:: Frank Klemm <[EMAIL PROTECTED]> wrote:
:: >> I've been doing some tests on the accuracy of decoder implementations.
:: >
:: > A full quality-optimized decoder will always fail the test.
:: >
:: > The "round to the nearest integer" is the worst thing you can do.
::
:: I don't understand. What are you talking about?
::
Quantization noise. One of the most ugliest noises in the world
sinse the Neanderthal man's has gone.
In the 80's quanization noise was the reason why a lot of CDs sounds so
worse and records so good. Current up-to-date HQ ADC and DAC converter have
no problems with dirty quantization noise. But in the era of computer sound I
often hear this special kind of noise again due to a lack of understandig
the problem.
:: Many quality decoders (e.g. mpg123) pass the test without trouble.
::
This isn't the matter.
:: Who is rounding what to the nearest integer?
::
If the Output is a AIFF floating point PCM file, there is no rounding to the
nearest integer (in the first approach). Otherwise you have to quantize
the result of the MP3 decoding process. The most often used (and worst)
operator for that is the "round-to-nearest-integer" quanization operator.
It generates the best technical SNR and the worst audible SNR.
May be a mail bomb of 200 KB for an example? (1 MP3, 2 programs, script +
description). Or should I upload the examples to an URL?
This would ease some explainations.
--
Mit freundlichen Gr��en
Frank Klemm
eMail | [EMAIL PROTECTED] home: [EMAIL PROTECTED]
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