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384 lines
10 KiB
384 lines
10 KiB
// |
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// amrFileCodec.cpp |
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// amrDemoForiOS |
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// |
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// Created by Tang Xiaoping on 9/27/11. |
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// Copyright 2011 test. All rights reserved. |
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// |
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#include "amrFileCodec.h" |
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int amrEncodeMode[] = {4750, 5150, 5900, 6700, 7400, 7950, 10200, 12200}; // amr 编码方式 |
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// 从WAVE文件中跳过WAVE文件头，直接到PCM音频数据 |
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void SkipToPCMAudioData(FILE* fpwave) |
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{ |
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RIFFHEADER riff; |
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FMTBLOCK fmt; |
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XCHUNKHEADER chunk; |
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WAVEFORMATX wfx; |
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int bDataBlock = 0; |
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// 1. 读RIFF头 |
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fread(&riff, 1, sizeof(RIFFHEADER), fpwave); |
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// 2. 读FMT块 - 如果 fmt.nFmtSize>16 说明需要还有一个附属大小没有读 |
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fread(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); |
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if ( chunk.nChunkSize>16 ) |
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{ |
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fread(&wfx, 1, sizeof(WAVEFORMATX), fpwave); |
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} |
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else |
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{ |
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memcpy(fmt.chFmtID, chunk.chChunkID, 4); |
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fmt.nFmtSize = chunk.nChunkSize; |
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fread(&fmt.wf, 1, sizeof(WAVEFORMAT), fpwave); |
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} |
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// 3.转到data块 - 有些还有fact块等。 |
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while(!bDataBlock) |
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{ |
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fread(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); |
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if ( !memcmp(chunk.chChunkID, "data", 4) ) |
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{ |
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bDataBlock = 1; |
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break; |
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} |
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// 因为这个不是data块,就跳过块数据 |
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fseek(fpwave, chunk.nChunkSize, SEEK_CUR); |
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} |
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} |
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// 从WAVE文件读一个完整的PCM音频帧 |
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// 返回值: 0-错误 >0: 完整帧大小 |
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int ReadPCMFrame(short speech[], FILE* fpwave, int nChannels, int nBitsPerSample) |
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{ |
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int nRead = 0; |
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int x = 0, y=0; |
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// unsigned short ush1=0, ush2=0, ush=0; |
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// 原始PCM音频帧数据 |
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unsigned char pcmFrame_8b1[PCM_FRAME_SIZE]; |
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unsigned char pcmFrame_8b2[PCM_FRAME_SIZE<<1]; |
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unsigned short pcmFrame_16b1[PCM_FRAME_SIZE]; |
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unsigned short pcmFrame_16b2[PCM_FRAME_SIZE<<1]; |
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if (nBitsPerSample==8 && nChannels==1) |
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{ |
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nRead = fread(pcmFrame_8b1, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave); |
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for(x=0; x<PCM_FRAME_SIZE; x++) |
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{ |
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speech[x] =(short)((short)pcmFrame_8b1[x] << 7); |
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} |
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} |
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else |
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if (nBitsPerSample==8 && nChannels==2) |
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{ |
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nRead = fread(pcmFrame_8b2, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave); |
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for( x=0, y=0; y<PCM_FRAME_SIZE; y++,x+=2 ) |
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{ |
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// 1 - 取两个声道之左声道 |
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speech[y] =(short)((short)pcmFrame_8b2[x+0] << 7); |
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// 2 - 取两个声道之右声道 |
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//speech[y] =(short)((short)pcmFrame_8b2[x+1] << 7); |
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// 3 - 取两个声道的平均值 |
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//ush1 = (short)pcmFrame_8b2[x+0]; |
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//ush2 = (short)pcmFrame_8b2[x+1]; |
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//ush = (ush1 + ush2) >> 1; |
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//speech[y] = (short)((short)ush << 7); |
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} |
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} |
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else |
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if (nBitsPerSample==16 && nChannels==1) |
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{ |
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nRead = fread(pcmFrame_16b1, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave); |
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for(x=0; x<PCM_FRAME_SIZE; x++) |
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{ |
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speech[x] = (short)pcmFrame_16b1[x+0]; |
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} |
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} |
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else |
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if (nBitsPerSample==16 && nChannels==2) |
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{ |
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nRead = fread(pcmFrame_16b2, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave); |
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for( x=0, y=0; y<PCM_FRAME_SIZE; y++,x+=2 ) |
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{ |
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//speech[y] = (short)pcmFrame_16b2[x+0]; |
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speech[y] = (short)((int)((int)pcmFrame_16b2[x+0] + (int)pcmFrame_16b2[x+1])) >> 1; |
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} |
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} |
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// 如果读到的数据不是一个完整的PCM帧, 就返回0 |
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if (nRead<PCM_FRAME_SIZE*nChannels) return 0; |
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return nRead; |
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} |
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// WAVE音频采样频率是8khz |
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// 音频样本单元数 = 8000*0.02 = 160 (由采样频率决定) |
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// 声道数 1 : 160 |
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// 2 : 160*2 = 320 |
