A Mark In Time
Start Here => Technical Help => Topic started by: Pottel on August 12, 2008, 11:21:12 PM
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thanks to the TTD for the info:
Why trade lossless media? Mp3 and Ogg sound good to me, what's the big deal?
Proponents of lossless and lossy audio formats seem immutably locked in a struggle for ideologic dominance. Each seems convinced of the superiority of each style and virtually unwilling to listen to the arguments presented by the opposing side. In this swarm of insults, baseless criticism, and pseudo-scientific testing methods, there is indeed an enormous difference, and understanding where each style of audio compression is appropriate is an extremely important facet of trading.
In simple terms, lossless compression schemes are capable of being decoded back to an identical .wav file as the one that created it. Lossy compression picks certain parts of the music and discards it in an attempt to shrink the filesize. The idea is to pick parts that the human ear is unable to discern and remove them, thus leaving no wasted space for storing files.
Quite simply, the latter is inappropriate for audio trading. The files which you trade will pass through hundreds, thousands, or even tens of thousands of hands. If each trader takes the liberty of compressing to their own lossy format of choice, the result will be catastrophic for the quality of the audio after several iterations. To ensure that everyone who desires a recording gets a chance to hear it in as good a quality as it was originally recorded, it is important to maintain a lossless lineage from user to user. Once a file has been compressed to a lossy format, that missing information can NEVER be replaced, and therefore files that have been compressed to lossy, even when converted back to lossless formats, are unsuitable for trading.
The truth about lossy file types is that, under proper scientific double blind studies, a very small percentage of humans are able to hear the difference between uncompressed .wav audio and high quality (192 KBps or higher) encoded lossy formats. These formats have their place. Many people compress their audio recordings to a lossy format for playing on portable players, their computers, or standalone home units. This is an effective method as the audio difference in one generation of lossless to lossy compression is likely to not cause an audible difference. Feel free to compress lossless recordings to whatever format you choose, but never, ever pass on files compressed to lossy formats or lossless files sourced from lossy formats to other traders.
For the good of the trading pool, please respect the difference between lossless (SHN, APE, FLAC, WAV, AIFF, etc) and lossy (MP3, OGG, AAC, etc) compression types. Only trade or pass on lossless files so that the overall quality of the trading pool remains high for everyone to enjoy.
Simply put, there are NO lossy file types (OGG-Vorbis, MP3, AAC, etc, etc) permitted for trade at this site. This is NOT a negotiable issue, there will be NO subforum for mp3 traders. If you ignore this rule and post lossy sourced material, there are ways to test for this and it will be discovered, resulting in your seed being deleted. Please respect the high quality standards we have put in place, and bring your mp3s elsewhere. If you are unsure of whether or not your seed is lossless, please post in the Technobabble forum and ask for assistance...we are glad to help.
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Thanks for sharing Pottel :)
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Makes absolute sense - great post Pottel.
On a slightly different note - can anyone enlighten me as to why we don't just post the original .wav files instead of converting them on the first place? I am sure there is a totally logical reason:-)
Many thanks.
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massive size difference, but same quality...therefore..
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Interesting - so does anyone know how this 'compression' process works without losing quality as in the case of MP3's and other lossy formats?
Cheers.
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I'm not an absolute supporter of lossles vs lossy, though I prefer lossless (i don't know why ;D). I think that these formats are sons of their own time: when the internet connections were slow and the Hard Disks (for storage) were small, the mp3 format was a good way to share music. Today is easy to share/store bigger files. I think that there are not so many differences to listen to a good mp3 or a flac file: the difference, I think, is more psychological than real. If there are audible differences, why you have to use sophisticate programs and algorithms to discern them? should be sufficient to listen to them. But it is not!
And I can't understand the TTD staff: If I send my own mp3 files to my friend X and he send these files to his friend Y, where is the problem? why they suppose that X will convert the original files to wav to compress again to mp3 to send these 2 times compressed files to Y? it is just illogical to me. If they think that mp3 is a valid format why they don't allow to share mp3 on their site? Their reasons sound ridiculous to me. :P
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Interesting - so does anyone know how this 'compression' process works without losing quality as in the case of MP3's and other lossy formats?
