Simplest AAC Parser.zip

/** * 最简单的 AAC 音频码流解析程序 * Simplest AAC Parser * * 原程序： * 雷霄骅 Lei Xiaohua * [email protected] * 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 * [email protected] * 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 AAC 码流分析程序，可以分离并解析 ADTS 帧。 * * This project is an AAC stream analysis program. * It can parse AAC bitstream and analysis ADTS frame of stream. * */ #include <stdio.h> #include <stdlib.h> #include <string.h> // 解决报错：fopen() 函数不安全 #pragma warning(disable:4996) int getADTSframe(unsigned char* buffer, int buf_size, unsigned char* data, int* data_size) { int size = 0; if (!buffer || !data || !data_size) { return -1; } while (1) { if (buf_size < 7) { // 一个 ADTS header 最少占 7 字节，如果小于 7 字节，说明不是一个 ADTS frame 或数据不完整 return -1; } // 同步字占 12 bit，为 0xfff if ((buffer[0] == 0xFF) && ((buffer[1] & 0xF0) == 0xF0)) { // frame_length，13 bit，表示当前 ADTS 帧的长度，存储在第 4 个字节的后两位，第 5 个字节，第 6 个字节的前三位 size |= ((buffer[3] & 0x03) << 11); // high 2 bit size |= buffer[4] << 3; // middle 8 bit size |= ((buffer[5] & 0xE0) >> 5); // low 3 bit break; } --buf_size; ++buffer; } if (buf_size < size) { return 1; } memcpy(data, buffer, size); *data_size = size; return 0; } int simplest_aac_parser(char *url) { int data_size = 0; int size = 0; int frame_cnt = 0; int offset = 0; // FILE *myout = fopen("output_log.txt", "wb+"); FILE *myout = stdout; unsigned char *aacframe = (unsigned char *)malloc(1024 * 5); unsigned char *aacbuffer = (unsigned char *)malloc(1024 * 1024); FILE *ifile = fopen(url, "rb"); if (!ifile) { printf("Open file error.\n"); return -1; } printf("-----+----+-------+-------------------+- ADTS Frame Table --+---------+------+-----------------+--------+\n"); printf(" NUM | ID | Layer | Protection Absent | Profile | Frequency | Channel | Size | Buffer Fullness | Blocks |\n"); printf("-----+----+-------+-------------------+---------------------+---------+------+-----------------+--------+\n"); while (!feof(ifile)) { data_size = fread(aacbuffer + offset, 1, 1024 * 1024 - offset, ifile); unsigned char* input_data = aacbuffer; while (1) { int ret = getADTSframe(input_data, data_size, aacframe, &size); if (ret == -1) break; else if (ret == 1) { memcpy(aacbuffer, input_data, data_size); offset = data_size; break; } char profile_str[50] = { 0 }; char frequence_str[10] = { 0 }; // ID，1 bit，表示 MPEG 版本，存储在第 2 字节的第五比特 // 值为 0 表示 MPEG-4，值为 1 表示 MPEG-2 unsigned char id = (aacframe[1] & 0x08) >> 3; // Layer，2 bit，表示音频流所属的层级，存储在第 2 字节的第 6、7 比特 unsigned char layer = (aacframe[1] & 0x00) >> 1; // Protection Absent，1 bit，指示是否启用 CRC 错误校验，存储在第 2 字节的最后一个比特 // 1 表示没有 CRC，整个 ADST 头为 7 字节；0 表示有 CRC，整个 ADST 头为 9 字节 unsigned char protection_absent = aacframe[1] & 0x01; // profile，2 bit，表示 AAC 规格，存储在第 3 字节的头两位 unsigned char profile = (aacframe[2] & 0xC0) >> 6; if (id == 1) // MPEG-2 { switch (profile) { case 0: sprintf(profile_str, "Main"); break; case 1: sprintf(profile_str, "LC"); break; case 2: sprintf(profile_str, "SSR"); break; default: sprintf(profile_str, "unknown"); break; } } else // MPEG-4 { switch (profile) { case 0: sprintf(profile_str, "AAC MAIN"); break; case 1: sprintf(profile_str, "AAC LC"); break; case 2: sprintf(profile_str, "AAC SSR"); break; case 3: sprintf(profile_str, "AAC LTP"); break; case 