Downsampling before brutefir, buffer underflow for 192 kHz files

[Dave Cook]

I have a single filter with a sample rate of 48000, so I want to downsample everything to 48000 samples/sec before passing it on to brutefir.   I created a template-flac-48000.conf in /etc/squeezebox/BrutefirDRC with the entry

flc flc *  b8:27:eb:33:ef:c4

    # IFT:{START=trim %t}D:{RESAMPLE=rate -v -L -s}

    [sox] -q -D -t flac $FILE$ -t wavpcm -c 2 -3 -e signed-integer - $START$ $LOUDNESS$ rate -v -L -s 48000 | [brutefirwrapper] b8:27:eb:33:ef:c4 /etc/squeezeboxserver/BrutefirDrc/settings/filter-b8_27_eb_33_ef_c4 | [sox] -q -D -t wavpcm - -t flac -C 0 -

Is this the right way to do this?  I'm guessing here.

This seems to work except that I get dropouts with 192k files.  I assume that the resampling can't keep up.  I do get an underflow message in the brutefir.log:

Output follows (2.071s)

Internal resolution is 64 bit floating point.

SSE2 capability detected -- optimisation enabled.

Creating 4 FFTW plans of size 16384...finished.

Loading 2 coefficient sets...finished.

Estimated CPU clock rate is 3311.971 MHz. CPU count is 4.

Filters in process 0: 0 

Filters in process 1: 1 

Audio processing starts now

Readahead complete (2.221s)

File I/O: Write failed: Broken pipe.

I/O module failed to write due to buffer underflow, aborting.

I tried added "--multi-threaded --buffer 131072" as suggested in the template file, but no luck.  This is a quad core Xeon, so I think it should be able to handle this.

Thanks for any hints,

Dave Cook

[dav...@gmail.com]

OK, to answer my own question, I finally figured out that the plugin will resample filters on the fly for you, once you correct the path to the sox binary in the brutefirwrapper helper script (line 204).

Dave Cook