amrFileCodec.mm 11 KB

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  1. //
  2. // amrFileCodec.cpp
  3. // amrDemoForiOS
  4. //
  5. // Created by Tang Xiaoping on 9/27/11.
  6. // Copyright 2011 test. All rights reserved.
  7. //
  8. #include "amrFileCodec.h"
  9. static int amrEncodeMode[] = {4750, 5150, 5900, 6700, 7400, 7950, 10200, 12200};
  10. // Skip the WAVE header to PCM audio data
  11. static void SkipToPCMAudioData(FILE* fpwave)
  12. {
  13. EM_RIFFHEADER riff;
  14. EM_FMTBLOCK fmt;
  15. EM_XCHUNKHEADER chunk;
  16. EM_WAVEFORMATX wfx;
  17. int bDataBlock = 0;
  18. // 1. Read the RIFF header
  19. fread(&riff, 1, sizeof(EM_RIFFHEADER), fpwave);
  20. // 2. Read the FMT chunk - if fmt.nFmtSize>16, read the remaining MATX
  21. fread(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
  22. if ( chunk.nChunkSize>16 )
  23. {
  24. fread(&wfx, 1, sizeof(EM_WAVEFORMATX), fpwave);
  25. }
  26. else
  27. {
  28. memcpy(fmt.chFmtID, chunk.chChunkID, 4);
  29. fmt.nFmtSize = chunk.nChunkSize;
  30. fread(&fmt.wf, 1, sizeof(EM_WAVEFORMAT), fpwave);
  31. }
  32. // 3.Switch to the data block
  33. while(!bDataBlock)
  34. {
  35. fread(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
  36. if ( !memcmp(chunk.chChunkID, "data", 4) )
  37. {
  38. bDataBlock = 1;
  39. break;
  40. }
  41. fseek(fpwave, chunk.nChunkSize, SEEK_CUR);
  42. }
  43. }
  44. // Read PCM frame from wave file
  45. // Return 0 for error, otherwise return a positive number of the size of frame
  46. static size_t ReadPCMFrame(short speech[], FILE* fpwave, int nChannels, int nBitsPerSample)
  47. {
  48. size_t nRead = 0;
  49. int x = 0, y=0;
  50. // unsigned short ush1=0, ush2=0, ush=0;
  51. // Original PCM autio frame data
  52. unsigned char pcmFrame_8b1[PCM_FRAME_SIZE];
  53. unsigned char pcmFrame_8b2[PCM_FRAME_SIZE<<1];
  54. unsigned short pcmFrame_16b1[PCM_FRAME_SIZE];
  55. unsigned short pcmFrame_16b2[PCM_FRAME_SIZE<<1];
  56. if (nBitsPerSample==8 && nChannels==1)
  57. {
  58. nRead = fread(pcmFrame_8b1, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave);
  59. for(x=0; x<PCM_FRAME_SIZE; x++)
  60. {
  61. speech[x] =(short)((short)pcmFrame_8b1[x] << 7);
  62. }
  63. }
  64. else
  65. if (nBitsPerSample==8 && nChannels==2)
  66. {
  67. nRead = fread(pcmFrame_8b2, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave);
  68. for( x=0, y=0; y<PCM_FRAME_SIZE; y++,x+=2 )
  69. {
  70. // 1 - Left Channel
  71. speech[y] =(short)((short)pcmFrame_8b2[x+0] << 7);
  72. // 2 - Right Channel
  73. //speech[y] =(short)((short)pcmFrame_8b2[x+1] << 7);
  74. // 3 - The average of two channels
  75. //ush1 = (short)pcmFrame_8b2[x+0];
  76. //ush2 = (short)pcmFrame_8b2[x+1];
  77. //ush = (ush1 + ush2) >> 1;
  78. //speech[y] = (short)((short)ush << 7);
  79. }
  80. }
  81. else
  82. if (nBitsPerSample==16 && nChannels==1)
  83. {
  84. nRead = fread(pcmFrame_16b1, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave);
  85. for(x=0; x<PCM_FRAME_SIZE; x++)
  86. {
  87. speech[x] = (short)pcmFrame_16b1[x+0];
  88. }
  89. }
  90. else
  91. if (nBitsPerSample==16 && nChannels==2)
  92. {
