// // amrFileCodec.cpp // amrDemoForiOS // // Created by Tang Xiaoping on 9/27/11. // Copyright 2011 test. All rights reserved. // #include "amrFileCodec.h" int amrEncodeMode[] = {4750, 5150, 5900, 6700, 7400, 7950, 10200, 12200}; // amr 编码方式 // 从WAVE文件中跳过WAVE文件头，直接到PCM音频数据 void SkipToPCMAudioData(FILE* fpwave) { RIFFHEADER riff; FMTBLOCK fmt; XCHUNKHEADER chunk; WAVEFORMATX wfx; int bDataBlock = 0; // 1. 读RIFF头 fread(&riff, 1, sizeof(RIFFHEADER), fpwave); // 2. 读FMT块 - 如果 fmt.nFmtSize>16 说明需要还有一个附属大小没有读 fread(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); if ( chunk.nChunkSize>16 ) { fread(&wfx, 1, sizeof(WAVEFORMATX), fpwave); } else { memcpy(fmt.chFmtID, chunk.chChunkID, 4); fmt.nFmtSize = chunk.nChunkSize; fread(&fmt.wf, 1, sizeof(WAVEFORMAT), fpwave); } // 3.转到data块 - 有些还有fact块等。 while(!bDataBlock) { fread(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); if ( !memcmp(chunk.chChunkID, "data", 4) ) { bDataBlock = 1; break; } // 因为这个不是data块,就跳过块数据 fseek(fpwave, chunk.nChunkSize, SEEK_CUR); } } // 从WAVE文件读一个完整的PCM音频帧 // 返回值: 0-错误 >0: 完整帧大小 int ReadPCMFrame(short speech[], FILE* fpwave, int nChannels, int nBitsPerSample) { int nRead = 0; int x = 0, y=0; // unsigned short ush1=0, ush2=0, ush=0; // 原始PCM音频帧数据 unsigned char pcmFrame_8b1[PCM_FRAME_SIZE]; unsigned char pcmFrame_8b2[PCM_FRAME_SIZE<<1]; unsigned short pcmFrame_16b1[PCM_FRAME_SIZE]; unsigned short pcmFrame_16b2[PCM_FRAME_SIZE<<1]; if (nBitsPerSample==8 && nChannels==1) { nRead = fread(pcmFrame_8b1, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave); for(x=0; x> 1; //speech[y] = (short)((short)ush << 7); } } else if (nBitsPerSample==16 && nChannels==1) { nRead = fread(pcmFrame_16b1, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave); for(x=0; x> 1; } } // 如果读到的数据不是一个完整的PCM帧, 就返回0 if (nRead 8位 unsigned char // 16 --> 16位 unsigned short int EncodeWAVEFileToAMRFile(const char* pchWAVEFilename, const char* pchAMRFileName, int nChannels, int nBitsPerSample) { FILE* fpwave; FILE* fpamr; /* input speech vector */ short speech[160]; /* counters */ int byte_counter, frames = 0, bytes = 0; /* pointer to encoder state structure */ void *enstate; /* requested mode */ enum Mode req_mode = MR122; int dtx = 0; /* bitstream filetype */ unsigned char amrFrame[MAX_AMR_FRAME_SIZE]; fpwave = fopen(pchWAVEFilename, "rb"); if (fpwave == NULL) { return 0; } // 创建并初始化amr文件 fpamr = fopen(pchAMRFileName, "wb"); if (fpamr == NULL) { fclose(fpwave); return 0; } /* write magic number to indicate single channel AMR file storage format */ bytes = fwrite(AMR_MAGIC_NUMBER, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr); /* skip to pcm audio data*/ SkipToPCMAudioData(fpwave); enstate = Encoder_Interface_init(dtx); while(1) { // read one pcm frame if (!ReadPCMFrame(speech, fpwave, nChannels, nBitsPerSample)) break; frames++; /* call encoder */ byte_counter = Encoder_Interface_Encode(enstate, req_mode, speech, amrFrame, 0); bytes += byte_counter; fwrite(amrFrame, sizeof (unsigned char), byte_counter, fpamr ); } Encoder_Interface_exit(enstate); fclose(fpamr); fclose(fpwave); return frames; } #pragma mark - Decode //decode void WriteWAVEFileHeader(FILE* fpwave, int nFrame) { char tag[10] = ""; // 1. 写RIFF头 RIFFHEADER riff; strcpy(tag, "RIFF"); memcpy(riff.chRiffID, tag, 4); riff.nRiffSize = 4 // WAVE + sizeof(XCHUNKHEADER) // fmt + sizeof(WAVEFORMATX) // WAVEFORMATX + sizeof(XCHUNKHEADER) // DATA + nFrame*160*sizeof(short); // strcpy(tag, "WAVE"); memcpy(riff.chRiffFormat, tag, 4); fwrite(&riff, 1, sizeof(RIFFHEADER), fpwave); // 2. 写FMT块 XCHUNKHEADER chunk; WAVEFORMATX wfx; strcpy(tag, "fmt "); memcpy(chunk.chChunkID, tag, 4); chunk.nChunkSize = sizeof(WAVEFORMATX); fwrite(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); memset(&wfx, 0, sizeof(WAVEFORMATX)); wfx.nFormatTag = 1; wfx.nChannels = 1; // 单声道 wfx.nSamplesPerSec = 8000; // 8khz wfx.nAvgBytesPerSec = 16000; wfx.nBlockAlign = 2; wfx.nBitsPerSample = 16; // 16位 fwrite(&wfx, 1, sizeof(WAVEFORMATX), fpwave); // 3. 