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- //
- // amrFileCodec.cpp
- // amrDemoForiOS
- //
- // Created by Tang Xiaoping on 9/27/11.
- // Copyright 2011 test. All rights reserved.
- //
- #include "amrFileCodec.h"
- static int amrEncodeMode[] = {4750, 5150, 5900, 6700, 7400, 7950, 10200, 12200};
- // Skip the WAVE header to PCM audio data
- static void SkipToPCMAudioData(FILE* fpwave)
- {
- EM_RIFFHEADER riff;
- EM_FMTBLOCK fmt;
- EM_XCHUNKHEADER chunk;
- EM_WAVEFORMATX wfx;
- int bDataBlock = 0;
-
- // 1. Read the RIFF header
- fread(&riff, 1, sizeof(EM_RIFFHEADER), fpwave);
-
- // 2. Read the FMT chunk - if fmt.nFmtSize>16, read the remaining MATX
- fread(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
- if ( chunk.nChunkSize>16 )
- {
- fread(&wfx, 1, sizeof(EM_WAVEFORMATX), fpwave);
- }
- else
- {
- memcpy(fmt.chFmtID, chunk.chChunkID, 4);
- fmt.nFmtSize = chunk.nChunkSize;
- fread(&fmt.wf, 1, sizeof(EM_WAVEFORMAT), fpwave);
- }
-
- // 3.Switch to the data block
- while(!bDataBlock)
- {
- fread(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
- if ( !memcmp(chunk.chChunkID, "data", 4) )
- {
- bDataBlock = 1;
- break;
- }
- fseek(fpwave, chunk.nChunkSize, SEEK_CUR);
- }
- }
- // Read PCM frame from wave file
- // Return 0 for error, otherwise return a positive number of the size of frame
- static size_t ReadPCMFrame(short speech[], FILE* fpwave, int nChannels, int nBitsPerSample)
- {
- size_t nRead = 0;
- int x = 0, y=0;
- // unsigned short ush1=0, ush2=0, ush=0;
-
- // Original PCM autio frame data
- 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<PCM_FRAME_SIZE; x++)
- {
- speech[x] =(short)((short)pcmFrame_8b1[x] << 7);
- }
- }
- else
- if (nBitsPerSample==8 && nChannels==2)
- {
- nRead = fread(pcmFrame_8b2, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave);
- for( x=0, y=0; y<PCM_FRAME_SIZE; y++,x+=2 )
- {
- // 1 - Left Channel
- speech[y] =(short)((short)pcmFrame_8b2[x+0] << 7);
- // 2 - Right Channel
- //speech[y] =(short)((short)pcmFrame_8b2[x+1] << 7);
- // 3 - The average of two channels
- //ush1 = (short)pcmFrame_8b2[x+0];
- //ush2 = (short)pcmFrame_8b2[x+1];
- //ush = (ush1 + ush2) >> 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<PCM_FRAME_SIZE; x++)
- {
- speech[x] = (short)pcmFrame_16b1[x+0];
- }
- }
- else
- if (nBitsPerSample==16 && nChannels==2)
- {
- nRead = fread(pcmFrame_16b2, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave);
- for( x=0, y=0; y<PCM_FRAME_SIZE; y++,x+=2 )
- {
- //speech[y] = (short)pcmFrame_16b2[x+0];
- speech[y] = (short)((int)((int)pcmFrame_16b2[x+0] + (int)pcmFrame_16b2[x+1])) >> 1;
- }
- }
-
- // Return 0 unless read a complete PCM frame
- if (nRead<PCM_FRAME_SIZE*nChannels) return 0;
-
- return nRead;
- }
- // WAVE audio processing frequency is 8khz
- // audio sample processing units = 8000*0.02 = 160 (decided by audio processing frequency)
- // audio channels 1 : 160
- // 2 : 160*2 = 320
- // bps decides the size of sample
- // bps = 8 --> 8 bits
- // 16 --> 16 bits
- int EM_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;
- size_t 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;
- }
-
- // Initialize the amr file
- 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
- static void WriteWAVEFileHeader(FILE* fpwave, int nFrame)
- {
- char tag[10] = "";
-
- // 1. RIFF header
- EM_RIFFHEADER riff;
- strcpy(tag, "RIFF");
- memcpy(riff.chRiffID, tag, 4);
- riff.nRiffSize = 4 // WAVE
- + sizeof(EM_XCHUNKHEADER) // fmt
- + sizeof(EM_WAVEFORMATX) // EM_WAVEFORMATX
- + sizeof(EM_XCHUNKHEADER) // DATA
- + nFrame*160*sizeof(short); //
- strcpy(tag, "WAVE");
- memcpy(riff.chRiffFormat, tag, 4);
- fwrite(&riff, 1, sizeof(EM_RIFFHEADER), fpwave);
-
- // 2. FMT chunk
- EM_XCHUNKHEADER chunk;
- EM_WAVEFORMATX wfx;
- strcpy(tag, "fmt ");
- memcpy(chunk.chChunkID, tag, 4);
- chunk.nChunkSize = sizeof(EM_WAVEFORMATX);
- fwrite(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
- memset(&wfx, 0, sizeof(EM_WAVEFORMATX));
- wfx.nFormatTag = 1;
- wfx.nChannels = 1; // Single channel
- wfx.nSamplesPerSec = 8000; // 8khz
- wfx.nAvgBytesPerSec = 16000;
- wfx.nBlockAlign = 2;
- wfx.nBitsPerSample = 16;
- fwrite(&wfx, 1, sizeof(EM_WAVEFORMATX), fpwave);
-
- // 3. Write data chunk
- strcpy(tag, "data");
- memcpy(chunk.chChunkID, tag, 4);
- chunk.nChunkSize = nFrame*160*sizeof(short);