4: sprintf(profile_str, "SBR"); break; case 5: sprintf(profile_str, "AAC scalable"); break; case 6: sprintf(profile_str, "TwinVQ"); break; case 7: sprintf(profile_str, "CELP"); break; case 8: sprintf(profile_str, "HVXC"); break; case 11: sprintf(profile_str, "TTSI"); break; case 12: sprintf(profile_str, "Main synthetic"); break; case 13: sprintf(profile_str, "Wavetable synthesis"); break; case 14: sprintf(profile_str, "General MIDI"); break; case 15: sprintf(profile_str, "Algorithmic Synthesis and Audio FX"); break; default: sprintf(profile_str, "reversed"); break; } } // Sampling Frequency Index，4 bit，表示采样率的索引，存储在第 3 字节的 3~6 位 unsigned char sampling_frequency_index = (aacframe[2] & 0x3C) >> 2; switch (sampling_frequency_index) { case 0: sprintf(frequence_str, "96000Hz"); break; case 1: sprintf(frequence_str, "88200Hz"); break; case 2: sprintf(frequence_str, "64000Hz"); break; case 3: sprintf(frequence_str, "48000Hz"); break; case 4: sprintf(frequence_str, "44100Hz"); break; case 5: sprintf(frequence_str, "32000Hz"); break; case 6: sprintf(frequence_str, "24000Hz"); break; case 7: sprintf(frequence_str, "22050Hz"); break; case 8: sprintf(frequence_str, "16000Hz"); break; case 9: sprintf(frequence_str, "12000Hz"); break; case 10: sprintf(frequence_str, "11025Hz"); break; case 11: sprintf(frequence_str, "8000Hz"); break; case 12: sprintf(frequence_str, "7350Hz"); break; case 13: case 14: sprintf(frequence_str, "reversed"); break; case 15: sprintf(frequence_str, "escape value"); break; default: sprintf(frequence_str, "unknown"); break; } // Private Bit，1 bit，私有比特，存储在第 3 字节的第七比特 unsigned char private_bit = (aacframe[2] & 0x02) >> 1; // Channel Configuration，3 bit，表示音频的通道数，存储在第 3 个字节的最后一比特，第 4 个字节前两个比特 unsigned char channel_configuration = 0; channel_configuration |= ((aacframe[2] & 0x01) << 2); // high 1 bit channel_configuration |= ((aacframe[3] & 0xC0) >> 6); // low 2 bit // Originality，1 bit，存储在第 4 个字节的第三比特 unsigned char originality = (aacframe[3] & 0x20) >> 5; // Home，1 bit，存储在第 4 个字节的第四比特 unsigned char home = (aacframe[3] & 0x10) >> 4; // Copyright Identification Bit，1 bit，存储在第 4 个字节的第五比特 unsigned char copyright_identification_bit = (aacframe[3] & 0x08) >> 3; // Copyright Identification Start，1 bit，存储在第 4 个字节的第六比特 unsigned char copyright_identification_start = (aacframe[3] & 0x04) >> 2; // Adts Buffer Fullness，11 bit，存储在第 6 个字节的后五个比特，第 7 个字节的前六个比特 // 0x7FF 表示码率可变的码流，0x000 表示固定码率的码流 int adts_buffer_fullness = 0; adts_buffer_fullness |= ((aacframe[5] & 0x1F) << 6); // high 5 bit adts_buffer_fullness |= ((aacframe[6] & 0xFC) >> 2); // low 6 bit // 存储在第 7 个字节的最后两比特，该字段表示当前 ADST 帧中所包含的 AAC 帧的个数减一 unsigned char number_of_raw_data_blocks_in_frame = aacframe[6] & 0x03; // NUM | ID | Layer | Protection Absent | Profile | Frequency | Channel | Size | Buffer Fullness | Blocks fprintf(myout, "%5d|%4d|%7d|%19d|%9s|%11s|%9d|%6d| %#X|%8d|\n", frame_cnt, id, layer, protection_absent, profile_str, frequence_str, channel_configuration, size, adts_buffer_fullness, number_of_raw_data_blocks_in_frame); data_size -= size; input_data += size; frame_cnt++; } } fclose(ifile); free(aacbuffer); free(aacframe); return 0; } int main() { char in_filename[] = "tdjm.aac"; simplest_aac_parser(in_filename); system("pause"); return 0; }