提取 PAT PMT C语言

PAT（Program Association Table）和PMT（Program Map Table）是数字视频广播领域中的两个协议。

在C语言中，提取PAT和PMT需要进行以下步骤：

1. 打开TS文件，读取TS包，获取PAT表的PID值。

2. 读取TS包，判断PID是否为PAT表的PID值，如果是则解析PAT表。

3. 解析PAT表，获取PMT表的PID值。

4. 读取TS包，判断PID是否为PMT表的PID值，如果是则解析PMT表。

5. 解析PMT表，获取视频流和音频流的PID值。

6. 读取TS包，判断PID是否为视频流或音频流的PID值，如果是则提取数据。

下面是示例代码：

#include <stdio.h>

typedef struct {
    unsigned char table_id;
    unsigned char section_syntax_indicator;
    unsigned short section_length;
    unsigned short transport_stream_id;
    unsigned char version_number;
    unsigned char current_next_indicator;
    unsigned char section_number;
    unsigned char last_section_number;
    unsigned int program_number;
    unsigned char reserved_3;
    unsigned int network_PID;
    unsigned int program_map_PID;
} PAT;

typedef struct {
    unsigned char table_id;
    unsigned char section_syntax_indicator;
    unsigned short section_length;
    unsigned int program_number;
    unsigned char reserved_3;
    unsigned char version_number;
    unsigned char current_next_indicator;
    unsigned char section_number;
    unsigned char last_section_number;
    unsigned short PCR_PID;
    unsigned short program_info_length;
    unsigned int stream_type;
    unsigned short elementary_PID;
    unsigned short ES_info_length;
} PMT;

int main() {
    FILE *fp = fopen("test.ts", "rb");
    if (fp == NULL) {
        printf("Open file failed!\n");
        return -1;
    }

    unsigned char buffer[188];
    PAT pat;
    PMT pmt;

    while (fread(buffer, 1, 188, fp) == 188) {
        // 判断PID是否为PAT表的PID值
        if (buffer[1] == 0x00) {
            pat.table_id = buffer[0];
            pat.section_syntax_indicator = (buffer[1] >> 7) & 0x01;
            pat.section_length = ((buffer[1] & 0x0f) << 8) | buffer[2];
            pat.transport_stream_id = (buffer[3] << 8) | buffer[4];
            pat.version_number = (buffer[5] >> 1) & 0x1f;
            pat.current_next_indicator = buffer[5] & 0x01;
            pat.section_number = buffer[6];
            pat.last_section_number = buffer[7];
            pat.network_PID = ((buffer[8] & 0x1f) << 8) | buffer[9];
            pat.program_map_PID = ((buffer[10] & 0x1f) << 8) | buffer[11];
        }
        // 判断PID是否为PMT表的PID值
        else if (buffer[1] == pmt.program_map_PID) {
            pmt.table_id = buffer[0];
            pmt.section_syntax_indicator = (buffer[1] >> 7) & 0x01;
            pmt.section_length = ((buffer[1] & 0x0f) << 8) | buffer[2];
            pmt.program_number = (buffer[3] << 8) | buffer[4];
            pmt.version_number = (buffer[5] >> 1) & 0x1f;
            pmt.current_next_indicator = buffer[5] & 0x01;
            pmt.section_number = buffer[6];
            pmt.last_section_number = buffer[7];
            pmt.PCR_PID = ((buffer[8] & 0x1f) << 8) | buffer[9];
            pmt.program_info_length = ((buffer[10] & 0x0f) << 8) | buffer[11];
            int i = 12 + pmt.program_info_length;
            while (i < 12 + pmt.section_length - 4) {
                pmt.stream_type = buffer[i];
                pmt.elementary_PID = ((buffer[i+1] & 0x1f) << 8) | buffer[i+2];
                pmt.ES_info_length = ((buffer[i+3] & 0x0f) << 8) | buffer[i+4];
                i += 5 + pmt.ES_info_length;
            }
        }
        // 提取视频流或音频流的数据
        else if (buffer[1] == pmt.elementary_PID) {
            // TODO: 提取数据
        }
    }

    fclose(fp);
    return 0;
}