mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-12-25 09:40:37 +00:00
8377afc0ba
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.
74 lines
2.1 KiB
Text
74 lines
2.1 KiB
Text
Seeking
|
|
-------
|
|
|
|
Seeking in GStreamer means configuring the pipeline for playback of the
|
|
media between a certain start and stop time, called a segment.
|
|
|
|
Different kinds of seeking exist:
|
|
|
|
- immediate seeking with low latency (FLUSH seek)
|
|
- seeking without flush, playback will start from the new
|
|
position after all the queues are emptied with old data.
|
|
- segment seeking with and without FLUSH, this can be used to
|
|
implement seamless looping or NLE functionality.
|
|
|
|
Seeking can be performed in different formats such as time, frames
|
|
or samples.
|
|
|
|
Seeking can be performed to an absolute position or relative to the
|
|
current playback position.
|
|
|
|
For seeking to work reliably, all plugins in the pipeline need to follow
|
|
the well-defined rules in this document.
|
|
|
|
Non segment seeking will make the pipeline emit EOS when the configured
|
|
playback range has been played.
|
|
|
|
Segment seeking will not emit an EOS at the end of the range but will
|
|
post a SEGMENT_STOP message on the bus. This message is posted by the
|
|
earliest element in the pipeline, typically a demuxer. After receiving
|
|
the message, the application can reconnect the pipeline or issue other
|
|
seek events in the pipeline.
|
|
|
|
The seek can also change the playback speed of the configured segment.
|
|
A speed of 1.0 is normal speed, 2.0 is double speed. Negative values
|
|
mean backward playback.
|
|
|
|
|
|
Generating seeking events
|
|
-------------------------
|
|
|
|
|
|
|
|
|
|
|
|
The different kinds of seeking methods and their internal workings are
|
|
described below.
|
|
|
|
|
|
FLUSH seeking
|
|
-------------
|
|
|
|
This is the most common way of performing a seek in a playback application.
|
|
The application issues a seek on the pipeline and the new media is immediatly
|
|
played after the seek calls returns.
|
|
|
|
|
|
seeking without FLUSH
|
|
---------------------
|
|
|
|
This seek type is typically performed after issuing segment seeks to finish
|
|
the playback of the pipeline.
|
|
|
|
|
|
segment seeking with FLUSH
|
|
--------------------------
|
|
|
|
This seek is typically performed when starting seamless looping.
|
|
|
|
|
|
segment seeking without FLUSH
|
|
-----------------------------
|
|
|
|
This seek is typically performed when continuing seamless looping.
|
|
|