FFMPEG: avcodec_send_packet(); error while using multithread - ffmpeg

Question

I wrote 2 threads to decode RTSP stream from IP camera as below:
RTSP_read_paket function used to read Packets from RTSP link, packets stored in a queue named Packet_buf.
std::queue<AVPacket> Packet_buf;
bool pkt_pending_k = false;
int RTSP_read_packet (string url)
{
rtsp_init(url);
int ret;
AVPacket packet;
av_init_packet(&packet);
while(1)
{
ret = av_read_frame(pFormatCtx,&packet);
if(ret==0)
{
if (packet.stream_index == video_stream_index)
{
Packet_buf.push(packet);
if((ready1 == false))
{
ready1 = true;
conv1.notify_one();
}
}
av_packet_unref(&packet);
cout<<"number of RTSP packet: "<<Packet_buf.size()<<endl;
}
}
return 0;
}
ffmpeg_decode read packets from Packet_buf to decode frames
AVFrame ffmpeg_decode( void )
{
AVPacket avpkt;
av_init_packet(&avpkt);
int ret;
conv1.wait(lk1,[]{return ready1;});
while(1)
{
while(1)
{
ret = avcodec_receive_frame(pCodecCtx,pFrame);
if(ret == AVERROR(EAGAIN)||ret==AVERROR_EOF){
break;
}
return pFrame;
}
if(!Packet_buf.empty())
{
if(pkt_pending_k == false)
{
avpkt = Packet_buf.front();
Packet_buf.pop();
}else{
pkt_pending_k = false;
}
}
ret = avcodec_send_packet(pCodecCtx, &avpkt); //program halting here
cout<<"-------------> ret = "<<ret<<endl;
if(ret==AVERROR(EAGAIN))
{
pkt_pending_k = true;
}
if(ret<0||ret==AVERROR_EOF)
{
cout<<"avcodec_send_packet: "<<ret<<endl;
break;
}
}
}
int main () {
thread Camera2_readPackets(RTSP_read_packet,url);
thread Camera2_decode(ffmpeg_decode,url);
Camera2_decode.join();
return 0;
}
My program halt at line:
ret = avcodec_send_packet(pCodecCtx, &avpkt);
Anyone can help me find the problem, thanks !
P/s:
rtsp_init function:
int rtsp_init (string url)
{
av_register_all();
avdevice_register_all();
avcodec_register_all();
avformat_network_init();
const char *filenameSrc = url.c_str();
pFormatCtx = avformat_alloc_context();
if ( pFormatCtx == NULL )
return -8;
AVDictionary *options = NULL;
av_dict_set(&options,"rtsp_flags","prefer_tcp",0);
av_dict_set(&options,"stimeout","1000000",0);
int avret = avformat_open_input( &pFormatCtx, filenameSrc, NULL, &options );
av_dict_free(&options);
if ( avret != 0 ) {
std::cout << "Open File Error 12" << std::endl;
return -12;
}
avret = avformat_find_stream_info( pFormatCtx, NULL );
if ( avret < 0 ) {
std::cout << "Get Stream Information Error 13" << std::endl;
avformat_close_input( &pFormatCtx );
pFormatCtx = NULL;
return -13;
}
av_dump_format( pFormatCtx, 0, filenameSrc, 0 );
video_stream_index = av_find_best_stream(pFormatCtx,AVMEDIA_TYPE_VIDEO,-1,-1,NULL,0);
if ( video_stream_index < 0 ) {
std::cout << "Video stream was not found Error 14" << std::endl;
avformat_close_input( &pFormatCtx );
pFormatCtx = NULL;
return -14;
}
pCodecCtx = avcodec_alloc_context3(NULL);
avret = avcodec_parameters_to_context(pCodecCtx,pFormatCtx->streams[video_stream_index]->codecpar);
if(avret<0)
{
std::cout << "codec not found Error 15" << std::endl;
return -15;
}
pCodec = avcodec_find_decoder( pCodecCtx->codec_id );
avret = avcodec_open2( pCodecCtx, pCodec, NULL );
if ( avret < 0) {
std::cout << "Open Codec Error 16" << std::endl;
return -16;
}
pFrame = av_frame_alloc();
pFrameRGB = av_frame_alloc();
pFrame->width = pCodecCtx->width;
pFrame->height = pCodecCtx->height;
pFrame->format = pCodecCtx->pix_fmt;
avret = av_frame_get_buffer(pFrame,0);
if (avret < 0)
{
return -17;
}
pFrameRGB->width = pCodecCtx->width;
pFrameRGB->height = pCodecCtx->height;
pFrameRGB->format = AV_PIX_FMT_BGR24;
avret = av_frame_get_buffer(pFrameRGB, 0);
if (avret < 0)
{
return -18;
}
return ( EXIT_SUCCESS );
}