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仔细证实): pic_order_cnt_type=2, 只有frame_num(无B帧);
71 pic_order_cnt_type=1, 暂未分析到;
72 pic_order_cnt_type=0, pic_order_cnt_lsb指示显示顺序, 一般为偶数增长(0, 2, 4, 6, 据说是什么场方式和帧方式, 场时其实是0 0 2 2 4 4).
73
74 ** 编码与显示的原因: 视频编码顺序与视频的播放顺序, 并不完全相同, 视频编码时, 如果采用了B帧编码, 由于B帧很多时候都是双向预测得来的,
75 这时会先编码B帧的后向预测图像(P帧), 然后再进行B帧编码, 因此会把视频原来的播放顺序打乱, 以新的编码顺序输出码流,
76 而在解码断接收到码流后, 需要把顺序还原成原本的播放顺序, 以输出正确的视频. 在编解码中, 视频的播放顺序序号叫做POC(picture order count).
77
78 ** 总结: 1. 码流中有很多SPS(序列), 一个序列中有多个图像, 一个图像中有多个片, 一个片中有多个块;
79 2. SPS中有seq_parameter_set_id. PPS中有pic_parameter_set_id, 并通过seq_parameter_set_id指明关联的序列.
80 SLICE中有pic_parameter_set_id, 指明关联的图像;
81 3. SPS中可计算宽高以及帧率, pic_order_cnt_type(显示顺序的类型);
82 SLICE HEADER中可算出解码的顺序, 以及根据pic_order_cnt_type算出显示顺序.
83 ************************************************************************************************************/
84 typedef enum e_h264_nalu_priority
85 {
86 NALU_PRIORITY_DISPOSABLE = 0,
87 NALU_PRIORITY_LOW = 1,
88 NALU_PRIORITY_HIGH = 2,
89 NALU_PRIORITY_HIGHEST = 3,
90 } E_H264_NALU_PRIORITY;
91
92 typedef enum e_h264_nalu_type
93 {
94 NALU_TYPE_SLICE = 1,
95 NALU_TYPE_DPA = 2,
96 NALU_TYPE_DPB = 3,
97 NALU_TYPE_DPC = 4,
98 NALU_TYPE_IDR = 5,
99 NALU_TYPE_SEI = 6,
100 NALU_TYPE_SPS = 7,
101 NALU_TYPE_PPS = 8,
102 NALU_TYPE_AUD = 9,
103 NALU_TYPE_EOSEQ = 10,
104 NALU_TYPE_EOSTREAM = 11,
105 NALU_TYPE_FILL = 12,
106 } E_H264_NALU_TYPE;
107
108 typedef struct t_h264_nalu_header
109 {
110 unsigned char forbidden_bit:1, nal_reference_idc:2, nal_unit_type:5;
111 } T_H264_NALU_HEADER;
112
113 typedef struct t_h264_nalu
114 {
115 int startCodeLen;
116
117 T_H264_NALU_HEADER h264NaluHeader;
118
119 unsigned int bodyLen;
120
121 unsigned char *bodyData;
122 } T_H264_NALU;
123
124 /**********************************************************************************
125 1. h264的起始码: 0x000001(3 Bytes)或0x00000001(4 Bytes);
126 2. 文件流中用起始码来区分NALU.
127 ***********************************************************************************/
128 static int FindStartCode3Bytes(unsigned char *scData)
129 {
130 int isFind = 0;
131
132 if ((0==scData[0]) && (0==scData[1]) && (1==scData[2]))
133 {
134 isFind = 1;
135 }
136
137 return isFind;
138 }
139
140 static int FindStartCode4Bytes(unsigned char *scData)
141 {
142 int isFind = 0;
143
144 if ((0==scData[0]) && (0==scData[1]) && (0==scData[2]) && (1 == scData[3]))
145 {
146 isFind = 1;
147 }
148
149 return isFind;
150 }
151
152 static int GetNaluDataLen(int startPos, int h264BitsSize, unsigned char *h264Bits)
153 {
154 int parsePos = 0;
155
156 parsePos = startPos;
157
158 while (parsePos < h264BitsSize)
159 {
160 if (FindStartCode3Bytes(&h264Bits[parsePos]))
161 {
162 return parsePos - startPos;
163 }
164 else if (FindStartCode4Bytes(&h264Bits[parsePos]))
165 {
166 return parsePos - startPos;
167 }
168 else
169 {
170 parsePos++;
171 }
172 }
173
174 return parsePos - startPos; // if file is end
175 }
176
177 static void ParseNaluData(const unsigned int naluLen, unsigned char* const nuluData)
178 {
179 static int naluNum = 0;
180
181 unsigned char *data = NULL;
182 unsigned char priorityStr[PRTNTF_STR_LEN+1] = {0};
183 unsigned char typ |