ALSA support for uniform audio. ALSA and OSS support now shares the

[disorder] / lib / uaudio.c

diff --git a/lib/uaudio.c b/lib/uaudio.c
index aa00f6619002f05aed80b4298da037a99ffe05df..f18af090418d8f8336a9e61b2d561b44702aa27a 100644 (file)
--- a/lib/uaudio.c
+++ b/lib/uaudio.c
@@ -28,6 +28,26 @@
 /** @brief Options for chosen uaudio API */
 static hash *uaudio_options;
 
+/** @brief Sample rate (Hz) */
+int uaudio_rate;
+
+/** @brief Bits per channel */
+int uaudio_bits;
+
+/** @brief Number of channels */
+int uaudio_channels;
+
+/** @brief Whether samples are signed or unsigned */
+int uaudio_signed;
+
+/** @brief Sample size in bytes
+ *
+ * NB one sample is a single point sample; up to @c uaudio_channels samples may
+ * play at the same time through different speakers.  Thus this value is
+ * independent of @ref uaudio_channels.
+ */
+size_t uaudio_sample_size;
+
 /** @brief Set a uaudio option */
 void uaudio_set(const char *name, const char *value) {
   if(!uaudio_options)
@@ -44,6 +64,31 @@ const char *uaudio_get(const char *name) {
   return value ? xstrdup(value) : NULL;
 }
 
+/** @brief Set sample format 
+ * @param rate Sample rate in KHz
+ * @param channels Number of channels (i.e. 2 for stereo)
+ * @param bits Number of bits per channel (typically 8 or 16)
+ * @param signed_ True for signed samples, false for unsigned
+ *
+ * Sets @ref uaudio_rate, @ref uaudio_channels, @ref uaudio_bits, @ref
+ * uaudio_signed and @ref uaudio_sample_size.
+ *
+ * Currently there is no way to specify non-native endian formats even if the
+ * underlying API can conveniently handle them.  Actually this would be quite
+ * convenient for playrtp, so it might be added at some point.
+ *
+ * Not all APIs can support all sample formats.  Generally the @c start
+ * function will do some error checking but some may be deferred to the point
+ * the device is opened (which might be @c activate).
+ */
+void uaudio_set_format(int rate, int channels, int bits, int signed_) {
+  uaudio_rate = rate;
+  uaudio_channels = channels;
+  uaudio_bits = bits;
+  uaudio_signed = signed_;
+  uaudio_sample_size = bits / CHAR_BIT;
+}
+
 /** @brief List of known APIs
  *
  * Terminated by a null pointer.