… the next frame when decode

* The constructors are easier to call.
* By default we explicitly copy the input parameters (width, height,
pixelFormat) to the output.

Added 'output' when the element concerns output.

* The constructors are easier to call.
* By default we explicitly copy the input parameters (sampleRate,
nbChannels) to the output.

Added 'output' when the element concerns output.

…ntext

* Just need to get the properties.
* See next commit.

Indicate that these are 'source' properties.

* Added const to local variables when it's possible.
* Renamed several local variables.

… specified channel does not exist

Previously debug.

No need to call updateOutput AudioReader::method when specify a
channelIndex in constructor.

…into dev_audioReaderChannelIndex

…into dev_audioReaderChannelIndex

…SamplesPerChannel

* CodedData: describes coded data.
* Frame: describes decoded (raw) audio or video data.
* Need to use AVFrame instead of AVPacket in avtranscoder Frame class.

* Create decoded/coded folders to split classes in data directory.
* Video/AudioFrameDesc are struct with puclic access to their
attributes.
* Sorry for this huge commit, but it is hard to split it.

* Not used.
* AudioGenerator: removed _frameDesc attributes and the methods to
manipulate it.

Renamed to inherit the setNextFrame method in based class.

"cannot allocate an array of constant size 0".

* Not tested.
* Not used.
* Can be done by accessing the full buffer thanks to getData method.

…channel index