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96 lines
3.7 KiB
Markdown
96 lines
3.7 KiB
Markdown
# TODO - Future Development
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## API/ABI
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- implement return values from events in addition to the gboolean.
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This should be done by making the event contain a GstStructure with
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input/output values, similar to GstQuery. A typical use case is
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performing a non-accurate seek to a keyframe, after the seek you
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want to get the new stream time that will actually be used to update
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the slider bar.
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- make gst\_pad\_push\_event() return a GstFlowReturn
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- GstEvent, GstMessage register like GstFormat or GstQuery.
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- query POSITION/DURATION return accuracy. Just a flag or accuracy
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percentage.
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- use | instead of + as divider in serialization of Flags
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(gstvalue/gststructure)
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- rethink how we handle dynamic replugging wrt segments and other
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events that already got pushed and need to be pushed again. Might
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need GstFlowReturn from gst\_pad\_push\_event(). FIXED in 0.11 with
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sticky events.
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- Optimize negotiation. We currently do a get\_caps() call when we
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link pads, which could potentially generate a huge list of caps and
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all their combinations, we need to avoid generating these huge lists
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by generating them We also need to incrementally return
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intersections etc, for this. somewhat incrementally when needed. We
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can do this with a gst\_pad\_iterate\_caps() call. We also need to
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incrementally return intersections etc, for this. FIXED in 0.11 with
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a filter on getcaps functions.
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- Elements in a bin have no clue about the final state of the parent
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element since the bin sets the target state on its children in small
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steps. This causes problems for elements that like to know the final
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state (rtspsrc going to PAUSED or READY is different in that we can
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avoid sending the useless PAUSED request).
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- Make serialisation of structures more consistent, readable and nicer
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code-wise.
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- pad block has several issues:
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- can’t block on selected things, like push, pull, pad\_alloc,
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events, …
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- can’t check why the block happened. We should also be able to
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get the item/ reason that blocked the pad.
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- it only blocks on datapassing. When EOS, the block never happens
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but ideally should because pad block should inform the app when
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there is no dataflow.
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- the same goes for segment seeks that don’t push in-band EOS
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events. Maybe segment seeks should also send an EOS event when
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they’re done.
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- blocking should only happen from one thread. If one thread does
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pad\_alloc and another a push, the push might be busy while the
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block callback is done.
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- maybe this name is overloaded. We need to look at some more use
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cases before trying to fix this. FIXED in 0.11 with BLOCKING
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probes.
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- rethink the way we do upstream renegotiation. Currently it’s done
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with pad\_alloc but this has many issues such as only being able to
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suggest 1 format and the need to allocate a buffer of this suggested
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format (some elements such as capsfilter only know about the format,
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not the size). We would ideally like to let upstream renegotiate a
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new format just like it did when it started. This could, for
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example, easily be triggered with a RENEGOTIATE event. FIXED in 0.11
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with RECONFIGURE events.
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- Remove the result format value in queries. FIXED in 0.11
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- Try to minimize the amount of acceptcaps calls when pushing buffers
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around. The element pushing the buffer usually negotiated already
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and decided on the format. The element receiving the buffer usually
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has to accept the caps anyway.
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## IMPLEMENTATION
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- implement more QOS, [qos](design/qos.md).
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- implement BUFFERSIZE.
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## DESIGN
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- unlinking pads in the PAUSED state needs to make sure the stream
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thread is not executing code. Can this be done with a flush to
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unlock all downstream chain functions? Do we do this automatically
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or let the app handle this?
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