* Use AVRationnal instead.
* VideoFrame: add getDarNum and getDarDen to get values of rational
whithout manipulate AVRational.
* AVRational has no constructor to initialize its attributes: initialize
AVRational in our classes.

* Create the new Context class in new files (hpp + cpp): no reason to
have it in common.
* Get Context files in option folder.

* Get our corresponding type of AVOption in the constructor.
* Function getTypeFromAVOption is private and is only used in the
constructor.
* Update OptionLoader: if a user wants the type of an option, he can use
option.getType().

Also rename enum values.

* Context:
     * has a map of options.
     * has a link to its corresponding avContext.
     * has getter to any of his options.
     * remove setters (the option has the setters).
* Option:
     * has a link to an AVOption.
     * has a link to its corresponding avContext.
     * has setters.
     * rename _options to _childOptions.
* When we want to set a value of an AVOption:
     * get an Option by a Context.
     * set its value by a set of Option.

* No more OptionLoader class: the options are manage by Context and
Option classes.
* Keep utilities functions of OptionLoader in a new file named util.
* Context:
     * add getOptions and getOptionsMap.
     * add documentation.
* OptionChecker app: fit to new architecture.

* FormatContext enbale to get options whithout care about allocate and
free an AVFormatContext: this is the job of the class.
* CodecContext enbale to get options whithout care about allocate and
free an AVCodecContext: this is the job of the class.
* Rename Context files to context.

* Rename codedStructures folder to codec.
* Rename CodedDesc to ICodec.
* Rename VideoDesc, AudioDesc, DataDesc to VideoCodec, AudioCodec,
DataCodec.

…ontext

Automatically generated.

…t in CodecContext

* Call the loadOptions from the constructors of FormatContext and
CodecContext.
* Context: need to add a default constructor.

…into dev_clean_refactoring

* Rename folder 'essenceTransform' to 'transform'.
* Rename files to ITransform, VideoTransform and AudioTransform.
* Rename classes to ITransform, VideoTransform and AudioTransform.
* No sense to have transforms for coded data. So transforms are
implicitly for essence (decoded) data.

The folder contains all classes about frame.

* Duplicate with Frame class.
* Add a typedef of Frame, CodedData, to represent buffer of coded data.

* In constructor, instanciate a videoCodec, or an AudioCodec, or a
DataCodec.
* Get the codec with getter (use reference).

* Indentation.
* Implement constructor per copy in cpp.

* Remove unnecessary includes.
* Clean FFmpeg forward declarations: declare the right type (struct or
enum). Avoid warning when compile on MAC OS and Windows.

This #define is already define in common.hpp. Not necessary to rewrite
it in every files.

Use only references as parameters to have unified API.

Use getChilds().size().

* hasChild function uses vector::size().
* getChilds function is const.

Provide pure virtual destructor.

* Symmetry with AvOutputAudio:
    * use an AudioCodec.
    * no need to allocate and free AV codec objects ; it is done by our
ICodec class.

* Symmetry with AvOutputVideo:
    * use a VideoCodec.
    * no need to allocate and free AV codec objects ; it is done by our
ICodec class.

* Define destructor the same way as IInputEssence.

Remove unnecessary "this".

For some FFmpeg versions, we need to include <libavutil/mem.h> to get
av_free function.

* Print warning, and not allocate AVCodec.
* Same idea in ffprobe: warn the user of the unsupported codec, but
allow him to manage other streams of the input file.

* Remove comments.
* Add @todo.
* Symmetry with readNextFrame with a subStreamIndex: use variables to
get "src" and "dst" when copy samples.

By default, a user doesn't want all printed on console.

* These functions threw a runtime_error with error named "SUCCESS".
* No visible consequences because we caught them when setProfile...

Merge in one function: setCodec.

* avcodec_register_all() can be call more than one time.
* In FFMpeg/Libav code they detect if codecs are registered.

Also reorder initialization of attributes in constructor.

Also rename getSampleFormat to getAVSampleFormat in this class.

* According to the class name "AudioCodec".
* "getAudioCodec" returns a reference instead of make a copy.
* Rename "setAudioDesc" to "setAudioCodec".

* According to the class name "VideoCodec".
* "getVideoCodec" returns a reference instead of make a copy.
* Rename "setVideoDesc" to "setVideoCodec".