  93. nRead = fread(pcmFrame_16b2, (nBitsPerSample/8), PCM_FRAME_SIZE*nChannels, fpwave);
  94. for( x=0, y=0; y<PCM_FRAME_SIZE; y++,x+=2 )
  95. {
  96. //speech[y] = (short)pcmFrame_16b2[x+0];
  97. speech[y] = (short)((int)((int)pcmFrame_16b2[x+0] + (int)pcmFrame_16b2[x+1])) >> 1;
  98. }
  99. }
  100. // Return 0 unless read a complete PCM frame
  101. if (nRead<PCM_FRAME_SIZE*nChannels) return 0;
  102. return nRead;
  103. }
  104. // WAVE audio processing frequency is 8khz
  105. // audio sample processing units = 8000*0.02 = 160 (decided by audio processing frequency)
  106. // audio channels 1 : 160
  107. // 2 : 160*2 = 320
  108. // bps decides the size of sample
  109. // bps = 8 --> 8 bits
  110. // 16 --> 16 bits
  111. int EM_EncodeWAVEFileToAMRFile(const char* pchWAVEFilename, const char* pchAMRFileName, int nChannels, int nBitsPerSample)
  112. {
  113. FILE* fpwave;
  114. FILE* fpamr;
  115. /* input speech vector */
  116. short speech[160];
  117. /* counters */
  118. int byte_counter, frames = 0;
  119. size_t bytes = 0;
  120. /* pointer to encoder state structure */
  121. void *enstate;
  122. /* requested mode */
  123. enum Mode req_mode = MR122;
  124. int dtx = 0;
  125. /* bitstream filetype */
  126. unsigned char amrFrame[MAX_AMR_FRAME_SIZE];
  127. fpwave = fopen(pchWAVEFilename, "rb");
  128. if (fpwave == NULL)
  129. {
  130. return 0;
  131. }
  132. // Initialize the amr file
  133. fpamr = fopen(pchAMRFileName, "wb");
  134. if (fpamr == NULL)
  135. {
  136. fclose(fpwave);
  137. return 0;
  138. }
  139. /* write magic number to indicate single channel AMR file storage format */
  140. bytes = fwrite(AMR_MAGIC_NUMBER, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr);
  141. /* skip to pcm audio data*/
  142. SkipToPCMAudioData(fpwave);
  143. enstate = Encoder_Interface_init(dtx);
  144. while(1)
  145. {
  146. // read one pcm frame
  147. if (!ReadPCMFrame(speech, fpwave, nChannels, nBitsPerSample)) break;
  148. frames++;
  149. /* call encoder */
  150. byte_counter = Encoder_Interface_Encode(enstate, req_mode, speech, amrFrame, 0);
  151. bytes += byte_counter;
  152. fwrite(amrFrame, sizeof (unsigned char), byte_counter, fpamr );
  153. }
  154. Encoder_Interface_exit(enstate);
  155. fclose(fpamr);
  156. fclose(fpwave);
  157. return frames;
  158. }
  159. #pragma mark - Decode
  160. //decode
  161. static void WriteWAVEFileHeader(FILE* fpwave, int nFrame)
  162. {
  163. char tag[10] = "";
  164. // 1. RIFF header
  165. EM_RIFFHEADER riff;
  166. strcpy(tag, "RIFF");
  167. memcpy(riff.chRiffID, tag, 4);
  168. riff.nRiffSize = 4 // WAVE
  169. + sizeof(EM_XCHUNKHEADER) // fmt
  170. + sizeof(EM_WAVEFORMATX) // EM_WAVEFORMATX
  171. + sizeof(EM_XCHUNKHEADER) // DATA
  172. + nFrame*160*sizeof(short); //
  173. strcpy(tag, "WAVE");
  174. memcpy(riff.chRiffFormat, tag, 4);
  175. fwrite(&riff, 1, sizeof(EM_RIFFHEADER), fpwave);
  176. // 2. FMT chunk
  177. EM_XCHUNKHEADER chunk;
  178. EM_WAVEFORMATX wfx;
  179. strcpy(tag, "fmt ");
  180. memcpy(chunk.chChunkID, tag, 4);
  181. chunk.nChunkSize = sizeof(EM_WAVEFORMATX);
  182. fwrite(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
