av_free crashes application randomly - FFMPEG C++

Question

I am trying to create a simple media-player for an introduction to the world of ffmpeg, the problem is that every time that I call av_freep(void*ptr) the application crashes.

If I don't call av_freep I get a memory leak and the memory used by the program increases up to 1000MB (Already measured), here is the code:

int16_t* audioBuffer=(int16_t*)av_malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE+FF_INPUT_BUFFER_PADDING_SIZE);

if(!audioBuffer){
    MessageBox(0,"Error allocating in audioBuffer","Error: Mem",MB_ICONWARNING | MB_OK);
    return -1;
}

int sz = MEDIA->DecodeAudioFrame((void*)audioBuffer,0);

Pa_WriteStream(MEDIA->output_stream,(int16_t*)audioBuffer,MEDIA->_audio_ccontext->frame_size);

av_freep(audioBuffer);

Here is my 'DecodeAudioFrame' function code:

int WbMedia::DecodeAudioFrame(void *audio_buf, int buf_size){
static AVFrame frame;
static AVPacket pkt;
static uint8_t *audio_pkt_data = NULL;
static int audio_pkt_size = 0;

int len1=0;

for(;;){
    bool do_rt = false;


    while(audio_pkt_size > 0){
        int obt_frame = 0;

        len1 = avcodec_decode_audio4(_audio_ccontext,&frame,&obt_frame,&pkt);
        if(len1 < 0){
            audio_pkt_size = 0;
            break;
        }

        audio_pkt_data+=len1;
        audio_pkt_size-=len1;

        if(obt_frame){
            data_size = av_samples_get_buffer_size(frame.linesize,channel_count,sample_fr,_audio_ccontext->sample_fmt,1);
            memcpy(audio_buf,frame.data[0],data_size);
        }

        if(data_size < 0){
            continue;
        }

        if(pkt.data){
            av_free_packet(&pkt);
        }
        return data_size;

    }

    if(pkt.data){
        av_free_packet(&pkt);
    }

    if(do_rt){
        return data_size;
    }

    // Try to get a new packet
    if(!audio_packets.empty()){
        WaitForSingleObject(Queue_Audio_Mutex,INFINITE);
            pkt = audio_packets.front();
            audio_packets.pop();
        ReleaseMutex(Queue_Audio_Mutex);

        audio_pkt_size = pkt.size;
        audio_pkt_data = pkt.data;
    }else{
        return -1;
    }
}
return 0;
}

I need help with this issue, I don't know if it is a bug or what I need to do. What's happening there? Why does it crashes on the av_freep call? How can I fix it?

Thanks

Answer 1

av_freep takes a pointer to the pointer you want to free; it sets the freed pointer to NULL afterwards. Therefore, you need to use it as

av_freep(&audioBuffer);

Alternatively, you can use

av_free(audioBuffer);
audioBuffer = NULL;

which is equivalent.