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Original commit message from CVS: * check/Makefile.am: * check/gst/gstevents.c: (GST_START_TEST), (event_probe), (test_event), (timediff), (gstevents_suite), (main): I wrote a test! * docs/design/part-seeking.txt: Spelling correction * docs/gst/tmpl/gstevent.sgml: Docs updates. * gst/base/gstbasesink.c: (gst_base_sink_handle_object): Treat a buffer-without-newsegment the same as a receiving a newsegment not in time format, and disable syncing to the clock with a warning. * gst/gstbus.c: (gst_bus_set_sync_handler): Assert if anyone tries to replace the existing sync_handler for bus, as only the owner should be setting it. * gst/gstevent.h: Have a fixed set of custom event enums with events identified by their structure name (as in 0.8), rather than a free-for-all allowing collisions between enum values from different plugins. * gst/gstpad.c: (gst_pad_class_init): Docs change. * gst/gstqueue.c: (gst_queue_handle_sink_event): Handle out-of-band downstream events from the sending thread.
75 lines
2.1 KiB
Plaintext
75 lines
2.1 KiB
Plaintext
Seeking
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-------
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Seeking in GStreamer means configuring the pipeline for playback of the
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media between a certain start and stop time, called a segment.
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Different kinds of seeking exist:
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- immediate seeking with low latency (FLUSH seek)
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- seeking without flush, playback will start from the new
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position after all the queues are emptied with old data.
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- segment seeking with and without FLUSH, this can be used to
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implement seamless looping or NLE functionality.
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Seeking can be performed in different formats such as time, frames
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or samples.
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Seeking can be performed to an absolute position or relative to the
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current playback position.
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For seeking to work reliably, all plugins in the pipeline need to follow
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the well-defined rules in this document.
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Non segment seeking will make the pipeline emit EOS when the configured
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playback range has been played.
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Segment seeking will not emit an EOS at the end of the range but will
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post a SEGMENT_STOP message on the bus. This message is posted by the
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earliest element in the pipeline, typically a demuxer. After receiving
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the message, the application can reconnect the pipeline or issue other
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seek events in the pipeline.
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The seek can also change the playback speed of the configured segment.
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A speed of 1.0 is normal speed, 2.0 is double speed. Negative values
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mean backward playback.
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Generating seeking events
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-------------------------
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The different kinds of seeking methods and their internal workings are
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described below.
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FLUSH seeking
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-------------
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This is the most common way of performing a seek in a playback application.
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The application issues a seek on the pipeline and the new media is immediatly
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played after the seek calls returns.
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seeking without FLUSH
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---------------------
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This seek type is typically performed after issuing segment seeks to finish
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the playback of the pipeline.
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segment seeking with FLUSH
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--------------------------
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This seek is typically performed when starting seamless looping.
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segment seeking without FLUSH
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-----------------------------
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This seek is typically performed when continuing seamless looping.
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