def, format: Document how to leave PCM parameters to be decided by the server

[pulseaudio] / src / pulse / def.h

diff --git a/src/pulse/def.h b/src/pulse/def.h
index 58190cb3c0f35d931803eb17afc1cf1132aa99b6..a01c902196393fd36af09b7f0c3915368e35d07b 100644 (file)
--- a/src/pulse/def.h
+++ b/src/pulse/def.h
@@ -232,20 +232,50 @@ typedef enum pa_stream_flags {
      * specified manual buffer metrics it is recommended to update
      * them with pa_stream_set_buffer_attr() to compensate for the
      * changed frame sizes. Only supported when the server is at least
-     * PA 0.9.8. It is ignored on older servers. \since 0.9.8 */
+     * PA 0.9.8. It is ignored on older servers.
+     *
+     * When creating streams with pa_stream_new_extended(), this flag has no
+     * effect. If you specify a format with PCM encoding, and you want the
+     * server to choose the sample format, then you should leave the sample
+     * format unspecified in the pa_format_info object. This also means that
+     * you can't use pa_format_info_from_sample_spec(), because that function
+     * always sets the sample format.
+     *
+     * \since 0.9.8 */
 
     PA_STREAM_FIX_RATE = 0x0080U,
     /**< Use the sample rate of the sink, and possibly ignore the rate
      * the sample spec contains. Usage similar to
-     * PA_STREAM_FIX_FORMAT.Only supported when the server is at least
-     * PA 0.9.8. It is ignored on older servers. \since 0.9.8 */
+     * PA_STREAM_FIX_FORMAT. Only supported when the server is at least
+     * PA 0.9.8. It is ignored on older servers.
+     *
+     * When creating streams with pa_stream_new_extended(), this flag has no
+     * effect. If you specify a format with PCM encoding, and you want the
+     * server to choose the sample rate, then you should leave the rate
+     * unspecified in the pa_format_info object. This also means that you can't
+     * use pa_format_info_from_sample_spec(), because that function always sets
+     * the sample rate.
+     *
+     * \since 0.9.8 */
 
     PA_STREAM_FIX_CHANNELS = 0x0100,
     /**< Use the number of channels and the channel map of the sink,
      * and possibly ignore the number of channels and the map the
      * sample spec and the passed channel map contains. Usage similar
      * to PA_STREAM_FIX_FORMAT. Only supported when the server is at
-     * least PA 0.9.8. It is ignored on older servers. \since 0.9.8 */
+     * least PA 0.9.8. It is ignored on older servers.
+     *
+     * When creating streams with pa_stream_new_extended(), this flag has no
+     * effect. If you specify a format with PCM encoding, and you want the
+     * server to choose the channel count and/or channel map, then you should
+     * leave the channels and/or the channel map unspecified in the
+     * pa_format_info object. This also means that you can't use
+     * pa_format_info_from_sample_spec(), because that function always sets
+     * the channel count (but if you only want to leave the channel map
+     * unspecified, then pa_format_info_from_sample_spec() works, because it
+     * accepts a NULL channel map).
+     *
+     * \since 0.9.8 */
 
     PA_STREAM_DONT_MOVE = 0x0200U,
     /**< Don't allow moving of this stream to another