本文共 4917 字，大约阅读时间需要 16 分钟。

代码对一些数据没做判断，仅仅是做个备忘！请谨慎参考！

#include 
   
    #include 
    
     void f32le_convert_to_fltp(float *f32le, float *fltp, int nb_samples) {  float *fltp_l = fltp;               // 左通道  float *fltp_r = fltp + nb_samples;  // 右通道  for (int i = 0; i < nb_samples; i++) {    fltp_l[i] = f32le[i * 2];    fltp_r[i] = f32le[i * 2 + 1];  }}static void get_adts_header(AVCodecContext *ctx, uint8_t *adts_header,                            int aac_length) {  uint8_t freq_idx = 0;  switch (ctx->sample_rate) {    case 96000:      freq_idx = 0;      break;    case 88200:      freq_idx = 1;      break;    case 64000:      freq_idx = 2;      break;    case 48000:      freq_idx = 3;      break;    case 44100:      freq_idx = 4;      break;    case 32000:      freq_idx = 5;      break;    case 24000:      freq_idx = 6;      break;    case 22050:      freq_idx = 7;      break;    case 16000:      freq_idx = 8;      break;    case 12000:      freq_idx = 9;      break;    case 11025:      freq_idx = 10;      break;    case 8000:      freq_idx = 11;      break;    case 7350:      freq_idx = 12;      break;    default:      freq_idx = 4;      break;  }  uint8_t chanCfg = ctx->channels;  uint32_t frame_length = aac_length + 7;  adts_header[0] = 0xFF;  adts_header[1] = 0xF1;  adts_header[2] = ((ctx->profile) << 6) + (freq_idx << 2) + (chanCfg >> 2);  adts_header[3] = (((chanCfg & 3) << 6) + (frame_length >> 11));  adts_header[4] = ((frame_length & 0x7FF) >> 3);  adts_header[5] = (((frame_length & 7) << 5) + 0x1F);  adts_header[6] = 0xFC;}void encode_audio(AVCodecContext *codec_ctx, AVFrame *frame, AVPacket *pkt,                  FILE *out_aac) {  int ret;  ret = avcodec_send_frame(codec_ctx, frame);  while (!ret) {    ret = avcodec_receive_packet(codec_ctx, pkt);    if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {      printf("EAGAIN OR EOF\n");      return;    } else if (ret < 0) {      printf("error 6\n");      exit(1);    }    if ((codec_ctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER)) {      uint8_t aac_header[7];//7个字节的adts header      get_adts_header(codec_ctx, aac_header, pkt->size);      ret = fwrite(aac_header, 1, 7, out_aac);      if (ret != 7) {        fprintf(stderr, "fwrite aac_header failed\n");        return -1;      }    }    fwrite(pkt->data, 1, pkt->size, out_aac);  }}/** * @brief 音频编码 PCM编码为AAC * @param argc * @param argv * @return */int main(int argc, char **argv) {  AVCodecContext *codec_ctx;  AVCodec *codec;  FILE *in_pcm;  FILE *out_aac;  AVPacket *pkt;  AVFrame *frame;  int ret;  if(argc != 3){      printf("param error\n");      exit(1);  }  in_pcm = fopen(argv[1], "rb");  out_aac = fopen(argv[2], "wb");  codec = avcodec_find_encoder(AV_CODEC_ID_AAC);  if (!codec) {    printf("error 1\n");    exit(1);  }  codec_ctx = avcodec_alloc_context3(codec);  codec_ctx->codec_id = AV_CODEC_ID_AAC;  codec_ctx->sample_rate = 44100;  codec_ctx->bit_rate = 512 * 1024;  codec_ctx->channels = 2;  codec_ctx->channel_layout = AV_CH_LAYOUT_STEREO;  codec_ctx->sample_fmt = AV_SAMPLE_FMT_FLTP;  codec_ctx->profile = FF_PROFILE_AAC_LOW;  codec_ctx->codec_type = AVMEDIA_TYPE_AUDIO;  codec_ctx->time_base = (AVRational){1, codec_ctx->sample_rate};  codec_ctx->flags = AV_CODEC_FLAG_GLOBAL_HEADER;  ret = avcodec_open2(codec_ctx, codec, NULL);  if (ret) {    printf("error 2\n");    exit(1);  }  frame = av_frame_alloc();  frame->nb_samples = codec_ctx->frame_size;  frame->channels = 2;  frame->channel_layout = AV_CH_LAYOUT_STEREO;  frame->format = codec_ctx->sample_fmt;  ret = av_frame_get_buffer(frame, 0);  int nb_samples = 0;  if (ret) {    printf("error 3\n");    exit(1);  }  pkt = av_packet_alloc();  av_init_packet(pkt);  int bytes_per_frame = av_get_bytes_per_sample(AV_SAMPLE_FMT_FLTP) *                        frame->nb_samples * frame->channels;  uint8_t *in_buf = (uint8_t *)av_mallocz(bytes_per_frame);  uint8_t *in_buf_temp = (uint8_t *)malloc(bytes_per_frame);  if (!in_buf_temp) {    printf("in_buf_temp malloc failed\n");    return 1;  }  while (fread(in_buf, 1, bytes_per_frame, in_pcm) == bytes_per_frame) {    ret = av_frame_make_writable(frame);    //fltp如果是按照packeted方式存储的，需要先转换成planar方式//    memset(in_buf_temp, 0, bytes_per_frame);//    f32le_convert_to_fltp((float *)in_buf, (float *)in_buf_temp,//                          frame->nb_samples);    ret = av_samples_fill_arrays(frame->data, frame->linesize, in_buf/*in_buf_temp*/,                                 frame->channels, frame->nb_samples,                                 frame->format, 0);    if (ret < 0) {      printf("error 4\n");      exit(1);    }    frame->pts = nb_samples;    nb_samples += frame->nb_samples;    encode_audio(codec_ctx, frame, pkt, out_aac);    memset(in_buf, 0, bytes_per_frame);  }  encode_audio(codec_ctx, NULL, pkt, out_aac);end:  fclose(in_pcm);  fclose(out_aac);  avcodec_free_context(&codec_ctx);  av_frame_free(&frame);  av_packet_free(&pkt);  printf("Hello World!\n");  return 0;}
    
   

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