Add documentation for speex rate plugin

Added the documentation for speex rate plugin.

From: Jean-Marc Valin <jean-marc.valin@usherbrooke.ca>

diff --git a/doc/Makefile.am b/doc/Makefile.am
index 5eda3bd3b43f8a67165bc1a79d201e412ca3633e..41a7ebe8efcd0688ab23868bdc7e8a04a24d6638 100644 (file)
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,2 +1,3 @@
 EXTRA_DIST = README-pcm-oss README-jack README-pulse README-maemo \
-       upmix.txt vdownmix.txt samplerate.txt a52.txt lavcrate.txt
+       upmix.txt vdownmix.txt samplerate.txt a52.txt lavcrate.txt \
+       speexrate.txt

diff --git a/doc/speexrate.txt b/doc/speexrate.txt
new file mode 100644 (file)
index 0000000..9f86e03
--- /dev/null
+++ b/doc/speexrate.txt
@@ -0,0 +1,29 @@
+Rate Converter Plugin Using Speex Resampler
+===========================================
+
+The plugin in rate subdirectory is an external rate converter using
+the Speex resampler (aka Public Parrot Hack) by Jean-Marc Valin.  You can 
+use this rate converter plugin by defining a rate PCM with "converter" 
+parameter, such as:
+
+       pcm.my_rate {
+               type rate
+               slave.pcm "hw"
+               converter "speexrate"
+       }
+
+The plug plugin has also a similar field, "rate_converter".
+
+Or, more easily, define a global variable "defaults.pcm.rate_converter",
+which is used as the default converter type by plug and rate plugins:
+
+       defaults.pcm.rate_converter "speexrate"
+
+Write the above in your ~/.asoundrc or /etc/asound.conf.
+
+The following converter types are available:
+
+  - speexrate_best     Use quality 10 (equivalent to SRC_SINC_BEST_QUALITY)
+  - speexrate_medium   Use quality 5 (equivalent to SRC_SINC_MEDIUM_QUALITY)
+  - speexrate          Use quality 3 (equivalent to SRC_SINC_FASTEST)
+