[Pidgin] #16315: New API for private Raw and RTP data streams

[Pidgin]

#16315: New API for private Raw and RTP data streams
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 Reporter:  kakaroto                |       Owner:
     Type:  patch                   |      Status:  new
Milestone:  Patches Needing Review  |   Component:  libpurple
  Version:  3.0.0hg                 |  Resolution:
 Keywords:                          |
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Comment (by kakaroto):

 Hi David,

 Thanks for all the work you've done with the patches.

 One reason for using appsrc/appsink is because we can't let the plugin
 provide us with a GstElement since the whole API is supposed to be
 independent of gstreamer/farstream as there are many abstraction layers
 there. Exposing the GstElement kind of defeats the purpose. While there is
 the media-gst.h, I don't think having to use it should be needed in order
 to use the MEDIA_APPLICATION.

 As for the blocking calls, they aren't actually blocking unless you
 specify it. Both the send and receive APIs have a blocking argument which
 if set to FALSE will make it non-blocking, otherwise, after it sends the
 data to the pipeline, it will wait until the data is flushed before
 returning.
 If you see them as blocking writes, it's possible that sipe is doing it
 that way. While data does travel through the main thread, it's only when
 it goes from/to pidgin, but otherwise, it gets sent to appsrc/appsink
 which have their own threads and all the processing is in that thread.
 It's possible something else needs to be optimized to avoid the issue
 you're experiencing.

 As for using filesrc/fdsrc, I'm not sure it's a good idea, mostly because
 I don't think there's any protocol which takes raw data this way, it will
 always be encapsulated somehow, so you will always need to modify the data
 in one way or another.
 As you can see here :
 https://github.com/tieto/sipe/commit/bae7b738dfe31baafbe50200f5895fc432fc170a
 for file transfers, you still need to parse the packets to see if it's a
 start-of-file, data-chunk, or end-of-file packet, so even with
 filesrc/fdsrc or whatever, you still need data to go through the
 application in order to be parsed, which means you need appsrc/apssink. It
 might work with fdsrc/fdsink for RDP though since I don't think there is
 any processing other than what freeRDP does.
 I know you weren't saying it should be replaced with filesrc/filesink, but
 I'm just saying that removing the appsrc/appsink system will just cause it
 to be moved into sipe for file transfers and you may have the exact same
 issues which are making you disliking it at the moment.

 It looks like some profiling may be in order...

 Thanks.

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Ticket URL: <https://developer.pidgin.im/ticket/16315#comment:12>
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