[Flac] FLAC: compression silence frames

[Harry Sack]

hi,

I was wondering how perfect silence frames (no audio at all) in a PCM stream
are encoded by the flac encoder.
Suppose I have a PCM audio file with some perfect silence frames in the
beginning and at the end of the audio recording and suppose I have the same
audio file but without the silence frames in the beginning and at the end
(so the second file is identical except for the silence frames in the
beginning and at the end of the stream).
How does the flac encoder encodes silence frames? Is there actually used
some space to store these? E.g. I was thinking it could do something like
storing an empty metadata block, with some identifier in it that tells it's
an empty frame, for each empty frame read in the PCM audio stream.

So basically my question is: will compressing a PCM audio file *with*
silence frames in the beginning/at the end give me +/- the same filesize as
compressing the same audio file but *without* the silence frames in the
beginning/at the end, because it's only some extra 'silence' that is
encoded? I can of course test this on some files but I wanted to know how
the flac encoder encodes internally silence frames, so I have a better
understand of this.


I also had a similar question: what kind of audio will give the least
compression ratio? Is this white noise or am I wrong?

thx in advance!
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