  183. memset(&wfx, 0, sizeof(EM_WAVEFORMATX));
  184. wfx.nFormatTag = 1;
  185. wfx.nChannels = 1; // Single channel
  186. wfx.nSamplesPerSec = 8000; // 8khz
  187. wfx.nAvgBytesPerSec = 16000;
  188. wfx.nBlockAlign = 2;
  189. wfx.nBitsPerSample = 16;
  190. fwrite(&wfx, 1, sizeof(EM_WAVEFORMATX), fpwave);
  191. // 3. Write data chunk
  192. strcpy(tag, "data");
  193. memcpy(chunk.chChunkID, tag, 4);
  194. chunk.nChunkSize = nFrame*160*sizeof(short);
  195. fwrite(&chunk, 1, sizeof(EM_XCHUNKHEADER), fpwave);
  196. }
  197. static const int myround(const double x)
  198. {
  199. return((int)(x+0.5));
  200. }
  201. // Calculate the AMR frame size with the frame header
  202. static int caclAMRFrameSize(unsigned char frameHeader)
  203. {
  204. int mode;
  205. int temp1 = 0;
  206. int temp2 = 0;
  207. int frameSize;
  208. temp1 = frameHeader;
  209. // Get AMR Encode Mode with the 3 - 6 digit of frame header
  210. temp1 &= 0x78; // 0111-1000
  211. temp1 >>= 3;
  212. mode = amrEncodeMode[temp1];
  213. // Calculate the arm auodio framze size
  214. // Theory: one frame is 20 mili seconds, then one second is 50 frames of audio data
  215. temp2 = myround((double)(((double)mode / (double)AMR_FRAME_COUNT_PER_SECOND) / (double)8));
  216. frameSize = myround((double)temp2 + 0.5);
  217. return frameSize;
  218. }
  219. // Read the first AMR frame - (Reference frame)
  220. // return 0 for error and 1 for success
  221. static int ReadAMRFrameFirst(FILE* fpamr, unsigned char frameBuffer[], int* stdFrameSize, unsigned char* stdFrameHeader)
  222. {
  223. //memset(frameBuffer, 0, sizeof(frameBuffer));
  224. // Read the frame header
  225. fread(stdFrameHeader, 1, sizeof(unsigned char), fpamr);
  226. if (feof(fpamr)) return 0;
  227. // Calculate the frame size with frame header
  228. *stdFrameSize = caclAMRFrameSize(*stdFrameHeader);
  229. // Read the first frame
  230. frameBuffer[0] = *stdFrameHeader;
  231. fread(&(frameBuffer[1]), 1, (*stdFrameSize-1)*sizeof(unsigned char), fpamr);
  232. if (feof(fpamr)) return 0;
  233. return 1;
  234. }
  235. static int ReadAMRFrame(FILE* fpamr, unsigned char frameBuffer[], int stdFrameSize, unsigned char stdFrameHeader)
  236. {
  237. size_t bytes = 0;
  238. unsigned char frameHeader; // 帧头
  239. //memset(frameBuffer, 0, sizeof(frameBuffer));
  240. // Read the frame header
  241. // If it is a bad frame(not a standard frame),continue for the next byte
  242. while(1)
  243. {
  244. bytes = fread(&frameHeader, 1, sizeof(unsigned char), fpamr);
  245. if (feof(fpamr)) return 0;
  246. if (frameHeader == stdFrameHeader) break;
  247. }
  248. // Audio data for the frame (frame header has beeen read)
  249. frameBuffer[0] = frameHeader;
  250. bytes = fread(&(frameBuffer[1]), 1, (stdFrameSize-1)*sizeof(unsigned char), fpamr);
  251. if (feof(fpamr)) return 0;
  252. return 1;
  253. }
  254. // Decode AMR to WAVE file
  255. int EM_DecodeAMRFileToWAVEFile(const char* pchAMRFileName, const char* pchWAVEFilename)
  256. {
  257. FILE* fpamr = NULL;
  258. FILE* fpwave = NULL;
  259. char magic[8];
  260. void * destate;
  261. int nFrameCount = 0;
