On Fri, 6 Nov 2020 20:19:02 -0500 "Tim E. Real" wrote: > On 11/6/20 10:06 AM, John Murphy wrote: > > On Fri, 6 Nov 2020 15:07:43 +0100 Fons Adriaensen wrote: > >> On Fri, Nov 06, 2020 at 01:22:42PM +0000, John Murphy wrote: > >> > >>> Then sox stat shows min/max amplitude +/- 0.5 for the wav capture and > >>> +/- 0.9 for the wav converted from w64. The converted file looks good > >>> in my editor too. > >> Still doesn't explain the difference, unless I'm missing something... > >> > > There's a loss of precision in the conversion process. Both the original > > recordings show 25 bit precision and the file sizes are the same (3.8MB). > > > > The converted file is only 16 bit and is 1.9MB. It sounds (and looks) > > louder. I doubt I could tell any loss of quality. Not explaining it. > > Just providing some facts. :) > > > Maybe this is relevant? > > According to my package manager, sox depends on libsndfile. > > On the libsndfile website: > http://www.mega-nerd.com/libsndfile/api.html#note1 > > it talks about normalization: > > > "When converting between integer data and floating point data, different > rules apply. > > The default behaviour when reading floating point data (sf_read_float() > or sf_read_double ()) > > from a file with integer data is normalisation. Regardless of whether > data in the file > > is 8, 16, 24 or 32 bit wide, the data will be read as floating point > data in the range [-1.0, 1.0]. > > Similarly, data in the range [-1.0, 1.0] will be written to an integer > PCM file so that > > a data value of 1.0 will be the largest allowable integer for the > given bit width. > > This normalisation can be turned on or off using the sf_command > <http://www.mega-nerd.com/libsndfile/command.html> interface" > > > I recall observing that this normalization does tend to make the result > 'louder'. > > Could this be what is being observed? That would seem to explain it and the output of sndfile-info appears to confirm (see my reply to Chris). Quite surprised it does that extra thing for me. Thanks all. -- Thanks again, John. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx https://lists.linuxaudio.org/listinfo/linux-audio-user
