tools: add pw-audioconvert

Takes an input file, processes it with audioconvert and writes to an
output file. Can be used to test all audioconvert features such as
resample, channelmix, filter-graph, format conversion, dither, etc.

Boilerplate written by Claude.

doc/dox/programs/index.md

@@ -4,6 +4,7 @@ Manual pages:
 
 - \subpage page_man_pipewire_1
 - \subpage page_man_pipewire-pulse_1
+- \subpage page_man_pw-audioconvert_1
 - \subpage page_man_pw-cat_1
 - \subpage page_man_pw-cli_1
 - \subpage page_man_pw-config_1

doc/dox/programs/pw-audioconvert.1.md

@@ -0,0 +1,62 @@
+\page page_man_pw-audioconvert_1 pw-audioconvert
+
+The PipeWire audioconvert utility
+
+# SYNOPSIS
+
+**pw-audioconvert** \[*OPTIONS*\] *INFILE* *OUTFILE*
+
+# DESCRIPTION
+
+Use the PipeWire audioconvert to convert input file to output file,
+following the given options.
+
+This is useful only for doing audio conversion but also apply effects
+on the audio using a filter-graph.
+
+It understands all audio file formats supported by `libsndfile` for input
+and output. The filename extension is used to guess the output file
+container and format with the WAV file format as the default.
+
+# OPTIONS
+
+\par -r RATE | \--rate=RATE
+Output sample rate. Default the same as the input sample rate.
+
+\par -f FORMAT | \--format=FORMAT
+Output sample format (s8 | s16 | s32 | f32 | f64). Default the same
+as the input format.
+
+\par -b BLOCKSIZE | \--blocksize=BLOCKSIZE
+Number of samples per iteration (default 4096)
+
+\par -P PROPERTIES | \--properties=PROPERTIES
+Set extra stream properties as a JSON object. One can also use @filename to
+read the JSON object with properties from filename.
+
+\par -c CHANNELS | \--channels=CHANNELS
+The number of output channels, default the same as the input.
+
+\par \--channel-map=VALUE
+The channelmap. Possible values include are either a predefined channel layout
+such as **Mono**, **Stereo**, **2.1**, **Quad**, **2.2**, **5.1**,
+or comma separated array of channel names such as **FL,FR**.
+
+\par -h
+Show help.
+
+\par -v
+Verbose operation.
+
+# EXAMPLES
+
+**pw-audioconvert** -r 48000 -f s32 in.wav out.wav
+
+# AUTHORS
+
+The PipeWire Developers <$(PACKAGE_BUGREPORT)>;
+PipeWire is available from <$(PACKAGE_URL)>
+
+# SEE ALSO
+
+\ref page_man_pipewire_1 "pipewire(1)"