On Sun, 3 Jan 2010, Sergei Steshenko wrote:
On Sun, 3 Jan 2010 05:47:36 -0800
Grant <emailgrant@xxxxxxxxx> wrote:
Can the conversion to S24_3LE be lossy?
- Grant
The conversion is to 24 bits. So, if the conversion is from lower numbers
of bits,it's lossless, if from higher - it's lossy.
Regards,
Sergei.
I think mpd outputs in a 32-bit format. If plughw converts that
32-bit format to S24_3LE, will it be lossy compared to the original
audio which is 16-bit or 24-bit? Or would mpd pad the 16-bit or
24-bit audio with zeros, and then plughw strips some of the zeros off?
- Grant
MPD may use as many bits as it likes, but are the bits present in the
original music file ? AFAIK not, i.e. the added buts are zeros and the
stripped bits are zeros.
It depends on how the bits are added. Usually the bits added are low order
bits-- this is to ensure that roundoff error does not keep adding noise to the
system, and to use a common calculational track no matter wha the input, and
so they use a size that is bigger then any possible. On the other hand they
may want extra headroom and add the padding at the high end instead. Now, if
the program were at all competent, they would make sure that the output was
the same as the input (ie do the stripping down internally) to make sure that
the problems feared would not occur. But then again, who knows if the authors
were competent.
Anyway, you could tell by running the input and output through sox and seeing
if the amplitude is the same. If it is, mpd behaves properly. If it is not,
then not.
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