- fwrite(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
- }
- static const int myround(const double x)
- {
- return((int)(x+0.5));
- }
- // Calculate the AMR frame size with the frame header
- static int caclAMRFrameSize(unsigned char frameHeader)
- {
- int mode;
- int temp1 = 0;
- int temp2 = 0;
- int frameSize;
-
- temp1 = frameHeader;
-
- // Get AMR Encode Mode with the 3 - 6 digit of frame header
- temp1 &= 0x78; // 0111-1000
- temp1 >>= 3;
-
- mode = amrEncodeMode[temp1];
-
- // Calculate the arm auodio framze size
- // Theory: one frame is 20 mili seconds, then one second is 50 frames of audio data
- temp2 = myround((double)(((double)mode / (double)AMR_FRAME_COUNT_PER_SECOND) / (double)8));
-
- frameSize = myround((double)temp2 + 0.5);
- return frameSize;
- }
- // Read the first AMR frame - (Reference frame)
- // return 0 for error and 1 for success
- static int ReadAMRFrameFirst(FILE* fpamr, unsigned char frameBuffer[], int* stdFrameSize, unsigned char* stdFrameHeader)
- {
- //memset(frameBuffer, 0, sizeof(frameBuffer));
-
- // Read the frame header
- fread(stdFrameHeader, 1, sizeof(unsigned char), fpamr);
- if (feof(fpamr)) return 0;
-
- // Calculate the frame size with frame header
- *stdFrameSize = caclAMRFrameSize(*stdFrameHeader);
-
- // Read the first frame
- frameBuffer[0] = *stdFrameHeader;
- fread(&(frameBuffer[1]), 1, (*stdFrameSize-1)*sizeof(unsigned char), fpamr);
- if (feof(fpamr)) return 0;
-
- return 1;
- }
- static int ReadAMRFrame(FILE* fpamr, unsigned char frameBuffer[], int stdFrameSize, unsigned char stdFrameHeader)
- {
- size_t bytes = 0;
- unsigned char frameHeader; // 帧头
-
- //memset(frameBuffer, 0, sizeof(frameBuffer));
-
- // Read the frame header
- // If it is a bad frame(not a standard frame),continue for the next byte
- while(1)
- {
- bytes = fread(&frameHeader, 1, sizeof(unsigned char), fpamr);
- if (feof(fpamr)) return 0;
- if (frameHeader == stdFrameHeader) break;
- }
-
- // Audio data for the frame (frame header has beeen read)
- frameBuffer[0] = frameHeader;
- bytes = fread(&(frameBuffer[1]), 1, (stdFrameSize-1)*sizeof(unsigned char), fpamr);
- if (feof(fpamr)) return 0;
-
- return 1;
- }
- // Decode AMR to WAVE file
- int EM_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];
-
- fpamr = fopen(pchAMRFileName, "rb");
-
- if ( fpamr==NULL ) return 0;
-
- // Check the amr file header
- fread(magic, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr);
- if (strncmp(magic, AMR_MAGIC_NUMBER, strlen(AMR_MAGIC_NUMBER)))
- {
- fclose(fpamr);
- return 0;
- }
-
- // Initialize the wave file
- // 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();
-
- // Read the first frame as a reference frame
- memset(amrFrame, 0, MAX_AMR_FRAME_SIZE);
- memset(pcmFrame, 0, PCM_FRAME_SIZE);
- ReadAMRFrameFirst(fpamr, amrFrame, &stdFrameSize, &stdFrameHeader);
-
- // Decode an AMR audio frame to PCM data
- Decoder_Interface_Decode(destate, amrFrame, pcmFrame, 0);
- nFrameCount++;
- fwrite(pcmFrame, sizeof(short), PCM_FRAME_SIZE, fpwave);
-
- // Decode every frame of AMR and write to WAVE file
- while(1)
- {
- memset(amrFrame, 0, MAX_AMR_FRAME_SIZE);
- memset(pcmFrame, 0, PCM_FRAME_SIZE);
- if (!ReadAMRFrame(fpamr, amrFrame, stdFrameSize, stdFrameHeader)) break;
-
- // Decode the AMR audio frame to PCM data
- 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);
-
- // Re-swrite the wave file header
- // fpwave = fopen([docFilePath cStringUsingEncoding:NSASCIIStringEncoding], "r+");
- fpwave = fopen(pchWAVEFilename, "r+");
- WriteWAVEFileHeader(fpwave, nFrameCount);
- fclose(fpwave);
-
- return nFrameCount;
- }
- int isMP3File(const char *filePath){
- FILE* fpamr = NULL;
- char magic[8];
- fpamr = fopen(filePath, "rb");
- if (fpamr==NULL) return 0;
- int isMp3 = 0;
- fread(magic, sizeof(char), strlen(MP3_MAGIC_NUMBER), fpamr);
- if (!strncmp(magic, MP3_MAGIC_NUMBER, strlen(MP3_MAGIC_NUMBER)))
- {
- isMp3 = 1;
- }
- fclose(fpamr);
- return isMp3;
- }
- int isAMRFile(const char *filePath){
- FILE* fpamr = NULL;
- char magic[8];
- fpamr = fopen(filePath, "rb");
- if (fpamr==NULL) return 0;
- int isAmr = 0;
- fread(magic, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr);
- if (!strncmp(magic, AMR_MAGIC_NUMBER, strlen(AMR_MAGIC_NUMBER)))
- {
- isAmr = 1;
- }
- fclose(fpamr);
- return isAmr;
- }
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