From b8a729a00f170241599e670ee3f3f65457b4320f Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 7 Apr 2006 01:29:33 +0000 Subject: * update docs for reworked latency API * rename pa_latency_info to pa_timing_info, since that describes better what it is. Most people will only use pa_stream_get_time() anyway git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@651 fefdeb5f-60dc-0310-8127-8f9354f1896f --- src/polyp/stream.h | 46 ++++++++++++++++++++++++++++++++++------------ 1 file changed, 34 insertions(+), 12 deletions(-) (limited to 'src/polyp/stream.h') diff --git a/src/polyp/stream.h b/src/polyp/stream.h index 99284ba3..ce041986 100644 --- a/src/polyp/stream.h +++ b/src/polyp/stream.h @@ -130,8 +130,11 @@ size_t pa_stream_readable_size(pa_stream *p); /** Drain a playback stream. Use this for notification when the buffer is empty */ pa_operation* pa_stream_drain(pa_stream *s, pa_stream_success_cb_t cb, void *userdata); -/** Update the latency info of a stream */ -pa_operation* pa_stream_update_latency_info(pa_stream *p, pa_stream_success_cb_t cb, void *userdata); +/** Request a timing info structure update for a stream. Use + * pa_stream_get_timing_info() to get access to the raw timing data, + * or pa_stream_get_time() or pa_stream_get_latency() to get cleaned + * up values. */ +pa_operation* pa_stream_update_timing_info(pa_stream *p, pa_stream_success_cb_t cb, void *userdata); /** Set the callback function that is called whenever the state of the stream changes */ void pa_stream_set_state_callback(pa_stream *s, pa_stream_notify_cb_t cb, void *userdata); @@ -171,20 +174,39 @@ pa_operation* pa_stream_trigger(pa_stream *s, pa_stream_success_cb_t cb, void *u pa_operation* pa_stream_set_name(pa_stream *s, const char *name, pa_stream_success_cb_t cb, void *userdata); /** Return the current playback/recording time. This is based on the - * counter accessible with pa_stream_get_counter(). This function - * requires a pa_latency_info structure as argument, which should be - * acquired using pa_stream_get_latency(). \since 0.6 */ + * data in the timing info structure returned by + * pa_stream_get_timing_info(). This function will usually only return + * new data if a timing info update has been recieved. Only if timing + * interpolation has been requested (PA_STREAM_INTERPOLATE_TIMING) + * the data from the last timing update is used for an estimation of + * the current playback/recording time based on the local time that + * passed since the timing info structure has been acquired. The time + * value returned by this function is guaranteed to increase + * monotonically. (that means: the returned value is always greater or + * equal to the value returned on the last call) This behaviour can + * be disabled by using PA_STREAM_NOT_MONOTONOUS. This may be + * desirable to deal better with bad estimations of transport + * latencies, but may have strange effects if the application is not + * able to deal with time going 'backwards'. \since 0.6 */ int pa_stream_get_time(pa_stream *s, pa_usec_t *r_usec); -/** Return the total stream latency. Thus function requires a - * pa_latency_info structure as argument, which should be aquired - * using pa_stream_get_latency(). In case the stream is a monitoring - * stream the result can be negative, i.e. the captured samples are - * not yet played. In this case *negative is set to 1. \since 0.6 */ +/** Return the total stream latency. This function is based on + * pa_stream_get_time(). In case the stream is a monitoring stream the + * result can be negative, i.e. the captured samples are not yet + * played. In this case *negative is set to 1. \since 0.6 */ int pa_stream_get_latency(pa_stream *s, pa_usec_t *r_usec, int *negative); -/** Return the latest latency data. \since 0.8 */ -const pa_latency_info* pa_stream_get_latency_info(pa_stream *s); +/** Return the latest raw timing data structure. The returned pointer + * points to an internal read-only instance of the timing + * structure. The user should make a copy of this structure if he + * wants to modify it. An in-place update to this data structure may + * be requested using pa_stream_update_timing_info(). If no + * pa_stream_update_timing_info() call was issued before, this + * function will fail with PA_ERR_NODATA. Please note that the + * write_index member field (and only this field) is updated on each + * pa_stream_write() call, not just when a timing update has been + * recieved. \since 0.8 */ +const pa_timing_info* pa_stream_get_timing_info(pa_stream *s); /** Return a pointer to the stream's sample specification. \since 0.6 */ const pa_sample_spec* pa_stream_get_sample_spec(pa_stream *s); -- cgit