A structure for all kinds of timing information of a stream. More...
Data Fields | |
| struct timeval | timestamp |
| The time when this timing info structure was current. | |
| int | synchronized_clocks |
| Non-zero if the local and the remote machine have synchronized clocks. | |
| pa_usec_t | sink_usec |
| Time in usecs a sample takes to be played on the sink. | |
| pa_usec_t | source_usec |
| Time in usecs a sample takes from being recorded to being delivered to the application. | |
| pa_usec_t | transport_usec |
| Estimated time in usecs a sample takes to be transferred to/from the daemon. | |
| int | playing |
| Non-zero when the stream is currently not underrun and data is being passed on to the device. | |
| 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 . | |
| int64_t | write_index |
| Current write index into the playback buffer in bytes. | |
| 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. | |
| int64_t | read_index |
| Current read index into the playback buffer in bytes. | |
| pa_usec_t | configured_sink_usec |
| The configured latency for the sink. | |
| pa_usec_t | configured_source_usec |
| The configured latency for the source. | |
| 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. | |
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(). Please note that this structure can be extended as part of evolutionary API updates at any time in any new release.
The configured latency for the sink.
The configured latency for the source.
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.
| 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 a the time you want to use it. Consider using PA_SEEK_RELATIVE_ON_READ instead.
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.
| 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.
Time in usecs a sample takes to be played on the sink.
For playback streams and record streams connected to a monitor source.
Time in usecs a sample takes from being recorded to being delivered to the application.
Only for record streams.
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.
| struct timeval pa_timing_info::timestamp |
The time when this timing info structure was current.
Estimated time in usecs a sample takes to be transferred to/from the daemon.
For both playback and record streams.
| 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 a the time you want to use it. Consider using PA_SEEK_RELATIVE instead.
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.
1.7.2