定义音频格式宏

#define PROFILE_AAC_LC 2
#define PROFILE_AAC_HE 5
#define PROFILE_AAC_HE_v2 29
#define PROFILE_AAC_LD 23
#define PROFILE_AAC_ELD 39

初始化

HANDLE_AACENCODER _encoder;

AACENC_ERROR rt = aacEncOpen(&_encoder, 0, 0);
  if (rt != AACENC_OK) {
    NSLog(@"aac enc open error %zd",rt);
    return;
  }
  aacEncoder_SetParam(_encoder, AACENC_AOT, PROFILE_AAC_HE_v2);
  aacEncoder_SetParam(_encoder, AACENC_BITRATE, 64 * 1000);
  aacEncoder_SetParam(_encoder, AACENC_SAMPLERATE, 44100);
  aacEncoder_SetParam(_encoder, AACENC_CHANNELMODE, MODE_2);

编码

  size_t length = xx;//pcm len
  char *point = xx; //pcm data
 
  AACENC_BufDesc in = {0};
  {
    INT bid = IN_AUDIO_DATA;
    INT elSize = 2;
    void *buf[1] = {point};
    in.bufs = buf;
    in.numBufs = 1;
    in.bufferIdentifiers = &bid;
    in.bufElSizes = &elSize;
  }
 
  AACENC_BufDesc out = {0};
  {
    INT size = 1024;
    INT bid = OUT_BITSTREAM_DATA;
    void *buf[1] = {malloc(1024)};
    INT elSize = 1;
   
    out.bufs = buf;
    out.bufSizes = &size;
    out.numBufs = 1;
    out.bufferIdentifiers = &bid;
    out.bufElSizes = &elSize;
  }
 
  AACENC_InArgs inArgs = {0};
  inArgs.numInSamples = (INT)length/2;
 
  AACENC_OutArgs outArgs = {0};
 
  AACENC_ERROR rt = aacEncEncode(_encoder, &in, &out, &inArgs, &outArgs);
  if (rt != AACENC_OK) {
    NSLog(@"aac enc encode error %zd",rt);
  }else{
    NSLog(@"aac enc encode size %zd %zd",outArgs.numOutBytes, out.bufSizes[0]);
  }
 
  if (out.bufs[0]) {
    free(out.bufs[0]);
  }

参考
vlc的例子 https://fossies.org/linux/vlc/modules/codec/fdkaac.c