写data块头 strcpy(tag, "data"); memcpy(chunk.chChunkID, tag, 4); chunk.nChunkSize = nFrame*160*sizeof(short); fwrite(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); } const int myround(const double x) { return((int)(x+0.5)); } // 根据帧头计算当前帧大小 int caclAMRFrameSize(unsigned char frameHeader) { int mode; int temp1 = 0; int temp2 = 0; int frameSize; temp1 = frameHeader; // 编码方式编号 = 帧头的3-6位 temp1 &= 0x78; // 0111-1000 temp1 >>= 3; mode = amrEncodeMode[temp1]; // 计算amr音频数据帧大小 // 原理: amr 一帧对应20ms，那么一秒有50帧的音频数据 temp2 = myround((double)(((double)mode / (double)AMR_FRAME_COUNT_PER_SECOND) / (double)8)); frameSize = myround((double)temp2 + 0.5); return frameSize; } // 读第一个帧 - (参考帧) // 返回值: 0-出错; 1-正确 int ReadAMRFrameFirst(FILE* fpamr, unsigned char frameBuffer[], int* stdFrameSize, unsigned char* stdFrameHeader) { memset(frameBuffer, 0, sizeof(frameBuffer)); // 先读帧头 fread(stdFrameHeader, 1, sizeof(unsigned char), fpamr); if (feof(fpamr)) return 0; // 根据帧头计算帧大小 *stdFrameSize = caclAMRFrameSize(*stdFrameHeader); // 读首帧 frameBuffer[0] = *stdFrameHeader; fread(&(frameBuffer[1]), 1, (*stdFrameSize-1)*sizeof(unsigned char), fpamr); if (feof(fpamr)) return 0; return 1; } // 返回值: 0-出错; 1-正确 int ReadAMRFrame(FILE* fpamr, unsigned char frameBuffer[], int stdFrameSize, unsigned char stdFrameHeader) { int bytes = 0; unsigned char frameHeader; // 帧头 memset(frameBuffer, 0, sizeof(frameBuffer)); // 读帧头 // 如果是坏帧(不是标准帧头)，则继续读下一个字节，直到读到标准帧头 while(1) { bytes = fread(&frameHeader, 1, sizeof(unsigned char), fpamr); if (feof(fpamr)) return 0; if (frameHeader == stdFrameHeader) break; } // 读该帧的语音数据(帧头已经读过) frameBuffer[0] = frameHeader; bytes = fread(&(frameBuffer[1]), 1, (stdFrameSize-1)*sizeof(unsigned char), fpamr); if (feof(fpamr)) return 0; return 1; } // 将AMR文件解码成WAVE文件 int DecodeAMRFileToWAVEFile(const char* pchAMRFileName, const char* pchWAVEFilename) { FILE* fpamr = NULL; FILE* fpwave = NULL; char magic[8]; void * destate; int nFrameCount = 0; int stdFrameSize; unsigned char stdFrameHeader; unsigned char amrFrame[MAX_AMR_FRAME_SIZE]; short pcmFrame[PCM_FRAME_SIZE]; // NSString * path = [[NSBundle mainBundle] pathForResource: @"test" ofType: @"amr"]; // fpamr = fopen([path cStringUsingEncoding:NSASCIIStringEncoding], "rb"); fpamr = fopen(pchAMRFileName, "rb"); if ( fpamr==NULL ) return 0; // 检查amr文件头 fread(magic, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr); if (strncmp(magic, AMR_MAGIC_NUMBER, strlen(AMR_MAGIC_NUMBER))) { fclose(fpamr); return 0; } // 创建并初始化WAVE文件 // NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); // NSString *documentPath = [paths objectAtIndex:0]; // NSString *docFilePath = [documentPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%s", pchWAVEFilename]]; // NSLog(@"documentPath=%@", documentPath); // // fpwave = fopen([docFilePath cStringUsingEncoding:NSASCIIStringEncoding], "wb"); fpwave = fopen(pchWAVEFilename,"wb"); WriteWAVEFileHeader(fpwave, nFrameCount); /* init decoder */ destate = Decoder_Interface_init(); // 读第一帧 - 作为参考帧 memset(amrFrame, 0, sizeof(amrFrame)); memset(pcmFrame, 0, sizeof(pcmFrame)); ReadAMRFrameFirst(fpamr, amrFrame, &stdFrameSize, &stdFrameHeader); // 解码一个AMR音频帧成PCM数据 Decoder_Interface_Decode(destate, amrFrame, pcmFrame, 0); nFrameCount++; fwrite(pcmFrame, sizeof(short), PCM_FRAME_SIZE, fpwave); // 逐帧解码AMR并写到WAVE文件里 while(1) { memset(amrFrame, 0, sizeof(amrFrame)); memset(pcmFrame, 0, sizeof(pcmFrame)); if (!ReadAMRFrame(fpamr, amrFrame, stdFrameSize, stdFrameHeader)) break; // 解码一个AMR音频帧成PCM数据 (8k-16b-单声道) Decoder_Interface_Decode(destate, amrFrame, pcmFrame, 0); nFrameCount++; fwrite(pcmFrame, sizeof(short), PCM_FRAME_SIZE, fpwave); } // NSLog(@"frame = %d", nFrameCount); Decoder_Interface_exit(destate); fclose(fpwave); // 重写WAVE文件头 // fpwave = fopen([docFilePath cStringUsingEncoding:NSASCIIStringEncoding], "r+"); fpwave = fopen(pchWAVEFilename, "r+"); WriteWAVEFileHeader(fpwave, nFrameCount); fclose(fpwave); return nFrameCount; }