6 Nov
2020
6 Nov
'20
11:20 p.m.
On Fri, November 6, 2020 7:22 am, John Murphy wrote:
I think I've discovered where my levels were going
awry. I was using
timemachine to record in w64 format and converting to wav. Now, using:
jack_capture -s --channels 2 --port system:capture* -d 10 -f w64 t1w64.w64
\
& jack_capture -s --channels 2 --port system:capture* -d 10 -f wav
t1wav.wav
then:
sox --no-clobber -S t1w64.w64 -b 16 t2wav.wav
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.
The w64 vs. wav file thing is not relevant unless you are recording for
more than a couple of hours at a time. The important distinction is that
jack_capture records as single precision floating point values by default,
and the "-b 16" argument to sox converts to 16 bit integer PCM.
What does sndfile-info show about t1w64.w64 and t2wav.wav files? I tried
using sox to convert a float file I had in an Ardour project directory to
PCM, and sndfile-info reported the exact same maximum value for both.
Using the sox stat effect also displayed the same maximum and minimum for
original and converted file as well, but sndfile-info might give you some
insight into why sox did not seem to show the same value.
--
Chris Caudle