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Lossy or Lossless? Please use this forum to post spectral and frequency analysis posts about shows you have your doubts about.

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  #1  
Old 2010-03-23, 05:42 PM
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Could anybody have a look, please?

I got this one as a .wav set. I know that this show was broadcasted (TV), but there should be a genuine audio recording of it as well. Still, i can't make too much sense of the analysis. Could it be lossy with these fine "lines" reaching up to the end of the spectrum?

If anybody could give me his or her opinion, that would be ace. Thanks!

3 sec. sample, frequency analysis & whole track spectral frequency analysis attached (hope it's ok like that?)..
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File Type: jpg 3SecFreqAnalysis.jpg
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File Type: jpg SpecFreq.jpg
( 749.9 KB, 21 views)
 
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  #2  
Old 2010-03-25, 04:34 PM
lintoni
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Re: Could anybody have a look, please?

mpeg compression may well have been used before the recording was made. Even if the TV broadcast was analogue, the material may have been compressed prior to the broadcast.
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  #3  
Old 2010-03-25, 07:23 PM
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Re: Could anybody have a look, please?

Hmm... i guess i expressed myself badly.. English is not my 1st language, sorry.

What i was trying to say is that i know the concert was ALSO broadcasted on TV. I said that because - for example - somebody having this audio ripped from a avi file or DVD could be one possibility.

However, there definitely ARE genuine audio recordings of the show as well. So i got this one as a "lossless wav audio recording". Suggesting it was flac>wav or flac>cdr>wav.

But if i get you right, this is lossy in any case? And you tend to say it indeed IS sourced from a video recording?

Thanks again!
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  #4  
Old 2010-03-25, 09:02 PM
lintoni
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Re: Could anybody have a look, please?

Quote:
Originally Posted by Dizcipline View Post
...

But if i get you right, this is lossy in any case?
It looks suspect to me.

Quote:
Originally Posted by Dizcipline View Post
And you tend to say it indeed IS sourced from a video recording?
The strong horozontal line showing on the SpecFreq at (I'm guessing, because there's no indication of the frequency on the screenshot) approx 15.7kHz is associated with NTSC TV equipment. However, it is impossible to say for sure if this came from the broadcast, or just because there was a TV switched on somewhere, close to the recording equipment. See this link for more on this.
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  #5  
Old 2010-03-25, 09:15 PM
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Re: Could anybody have a look, please?

The spectrum analyzer shot you posted strongly suggests lossy data compression having been applied.

If you want to be sure, try to take another shot of the spectrum analyzer, but with the span at 3 seconds or so instead of the whole file.

That will make it evident.
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  #6  
Old 2010-03-25, 09:46 PM
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Re: Could anybody have a look, please?

Quote:
Originally Posted by lintoni View Post
It looks suspect to me.



The strong horozontal line showing on the SpecFreq at (I'm guessing, because there's no indication of the frequency on the screenshot) approx 15.7kHz is associated with NTSC TV equipment. However, it is impossible to say for sure if this came from the broadcast, or just because there was a TV switched on somewhere, close to the recording equipment. See this link for more on this.

Yes, i know about that, actually that was another reason why i thought mentioning that the show was also filmed and broadcasted wouldn't harm, maybe.

Anyway, here's a 3 seconds snippet:

Thanks for you help guys, this place is great!
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File Type: jpg SpecFreq3Sec.jpg
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  #7  
Old 2010-03-25, 10:07 PM
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Re: Could anybody have a look, please?

lossy
probably not horrible.. it's a mild algorithm, whatever it is...

is that half-second clicking audible? Would sound like a soft helicopter idle, I'd think.

The noise just under 16kHz is likely flyback rf interference from a CRT near the recording gear or near the transfer gear.

The fact that it is there suggests this is an analog recording and has probably seen the lossy data compression applied after the recording, I'd go as far as to guess the rate is VBR, too.
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  #8  
Old 2010-03-25, 10:40 PM
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Dizcipline Dizcipline is offline
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Re: Could anybody have a look, please?

At least I cannot hear the clicking, no. I tried to check some of the more quiet parts of the recording, but i can't hear anything.

Thanks again, i guess I'll keep looking for a lossless copy then.
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