Option.hpp

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#ifndef _AV_TRANSCODER_OPTION_HPP
#define _AV_TRANSCODER_OPTION_HPP

#include <AvTranscoder/common.hpp>

extern "C" {
#include <libavutil/opt.h>
}

#include <vector>
#include <string>
#include <map>
#include <utility>

namespace avtranscoder
{

enum EOptionBaseType
{
    eOptionBaseTypeBool,
    eOptionBaseTypeInt,
    eOptionBaseTypeDouble,
    eOptionBaseTypeString,
    eOptionBaseTypeRatio,
    eOptionBaseTypeChoice,
    eOptionBaseTypeGroup,
    eOptionBaseTypeChild, // Option which belongs to Choice or Group
    eOptionBaseTypeUnknown
};

/**
 * @brief Wrapper of AVOption.
 * Get its type to know what the option is about: Int, Double, Ratio, Choice...
 * Parse its array of options to get the potential childs (Choice and Group).
 */
class AvExport Option
{
public:
    Option(AVOption& avOption, void* avContext);
    ~Option() {}

    EOptionBaseType getType() const;

    std::string getName() const { return std::string(_avOption->name ? _avOption->name : ""); }
    std::string getHelp() const { return std::string(_avOption->help ? _avOption->help : ""); }
    std::string getUnit() const { return std::string(_avOption->unit ? _avOption->unit : ""); }
    int getOffset() const { return _avOption->offset; }
    double getMin() const { return _avOption->min; }
    double getMax() const { return _avOption->max; }

    // flags
    int getFlags() const { return _avOption->flags; }
    bool isEncodingOpt() const { return (_avOption->flags & AV_OPT_FLAG_ENCODING_PARAM) == AV_OPT_FLAG_ENCODING_PARAM; }
    bool isDecodingOpt() const { return (_avOption->flags & AV_OPT_FLAG_DECODING_PARAM) == AV_OPT_FLAG_DECODING_PARAM; }
    bool isAudioOpt() const { return (_avOption->flags & AV_OPT_FLAG_AUDIO_PARAM) == AV_OPT_FLAG_AUDIO_PARAM; }
    bool isVideoOpt() const { return (_avOption->flags & AV_OPT_FLAG_VIDEO_PARAM) == AV_OPT_FLAG_VIDEO_PARAM; }
    bool isSubtitleOpt() const { return (_avOption->flags & AV_OPT_FLAG_SUBTITLE_PARAM) == AV_OPT_FLAG_SUBTITLE_PARAM; }

    // get default value
    bool getDefaultBool() const;
    int getDefaultInt() const;
    double getDefaultDouble() const;
    std::string getDefaultString() const;
    std::pair<int, int> getDefaultRatio() const;

    // get value
    bool getBool() const;
    int getInt() const;
    double getDouble() const;
    std::string getString() const;
    std::pair<int, int> getRatio() const;

    // set value
    void setFlag(const std::string& flag, const bool enable);
    void setBool(const bool value);
    void setInt(const int value);
    void setDouble(const double value);
    void setString(const std::string& value);
    void setRatio(const int num, const int den);

    // array of childs
    bool hasChild() const { return _childOptions.size(); }
    const std::vector<Option>& getChilds() const { return _childOptions; }
    const Option& getChildAtIndex(const size_t index) const { return _childOptions.at(index); }
    int getDefaultChildIndex() const { return _defaultChildIndex; }

    void setDefaultChildIndex(size_t index) { _defaultChildIndex = index; }
    void appendChild(const Option& child);

private:
    EOptionBaseType getTypeFromAVOption(const std::string& unit, const AVOptionType avType);

    /**
     * @brief Check the return value from FFmpeg functions
     * @note Throw run_time exception if error
     */
    void checkFFmpegGetOption(const int ffmpegReturnCode) const;
    void checkFFmpegSetOption(const int ffmpegReturnCode, const std::string& optionValue);

private:
    AVOption* _avOption; ///< Has link (no ownership)
    EOptionBaseType _type;

    /**
     * @brief Pointer to the corresponding context.
     * Need it to set and get the option values.
     */
    void* _avContext; ///< Has link (no ownership)

    /**
     * If the option corresponds to a Choice or a Group, it can contain childs,
     * which are also options.
     */
    std::vector<Option> _childOptions;
    size_t _defaultChildIndex;
};

typedef std::vector<Option> OptionArray;
typedef std::map<std::string, Option> OptionMap; ///< Key: option name / value: option

#ifndef SWIG
/**
 * @param outOptions: map or array of options
 * @param av_class: a libav context (could be an AVFormatContext or an AVCodecContext).
 * @param req_flags: libav flag (AV_OPT_FLAG_XXX), which is a filter for AVOption loaded by the Context (default = 0: no flag
 * restriction).
 */
void AvExport loadOptions(OptionMap& outOptions, void* av_class, int req_flags = 0);
void AvExport loadOptions(OptionArray& outOptions, void* av_class, int req_flags = 0);
#endif
}

#endif