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Topic: a true ape file (Read 5691 times) previous topic - next topic
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a true ape file

How do I know that a downloaded ape file is lossless "all the way" and not a file compressed to mp3 and then transformed to wav and then "losslessy" compressed to ape?

Is there a method to use (not my ears)? The filesize?

greetings

a true ape file

Reply #1 –
Quote
Originally posted by Luckyduck
How do I know that a downloaded ape file is lossless "all the way" and not a file compressed to mp3 and then transformed to wav and then "losslessy" compressed to ape?


Hummm... maybe checking if the high frequencies have been chopped (lowpass)?

I can't think of any other way.

a true ape file

Reply #2 –
note that this method can just tell you anything if lossy compression have occured, not if there's hasn't.
And a lowpass have had to have been used.
If you see a clear freq. cut you can be pretty certain.
you can't really know.

a true ape file

Reply #3 –
Pretty messed up world when you have to worry about someone taking a lossy compressed file and then compressing it using a lossless codec. Wouldn't the resulting file end up being bigger than the original lossy?

Then again, I knew a guy that downloaded really low bitrate mp3's and then recompressed them at a higher bitrate because he thought they would sound better this way. Never could convince him that he was terribly wrong and stupid for doing this, but it wasn't something worth spending more than a few minutes on.

a true ape file

Reply #4 –
A little while ago I discovered when an MP3 was decompressed and re-encoded with LAME that it had an extra frame for no apparant reason. Anyway, almost useless to know unless there's something contained in that extra frame...
"Something bothering you, Mister Spock?"

a true ape file

Reply #5 –
there is a practical reason, I've been downloading some ape file and I thought they didn't sound as nice.....  and I'm just curious

a true ape file

Reply #6 –
find another source to get the same audio; make sure you have a different file (bytes) same song (#seconds,...) and see if you can find another quality of the same song. This was pretty much stating out the obvious tho'

a true ape file

Reply #7 –
Cool Edit 2.
Start playing and go to freq analisys.
Pay att to the freq over 13/15 khz.
The low pass filter action depends on
the encoder/bitrates/settings and
will vary from 13 khz up to 19khz(average).
Converted ape/wav's from mp3 or other lossy
format are easy to recognize.(specially
bitrates under 192).
At higher bitrates(256 and up), the high
freq look like "almost normal", but you'll still
observe frequent "drops" and
less intensity than in an true wav/ape.


LIF

EDIT:

I've seen "fake" ape files(converted from mp3) several
times in the last months.
Before burning, I always check and simply discard the
"fake" ones.
Many people dont realized that once converted to
mp3(or any other lossy codec), you will never
have the same quality again. So, they burn CDA's
from mp3's and think have a 1:1 copy. Later
they rip and post them!!!!
"Jazz washes away the dust of everyday life" (Art Blakey)