs. CD - Is The Difference Audible?
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