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Properties
| guint | current-level-buffers | Read |
| guint | current-level-bytes | Read |
| guint64 | current-level-time | Read |
| gboolean | flush-on-eos | Read / Write |
| GstQueueLeaky | leaky | Read / Write |
| guint | max-size-buffers | Read / Write |
| guint | max-size-bytes | Read / Write |
| guint64 | max-size-time | Read / Write |
| guint | min-threshold-buffers | Read / Write |
| guint | min-threshold-bytes | Read / Write |
| guint64 | min-threshold-time | Read / Write |
| gboolean | silent | Read / Write |
Description
Data is queued until one of the limits specified by the “max-size-buffers”, “max-size-bytes” and/or “max-size-time” properties has been reached. Any attempt to push more buffers into the queue will block the pushing thread until more space becomes available.
The queue will create a new thread on the source pad to decouple the processing on sink and source pad.
You can query how many buffers are queued by reading the “current-level-buffers” property. You can track changes by connecting to the notify::current-level-buffers signal (which like all signals will be emitted from the streaming thread). The same applies to the “current-level-time” and “current-level-bytes” properties.
The default queue size limits are 200 buffers, 10MB of data, or one second worth of data, whichever is reached first.
As said earlier, the queue blocks by default when one of the specified maximums (bytes, time, buffers) has been reached. You can set the “leaky” property to specify that instead of blocking it should leak (drop) new or old buffers.
The “underrun” signal is emitted when the queue has less data than the specified minimum thresholds require (by default: when the queue is empty). The “overrun” signal is emitted when the queue is filled up. Both signals are emitted from the context of the streaming thread.
Synopsis
Property Details
The “current-level-buffers” property
“current-level-buffers” guint
Current number of buffers in the queue.
Flags: Read
Default value: 0
The “current-level-bytes” property
“current-level-bytes” guint
Current amount of data in the queue (bytes).
Flags: Read
Default value: 0
The “current-level-time” property
“current-level-time” guint64
Current amount of data in the queue (in ns).
Flags: Read
Default value: 0
The “flush-on-eos” property
“flush-on-eos” gboolean
Discard all data in the queue when an EOS event is received, and pass on the EOS event as soon as possible (instead of waiting until all buffers in the queue have been processed, which is the default behaviour).
Flushing the queue on EOS might be useful when capturing and encoding from a live source, to finish up the recording quickly in cases when the encoder is slow. Note that this might mean some data from the end of the recording data might be lost though (never more than the configured max. sizes though).
Flags: Read / Write
Default value: FALSE
Since: 1.2
The “leaky” property
“leaky” GstQueueLeaky
Where the queue leaks, if at all.
Flags: Read / Write
Default value: Not Leaky
The “max-size-buffers” property
“max-size-buffers” guint
Max. number of buffers in the queue (0=disable).
Flags: Read / Write
Default value: 200
The “max-size-bytes” property
“max-size-bytes” guint
Max. amount of data in the queue (bytes, 0=disable).
Flags: Read / Write
Default value: 10485760
The “max-size-time” property
“max-size-time” guint64
Max. amount of data in the queue (in ns, 0=disable).
Flags: Read / Write
Default value: 1000000000
The “min-threshold-buffers” property
“min-threshold-buffers” guint
Min. number of buffers in the queue to allow reading (0=disable).
Flags: Read / Write
Default value: 0
The “min-threshold-bytes” property
“min-threshold-bytes” guint
Min. amount of data in the queue to allow reading (bytes, 0=disable).
Flags: Read / Write
Default value: 0
The “min-threshold-time” property
“min-threshold-time” guint64
Min. amount of data in the queue to allow reading (in ns, 0=disable).
Flags: Read / Write
Default value: 0
The “silent” property
“silent” gboolean
Don't emit queue signals. Makes queues more lightweight if no signals are needed.
Flags: Read / Write
Default value: FALSE
Signal Details
The “overrun” signal
void user_function (GstQueue *queue, gpointer user_data)
Reports that the buffer became full (overrun). A buffer is full if the total amount of data inside it (num-buffers, time, size) is higher than the boundary values which can be set through the GObject properties.
Flags: Run First
The “pushing” signal
void user_function (GstQueue *queue, gpointer user_data)
Reports when the queue has enough data to start pushing data again on the source pad.
Flags: Run First
The “running” signal
void user_function (GstQueue *queue, gpointer user_data)
Reports that enough (min-threshold) data is in the queue. Use this signal together with the underrun signal to pause the pipeline on underrun and wait for the queue to fill-up before resume playback.
Flags: Run First
The “underrun” signal
void user_function (GstQueue *queue, gpointer user_data)
Reports that the buffer became empty (underrun). A buffer is empty if the total amount of data inside it (num-buffers, time, size) is lower than the boundary values which can be set through the GObject properties.
Flags: Run First