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willndmb
2008-09-24, 01:11 PM
maybe i am totally missing the point, if so please explain it to me...

for a show such as the farm aid 08 sets which were recorded via directTV > r09
can "we" use our eyes and let the recording/torrent stay active
http://www.thetradersden.org/forums/showpost.php?p=982924&postcount=1

i understand that it has some compression to it but if it sounds good whats the problem?
compared to
a recording that was stealth and sounds like crap (not saying in this case there is a stealth recording or that it sounds like crap - just an example)

i think most people would rather have the compressed recording that sounds good
vs
uncompressed recording that sounds like crap

just trying to understand what we are looking for in quality of torrents, so please explain if i am missing something important

direwolf-pgh
2008-09-24, 03:01 PM
good question IMO.. Id like to hear the answer as well - for my own education/understanding.

The specs look good/great to me..but I know there are some here that freak anytime the term compression comes up..lolololollol.

Often, the broadcast HDTV video signal soundtrack is Dolby Digital 5.1 surround sound, enabling full, surround sound capabilities, while STBC television signals include either monophonic or stereophonic audio, or both. Stereophonic broadcasts can be encoded with Dolby Surround audio signal. Brasil opted to upgrade the ISDB-T Japanese standard to H.264/MPEG-4 AVC in the video compression and HE-AAC for audio compression because Dolby is not open and the royalty fees are more expensive than that of H.264 and renamed the upgraded standard to ISDB-Tb that now became the International ISDB-T standard. pic was from here (http://en.wikipedia.org/wiki/High_Definition_TV)

direwolf-pgh
2008-09-24, 03:06 PM
more audio info per type
Dolby Digital, or AC-3, is the common version containing up to six discrete channels of sound. The most elaborate mode in common usage involves five channels for normal-range speakers (20 Hz – 20,000 Hz) (right front, center, left front, right rear and left rear) and one channel (20 Hz – 120 Hz) for the subwoofer driven low-frequency effects. Mono and stereo modes are also supported. AC-3 supports audio sample-rates up to 48kHz.

MPEG-1 Layer II is defined in ISO/IEC 11172-3

Sampling rates: 32, 44.1 and 48 kHz
Bitrates: 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320 and 384 kbit/s
An extension has been provided in MPEG-2 Layer II and is defined in ISO/IEC 13818-3

Additional sampling rates: 16, 22.05 and 24 kHz
Additional bitrates: 8, 16, 24, 40 and 144 kbit/s
The format is based on successive digital frames of 1152 sampling intervals with four possible formats:

Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at many bit rates.

AAC has been standardized by ISO and IEC, as part of the MPEG-2 & MPEG-4 specifications. The MPEG-2 standard contains several audio coding methods, including the MP3 coding scheme. AAC is able to include 48 full-bandwidth (up to 96 kHz) audio channels in one stream plus 15 low frequency enhancement (LFE, limited to 120 Hz) channels and up to 15 data streams. AAC is able to achieve indistinguishable audio quality at data rates of 320 kbit/s (64kbit/s/channel) for five channels. The quality is close to CD also at 96 kbit/s (48kbit/s/channel) for stereo.

AAC's best known use is as the default audio format of Apple's iPhone, iPod, iTunes, and the format used for all iTunes Store audio (with extensions for proprietary digital rights management).

Five
2008-09-24, 03:28 PM
seems it was captured well, but look at what we've got here:

direwolf-pgh
2008-09-24, 03:32 PM
you have that in 10ths of a second, ok. but help explain what you see here - is the audio signal type known yet?

I'm curious as HDTV audio is new to me. whats wrong with AC-3 ? a 20Hz ~ 20,000Hz @<hidden> 48kHz - doesnt sound bad.

Five
2008-09-24, 03:32 PM
^that's something like mp3 at 138kbps cbr (the setting you get if you cluelessly install an mp3-encoding prog without changing any of the presets).

AC3 ripped from DVD is not allowed to be seeded in the Audio section and that has frequency response all the way up to 20kHz.

so perhaps it is better to leave this audio with the video!

its also very difficult to moderate... "hmmm... looks like its about half the bitrate it should be, do we allow this or not" :confused

all due respect to the taper for making the effort, of course, it just doesn't fly in the audio section here (sorry!)

Five
2008-09-24, 03:36 PM
you have that in 10ths of a second.. help explain what you see here & is the audio signal known yet? I'm curious as this is new to me.
its a window of 2.791 seconds. the closer to black, the less activity, the closer to yellow the more. the frequencies are indicated on the right (gets higher as you go up), time along the bottom. so its cutting off at about 16kHz and looking like it was put together with a virtual lego kit.

audio ripped from a dvd with AC3 codec (which is not allowed to be seeded here either) normally looks like this (!):

Five
2008-09-24, 03:39 PM
I'm curious as HDTV audio is new to me. whats wrong with AC-3 ? a 20Hz ~ 20,000Hz would be a good thing.
when it comes to lossy codecs the cutoff is the simplest indication... however, there is more going on below that line, it is not simply that the stuff over 20kHz that only dogs can hear is being discarded.

the farm aid spectral screencap you can see the codec digging in and shaping it below the sad 16kHz cutoff :disbelief

saltman
2008-09-24, 03:43 PM
whats wrong with AC-3ac3 is the mp3 of the video world.


The difficulty in moderation of subjective sounds is immense. How would we distinguish what is best? It's easier and best for most users to exclude these types of sources. There are probably other places where this would fly.