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// bps决定样本(sample)大小 |
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// bps = 8 --> 8位 unsigned char |
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// 16 --> 16位 unsigned short |
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int EncodeWAVEFileToAMRFile(const char* pchWAVEFilename, const char* pchAMRFileName, int nChannels, int nBitsPerSample) |
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{ |
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FILE* fpwave; |
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FILE* fpamr; |
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/* input speech vector */ |
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short speech[160]; |
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/* counters */ |
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int byte_counter, frames = 0, bytes = 0; |
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/* pointer to encoder state structure */ |
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void *enstate; |
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/* requested mode */ |
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enum Mode req_mode = MR122; |
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int dtx = 0; |
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/* bitstream filetype */ |
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unsigned char amrFrame[MAX_AMR_FRAME_SIZE]; |
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fpwave = fopen(pchWAVEFilename, "rb"); |
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if (fpwave == NULL) |
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{ |
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return 0; |
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} |
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// 创建并初始化amr文件 |
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fpamr = fopen(pchAMRFileName, "wb"); |
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if (fpamr == NULL) |
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{ |
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fclose(fpwave); |
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return 0; |
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} |
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/* write magic number to indicate single channel AMR file storage format */ |
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bytes = fwrite(AMR_MAGIC_NUMBER, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr); |
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/* skip to pcm audio data*/ |
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SkipToPCMAudioData(fpwave); |
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enstate = Encoder_Interface_init(dtx); |
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while(1) |
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{ |
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// read one pcm frame |
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if (!ReadPCMFrame(speech, fpwave, nChannels, nBitsPerSample)) break; |
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frames++; |
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/* call encoder */ |
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byte_counter = Encoder_Interface_Encode(enstate, req_mode, speech, amrFrame, 0); |
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bytes += byte_counter; |
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fwrite(amrFrame, sizeof (unsigned char), byte_counter, fpamr ); |
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} |
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Encoder_Interface_exit(enstate); |
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fclose(fpamr); |
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fclose(fpwave); |
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return frames; |
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} |
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#pragma mark - Decode |
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//decode |
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void WriteWAVEFileHeader(FILE* fpwave, int nFrame) |
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{ |
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char tag[10] = ""; |
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// 1. 写RIFF头 |
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RIFFHEADER riff; |
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strcpy(tag, "RIFF"); |
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memcpy(riff.chRiffID, tag, 4); |
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riff.nRiffSize = 4 // WAVE |
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+ sizeof(XCHUNKHEADER) // fmt |
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+ sizeof(WAVEFORMATX) // WAVEFORMATX |
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+ sizeof(XCHUNKHEADER) // DATA |
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+ nFrame*160*sizeof(short); // |
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strcpy(tag, "WAVE"); |
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memcpy(riff.chRiffFormat, tag, 4); |
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fwrite(&riff, 1, sizeof(RIFFHEADER), fpwave); |
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// 2. 写FMT块 |
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XCHUNKHEADER chunk; |
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WAVEFORMATX wfx; |
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strcpy(tag, "fmt "); |
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memcpy(chunk.chChunkID, tag, 4); |
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chunk.nChunkSize = sizeof(WAVEFORMATX); |
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fwrite(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); |
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memset(&wfx, 0, sizeof(WAVEFORMATX)); |
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wfx.nFormatTag = 1; |
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wfx.nChannels = 1; // 单声道 |
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wfx.nSamplesPerSec = 8000; // 8khz |
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wfx.nAvgBytesPerSec = 16000; |
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wfx.nBlockAlign = 2; |
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wfx.nBitsPerSample = 16; // 16位 |
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fwrite(&wfx, 1, sizeof(WAVEFORMATX), fpwave); |
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// 3. 写data块头 |
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strcpy(tag, "data"); |
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memcpy(chunk.chChunkID, tag, 4); |
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chunk.nChunkSize = nFrame*160*sizeof(short); |
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fwrite(&chunk, 1, sizeof(XCHUNKHEADER), fpwave); |
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} |
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const int myround(const double x) |
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{ |
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return((int)(x+0.5)); |
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} |
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// 根据帧头计算当前帧大小 |
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int caclAMRFrameSize(unsigned char frameHeader) |
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{ |
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int mode; |
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int temp1 = 0; |
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int temp2 = 0; |
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int frameSize; |
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temp1 = frameHeader; |
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// 编码方式编号 = 帧头的3-6位 |
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temp1 &= 0x78; // 0111-1000 |
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temp1 >>= 3; |
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mode = amrEncodeMode[temp1]; |
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// 计算amr音频数据帧大小 |
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// 原理: amr 一帧对应20ms，那么一秒有50帧的音频数据 |
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temp2 = myround((double)(((double)mode / (double)AMR_FRAME_COUNT_PER_SECOND) / (double)8)); |
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frameSize = myround((double)temp2 + 0.5); |
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return frameSize; |
