h264parser.h

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// SPDX-License-Identifier: AGPL-3.0-or-later
 
#ifndef __H264PARSER_H
#define __H264PARSER_H
 
#include <set>
#include <string>
#include <vector>
 
extern "C" {
#include <libavcodec/avcodec.h>
}
 
typedef enum {
    NALU_TYPE_NON_IDR = (1 << 0),
    NALU_TYPE_PART_A  = (1 << 1),
    NALU_TYPE_PART_B  = (1 << 2),
    NALU_TYPE_PART_C  = (1 << 3),
    NALU_TYPE_IDR     = (1 << 4),
    NALU_TYPE_SEI     = (1 << 5),
    NALU_TYPE_SPS     = (1 << 6),
    NALU_TYPE_PPS     = (1 << 7),
    NALU_TYPE_AUD     = (1 << 8)
} NalUnitTypes;
 
class cH264Parser {
private:
    struct RefPicMod {
        int list;
        int idc;
        int abs_diff_pic_num_minus1;
        int long_term_pic_num;
    };
 
public:
    cH264Parser(AVPacket *, int, int, int);
    void BuildInvalidReferenceString(int);
    void BuildValidReferenceString(void);
    void AddFrameNumber(int);
    void AddInvalidReference(int, int);
    void AddValidReference(int);
    void PrintNalUnits(void);
    void PrintStreamData(void);
 
    std::string GetNalUnitString(void) { return m_naluString; };
    int GetWidth(void) { return m_width; };
    int GetHeight(void) { return m_height; };
    bool IsMbaff(void) { return m_mbaff; };
    bool HasSPS(void) { return m_hasSPS; };
    bool HasPPS(void) { return m_hasPPS; };
    bool IsPSlice() const { return m_sliceType == 0; }
    bool IsBSlice() const { return m_sliceType == 1; }
    bool IsISlice() const { return m_sliceType == 2; }
    bool IsIDR() const { return m_isIDR; }
    bool IsReference() const { return m_isReference; }
    int GetFrameNum() const { return m_frameNum; }
    const std::vector<RefPicMod>& GetRefMods() const { return m_refMods; }
    int GetLog2MaxFrameNumMinus4() const { return m_log2MaxFrameNumMinus4; }
    int GetPpsNumRefIdxL0DefaultActiveMinus1(void) { return m_ppsNumRefIdxL0DefaultActiveMinus1; };
    int GetPpsNumRefIdxL1DefaultActiveMinus1(void) { return m_ppsNumRefIdxL1DefaultActiveMinus1; };
    int GetNumRefIdxL0Active(void) { return m_numRefIdxL0Active; };
    int GetNumRefIdxL1Active(void) { return m_numRefIdxL1Active; };
    bool HasInvalidReferences(void) { return m_hasInvalidReferences; };
    bool HasInvalidBackwardReferences(void) { return m_hasInvalidBackwardReferences; };
    bool HasParseError(void) const { return m_parseError; };
 
private:
    AVPacket *m_pAvpkt;
    const unsigned char *m_pStart;
    std::vector<uint8_t> m_rbsp;
    unsigned short m_nLength;
    int m_nCurrentBit;
 
    int m_nalutype = 0;
    int m_width = 0;
    int m_height = 0;
    bool m_hasSPS = false;
    bool m_hasPPS = false;
    bool m_isIDR = false;
    bool m_isReference = false;
    bool m_mbaff = false;
    bool m_parseError = false;
 
    std::string m_naluString;
 
    int m_sliceType = -1;      // normalized: 0=P, 2=I
    int m_frameNum = -1;
    int m_nalRefIdc = 0;
    std::set<int> m_invalidReferences;
    std::set<int> m_validReferences;
    std::vector<RefPicMod> m_refMods;
    bool m_hasInvalidReferences = false;
    bool m_hasInvalidBackwardReferences = false;
    bool m_hasValidReferences = false;
 
    int m_log2MaxFrameNumMinus4 = -4;             // saved from SPS
    int m_ppsNumRefIdxL0DefaultActiveMinus1 = -1; // saved from PPS
    int m_ppsNumRefIdxL1DefaultActiveMinus1 = -1; // saved from PPS
    int m_numRefIdxL0Active;
    int m_numRefIdxL1Active;
 
    unsigned int ReadBit(void);
    unsigned int ReadBits(int);
    unsigned int ReadExponentialGolombCode(void);
    unsigned int ReadSE(void);
    int GetSPSOffset(void);
    int GetPPSOffset(void);
    int GetSliceOffset(void);
    void ConvertEBSPtoRBSP(const uint8_t *, int);
};
 
#endif