Qml camera example does not show any preview

Videooutput does not show any preview.
Example:

VideoOutput {
id:videoout
source: camera
anchors.fill: parent
focus : visible
}

but i've tried also with the declarative camera example, without touching a single line. Even with the code of ImageSharing App showed at the recent Mobile RoadShow in London.

The preview is shown in desktop but neither in android armeabi-v7a HTC ONE Android 4.3 nor iphone 4 IOS 7 the preview is showing.
Here is the debug output on android:

I/SensorManager( 4955): protected boolean registerListenerImpl(SensorEventListener listener, Sensor sensor, int delay, Handler handler): listener = org.qtproject.qt5.android.sensors.QtSensors@42122400, sensor = {Sensor name="BOSCH BMA250 3-axis Accelerometer", vendor="BOSCH", version=1, type=1, maxRange=39.2266, resolution=0.038307227, power=0.1, minDelay=10000}, delay = 20000, handler = null
I/SensorManager( 4955): protected boolean registerListenerImpl(SensorEventListener listener, Sensor sensor, int delay, Handler handler): listener = android.view.OrientationEventListener$SensorEventListenerImpl@42121ff0, sensor = {Sensor name="BOSCH BMA250 3-axis Accelerometer", vendor="BOSCH", version=1, type=1, maxRange=39.2266, resolution=0.038307227, power=0.1, minDelay=10000}, delay = 200000, handler = null
D/qdmemalloc( 4955): ion: Mapped buf base:0x73051000 size:462848 offset:0 fd:74
D/qdmemalloc( 4955): ion: Mapped buf base:0x70573000 size:4096 offset:0 fd:75
D/qdmemalloc( 4955): ion: Mapped buf base:0x730c2000 size:462848 offset:0 fd:76
D/qdmemalloc( 4955): ion: MappeI can provide some additional informationd buf base:0x70574000 size:4096 offset:0 fd:77
D/qdmemalloc( 4955): ion: Mapped buf base:0x73133000 size:462848 offset:0 fd:78
D/qdmemalloc( 4955): ion: Mapped buf base:0x70575000 size:4096 offset:0 fd:79
D/qdmemalloc( 4955): ion: Mapped buf base:0x731a4000 size:462848 offset:0 fd:80
D/qdmemalloc( 4955): ion: Mapped buf base:0x70576000 size:4096 offset:0 fd:81
D/qdmemalloc( 4955): ion: Mapped buf base:0x73215000 size:462848 offset:0 fd:82
D/qdmemalloc( 4955): ion: Mapped buf base:0x70577000 size:4096 offset:0 fd:83
D/qdmemalloc( 4955): ion: Mapped buf base:0x73286000 size:462848 offset:0 fd:84
D/qdmemalloc( 4955): ion: Mapped buf base:0x70578000 size:4096 offset:0 fd:85
D/qdmemalloc( 4955): ion: Mapped buf base:0x732f7000 size:462848 offset:0 fd:86
D/qdmemalloc( 4955): ion: Mapped buf base:0x70579000 size:4096 offset:0 fd:87
D/qdmemalloc( 4955): ion: Mapped buf base:0x73368000 size:462848 offset:0 fd:88
D/qdmemalloc( 4955): ion: Mapped buf base:0x7300c000 size:4096 offset:0 fd:89
D/qdmemalloc( 4955): ion: Mapped buf base:0x733d9000 size:462848 offset:0 fd:90
D/qdmemalloc( 4955): ion: Mapped buf base:0x7300d000 size:4096 offset:0 fd:91

Added info: This is HTC-specific issue. Front camera preview is working, back camera preview is not workig. See comment below for camera selection method