Caps Negotiation Confusion.

[Stirling Westrup]

Reading through the above log, I am more confused than ever. As far as
I can tell, full caps negotiation does take place (although it happens
far later than I expected) and all the elements *seem* to accept the
caps event they get (I say seems because I'm not 100% sure what all
the debug statements actually mean).

However my graph dump once in the playing state still doesn't show
correctly negotiated caps. I don't get it.


On Mon, Jan 28, 2013 at 4:20 PM, Stirling Westrup <swestrup at gmail.com> wrote:
> Okay, here's some more info. I'm working on a project to display video
> content on a video wall made up of a rectangular array of monitors.
> Right now it works fine if I just play video files, but my boss would
> like me to be able to show live content as well, such as a video
> camera feed, or a capture from an X session. This latter is what I
> chose to implement first, and its what I'm now trying to debug. To
> simplify the tests, this example just reads from a single source and
> outputs it to a single monitor, but the program is intended to be able
> to handle multiple video and audio channels and to dynamically
> reconfigure things while a source is playing, hence the complexity of
> the pipeline.
>
> Alas I cannot just upload my code to a public forum as this thing will
> eventually be commercial. However I can upload selected portions if
> need be.
>
> In the meantime, here's a pair of .png graphs. One from launch showing
> what shape I expect the pipeline to be in, and one from my program
> (named 'vaal') showing the actual state of things once I enter the
> PAUSED state.
>
> https://docs.google.com/file/d/0BwCOnjTaGreOOHlUVW5WcEQtelU/edit
> https://docs.google.com/file/d/0BwCOnjTaGreOZWVnbElzOEtxYmM/edit
>
> And finally, here's a full-blown debug trace of me running the program
> and it getting all the way into the playing state without actually
> ever delivering any data to the output screen:
>
> https://docs.google.com/file/d/0BwCOnjTaGreOTFRUUGhESGtZZE0/edit
>
> On Mon, Jan 28, 2013 at 1:31 PM, Tim-Philipp Müller <t.i.m at zen.co.uk> wrote:
>> On Mon, 2013-01-28 at 11:41 -0500, Stirling Westrup wrote:
>>
>>> Right now I have an interesting problem in that caps negotiation is
>>> not completing in my pipeline. This has to be a side effect of
>>> dynamically building the pipeline in stages as caps negotiation
>>> completes and gives the expected results if I build and run an exact
>>> copy of the pipeline via gst-launch.
>>>
>>> For background, my pipeline can either run in pull or push mode. It
>>> runs in pull mode when I supply a file video source, and in push mode
>>> when I supply a live video source (like an X session capture).
>>>
>>> In pull mode, everything works fine. In push mode, the pipeline
>>> successfully gets into the PAUSED state and a gst_pad_query_caps of
>>> source pad at the end of the video processing chain returns a fixed
>>> set of caps, as I would hope. However a call to
>>> gst_pad_get_current_caps at that same location always returns ANY. A
>>> dot-dump of the pipeline at that point shows that essentially no
>>> negotiation has taken place, at all.
>>>
>>> I can't figure out what I need to do to ensure the pipeline completes
>>> negotiation.
>>
>> It would be easier to help with some more information, such as:
>>
>>  - pipeline
>>  - code
>>  - png graph
>>
>> Otherwise one can just say: check backwards which pads get negotiated
>> and not, somewhere a caps event (1.0) or buffer (0.10) must not have
>> gone through.
>>
>>  Cheers
>>   -Tim
>>
>>
>> _______________________________________________
>> gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>
>
> --
> Stirling Westrup
> Programmer, Entrepreneur.
> https://www.linkedin.com/e/fpf/77228
> http://www.linkedin.com/in/swestrup
> http://technaut.livejournal.com
> http://sourceforge.net/users/stirlingwestrup



-- 
Stirling Westrup
Programmer, Entrepreneur.
https://www.linkedin.com/e/fpf/77228
http://www.linkedin.com/in/swestrup
http://technaut.livejournal.com
http://sourceforge.net/users/stirlingwestrup