Simplest FLV Parser.zip

/** * 最简单的 FLV 封装格式解析程序 * Simplest FLV Parser * * 原程序： * 雷霄骅 Lei Xiaohua * leixiaohua1020@126.com * 中国传媒大学/数字电视技术 * Communication University of China / Digital TV Technology * http://blog.csdn.net/leixiaohua1020 * * 修改： * 刘文晨 Liu Wenchen * 812288728@qq.com * 电子科技大学/电子信息 * University of Electronic Science and Technology of China / Electronic and Information Science * https://blog.csdn.net/ProgramNovice * * 本项目是一个 FLV 封装格式解析程序，可以将 FLV 中的 MP3 音频码流分离出来。 * * This project is a FLV format analysis program. * It can analysis FLV file and extract MP3 audio stream. * */ #include <stdio.h> #include <stdlib.h> #include <string.h> // Important #pragma pack(1) // 解决报错：fopen() 函数不安全 #pragma warning(disable:4996) #define PREVIOUS_TAG_SIZE_LENGTH 4 // Tag Type #define TAG_TYPE_AUDIO 8 #define TAG_TYPE_VIDEO 9 #define TAG_TYPE_SCRIPT 18 // 1 字节，8 bit typedef unsigned char UI8; // 2 字节，16 bit typedef unsigned short UI16; // 4 字节，32 bit typedef unsigned int UI32; // FLV header，9 字节 typedef struct { UI8 Signature[3]; // 'F' (0x46)，'L' (0x4C)，'V' (0x56) UI8 Version; // FLV 版本，一般为 0x01，表示 FLV 版本 1 UI8 TypeFlags; // b0 是否存在视频流，b2 是否存在音频流，其他字段保留，值为 0 UI32 DataOffset; // FLV Header 长度，单位：字节，一般为 9 } FLVHEADER; // FLV tag header，11 字节 typedef struct { UI8 TagType; // tag 类型，8 = 音频，9 = 视频，18 = 脚本数据 UI8 DataSize[3]; // tag data 部分的大小，不包含 tag header UI8 Timestamp[3]; // 当前 tag 的解码时间戳 (DTS)，相对值，单位：ms UI8 TimestampExtended; // 和 Timestamp 字段一起构成一个 32 位值, 此字段为高 8 位，单位：ms UI8 StreamID[3]; // 总是 0 } TAGHEADER; // turn a BigEndian byte array into a LittleEndian integer unsigned int reverse_bytes(UI8 *p, char c) { int r = 0; int i; for (i = 0; i < c; i++) r |= (*(p + i) << (((c - 1) * 8) - 8 * i)); return r; } /** * Analysis FLV file * @param url Location of input FLV file */ int simplest_flv_parser(char *url) { // whether output audio / video stream int output_a = 1; int output_v = 1; FILE *ifh = NULL, *vfh = NULL, *afh = NULL; // FILE *myout = fopen("output_log.txt", "wb+"); FILE *myout = stdout; FLVHEADER flv_header; TAGHEADER tag_header; UI32 PreviousTagSize, PreviousTagSize_z = 0; UI32 ts = 0, ts_new = 0; ifh = fopen(url, "rb+"); if (ifh == NULL) { printf("Failed to open files.\n"); return -1; } // read FLV header fread((char *)&flv_header, sizeof(FLVHEADER), 1, ifh); // print FLV header information fprintf(myout, "================== FLV Header ==================\n"); fprintf(myout, "Signature: %c %c %c\n", flv_header.Signature[0], flv_header.Signature[1], flv_header.Signature[2]); fprintf(myout, "Version: 0x%X\n", flv_header.Version); fprintf(myout, "TypeFlags: 0x%X", flv_header.TypeFlags); // b2 是否存在音频流，1 = 存在，0 = 不存在 fprintf(myout, "，Audio identification: %d，", (flv_header.TypeFlags & 0x04) >> 2); // b0 是否存在视频流，1 = 存在，0 = 不存在 fprintf(myout, "Video identification: %d\n", flv_header.TypeFlags & 0x01); UI32 header_size = reverse_bytes((UI8 *)&flv_header.DataOffset, sizeof(flv_header.DataOffset)); fprintf(myout, "HeaderSize: 0x%X\n", header_size); fprintf(myout, "================================================\n"); // move the file pointer to the end of the header fseek(ifh, header_size, SEEK_SET); // SEEK_SET 表示文件开头 // process each FLV tag do { /** * int _getw(FILE *stream)：以二进制形式读取一个整数 * @param stream 指向 FILE 结构的指针 * @return 返回流中下一个整数值 */ PreviousTagSize = _getw(ifh); // read FLV tag header fread((char *)&tag_header, sizeof(TAGHEADER), 1, ifh); char tagtype_str[10]; switch (tag_header.TagType) { case TAG_TYPE_AUDIO: