mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-07-17 11:58:23 +00:00
c4abf79f02
Original commit message from CVS: * docs/design/part-events.txt: * docs/design/part-gstpipeline.txt: * docs/design/part-messages.txt: * docs/design/part-overview.txt: * docs/design/part-seeking.txt: * docs/design/part-states.txt: * docs/design/part-trickmodes.txt: * docs/manual/advanced-position.xml: Small docs updates. * gst/gstobject.h: People think !! is ugly, this looks better. * gst/gstpad.c: (gst_pad_set_blocked_async): Remove !! since it's fixed elsewhere now.
101 lines
2.9 KiB
Plaintext
101 lines
2.9 KiB
Plaintext
Messages
|
|
--------
|
|
|
|
Messages are refcounted lightweight objects to signal the application
|
|
of pipeline events.
|
|
|
|
Messages are implemented as a subclass of GstMiniObject with a generic
|
|
GstStructure as the content. This allows for writing custom messages without
|
|
requiring an API change while allowing a wide range of different types
|
|
of messages.
|
|
|
|
Messages are posted by objects in the pipeline and are passed to the
|
|
application using the GstBus.
|
|
|
|
|
|
Message types
|
|
-------------
|
|
|
|
GST_MESSAGE_EOS:
|
|
|
|
Posted by sink elements. This message is posted to the application when
|
|
all the sinks in a pipeline posted an EOS message. When performing a seek,
|
|
the EOS state of the pipeline and sinks is undone.
|
|
|
|
GST_MESSAGE_ERROR:
|
|
|
|
An element in the pipeline got into an error state. The message carries
|
|
a GError and a debug string describing the error. This usually means that
|
|
part of the pipeline is not streaming anymore.
|
|
|
|
GST_MESSAGE_WARNING:
|
|
|
|
An element in the pipeline encountered a condition that made it produce a
|
|
warning. This could be a recoverable decoding error or some other non fatal
|
|
event. The pipeline continues streaming after a warning.
|
|
|
|
GST_MESSAGE_INFO:
|
|
|
|
An element produced an informational message.
|
|
|
|
GST_MESSAGE_TAG:
|
|
|
|
An element decoded metadata about the stream. The message carries a GstTagList
|
|
with the tag information.
|
|
|
|
GST_MESSAGE_BUFFERING:
|
|
|
|
An element is buffering data and that could potentially take some time.
|
|
|
|
GST_MESSAGE_STATE_CHANGED:
|
|
|
|
An element changed state in the pipeline. The message carries the old, new
|
|
and pending state of the element.
|
|
|
|
GST_MESSAGE_STEP_DONE:
|
|
|
|
An element stepping frames has finished.
|
|
|
|
GST_MESSAGE_CLOCK_PROVIDE:
|
|
|
|
An element notifies it capability of providing a clock for the pipeline.
|
|
|
|
GST_MESSAGE_CLOCK_LOST:
|
|
|
|
The current clock as selected by the pipeline became unusable. The pipeline
|
|
will select a new clock on the next PLAYING state change.
|
|
|
|
GST_MESSAGE_NEW_CLOCK:
|
|
|
|
A new clock was selected for the pipeline.
|
|
|
|
GST_MESSAGE_STRUCTURE_CHANGE:
|
|
|
|
The pipeline changed of structure, This means elements were added or removed or
|
|
pads were linked or unlinked.
|
|
|
|
GST_MESSAGE_STREAM_STATUS:
|
|
|
|
An element posted information about the stream it is handling. This could include
|
|
information about the length of the stream.
|
|
|
|
GST_MESSAGE_APPLICATION:
|
|
|
|
The application posted a message.
|
|
|
|
GST_MESSAGE_ELEMENT:
|
|
|
|
Element-specific message, see the specific element's documentation
|
|
|
|
GST_MESSAGE_SEGMENT_START:
|
|
|
|
An element started playback of a new segment. This message is not forwarded
|
|
the the application but is used internally to schedule SEGMENT_DONE messages.
|
|
|
|
GST_MESSAGE_SEGMENT_DONE:
|
|
|
|
An element or bin completed playback of a segment. This message is only posted
|
|
on the bus if a SEGMENT seek is performed on a pipeline.
|
|
|
|
|