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| author | Georg Brandl <georg@python.org> | 2008-03-24 09:34:34 (GMT) |
|---|---|---|
| committer | Georg Brandl <georg@python.org> | 2008-03-24 09:34:34 (GMT) |
| commit | 9bdead0aed698aea001a9d5ace63e96e904d6fa3 (patch) | |
| tree | bc31a92594f3c8f4330a2eb04fd525272e1aedaf /Doc/library | |
| parent | b72233ce6303aabe7960170f98c5626771751fe7 (diff) | |
| download | cpython-9bdead0aed698aea001a9d5ace63e96e904d6fa3.zip cpython-9bdead0aed698aea001a9d5ace63e96e904d6fa3.tar.gz cpython-9bdead0aed698aea001a9d5ace63e96e904d6fa3.tar.bz2 | |
#1700821: add a note to audioop docs about signedness of sample formats.
Diffstat (limited to 'Doc/library')
| -rw-r--r-- | Doc/library/audioop.rst | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Doc/library/audioop.rst b/Doc/library/audioop.rst index f6d762f..02bd755 100644 --- a/Doc/library/audioop.rst +++ b/Doc/library/audioop.rst @@ -141,6 +141,18 @@ The module defines the following variables and functions: Convert samples between 1-, 2- and 4-byte formats. + .. note:: + + In some audio formats, such as .WAV files, 16 and 32 bit samples are + signed, but 8 bit samples are unsigned. So when converting to 8 bit wide + samples for these formats, you need to also add 128 to the result:: + + new_frames = audioop.lin2lin(frames, old_width, 1) + new_frames = audioop.bias(new_frames, 1, 128) + + The same, in reverse, has to be applied when converting from 8 to 16 or 32 + bit width samples. + .. function:: lin2ulaw(fragment, width) |