sprintf(tagtype_str, "Audio"); break; case TAG_TYPE_VIDEO: sprintf(tagtype_str, "Video"); break; case TAG_TYPE_SCRIPT: sprintf(tagtype_str, "Script"); break; default: sprintf(tagtype_str, "unknown"); break; } // 当前 tag data 部分的大小，不包含 tag header int tagheader_datasize = tag_header.DataSize[0] * 65536 + tag_header.DataSize[1] * 256 + tag_header.DataSize[2]; // 当前 tag 的解码时间戳 (DTS)，相对值，单位：ms int tagheader_timestamp = tag_header.Timestamp[0] * 65536 + tag_header.Timestamp[1] * 256 + tag_header.Timestamp[2]; fprintf(myout, "[%6s] %6d %6d |", tagtype_str, tagheader_datasize, tagheader_timestamp); // if we are not past the end of file, process the tag if (feof(ifh)) break; // process tag by type switch (tag_header.TagType) { case TAG_TYPE_AUDIO: { char audio_tag_str[100] = { 0 }; strcat(audio_tag_str, "| "); /** * int fgetc(FILE *stream)：从文件指针 stream 指向的文件中读取一个字符，读取一个字节后，光标位置后移一个字节 * @param stream 指向 FILE 结构的指针 * @return 返回流中读取的一个整数值 */ UI8 audio_tag_header = fgetc(ifh); // audio tag header 占 1 字节 // 前 4 bit 表示音频格式 int SoundFormat = (audio_tag_header & 0xF0) >> 4; switch (SoundFormat) { case 0: strcat(audio_tag_str, "Linear PCM, platform endian"); break; case 1: strcat(audio_tag_str, "ADPCM"); break; case 2: strcat(audio_tag_str, "MP3"); break; case 3: strcat(audio_tag_str, "Linear PCM, little endian"); break; case 4: strcat(audio_tag_str, "Nellymoser 16-kHz mono"); break; case 5: strcat(audio_tag_str, "Nellymoser 8-kHz mono"); break; case 6: strcat(audio_tag_str, "Nellymoser"); break; case 7: strcat(audio_tag_str, "G.711 A-law logarithmic PCM"); break; case 8: strcat(audio_tag_str, "G.711 mu-law logarithmic PCM"); break; case 9: strcat(audio_tag_str, "reserved"); break; case 10: strcat(audio_tag_str, "AAC"); break; case 11: strcat(audio_tag_str, "Speex"); break; case 14: strcat(audio_tag_str, "MP3 8-Khz"); break; case 15: strcat(audio_tag_str, "Device-specific sound"); break; default: strcat(audio_tag_str, "unknown"); break; } strcat(audio_tag_str, "| "); // 第 5、6 bit 表示采样率 int SoundRate = (audio_tag_header & 0x0C) >> 2; switch (SoundRate) { case 0: strcat(audio_tag_str, "5.5-kHz"); break; case 1: strcat(audio_tag_str, "11-kHz"); break; case 2: strcat(audio_tag_str, "22-kHz"); break; case 3: strcat(audio_tag_str, "44-kHz"); break; default: strcat(audio_tag_str, "unknown"); break; } strcat(audio_tag_str, "| "); // 第 7 bit 表示采样精度 int SoundSize = (audio_tag_header & 0x02) >> 1; switch (SoundSize) { case 0: strcat(audio_tag_str, "8Bit"); break; case 1: strcat(audio_tag_str, "16Bit"); break; default: strcat(audio_tag_str, "unknown"); break; } strcat(audio_tag_str, "| "); // 第 8 bit 表示音频声道 int SoundType = audio_tag_header & 0x01; switch (SoundType) { case 0: strcat(audio_tag_str, "Mono"); break; case 1: strcat(audio_tag_str, "Stereo"); break; default: strcat(audio_tag_str, "unknown"); break; } fprintf(myout, "%s", audio_tag_str); if (SoundFormat == 10) { // 如果音频格式为 10，即是 AAC 格式。 // AudioTagHeader 中会多出一个字节 AACPacketType，这个字段来表示 AACAUDIODATA 的类型， // 0 = AAC sequence header，1 = AAC raw。 char aac_pakect_type[100] = { 0 }; UI8 AACPacketType = fgetc(ifh); switch (AACPacketType) { case 0: strcat(aac_pakect_type, "AAC sequence header"); break; case 1: strcat(aac_pakect_type, "AAC raw"); break; default: strcat(aac_pakect_type, "unknown"); break; } fprintf(myout, "| %s", aac_pakect_type); // 文件指针回退 1 字节 fseek(ifh, -1, SEEK_CUR); // SEEK_CUR 表示文件当前位置 } // if the output file hasn't been opened, open it. if (output_a != 0