[Live-devel] Push (instead of Pull) to custom DeviceSource

[Ross Finlayson]

>I'd like to just call doGetNextFrame() at my own pace when I have data
>ready for it.

No, "getNextFrame()" (and thus "doGetNextFrame()") must be called by 
the downstream object, when it is willing to receive data - i.e., the 
'pull' model.

What you can do, however, is arrange to call your "deliverFrame()" 
function (*not* "doGetNextFrame()") when data becomes available.  The 
best way to do this is to have "the availability of new data" be an 
'event', that gets handled within the event loop.

Is your input device an open file (this is often true if you're 
running a Unix (including Linux) system)?  If so, then you can do 
this easily using "TaskScheduler::turnOnBackgroundReadHandling()". 
If not, then you can use the "watchVariable" feature of 
"doEventLoop()" to do this - along with a separate thread that 
watches for the availability of new data, and sets the 
"watchVariable" when this happens.  (See the FAQ.)  (Alternatively, 
you could write your own "TaskScheduler" subclass in order to make 
the availability of new data an 'event', but that is far more 
complicated to do.)
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/