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"z1x2c3v4z1x2c3v4", <br>
<br>
<font face="Courier New, Courier, monospace">I think a sine wave is
not the best way to test a compression algorithm since the only
uncorrelated component is the quantizing error, which is very
small.<br>
<br>
First of all, my test for a 100 % 440 Hz tone yields 24.10 %
instead of 30.66 % as yours.<br>
<br>
Second, for 16 bit, 44100 Hz the slope is so large that if the
first sample is 0 then the second sample is about 1854 (being 100%
= 32767). This means that atenuating it to a 5 % and then
multiplying by 20 probably will recover the signal accurately.<br>
<br>
But if instead of a full scale sine wave you generate a signal
that starts being a sine wave of an amplitiude equal to <br>
<br>
10 / 32767 = 0.00030518<br>
<br>
(equivalent to an amplitude -70.3087 dB) <br>
<br>
and then, after, say, 10 s, follows a full scale (100 % = 0 dB)
sine wave, then you'll find that the decoded signal is different
from the original one if you apply your method, since normalizing
to a anythig but 100 % will render the first part severely and
unrecoverably distorted. And normalizing to a 5 % actually will
make the signal vanish, so no matter by how much you multiply it,
it will keep being 0.<br>
<br>
Federico Miyara<br>
<br>
</font><br>
<br>
<div class="moz-cite-prefix">On 19/08/2017 18:37, z1x2c3v4z1x2c3v4
wrote:<br>
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<p>Hi FLAC team.</p>
<p><br>
</p>
<p>I feel I have found a super high compression way of FLAC. I
have tested a 1 hour WAV file of 440HTZ with a 5,25,50,75,100
normalize volume preset. This dramatically changes the
compression size of the end FLAC file even though the WAV file
size is identical for all 5 WAV files. Only the volume is
different. When you renormalize the WAV to its original volume
the file is still 100% original.</p>
<p><br>
</p>
<p>My tests are the following.</p>
<p>source file WAV. 1 hour 440HTZ tone. 600MB.</p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;">volume
at 100. FLAC </span><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji", NotoColorEmoji,
"Segoe UI Symbol", "Android Emoji",
EmojiSymbols; font-size: 16px;">file size is 184MB.</span><br>
</p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;">volume
at 75. FLAC </span><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji", NotoColorEmoji,
"Segoe UI Symbol", "Android Emoji",
EmojiSymbols; font-size: 16px;">file size is 166MB.</span><br>
</p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;">volume
at 50. FLAC </span><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji", NotoColorEmoji,
"Segoe UI Symbol", "Android Emoji",
EmojiSymbols; font-size: 16px;">file size is 143MB.</span><br>
</p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;">volume
at 25. FLAC </span><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji", NotoColorEmoji,
"Segoe UI Symbol", "Android Emoji",
EmojiSymbols; font-size: 16px;">file size is 109MB.</span><br>
</p>
<p>volume at 5. FLAC file size is 96MB.</p>
<p><br>
</p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI
Symbol", "Android Emoji", EmojiSymbols;
font-size: 16px;"><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji",
NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size:
16px;">From184MB to 96MB.</span></span></span></span></p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI
Symbol", "Android Emoji", EmojiSymbols;
font-size: 16px;"><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji",
NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size:
16px;">As you can see from the full 100
normalize volume to the 5 normalize volume it is half
the file size.</span></span></span></span></p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI
Symbol", "Android Emoji", EmojiSymbols;
font-size: 16px;"><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji",
NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size:
16px;">So to put it. I think that you should have your
compression of FLAC to also include a normalize volume
shift to further compress the end product. Either have
a default setting or allow a user to input an option
in the command line arguments to add
a normalize volume value. Then to uncompress it back
to a WAV file FLAC would read the volume header in the
FLAC file to apply the WAV original normalize volume
and expand it back to its original state. </span></span></span></span></p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI
Symbol", "Android Emoji", EmojiSymbols;
font-size: 16px;"><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji",
NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size:
16px;"><br>
</span></span></span></span></p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI
Symbol", "Android Emoji", EmojiSymbols;
font-size: 16px;"><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji",
NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size:
16px;">Then have the FLAC decoder for all the players
out there to read the volume header so to play the
FLAC at the WAV original normalize volume.</span></span></span></span></p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI
Symbol", "Android Emoji", EmojiSymbols;
font-size: 16px;"><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji",
NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size:
16px;"><br>
</span></span></span></span></p>
<p><span style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;"><span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI
Symbol", "Android Emoji", EmojiSymbols;
font-size: 16px;"><span style="font-family: Calibri,
Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji",
NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size:
16px;">I hope I have helped to develop FLAC further.</span></span></span></span></p>
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