PulseAudio 16.1

Data Fields
pa_timing_info Struct Reference

A structure for all kinds of timing information of a stream. More...

`#include <def.h>`

## Data Fields
struct timeval | timestamp
| The system clock time when this timing info structure was current. More...
int | synchronized_clocks
| Non-zero if the local and the remote machine have synchronized clocks. More...
pa_usec_t | sink_usec
| Time in usecs a sample takes to be played on the sink. More...
pa_usec_t | source_usec
| Time in usecs a sample takes from being recorded to being delivered to the application. More...
pa_usec_t | transport_usec
| Estimated time in usecs a sample takes to be transferred to/from the daemon. More...
int | playing
| Non-zero when the stream is currently not underrun and data is being passed on to the device. More...
int | write_index_corrupt
| Non-zero if write_index is not up-to-date because a local write command that corrupted it has been issued in the time since this latency info was current . More...
int64_t | write_index
| Current write index into the playback buffer in bytes. More...
int | read_index_corrupt
| Non-zero if read_index is not up-to-date because a local pause or flush request that corrupted it has been issued in the time since this latency info was current. More...
int64_t | read_index
| Current read index into the playback buffer in bytes. More...
pa_usec_t | configured_sink_usec
| The configured latency for the sink. More...
pa_usec_t | configured_source_usec
| The configured latency for the source. More...
int64_t | since_underrun
| Bytes that were handed to the sink since the last underrun happened, or since playback started again after the last underrun. More...

## Detailed Description

A structure for all kinds of timing information of a stream.

See pa_stream_update_timing_info() and pa_stream_get_timing_info(). The total output latency a sample that is written with pa_stream_write() takes to be played may be estimated by sink_usec+buffer_usec+transport_usec (where buffer_usec is defined as pa_bytes_to_usec(write_index-read_index)). The output buffer which buffer_usec relates to may be manipulated freely (with pa_stream_write()'s seek argument, pa_stream_flush() and friends), the buffers sink_usec and source_usec relate to are first-in first-out (FIFO) buffers which cannot be flushed or manipulated in any way. The total input latency a sample that is recorded takes to be delivered to the application is: source_usec+buffer_usec+transport_usec-sink_usec. (Take care of sign issues!) When connected to a monitor source sink_usec contains the latency of the owning sink. The two latency estimations described here are implemented in pa_stream_get_latency().

All time values are in the sound card clock domain, unless noted otherwise. The sound card clock usually runs at a slightly different rate than the system clock.

Please note that this structure can be extended as part of evolutionary API updates at any time in any new release.

## Field Documentation

## ◆ configured_sink_usec

pa_usec_t pa_timing_info::configured_sink_usec

The configured latency for the sink.

Since
  0.9.11

## ◆ configured_source_usec

pa_usec_t pa_timing_info::configured_source_usec

The configured latency for the source.

Since
  0.9.11

## ◆ playing

int pa_timing_info::playing

Non-zero when the stream is currently not underrun and data is being passed on to the device.

Only for playback streams. This field does not say whether the data is actually already being played. To determine this check whether since_underrun (converted to usec) is larger than sink_usec.

## ◆ read_index

int64_t pa_timing_info::read_index

Current read index into the playback buffer in bytes.

Think twice before using this for seeking purposes: it might be out of date at the time you want to use it. Consider using PA_SEEK_RELATIVE_ON_READ instead.

## ◆ read_index_corrupt

int pa_timing_info::read_index_corrupt

Non-zero if read_index is not up-to-date because a local pause or flush request that corrupted it has been issued in the time since this latency info was current.

## ◆ since_underrun

int64_t pa_timing_info::since_underrun

Bytes that were handed to the sink since the last underrun happened, or since playback started again after the last underrun.

playing will tell you which case it is.

Since
  0.9.11

## ◆ sink_usec

pa_usec_t pa_timing_info::sink_usec

Time in usecs a sample takes to be played on the sink.

For playback streams and record streams connected to a monitor source.

## ◆ source_usec

pa_usec_t pa_timing_info::source_usec

Time in usecs a sample takes from being recorded to being delivered to the application.

Only for record streams.

## ◆ synchronized_clocks

int pa_timing_info::synchronized_clocks

Non-zero if the local and the remote machine have synchronized clocks.

If synchronized clocks are detected transport_usec becomes much more reliable. However, the code that detects synchronized clocks is very limited and unreliable itself.

## ◆ timestamp

struct timeval pa_timing_info::timestamp

The system clock time when this timing info structure was current.

## ◆ transport_usec

pa_usec_t pa_timing_info::transport_usec

Estimated time in usecs a sample takes to be transferred to/from the daemon.

For both playback and record streams.

## ◆ write_index

int64_t pa_timing_info::write_index

Current write index into the playback buffer in bytes.

Think twice before using this for seeking purposes: it might be out of date at the time you want to use it. Consider using PA_SEEK_RELATIVE instead.

## ◆ write_index_corrupt

int pa_timing_info::write_index_corrupt

Non-zero if write_index is not up-to-date because a local write command that corrupted it has been issued in the time since this latency info was current .

Only write commands with SEEK_RELATIVE_ON_READ and SEEK_RELATIVE_END can corrupt write_index.

The documentation for this struct was generated from the following file:

- def.h