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Dependencies and Prerequisites

Introduction
Supported Compilers
Sounds and Qt Extended

Helix Media Engine Integration
GStreamer Media Engine Integration
Directly Playing Sounds to Hardware

Video4Linux
3rd Party libraries
Related topics

Getting started
System Customization Guide

Introduction

In order for Qt Extended to run as intended the following prerequisites must be satisfied:

a suitable compiler must be installed
Linux kernel that provides shared memory, mmap, sockets and Framebuffer support as specified in the integration guide.
compliance with the Qt Extended root file system requirements
compliance with the General Qt Requirements.
If Qt Extended is being built with Safe Execution Environment - (SXE) support, then the kernel must be patched to have LIDS support.
If Qt Extended is being built with Digital Rights Management(DRM) support, then version 2.4 of drmagent from BeepScience must be installed ( Note: A commercial license from BeepScience is required to use the BeepScience drmagent).
If Qt Extended is being built with Helix please refer to Helix for further information about using Helix with Qt Extended.
For dependencies related to playing sounds see Sounds and Qt Extended
For dependencies related to Bluetooth see Bluetooth Support

Supported Compilers

In general terms any version of GCC greater than or equal to 3.4 may be used to compile/cross-compile Qt Extended. The following table provides additional information about the status of a given versions of GCC.

Property	Version(s)
Minimum	GCC 3.4
Recommended	GCC 3.4.3, GCC 3.4.5, GCC 4.1.1 (uses symbol visibility)
Not recommended	GCC 4.0.2, GCC 4.1.0

For further information about GCC see: http://www.gnu.org

Sounds and Qt Extended

Qt Extended can be configured to play sounds via a media engine integration or by playing sounds directly to the sound hardware. One or more media engine integration can be enable via the -mediaengines option see also

    ./configure -help -verbose

Helix Media Engine Integration

For details on how to use the Helix Integration see Qt Extended Helix Integration.

GStreamer Media Engine Integration

Before attempting to configure Qt Extended with GStreamer support enabled ensure that all requirements as stated at http://gstreamer.freedesktop.org/ are met.

Directly Playing Sounds to Hardware

When a media engine integration is not used Qt Extended requires that either:

A OSS Linux sound driver is used
A ALSA sound support with OSS compatibility

In addition Qt Extended requires that /dev/dsp is writable and supports the following ioctls:

SNDCTL_DSP_SETFRAGMENT - Qt Extended will set this to 0x4000c.
SNDCTL_DSP_SETFM - Qt Extended will set this to AFMT_S16_LE
SNDCTL_DSP_STEREO - Qt Extended will set this to 1/true.
SNDCTL_DSP_SPEED - Qt Extended will set this to 44100.
SNDCTL_DSP_GETOSPACE.

Qt Extended also requires that /dev/dsp can be opened as both blocking and non-blocking. The values set above are the Qt Extended preferred settings for the audio device, and some deviation is allowed. However smooth playing of audio is not guaranteed if the above ioctls cannot be set to the Qt Extended preferred settings.

For example your device only plays at 22500 speed, then it is required to report this when the SNDCTL_DSP_SPEED ioctl is called and should not result in a drop in audio quality. However not supporting GETOSPACE, non-blocking write or SNDCTL_DSP_SET_FRAGMENT will almost certainly result loss of audio quality.

Video4Linux

The Camera application requires a kernel with Video4Linux version 1 or version 2 support. This is not provided with Qt Extended.

Please refer to the official Video for Linux resources site for details about this API.

3rd Party libraries

For a list of 3rd party libraries that Qt Extended may use see Qt Extended Licensing