videorec: Fix flushing encoders
When passing NULL frames, encoders empty their queues, but we have
to stop polling from them when they don't any more data.
# -------------------------------------------------
# Project created by QtCreator 2010-11-27T22:18:20
# -------------------------------------------------
TARGET = drawMapTest
TEMPLATE = app
SOURCES += main.cpp \
mainwindow.cpp \
drawmapscene.cpp \
qaspectratiolayout.cpp \
drawmapwidget.cpp
HEADERS += mainwindow.h \
drawmapscene.h \
qaspectratiolayout.h \
drawmapwidget.h
FORMS += mainwindow.ui