Receiving RTSP stream using FFMPEG library

Question

I have an IPCamera on my LAN streaming video using RTSP. I have been able to capture and display it successfully using ffplay command:

ffplay rtsp://admin:[email protected]:7070  

(with authentication)

So I would like to achieve the same using programming in C/C++ using ffmpeg library. I guess this must be possible.

So let me phrase two simple questions :

1. How do I receive the stream in a C/C++ program using FFMPEG library? (just provide some URL/tutorial, as google was not helpful)

2. How do I display the received video? (same here, some good URL to direct me).

Answer 1

For rtsp streams the following is working for me (after receiving frames i save the result to a ppm file):

    #include <stdio.h> #include <stdlib.h> #include <iostream> #include <fstream> #include <sstream>  extern "C" {     #include <avcodec.h>     #include <avformat.h>     #include <avio.h>     #include <swscale.h> }  void log_callback(void *ptr, int level, const char *fmt, va_list vargs) {    static char message[8192];    const char *module = NULL;      if (ptr)     {         AVClass *avc = *(AVClass**) ptr;         module = avc->item_name(ptr);     }    vsnprintf_s(message, sizeof(message), fmt, vargs);     std::cout << "LOG: " << message << std::endl; }   int main(int argc, char** argv) {      SwsContext *img_convert_ctx;     AVFormatContext* context = avformat_alloc_context();     AVCodecContext* ccontext = avcodec_alloc_context();     int video_stream_index;      av_register_all();     avformat_network_init();     //av_log_set_callback(&log_callback);      //open rtsp     if(avformat_open_input(&context, "rtsp://134.169.178.187:8554/h264.3gp",NULL,NULL) != 0){         return EXIT_FAILURE;     }      if(avformat_find_stream_info(context,NULL) < 0){         return EXIT_FAILURE;     }      //search video stream     for(int i =0;i<context->nb_streams;i++){         if(context->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)             video_stream_index = i;     }      AVPacket packet;     av_init_packet(&packet);      //open output file     //AVOutputFormat* fmt = av_guess_format(NULL,"test2.mp4",NULL);     AVFormatContext* oc = avformat_alloc_context();     //oc->oformat = fmt;     //avio_open2(&oc->pb, "test.mp4", AVIO_FLAG_WRITE,NULL,NULL);      AVStream* stream=NULL;     int cnt = 0;     //start reading packets from stream and write them to file     av_read_play(context);//play RTSP      AVCodec *codec = NULL;     codec = avcodec_find_decoder(CODEC_ID_H264);     if (!codec) exit(1);      avcodec_get_context_defaults3(ccontext, codec);     avcodec_copy_context(ccontext,context->streams[video_stream_index]->codec);     std::ofstream myfile;      if (avcodec_open(ccontext, codec) < 0) exit(1);      img_convert_ctx = sws_getContext(ccontext->width, ccontext->height, ccontext->pix_fmt, ccontext->width, ccontext->height,                             PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL);      int size = avpicture_get_size(PIX_FMT_YUV420P, ccontext->width, ccontext->height);     uint8_t* picture_buf = (uint8_t*)(av_malloc(size));     AVFrame* pic = avcodec_alloc_frame();     AVFrame* picrgb = avcodec_alloc_frame();     int size2 = avpicture_get_size(PIX_FMT_RGB24, ccontext->width, ccontext->height);     uint8_t* picture_buf2 = (uint8_t*)(av_malloc(size2));     avpicture_fill((AVPicture *) pic, picture_buf, PIX_FMT_YUV420P, ccontext->width, ccontext->height);     avpicture_fill((AVPicture *) picrgb, picture_buf2, PIX_FMT_RGB24, ccontext->width, ccontext->height);      while(av_read_frame(context,&packet)>=0 && cnt <1000)     {//read 100 frames          std::cout << "1 Frame: " << cnt << std::endl;         if(packet.stream_index == video_stream_index){//packet is video             std::cout << "2 Is Video" << std::endl;             if(stream == NULL)             {//create stream in file                 std::cout << "3 create stream" << std::endl;                 stream = avformat_new_stream(oc,context->streams[video_stream_index]->codec->codec);                 avcodec_copy_context(stream->codec,context->streams[video_stream_index]->codec);                 stream->sample_aspect_ratio = context->streams[video_stream_index]->codec->sample_aspect_ratio;             }             int check = 0;             packet.stream_index = stream->id;             std::cout << "4 decoding" << std::endl;             int result = avcodec_decode_video2(ccontext, pic, &check, &packet);             std::cout << "Bytes decoded " << result << " check " << check << std::endl;             if(cnt > 100)//cnt < 0)             {                 sws_scale(img_convert_ctx, pic->data, pic->linesize, 0, ccontext->height, picrgb->data, picrgb->linesize);                 std::stringstream name;                 name << "test" << cnt << ".ppm";                 myfile.open(name.str());                 myfile << "P3 " << ccontext->width << " " << ccontext->height << " 255\n";                 for(int y = 0; y < ccontext->height; y++)                 {                     for(int x = 0; x < ccontext->width * 3; x++)                         myfile << (int)(picrgb->data[0] + y * picrgb->linesize[0])[x] << " ";                 }                 myfile.close();             }             cnt++;         }         av_free_packet(&packet);         av_init_packet(&packet);     }     av_free(pic);     av_free(picrgb);     av_free(picture_buf);     av_free(picture_buf2);      av_read_pause(context);     avio_close(oc->pb);     avformat_free_context(oc);      return (EXIT_SUCCESS); }