/**
* gst_clock_set_resolution:
* @clock: a #GstClock
* @resolution: The resolution to set
*
* Set the accuracy of the clock. Some clocks have the possibility to operate
* with different accuracy at the expense of more resource usage. There is
* normally no need to change the default resolution of a clock. The resolution
* of a clock can only be changed if the clock has the
* #GST_CLOCK_FLAG_CAN_SET_RESOLUTION flag set.
*
* Returns: the new resolution of the clock.
*/
GstClockTime
gst_clock_set_resolution (GstClock * clock, GstClockTime resolution)
{
GstClockPrivate *priv;
GstClockClass *cclass;
g_return_val_if_fail (GST_IS_CLOCK (clock), 0);
g_return_val_if_fail (resolution != 0, 0);
cclass = GST_CLOCK_GET_CLASS (clock);
priv = clock->priv;
if (cclass->change_resolution)
priv->resolution =
cclass->change_resolution (clock, priv->resolution, resolution);
return priv->resolution;
}
EXPORT_C
#endif
GstClockTime
gst_clock_set_resolution (GstClock * clock, GstClockTime resolution)
{
GstClockClass *cclass;
g_return_val_if_fail (GST_IS_CLOCK (clock), 0);
g_return_val_if_fail (resolution != 0, 0);
cclass = GST_CLOCK_GET_CLASS (clock);
if (cclass->change_resolution)
clock->resolution =
cclass->change_resolution (clock, clock->resolution, resolution);
return clock->resolution;
}
/**
* gst_clock_get_calibration
* @clock: a #GstClock
* @internal: a location to store the internal time
* @external: a location to store the external time
* @rate_num: a location to store the rate numerator
* @rate_denom: a location to store the rate denominator
*
* Gets the internal rate and reference time of @clock. See
* gst_clock_set_calibration() for more information.
*
* @internal, @external, @rate_num, and @rate_denom can be left %NULL if the
* caller is not interested in the values.
*
* MT safe.
*/
void
gst_clock_get_calibration (GstClock * clock, GstClockTime * internal,
GstClockTime * external, GstClockTime * rate_num, GstClockTime * rate_denom)
{
gint seq;
g_return_if_fail (GST_IS_CLOCK (clock));
do {
seq = read_seqbegin (clock);
if (rate_num)
*rate_num = clock->rate_numerator;
if (rate_denom)
*rate_denom = clock->rate_denominator;
if (external)
*external = clock->external_calibration;
if (internal)
*internal = clock->internal_calibration;
} while (read_seqretry (clock, seq));
}
EXPORT_C
#endif
void
gst_clock_get_calibration (GstClock * clock, GstClockTime * internal,
GstClockTime * external, GstClockTime * rate_num, GstClockTime * rate_denom)
{
g_return_if_fail (GST_IS_CLOCK (clock));
GST_OBJECT_LOCK (clock);
if (rate_num)
*rate_num = clock->rate_numerator;
if (rate_denom)
*rate_denom = clock->rate_denominator;
if (external)
*external = clock->external_calibration;
if (internal)
*internal = clock->internal_calibration;
GST_OBJECT_UNLOCK (clock);
}
/**
* gst_clock_set_calibration
* @clock: a #GstClock to calibrate
* @internal: a reference internal time
* @external: a reference external time
* @rate_num: the numerator of the rate of the clock relative to its
* internal time
* @rate_denom: the denominator of the rate of the clock
*
* Adjusts the rate and time of @clock. A rate of 1/1 is the normal speed of
* the clock. Values bigger than 1/1 make the clock go faster.
*
* @internal and @external are calibration parameters that arrange that
* gst_clock_get_time() should have been @external at internal time @internal.
* This internal time should not be in the future; that is, it should be less
* than the value of gst_clock_get_internal_time() when this function is called.
*
* Subsequent calls to gst_clock_get_time() will return clock times computed as
* follows:
*
* <programlisting>
* time = (internal_time - internal) * rate_num / rate_denom + external
* </programlisting>
*
* This formula is implemented in gst_clock_adjust_unlocked(). Of course, it
* tries to do the integer arithmetic as precisely as possible.
*
* Note that gst_clock_get_time() always returns increasing values so when you
* move the clock backwards, gst_clock_get_time() will report the previous value
* until the clock catches up.
*
* MT safe.
