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Kingbuzz
2009-10-15, 03:32 PM
Hello guys,

I have 3 samples here and I'm not sure if they are truly lossless.

1st example looks weird to me in FA also channels look different in SA.

2nd and 3rd example both peak all the way to the top but have black areas above 20khz in SA and some drop offs at 21khz in FA.

paddington
2009-10-15, 05:28 PM
What you have there doesn't show anything regarding lossy compression one way or the other. We can only guess with that. We'd need to see a 2-3 sec slice on the SA to view the blocks that are removed by the lossy data compression (if there are any).

What is DOES show, in #2, is an FM radio stereo pilot tone (19kHz) which could also explain the abrupt cut, depending on how it has been processed, post-receiver.

Also, in #3, the noise slightly below 16kHz is the flyback in a CRT video display that was likely picked up during analog recording or dubbing. Very common.

Kingbuzz
2009-10-15, 05:58 PM
Thank you for your fast reply and here are 2 sec slices as you requested:

paddington
2009-10-15, 06:00 PM
pretty sure we happy

the recordings aren't flawless, but they aren't MP3.

recommend you wait for second opinion from Five as to whether they are some modern version of ATRAC3, which isn't as easy to spot (or as noticeable when listening) due to much less abrupt aliasing.

Five
2009-10-16, 03:15 PM
the first looks normal. the 21kHz drop in the 2nd and 3rd is strange. 256kbps cbr mp3 cuts off around here (see here (http://www.thetradersden.org/forums/showthread.php?t=32490)) but your shows have some bit of distortion above the line (uncharacteristic) and I can't spot mp3 artifacts. perhaps it was pitch correction? :hmm: not certain.

anyhow, I can't point to direct evidence so 'innocent until proven guilty...'

the 2nd and 3rd are a little suspicous for sure... perhaps see if there's any variant filesets for these two dates that might be free from the drop at 21kHz.