mmal port callbacks on JPEG component issue - Raspberry Pi Forums

some users of app (mmal fork of motion) have reported problem when using latest raspbian+firmware (see http://www.raspberrypi.org/forums/viewt ... 31#p570931 , http://www.raspberrypi.org/forums/viewt ... 87#p567587).

i'm little stumped @ moment, wondering if else mmal programming experience comment on following? or if knows recent mmal, kernel or pi firmware changes might affect app? info gratefully received.

mmal configuration shows problem this:

code: select all

camera: [video port output] -> splitter: [output 0] -> jpeg encoder: [output] -> callback                                          [output 1] -> resize:       [output] -> callback  

each port connects callback associated buffer pool of size recommended port, , associated queue. callbacks when called put indicated buffer associated queue. application polls these queues retrieve each buffer, extracts contents, releases buffer , sends port in usual fashion.

see in application callbacks both resize , jpeg encoder happening, after few iterations app stops getting callbacks jpeg encoder port. because of way app written, hangs waiting buffers appear in queue (there's separate timeout watchdog running elsewhere wakes make app fail gracefully). according logging in code, buffer handling has proceeded expected (i.e. buffers returned ports, no leaks).

if app shutdown after point, runs through code shut down mmal (disable ports, disable , destroy components, etc) , @ point callbacks buffers jpeg encoder - it's late then.

on earlier versions of raspbian/pi firmware, model works absolutely fine (e.g. linux version 3.6.11+ #557 preempt wed oct 2 18:49:09 bst 2013).

problem seems related jpeg encoder component - if mmal configuration modified remove , attach callback output 0 of splitter, works fine on latest raspbian & firmware.

sounds pretty same problem i'm facing:
http://www.raspberrypi.org/forums/viewt ... 76#p569876

regards
ralf

raspberrypi