问iPhone ffmpeg dev使用libav将AMR解码为ACC编解码器

EN

audioFormat.mFormatID = kAudioFormatAMR; 
int err = AudioQueueNewOutput(&audioFormat, MyAudioQueueOutputCallback, self, NULL, kCFRunLoopCommonModes, 0, &audioQueue);

avcodec_decode_audio3

avcodec_encode_audio

- (AVPacket) encodeRawFrame:(const short *) in_buffer withSize:(unsigned int) in_buf_byte_size
{
    AVPacket res;
    AVCodec *codec;
    AVCodecContext *c= NULL;
    int count, out_size, outbuf_size, frame_byte_size;
    uint8_t *outbuf;

    avcodec_init();
    avcodec_register_all();

    printf("Audio encoding\n");

    codec = avcodec_find_encoder(CODEC_ID_AAC);
    if (!codec) {
        fprintf(stderr, "codec not found\n");
        return res;
    }

    c= avcodec_alloc_context();

    c->bit_rate = 64000;
    c->sample_rate = 24000;
    c->channels = 2;

    if (avcodec_open(c, codec) < 0) 
    {
        fprintf(stderr, "could not open codec\n");
    }
    else
    {
        frame_byte_size=c->frame_size*2*2;
        count = in_buf_byte_size/frame_byte_size;

        fprintf(stderr, "Number of frames: %d\n", count);

        outbuf_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
        outbuf = (uint8_t*) malloc(outbuf_size);

        out_size = avcodec_encode_audio(c, outbuf, outbuf_size, &in_buffer[frame_byte_size*i]);
        if(out_size >= 0)
        {
            res.size = outbuf_size;
            res.data = malloc(outbuf_size);                
        }

        free(outbuf);
    }


    avcodec_close(c);
    av_free(c);
    return res;
}