Cheers.
I have not technical competence, but I think it works (about) like winzip: you need a compressor (the program to create lossless files) and a de-compressor (the program to read/decomprime these files). This is the reason why your cd player can't read flac files. Maybe I'm wrong ;D
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they do not say that someone would convert back to lossless on purpose (although i have seen it happen) but that at the end of the line someone with no knowledge will do it, not knowing realising it and then spread this file again, and that is where the gene pool gets dirty.
also, it is not extreme, but the difference CAN be heard especially when the audience cheers or when drums hit cymbals and stuff, but the most clear it becomes with that audience cheer.
then again, it is just a matter of knowing what files you got, and clearly separating them (as i do for personal use, i.e. Ipod)
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they do not say that someone would convert back to lossless on purpose (although i have seen it happen) but that at the end of the line someone with no knowledge will do it, not knowing realising it and then spread this file again, and that is where the gene pool gets dirty.
also, it is not extreme, but the difference CAN be heard especially when the audience cheers or when drums hit cymbals and stuff, but the most clear it becomes with that audience cheer.
then again, it is just a matter of knowing what files you got, and clearly separating them (as i do for personal use, i.e. Ipod)
I'm not totally agree Maarten. for me the most is philosophy. before came out those programs to discern lossy sourced cd, the only way to be quite sure about the quality of a cd was to trade with serious and well-known traders. nobody (at least not the most) was able to discern these formats with a simple listen (you could have just a suspect, but not the certainty). Anyway, being not sure about the source of all my cds (for my listen they are good, but for the others who knows?) I prefer to trade DVDs only ;D
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also dvd's can be lossy converted to DVD..... :(
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also dvd's can be lossy converted to DVD..... :(
maybe my sight is better than my hearing, but I'm pretty sure I can distinguish a DVD sourced from an avi/vcd file ;)
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also dvd's can be lossy converted to DVD..... :(
maybe my sight is better than my hearing, but I'm pretty sure I can distinguish a DVD sourced from an avi/vcd file ;)
Not so sure about this - most of the sound/video quality depends on what equipment the recording was made on in the first place. If it was with a mono microphone and a casette recorder and then converted to a WAV file and then this WAV file was subsequently recorded to a lossless file and a lossy file who could tell the difference 1st Gen?
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absolutely simon.
that is the point with old pink floyd recordings for example...
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I'm not an absolute supporter of lossles vs lossy, though I prefer lossless (i don't know why ;D). I think that these formats are sons of their own time: when the internet connections were slow and the Hard Disks (for storage) were small, the mp3 format was a good way to share music. Today is easy to share/store bigger files. I think that there are not so many differences to listen to a good mp3 or a flac file: the difference, I think, is more psychological than real. If there are audible differences, why you have to use sophisticate programs and algorithms to discern them? should be sufficient to listen to them. But it is not!
And I can't understand the TTD staff: If I send my own mp3 files to my friend X and he send these files to his friend Y, where is the problem? why they suppose that X will convert the original files to wav to compress again to mp3 to send these 2 times compressed files to Y? it is just illogical to me. If they think that mp3 is a valid format why they don't allow to share mp3 on their site? Their reasons sound ridiculous to me. :P
Behind every recording that is shared on "TTD", there is a person who made the original recording; a taper. Most tapers are "quality minded" people that go to great lengths to record and share shows in the best possible quality. After that, no one wants their tapes passed around as crappy mp3s that delete data from the original recording.
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Listening to lossy music too often do harm to our ears, that's the simplest reason why I choose lossless formatted music. And for our man Mark, it deserves to keep in lossless.
Wishes
Allen
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Behind every recording that is shared on "TTD", there is a person who made the original recording; a taper. Most tapers are "quality minded" people that go to great lengths to record and share shows in the best possible quality. After that, no one wants their tapes passed around as crappy mp3s that delete data from the original recording.