You analogy of the poor lossless source vs decent lossy source illustrates the disadvantage of having rules. You can't be perfect. mp3 and lossy sources are easy to test for (as illustrated by five) and that's the best public trackers can do that aim for the best quality. I think our rules in this matter promote the greater good with the least sacrifice.

direwolf-pgh
2008-09-24, 03:47 PM
right. the second pic makes more sense what it should look like (if its was an AC3 signal). so the first pic shows it was jacked up during the capture.

i think my next question would be:

if you are not impressed with HDTV AC-3.. why would you be impressed with anything captured from a radio station.. which is allowed in the audio section.

if technology is at a set standard for a certain media outlet.. should all audio recordings be held accountable to the highest standard possible? often, the lineage of the recording accounts for acceptable limitations.

ac3 is the mp3 of the video world. damn it salt I dont enjoy disagreeing with you. honest!! but thats not what Ive read.
I read AAC is the mp3 of video. AC3 is decent. 20 ~ 20,000Hz @<hidden> 48kHz. perhaps I've read something incorrectly.

I mean until everything is Dolby TrueHD (24 bit, 96 kHz audio channels at up to 18 Mbit/s over 14 channels) you can just say everything sucks and shouldnt be allowed.
and one day Dolby TrueHD will suck too. the second pic posted AC3 looks really good to my eye.

Five
2008-09-24, 04:06 PM
right. the second pic makes more sense what it should look like. so the first pic shows it was jacked up during the capture.
no, I don't think it was. its mind-boggling. if everybody in every country broadcast with the same standards it would be so much more clear cut and easy to deal with, but as it stands you never know what's inside until you take a peek.

or maybe it was jacked up :confused: anyhow, lets keep the audio from video with the video.

i think my next question would be:

if you are not impressed with HDTV AC-3.. why would you be impressed with anything captured from a radio station.. which is allowed in the audio section.

if technology is at a set standard for a certain media.. should all audio recording be held accountable to the highest standard ? often, the lineage of the recording accounts for acceptable limitations.
radio varies all over the place when it comes to DAB, mostly its just terrible, like an md deck in the lowest-quality setting, but once in a while it exceeds expectations and is about as good as ATRAC (MD) in the highest-quality setting.

since its so unpredictable we would need a mod to download a track from every single DAB broadcast to analyze and probably still pull 99% of them anyhow if we wanted to get into allowing some of the higher-quality stuff!. we don't have a person like that and frankly nobody wants that job (I don't!).

The open-air broadcasts are 99% lossy for some years now but they have a couple big advantages over DAB: they are very consistent in quality, cutting off at about the same point that the old broadcasts used to (but lossy these days :( ), and they sound better than the DAB broadcasts.

prime example is the '69 zep show in france that surfaced in december. the 'prefm 192kbps mp3 source' surfaced, but strangely the open-air tape sounded the best :hmm:

'by the book' we should not allow any modern fm broadcast, but in light of the above info and not wanting to completely kill home taping of radio broadcasts at this site we do allow modern (most often lossy) broadcasts so long as they were recorded open-air or equivalent. in many places you can get FM thru (analog) cable that is not scrunched like DAB but rather looks like a typical modern FM, that is okay as well.

more here:
http://www.thetradersden.org/forums/showthread.php?t=9766

direwolf-pgh
2008-09-24, 04:15 PM
^ that was a good post with good points. gotcha.

the first pic looks to me like solo beats (snare drum).. the second pic is clearly a song moving along at full strength..then a segue into another track/bit at the end

.. as far as the spectrum & range.. honestly, It doesnt look bad..I've seen a lot worse.. thats all I'm sayin'.

either way.. thanks for helping me out with thoughts on the subject.

Five
2008-09-24, 04:17 PM
:thumbsup

now quit breakin' my ballz ;)

rspencer
2008-09-24, 05:29 PM
At least he didn't call you a dumbass, or make any reference to "monkey balls." ;)

willndmb
2008-09-24, 08:22 PM
thanks for the info
i respect the sites way of doing things but i think some consideration should be given to records like this
i only say that because i have heard some god awful recordings that are not compressed and allowed
i have also heard some great compressed recordings that are not allowed

maybe a better example of "consideration" are records from sirius (because there is no chance of a aud recording coming from it)
if a compressed recording taken from a line out of a receiver into a recorder is the only recording we will ever see, i much rather be able to get a copy then not

rspencer
2008-09-24, 08:57 PM
You can still get a copy, just not here (due to the rules of TTD).

The problem with exceptions & adding more & more rules & clauses is a matter of objectivity as well as workload.

The judgments of "god awful" and "great" are entirely subjective. Not picking on you, just used your words as an example. And then someone would have to listen to approve every show, using their own subjectivity.

Compressed or not, lossy vs. lossless, is a more objective standard. And a review of the lossy vs lossless section will show you that even then there are sometimes difficulties being sure.

willndmb
2008-09-25, 10:24 AM
true

AAR.oner
2008-09-25, 12:27 PM
The problem with exceptions & adding more & more rules & clauses is a matter of objectivity as well as workload.



this is the point so many people don't understand [not you willndmb, just people in general]

if we took every "exception" into consideration, we'd have to have dozens of mods working around the clock...the mods here are few and not paid, therefor we have to keep it somewhat simple when it comes to requirements

now if anyone wants to cover my salary each year and have a T1 line installed at my house, i'll be more than happy to take each and every show into consideration ;)

pawel
2008-09-25, 04:12 PM
^ me too :D

Five
2008-09-25, 07:03 PM
You can still get a copy, just not here (due to the rules of TTD).

The problem with exceptions & adding more & more rules & clauses is a matter of objectivity as well as workload.

The judgments of "god awful" and "great" are entirely subjective. Not picking on you, just used your words as an example. And then someone would have to listen to approve every show, using their own subjectivity.

Compressed or not, lossy vs. lossless, is a more objective standard. And a review of the lossy vs lossless section will show you that even then there are sometimes difficulties being sure.
:clap: