2006-02-28 15:54:06 +00:00
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Streams
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-------
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This document describes the objects that are passed from element to
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element in the streaming thread.
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Stream objects
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--------------
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The following objects are to be expected in the streaming thread:
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- events
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- NEW_SEGMENT (NS)
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- EOS (EOS) *
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- TAG (T)
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- buffers (B) *
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Objects marked with * need to be synchronised to the clock in sinks
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and live sources.
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Typical stream
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--------------
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A typical stream starts with a newsegment event that marks the
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buffer timestamp range. After that buffers are send one after the
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other. After the last buffer an EOS marks the end of the stream. No
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more buffer are to be processed after the EOS event.
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+--+ +-++-+ +-+ +---+
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|NS| |B||B| ... |B| |EOS|
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+--+ +-++-+ +-+ +---+
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1) NEW_SEGMENT, rate, start/stop, time
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2006-03-13 10:32:26 +00:00
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- marks valid buffer timestamp range (start, stop)
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- marks stream_time of buffers (time)
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- marks playback rate (rate)
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docs/design/part-overview.txt: Make upsteam/downstream concepts more clear.
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.
2006-05-08 09:52:33 +00:00
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- marks applied rate (applied_rate)
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2006-02-28 15:54:06 +00:00
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2) N buffers
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- displayable buffers are between start/stop of the NEW_SEGMENT
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2006-03-13 10:32:26 +00:00
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2006-02-28 15:54:06 +00:00
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- display_time: (B.timestamp - NS.start) * NS.abs_rate
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2006-03-13 10:32:26 +00:00
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* used to calculate stream_time and sync_time
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2006-02-28 15:54:06 +00:00
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- stream_time: display_time + NS.time
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2006-03-13 10:32:26 +00:00
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* current position in stream between 0 and duration
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- sync_time: display_time + NS.accum + base_time
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* used to synchronize against the clock.
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2006-02-28 15:54:06 +00:00
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3) EOS
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- marks the end of data, nothing is to be expected after EOS
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2006-03-13 10:32:26 +00:00
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