*/
void
gst_clock_set_calibration (GstClock * clock, GstClockTime internal, GstClockTime
external, GstClockTime rate_num, GstClockTime rate_denom)
{
g_return_if_fail (GST_IS_CLOCK (clock));
g_return_if_fail (rate_num != GST_CLOCK_TIME_NONE);
g_return_if_fail (rate_denom > 0 && rate_denom != GST_CLOCK_TIME_NONE);
write_seqlock (clock);
GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock,
"internal %" GST_TIME_FORMAT " external %" GST_TIME_FORMAT " %"
G_GUINT64_FORMAT "/%" G_GUINT64_FORMAT " = %f", GST_TIME_ARGS (internal),
GST_TIME_ARGS (external), rate_num, rate_denom,
gst_guint64_to_gdouble (rate_num) / gst_guint64_to_gdouble (rate_denom));
clock->internal_calibration = internal;
clock->external_calibration = external;
clock->rate_numerator = rate_num;
clock->rate_denominator = rate_denom;
write_sequnlock (clock);
}
EXPORT_C
#endif
GstClockTime
gst_clock_get_time (GstClock * clock)
{
GstClockTime ret;
g_return_val_if_fail (GST_IS_CLOCK (clock), GST_CLOCK_TIME_NONE);
ret = gst_clock_get_internal_time (clock);
GST_OBJECT_LOCK (clock);
/* this will scale for rate and offset */
ret = gst_clock_adjust_unlocked (clock, ret);
GST_OBJECT_UNLOCK (clock);
GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock, "adjusted time %" GST_TIME_FORMAT,
GST_TIME_ARGS (ret));
return ret;
}
/**
* gst_clock_get_time
* @clock: a #GstClock to query
*
* Gets the current time of the given clock. The time is always
* monotonically increasing and adjusted according to the current
* offset and rate.
*
* Returns: the time of the clock. Or GST_CLOCK_TIME_NONE when
* given invalid input.
*
* MT safe.
*/
GstClockTime
gst_clock_get_time (GstClock * clock)
{
GstClockTime ret;
gint seq;
g_return_val_if_fail (GST_IS_CLOCK (clock), GST_CLOCK_TIME_NONE);
do {
/* reget the internal time when we retry to get the most current
* timevalue */
ret = gst_clock_get_internal_time (clock);
seq = read_seqbegin (clock);
/* this will scale for rate and offset */
ret = gst_clock_adjust_unlocked (clock, ret);
} while (read_seqretry (clock, seq));
GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, clock, "adjusted time %" GST_TIME_FORMAT,
GST_TIME_ARGS (ret));
return ret;
}
/**
* gst_clock_add_observation_unapplied:
* @clock: a #GstClock
* @slave: a time on the slave
* @master: a time on the master
* @r_squared: (out): a pointer to hold the result
* @internal: (out) (allow-none): a location to store the internal time
* @external: (out) (allow-none): a location to store the external time
* @rate_num: (out) (allow-none): a location to store the rate numerator
* @rate_denom: (out) (allow-none): a location to store the rate denominator
*
* Add a clock observation to the internal slaving algorithm the same as
* gst_clock_add_observation(), and return the result of the master clock
* estimation, without updating the internal calibration.
*
* The caller can then take the results and call gst_clock_set_calibration()
* with the values, or some modified version of them.
*
* Since: 1.6
*/
gboolean
gst_clock_add_observation_unapplied (GstClock * clock, GstClockTime slave,
GstClockTime master, gdouble * r_squared,
GstClockTime * internal, GstClockTime * external,
GstClockTime * rate_num, GstClockTime * rate_denom)
{
GstClockTime m_num, m_denom, b, xbase;
GstClockPrivate *priv;
guint n;
g_return_val_if_fail (GST_IS_CLOCK (clock), FALSE);
g_return_val_if_fail (r_squared != NULL, FALSE);
priv = clock->priv;
GST_CLOCK_SLAVE_LOCK (clock);
GST_CAT_LOG_OBJECT (GST_CAT_CLOCK, clock,
"adding observation slave %" GST_TIME_FORMAT ", master %" GST_TIME_FORMAT,
GST_TIME_ARGS (slave), GST_TIME_ARGS (master));
priv->times[(4 * priv->time_index)] = slave;
priv->times[(4 * priv->time_index) + 2] = master;
priv->time_index++;
if (G_UNLIKELY (priv->time_index == priv->window_size)) {
priv->filling = FALSE;
priv->time_index = 0;
}
if (G_UNLIKELY (priv->filling && priv->time_index < priv->window_threshold))
goto filling;
n = priv->filling ? priv->time_index : priv->window_size;
if (!_priv_gst_do_linear_regression (priv->times, n, &m_num, &m_denom, &b,
&xbase, r_squared))
goto invalid;
GST_CLOCK_SLAVE_UNLOCK (clock);
GST_CAT_LOG_OBJECT (GST_CAT_CLOCK, clock,
"adjusting clock to m=%" G_GUINT64_FORMAT "/%" G_GUINT64_FORMAT ", b=%"
G_GUINT64_FORMAT " (rsquared=%g)", m_num, m_denom, b, *r_squared);
if (internal)
*internal = xbase;
if (external)
*external = b;
if (rate_num)
*rate_num = m_num;
if (rate_denom)
*rate_denom = m_denom;
return TRUE;
filling:
{
GST_CLOCK_SLAVE_UNLOCK (clock);
return FALSE;
}
invalid:
{
/* no valid regression has been done, ignore the result then */
GST_CLOCK_SLAVE_UNLOCK (clock);
return TRUE;
}
}
