Autres/audacity
1
0
Fork 0
mirror of https://github.com/cookiengineer/audacity synced 2025-11-23 17:30:17 +01:00
Code Issues Releases Wiki Activity

Comments about dithering in ImportAup

Browse Source
This commit is contained in:
Paul Licameli
2020-12-01 14:58:08 -05:00
parent 43310b6a1e
commit 528b57ff8e
1 changed files with 27 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
src/import/ImportAUP.cpp
View File

@@ -1573,6 +1573,8 @@ bool AUPImportFileHandle::AddSamples(const FilePath &blockFilename,
size_t framesRead = 0;
// These cases preserve the logic formerly in BlockFile.cpp,
// which was deleted at commit 98d1468.
if (channels == 1 && format == int16Sample && sf_subtype_is_integer(info.format))
{
// If both the src and dest formats are integer formats,
@@ -1624,6 +1626,18 @@ bool AUPImportFileHandle::AddSamples(const FilePath &blockFilename,
}
else
{
/*
Therefore none of the three cases above:
!(channels == 1 && format == int16Sample && sf_subtype_is_integer(info.format))
&&
!(channels == 1 && format == int24Sample && sf_subtype_is_integer(info.format))
&&
!(format == int16Sample && !sf_subtype_more_than_16_bits(info.format))
So format is not 16 bits with wider file format (third conjunct),
but still maybe it is 24 bits with float file format (second conjunct).
*/
// Otherwise, let libsndfile handle the conversion and
// scaling, and pass us normalized data as floats. We can
// then convert to whatever format we want.
@@ -1639,6 +1653,19 @@ bool AUPImportFileHandle::AddSamples(const FilePath &blockFilename,
return true;
}
/*
Dithering will happen in CopySamples if format is 24 bits.
Should that be done?
Either the file is an ordinary simple block file -- and presumably the
track was saved specifying a matching format, so format is float and
there is no dithering.
Or else this is the very unusual case of an .auf file, importing PCM data
on demand. The destination format is narrower, requiring dither, only
if the user also specified a narrow format for the track. In such a
case, dithering is right.
*/
CopySamples((samplePtr)(tmpptr + channel),
floatSample,
bufptr,