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int pa_stream_get_latency ( pa_stream s,
pa_usec_t r_usec,
int *  negative 

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.

If no timing information has been recieved yet this call will return PA_ERR_NODATA. For more details see pa_stream_get_timing_info() and pa_stream_get_time().

Definition at line 2294 of file stream.c.

References PA_ERR_BADSTATE, PA_ERR_FORKED, PA_ERR_NODATA, PA_STREAM_PLAYBACK, PA_STREAM_READY, PA_STREAM_RECORD, PA_STREAM_UPLOAD, pa_timing_info::read_index, pa_timing_info::read_index_corrupt, pa_timing_info::write_index, and pa_timing_info::write_index_corrupt.

    pa_usec_t t, c;
    int r;
    int64_t cindex;

    pa_assert(PA_REFCNT_VALUE(s) >= 1);

    PA_CHECK_VALIDITY(s->context, !pa_detect_fork(), PA_ERR_FORKED);
    PA_CHECK_VALIDITY(s->context, s->direction != PA_STREAM_UPLOAD, PA_ERR_BADSTATE);
    PA_CHECK_VALIDITY(s->context, s->timing_info_valid, PA_ERR_NODATA);
    PA_CHECK_VALIDITY(s->context, s->direction != PA_STREAM_PLAYBACK || !s->timing_info.write_index_corrupt, PA_ERR_NODATA);
    PA_CHECK_VALIDITY(s->context, s->direction != PA_STREAM_RECORD || !s->timing_info.read_index_corrupt, PA_ERR_NODATA);

    if ((r = pa_stream_get_time(s, &t)) < 0)
        return r;

    if (s->direction == PA_STREAM_PLAYBACK)
        cindex = s->timing_info.write_index;
        cindex = s->timing_info.read_index;

    if (cindex < 0)
        cindex = 0;

    c = pa_bytes_to_usec((uint64_t) cindex, &s->sample_spec);

    if (s->direction == PA_STREAM_PLAYBACK)
        *r_usec = time_counter_diff(s, c, t, negative);
        *r_usec = time_counter_diff(s, t, c, negative);

    return 0;

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