roar_vs_sync(3) RoarAudio Programmer's Manual roar_vs_sync(3)NAME
roar_vs_sync - Sync VS object with server
SYNOPSIS
#include <roaraudio.h>
int roar_vs_sync (roar_vs_t * vss, int wait, int * error);
DESCRIPTION
This function syncs the local data buffers with the server by flushing them. The parameter wait is used to tell the function if it should
also wait for the flushed data to be played (sometimes called drain by other sound systems). This mode is not recommended expect at end of
stream as it will result in buffer underruns.
This function does only flush IO buffers not the ring buffers in buffered mode. Use roar_vs_iterate(3) or roar_vs_run(3) to do this.
PARAMETERS
vss The VS object to be synced.
wait Specifies if the calls should block untill all data has been played. Must be ROAR_VS_WAIT or ROAR_VS_NOWAIT.
error This is a pointer to a integer used to store the error value in case of error. This can be NULL if not used but it is very recom-
mended to use this error value to report good error messages to the user.
RETURN VALUE
On success these calls return 0. On error, -1 is returned.
NOTES
This function uses the WAIT protocol command if wait is set to ROAR_VS_WAIT. This is not supported by all servers.
EXAMPLES
FIXME
SEE ALSO roarvs(7), libroar(7), RoarAudio(7).
RoarAudio May 2011 roar_vs_sync(3)
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roar_vs_position(3) RoarAudio Programmer's Manual roar_vs_position(3)NAME
roar_vs_position, roar_vs_latency, roar_vs_latency2 - Get stream position information
SYNOPSIS
#include <roaraudio.h>
ssize_t roar_vs_position(roar_vs_t * vss, int backend, int * error);
roar_mus_t roar_vs_latency(roar_vs_t * vss, int backend, int * error);
roar_mus_t roar_vs_latency2(roar_vs_t * vss, int backend, int wait, int * error);
DESCRIPTION
roar_vs_position() returns the current server site position of the stream plus the current offset for the selected backend.
roar_vs_latency() returns the latency between the client site stream position and the server site position plus the latency by the backend.
Use of roar_vs_latency() is not recommended as it requires the codec to use a true constant bit rate.
roar_vs_latency2() is perfectly equivalent to roar_vs_latency() expect that it takes the additional parameter wait. The wait parameter may
have the values ROAR_VS_WAIT, ROAR_VS_NOWAIT and ROAR_VS_ASYNC. If it is ROAR_VS_WAIT the function does the same as roar_vs_latency(). If
the parameter is ROAR_VS_NOWAIT roar_vs_latency2() will return interpolated data based on old data collected by calls to roar_vs_latency(),
roar_vs_latency2() or roar_vs_position(). ROAR_VS_ASYNC is used to trigger asyncron updates to this internal state. Asyncron operations
need to be enabled before they can be used. See roar_vs_ctl(3).
Calling these functions too often will result in bad performance and incorrect data (pool interval smaller than server response time).
Polling up to 20 times per second shoudn't be a problem.
PARAMETERS
vss The VS object to be used.
backend
The backend used for correction. This can be a stream ID of the stream to use as backend or one of the special values defined by the
constants ROAR_VS_BACKEND_*. ROAR_VS_BACKEND_NONE is used to ask for no correction. ROAR_VS_BACKEND_DEFAULT is used to ask for the
default correction. This should be used in all common cases. ROAR_VS_BACKEND_FIRST is used to ask for correction based on the first
primary stream on the same mixer.
wait Tells the API if the call should wait or not. Must be ROAR_VS_WAIT, ROAR_VS_NOWAIT or ROAR_VS_ASYNC.
error This is a pointer to a integer used to store the error value in case of error. This can be NULL if not used but it is very recom-
mended to use this error value to report good error messages to the user.
RETURN VALUE
roar_vs_position() returns the stream position on success and -1 on error. Stream position is the current position of the stream in units
of samples (not frames!).
roar_vs_latency() returns the stream latency on success and zero on error. However zero is a valid value. In case of error error is set to
the error. In case of no error but zero latency error is cleared (set to ROAR_ERROR_NONE). Latency is retruned in mu-seconds (1/10^-6s).
EXAMPLES
FIXME
SEE ALSO roarvs(7), libroar(7), RoarAudio(7).
RoarAudio June 2011 roar_vs_position(3)