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docs: update stream docs for SEGMENT_START event

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This commit is contained in:
Tim-Philipp Müller 2012-07-09 16:20:49 +01:00
parent 8ebaf79781
commit 867051c7f6
2 changed files with 24 additions and 11 deletions
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3
docs/design/part-caps.txt
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@ -8,7 +8,8 @@ Caps are exposed on GstPadTemplates to describe all possible types a
given pad can handle. They are also stored in the registry along with given pad can handle. They are also stored in the registry along with
a description of the element. a description of the element.
Caps are exposed on the element pads using the _get_caps() pad function. Caps are exposed on the element pads via CAPS and ACCEPT_CAPS queries.
This function describes the possible types that the pad can handle or This function describes the possible types that the pad can handle or
produce (see part-pads.txt and part-negotiation.txt). produce (see part-pads.txt and part-negotiation.txt).

32
docs/design/part-streams.txt
View file

@ -11,10 +11,11 @@ Stream objects
The following objects are to be expected in the streaming thread: The following objects are to be expected in the streaming thread:
- events - events
- SEGMENT (S) - STREAM_START (START)
- EOS (EOS) * - SEGMENT (SEGMENT)
- EOS * (EOS)
- TAG (T) - TAG (T)
- buffers (B) * - buffers * (B)
Objects marked with * need to be synchronised to the clock in sinks Objects marked with * need to be synchronised to the clock in sinks
and live sources. and live sources.
@ -23,16 +24,21 @@ and live sources.
Typical stream Typical stream
~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~
A typical stream starts with a segment event that marks the A typical stream starts with a stream start event that marks the
start of the stream, followed by a segment event that marks the
buffer timestamp range. After that buffers are sent one after the buffer timestamp range. After that buffers are sent one after the
other. After the last buffer an EOS marks the end of the stream. No other. After the last buffer an EOS marks the end of the stream. No
more buffers are to be processed after the EOS event. more buffers are to be processed after the EOS event.
+-+ +-++-+ +-+ +---+ +-----+-------+ +-++-+ +-+ +---+
|S| |B||B| ... |B| |EOS| |START|SEGMENT| |B||B| ... |B| |EOS|
+-+ +-++-+ +-+ +---+ +-----+-------+ +-++-+ +-+ +---+
1) SEGMENT, rate, start/stop, time 1) STREAM_START
- marks the start of a stream; unlike the SEGMENT event, there
will be no STREAM_START event after flushing seeks.
2) SEGMENT, rate, start/stop, time
- marks valid buffer timestamp range (start, stop) - marks valid buffer timestamp range (start, stop)
- marks stream_time of buffers (time). This is the stream time of buffers - marks stream_time of buffers (time). This is the stream time of buffers
with a timestamp of NS.start. with a timestamp of NS.start.
@ -42,7 +48,7 @@ Typical stream
- marks running_time of buffers. This is the time used to synchronize - marks running_time of buffers. This is the time used to synchronize
against the clock. against the clock.
2) N buffers 3) N buffers
- displayable buffers are between start/stop of the SEGMENT. Buffers - displayable buffers are between start/stop of the SEGMENT. Buffers
outside the segment range should be dropped or clipped. outside the segment range should be dropped or clipped.
@ -62,9 +68,15 @@ Typical stream
* current position in stream between 0 and duration. * current position in stream between 0 and duration.
3) EOS 4) EOS
- marks the end of data, nothing is to be expected after EOS, elements - marks the end of data, nothing is to be expected after EOS, elements
should refuse more data and return GST_FLOW_EOS. A FLUSH_STOP should refuse more data and return GST_FLOW_EOS. A FLUSH_STOP
event clears the EOS state of an element. event clears the EOS state of an element.
Elements
~~~~~~~~
These events are generated typically either by the GstBaseSrc class for
sources operating in push mode, or by a parser/demuxer operating in pull-mode
and pushing parsed/demuxed data downstream.