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} |
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// 读第一个帧 - (参考帧) |
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// 返回值: 0-出错; 1-正确 |
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int ReadAMRFrameFirst(FILE* fpamr, unsigned char frameBuffer[], int* stdFrameSize, unsigned char* stdFrameHeader) |
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{ |
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memset(frameBuffer, 0, sizeof(frameBuffer)); |
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// 先读帧头 |
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fread(stdFrameHeader, 1, sizeof(unsigned char), fpamr); |
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if (feof(fpamr)) return 0; |
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// 根据帧头计算帧大小 |
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*stdFrameSize = caclAMRFrameSize(*stdFrameHeader); |
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// 读首帧 |
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frameBuffer[0] = *stdFrameHeader; |
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fread(&(frameBuffer[1]), 1, (*stdFrameSize-1)*sizeof(unsigned char), fpamr); |
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if (feof(fpamr)) return 0; |
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return 1; |
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} |
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// 返回值: 0-出错; 1-正确 |
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int ReadAMRFrame(FILE* fpamr, unsigned char frameBuffer[], int stdFrameSize, unsigned char stdFrameHeader) |
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{ |
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int bytes = 0; |
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unsigned char frameHeader; // 帧头 |
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memset(frameBuffer, 0, sizeof(frameBuffer)); |
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// 读帧头 |
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// 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 |
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while(1) |
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{ |
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bytes = fread(&frameHeader, 1, sizeof(unsigned char), fpamr); |
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if (feof(fpamr)) return 0; |
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if (frameHeader == stdFrameHeader) break; |
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} |
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// 读该帧的语音数据(帧头已经读过) |
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frameBuffer[0] = frameHeader; |
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bytes = fread(&(frameBuffer[1]), 1, (stdFrameSize-1)*sizeof(unsigned char), fpamr); |
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if (feof(fpamr)) return 0; |
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return 1; |
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} |
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// 将AMR文件解码成WAVE文件 |
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int DecodeAMRFileToWAVEFile(const char* pchAMRFileName, const char* pchWAVEFilename) |
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{ |
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FILE* fpamr = NULL; |
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FILE* fpwave = NULL; |
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char magic[8]; |
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void * destate; |
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int nFrameCount = 0; |
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int stdFrameSize; |
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unsigned char stdFrameHeader; |
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unsigned char amrFrame[MAX_AMR_FRAME_SIZE]; |
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short pcmFrame[PCM_FRAME_SIZE]; |
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// NSString * path = [[NSBundle mainBundle] pathForResource: @"test" ofType: @"amr"]; |
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// fpamr = fopen([path cStringUsingEncoding:NSASCIIStringEncoding], "rb"); |
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fpamr = fopen(pchAMRFileName, "rb"); |
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if ( fpamr==NULL ) return 0; |
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// 检查amr文件头 |
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fread(magic, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr); |
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if (strncmp(magic, AMR_MAGIC_NUMBER, strlen(AMR_MAGIC_NUMBER))) |
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{ |
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fclose(fpamr); |
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return 0; |
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} |
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// 创建并初始化WAVE文件 |
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// NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); |
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// NSString *documentPath = [paths objectAtIndex:0]; |
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// NSString *docFilePath = [documentPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%s", pchWAVEFilename]]; |
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// NSLog(@"documentPath=%@", documentPath); |
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// |
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// fpwave = fopen([docFilePath cStringUsingEncoding:NSASCIIStringEncoding], "wb"); |
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fpwave = fopen(pchWAVEFilename,"wb"); |
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WriteWAVEFileHeader(fpwave, nFrameCount); |
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/* init decoder */ |
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destate = Decoder_Interface_init(); |
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// 读第一帧 - 作为参考帧 |
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memset(amrFrame, 0, sizeof(amrFrame)); |
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memset(pcmFrame, 0, sizeof(pcmFrame)); |
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ReadAMRFrameFirst(fpamr, amrFrame, &stdFrameSize, &stdFrameHeader); |
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// 解码一个AMR音频帧成PCM数据 |
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Decoder_Interface_Decode(destate, amrFrame, pcmFrame, 0); |
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nFrameCount++; |
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fwrite(pcmFrame, sizeof(short), PCM_FRAME_SIZE, fpwave); |
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// 逐帧解码AMR并写到WAVE文件里 |
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while(1) |
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{ |
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memset(amrFrame, 0, sizeof(amrFrame)); |
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memset(pcmFrame, 0, sizeof(pcmFrame)); |
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if (!ReadAMRFrame(fpamr, amrFrame, stdFrameSize, stdFrameHeader)) break; |
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// 解码一个AMR音频帧成PCM数据 (8k-16b-单声道) |
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Decoder_Interface_Decode(destate, amrFrame, pcmFrame, 0); |
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nFrameCount++; |
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fwrite(pcmFrame, sizeof(short), PCM_FRAME_SIZE, fpwave); |
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} |
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// NSLog(@"frame = %d", nFrameCount); |
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Decoder_Interface_exit(destate); |
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fclose(fpwave); |
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// 重写WAVE文件头 |
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// fpwave = fopen([docFilePath cStringUsingEncoding:NSASCIIStringEncoding], "r+"); |
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fpwave = fopen(pchWAVEFilename, "r+"); |
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WriteWAVEFileHeader(fpwave, nFrameCount); |
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fclose(fpwave); |
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return nFrameCount; |
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} |