  262. int stdFrameSize;
  263. unsigned char stdFrameHeader;
  264. unsigned char amrFrame[MAX_AMR_FRAME_SIZE];
  265. short pcmFrame[PCM_FRAME_SIZE];
  266. fpamr = fopen(pchAMRFileName, "rb");
  267. if ( fpamr==NULL ) return 0;
  268. // Check the amr file header
  269. fread(magic, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr);
  270. if (strncmp(magic, AMR_MAGIC_NUMBER, strlen(AMR_MAGIC_NUMBER)))
  271. {
  272. fclose(fpamr);
  273. return 0;
  274. }
  275. // Initialize the wave file
  276. // NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  277. // NSString *documentPath = [paths objectAtIndex:0];
  278. // NSString *docFilePath = [documentPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%s", pchWAVEFilename]];
  279. // NSLog(@"documentPath=%@", documentPath);
  280. //
  281. // fpwave = fopen([docFilePath cStringUsingEncoding:NSASCIIStringEncoding], "wb");
  282. fpwave = fopen(pchWAVEFilename,"wb");
  283. WriteWAVEFileHeader(fpwave, nFrameCount);
  284. /* init decoder */
  285. destate = Decoder_Interface_init();
  286. // Read the first frame as a reference frame
  287. memset(amrFrame, 0, MAX_AMR_FRAME_SIZE);
  288. memset(pcmFrame, 0, PCM_FRAME_SIZE);
  289. ReadAMRFrameFirst(fpamr, amrFrame, &stdFrameSize, &stdFrameHeader);
  290. // Decode an AMR audio frame to PCM data
  291. Decoder_Interface_Decode(destate, amrFrame, pcmFrame, 0);
  292. nFrameCount++;
  293. fwrite(pcmFrame, sizeof(short), PCM_FRAME_SIZE, fpwave);
  294. // Decode every frame of AMR and write to WAVE file
  295. while(1)
  296. {
  297. memset(amrFrame, 0, MAX_AMR_FRAME_SIZE);
  298. memset(pcmFrame, 0, PCM_FRAME_SIZE);
  299. if (!ReadAMRFrame(fpamr, amrFrame, stdFrameSize, stdFrameHeader)) break;
  300. // Decode the AMR audio frame to PCM data
  301. Decoder_Interface_Decode(destate, amrFrame, pcmFrame, 0);
  302. nFrameCount++;
  303. fwrite(pcmFrame, sizeof(short), PCM_FRAME_SIZE, fpwave);
  304. }
  305. //NSLog(@"frame = %d", nFrameCount);
  306. Decoder_Interface_exit(destate);
  307. fclose(fpwave);
  308. // Re-swrite the wave file header
  309. // fpwave = fopen([docFilePath cStringUsingEncoding:NSASCIIStringEncoding], "r+");
  310. fpwave = fopen(pchWAVEFilename, "r+");
  311. WriteWAVEFileHeader(fpwave, nFrameCount);
  312. fclose(fpwave);
  313. return nFrameCount;
  314. }
  315. int isMP3File(const char *filePath){
  316. FILE* fpamr = NULL;
  317. char magic[8];
  318. fpamr = fopen(filePath, "rb");
  319. if (fpamr==NULL) return 0;
  320. int isMp3 = 0;
  321. fread(magic, sizeof(char), strlen(MP3_MAGIC_NUMBER), fpamr);
  322. if (!strncmp(magic, MP3_MAGIC_NUMBER, strlen(MP3_MAGIC_NUMBER)))
  323. {
  324. isMp3 = 1;
  325. }
  326. fclose(fpamr);
  327. return isMp3;
  328. }
  329. int isAMRFile(const char *filePath){
  330. FILE* fpamr = NULL;
  331. char magic[8];
  332. fpamr = fopen(filePath, "rb");
  333. if (fpamr==NULL) return 0;
  334. int isAmr = 0;
  335. fread(magic, sizeof(char), strlen(AMR_MAGIC_NUMBER), fpamr);
  336. if (!strncmp(magic, AMR_MAGIC_NUMBER, strlen(AMR_MAGIC_NUMBER)))
  337. {
  338. isAmr = 1;
  339. }
  340. fclose(fpamr);
  341. return isAmr;
  342. }