mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-18 15:51:11 +00:00
b9dbb55105
Original commit message from CVS: * docs/design/part-overview.txt: Make upsteam/downstream concepts more clear. Give an example of serialized/non-serialized events. * docs/design/part-events.txt: * docs/design/part-streams.txt: Mention applied_rate. * docs/design/part-trickmodes.txt: Mention applied rate, flesh out some more use cases. * gst/gstevent.c: (gst_event_new_new_segment), (gst_event_parse_new_segment), (gst_event_new_new_segment_full), (gst_event_parse_new_segment_full), (gst_event_new_tag), (gst_event_parse_tag), (gst_event_new_buffer_size), (gst_event_parse_buffer_size), (gst_event_new_qos), (gst_event_parse_qos), (gst_event_parse_seek), (gst_event_new_navigation): * gst/gstevent.h: Add applied_rate field to NEWSEGMENT event. API: gst_event_new_new_segment_full() API: gst_event_parse_new_segment_full() * gst/gstsegment.c: (gst_segment_init), (gst_segment_set_seek), (gst_segment_set_newsegment), (gst_segment_set_newsegment_full), (gst_segment_to_stream_time), (gst_segment_to_running_time): * gst/gstsegment.h: Add applied_rate to GstSegment structure. Make calculation of stream_time and running_time more correct wrt rate/applied_rate. Add some more docs. API: GstSegment::applied_rate field API: gst_segment_set_newsegment_full(); * libs/gst/base/gstbasesink.c: (gst_base_sink_configure_segment), (gst_base_sink_get_sync_times), (gst_base_sink_get_position): * libs/gst/base/gstbasetransform.c: (gst_base_transform_sink_eventfunc), (gst_base_transform_handle_buffer): Parse and use applied_rate in the GstSegment field. * tests/check/gst/gstevent.c: (GST_START_TEST): Add check for applied_rate field. * tests/check/gst/gstsegment.c: (GST_START_TEST), (gstsegments_suite): Add more checks for various GstSegment operations.
56 lines
1.5 KiB
Text
56 lines
1.5 KiB
Text
Streams
|
|
-------
|
|
|
|
This document describes the objects that are passed from element to
|
|
element in the streaming thread.
|
|
|
|
|
|
Stream objects
|
|
--------------
|
|
|
|
The following objects are to be expected in the streaming thread:
|
|
|
|
- events
|
|
- NEW_SEGMENT (NS)
|
|
- EOS (EOS) *
|
|
- TAG (T)
|
|
- buffers (B) *
|
|
|
|
Objects marked with * need to be synchronised to the clock in sinks
|
|
and live sources.
|
|
|
|
|
|
Typical stream
|
|
--------------
|
|
|
|
A typical stream starts with a newsegment event that marks the
|
|
buffer timestamp range. After that buffers are send one after the
|
|
other. After the last buffer an EOS marks the end of the stream. No
|
|
more buffer are to be processed after the EOS event.
|
|
|
|
+--+ +-++-+ +-+ +---+
|
|
|NS| |B||B| ... |B| |EOS|
|
|
+--+ +-++-+ +-+ +---+
|
|
|
|
1) NEW_SEGMENT, rate, start/stop, time
|
|
- marks valid buffer timestamp range (start, stop)
|
|
- marks stream_time of buffers (time)
|
|
- marks playback rate (rate)
|
|
- marks applied rate (applied_rate)
|
|
|
|
2) N buffers
|
|
- displayable buffers are between start/stop of the NEW_SEGMENT
|
|
|
|
- display_time: (B.timestamp - NS.start) * NS.abs_rate
|
|
* used to calculate stream_time and sync_time
|
|
|
|
- stream_time: display_time + NS.time
|
|
* current position in stream between 0 and duration
|
|
|
|
- sync_time: display_time + NS.accum + base_time
|
|
* used to synchronize against the clock.
|
|
|
|
3) EOS
|
|
- marks the end of data, nothing is to be expected after EOS
|
|
|
|
|