I understand your (and the tapers') position. What I can't understand, reading the first Pottel's post, is that TTD staff consider mp3 very similar to lossless, but they don't allow to share mp3 on their site. It was more simple to say: "mp3 is not allowed because it is a crappy audio format" (being it true or not).
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Behind every recording that is shared on "TTD", there is a person who made the original recording; a taper. Most tapers are "quality minded" people that go to great lengths to record and share shows in the best possible quality. After that, no one wants their tapes passed around as crappy mp3s that delete data from the original recording.
I' understand your (and the tapers') position. What I can't undestand, reading the first pottel's post, is that TTD staff consider mp3 very similar to lossless, but they don't allow to share mp3 on their site. It was more simple to say: "mp3 is not allowed because it is a crappy audio format" (being it true or not).
It is not so much as being a crappy format - it is a good format for most of the time - but it is as Pottel says - each time you make an MP3 you rip the guts out of the recording and a few generations down the line makes it sound like something from Mars recorded by a passing spaceship. And it is not possible to prevent people degrading recordings in this way.:-)
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I think with have the internet has moved on, there is now no real excuse to share the same music in the original format you received it in. This hopefully being a lossless format. Then for your own use there is no harm in compressing it. I for example convert everything in AAC for my iPod. There is no way all my music would fit on my iPod in a lossless format!! But I'm sure to keep the original lossless versions :)
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I'd like to get this thread going again, for I need some help.
First, easy: DVD files depend, don't they, on the resolution and quality of the equipment. I've downloaded some files from you tube that seem to be better quality than original dvds from a show. Youtube now lets you download a higher quality file than flv. And again, the quality of the file depends on the uploader.
My other question is more problematical: Audio. The other day Allen told me that one of my files on the hub was lossy.
I had spot checked the cd and the ones I checked seemed to be lossless. How does it happen that one or more files on a cdr would be lossy and others lossless? And also how would one checker find a file to be lossless and another find it to be lossy? I need a brave and expert techie to help me with these problems.
And then, could you guys help me with reading the checks. If a wav file shows the tops and bottoms of the wave cut off, I figure the recording is lossy. There are degrees to this, aren't there? One recording will show just the tip of a wave cut, another will show major cut offs.
And the spectrum: Knut always uploads a spectrum reading with his recordings, but I have no idea how to read one.
Help!!! Please!!!! And thanks
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I'd like to get this thread going again, for I need some help.
First, easy: DVD files depend, don't they, on the resolution and quality of the equipment.
Yes, but I don't know of a single external DVD recorder that transfers VHS to DVD using LPCM audio. So this would have to be done manually when capturing to a PC.
My other question is more problematical: Audio. The other day Allen told me that one of my files on the hub was lossy.
I had spot checked the cd and the ones I checked seemed to be lossless. How does it happen that one or more files on a cdr would be lossy and others lossless? And also how would one checker find a file to be lossless and another find it to be lossy? I need a brave and expert techie to help me with these problems.
Well, it's possible. Seems unlikely, but if it's a compilation of tracks, probably...
And also how would one checker find a file to be lossless and another find it to be lossy?
The only check that is accurate is looking at frequency analysis and a spectral view zoomed in to a 2-5 second sample.
And then, could you guys help me with reading the checks. If a wav file shows the tops and bottoms of the wave cut off, I figure the recording is lossy. There are degrees to this, aren't there? One recording will show just the tip of a wave cut, another will show major cut offs.
First of all, you will only see this cut-off at the top, not the bottom. Yes, there are degrees to this, depending upon the codec used. If you are unsure about one, just cut a 2-5 second sample out of the track, flac it, and attach it to a new post here. I'm sure someone would be happy to analyze it.
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Thank you, Dan! How do you read a spectral view?
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Thank you, Dan! How do you read a spectral view?
Really, even if you just look at the pictures, the link below is a great guide. Read the actual guide for more information- it provides greater depth than anything I could write here.
http://www.audiohub.org/get/fa/sa.htm