Recherche avancée

Sur d’autres sites (13627)

• Dramatic loss in quality while streaming video with FFMPEG and filter_complex

  17 juin 2022, par Holocene121

  I'm trying to overlay an image while I stream a .MP4 video to RTMP.

  


  It's currently working with the following command, however, there is a dramatic difference in quality. It is now pixelated and fuzzy.

  


  ffmpeg -re -i "video.mp4" -i "image.png" -filter_complex overlay -c:a copy -f flv rtmp://localhost/live/stream


  


  Is there a way to maintain close to the original quality while still overlaying an image ?

  


• Streaming engines best practice in C

  20 novembre 2014, par ash

  LANG : C / ENV : Linux

  I am developing a streaming engine, for now I am able to start, stop and pause the stream, but seeking is the operation that’s giving me a lot of headache, I already asked a question here before and fixed some issues inside the code from the answers.

  Using lseek() function, I am passing the open streaming file descriptor as first argument, plus I am using UDP for transmitting, something like the following code :

  transport_fd = open(tsfile, O_RDONLY);
  
  int offset = 1024;
  
  off_t offsetIndicator;
  
  if ((offsetIndicator=lseek(transport_fd, offset, SEEK_CUR))<0) printf("Error seeking\n");

  Whenever I try to seek while streaming, the streaming stops and the pictures hangs.

  Is there anything I should pay attention to ?, i.e : like attempting to sleep() or nanosleep() after seeking into the file in order for the changes to take effect.

  I couldn’t find examples, papers or realted articles for best practices in such engines.

  EDIT :

  After testing, it seems like the file continued to stream but receiving devices on the network didn’t catch the stream connection anymore, and calculating the time it took to finish after subtract seeking time, the stream seems to be finished normally.

  CODE SNIPPET :

  while (!completed) 
  
  {
  
      while (/* Comparing conditions */ && !completed)
  
      { 
  
          if (seekLck == 1) // seekLck is a semaphore to test seek signal from father process initiated by 0
  
          {
  
              int offset = 1024;
  
              off_t offsetIndicator;
  
              if ((offsetIndicator=lseek(transport_fd, offset, SEEK_CUR))<0) 
  
                  printf("Error seeking\n");
  
              nanosleep(&nano_sleep_packet, 0); //Try to sleep to see if it is still hanging, didn't work 
  
              seekLck = 0;
  
          }   
  
          len = read(transport_fd, send_buf, packet_size);
  
          if(len < 0) {
  
              fprintf(stderr, "File read error \n");
  
              completed = 1;
  
          } 
  
          else if (len == 0)
  
          {
  
              fprintf(stderr, "Sent done\n");
  
              completed = 1;
  
          }
  
          else
  
          {
  
              sent = sendto(sockfdstr, send_buf, len, 0, (struct sockaddr *)&addr, sizeof(struct sockaddr_in));
  
              if(sent <= 0)
  
              {
  
                  perror("send(): error ");
  
                  completed = 1;
  
              }
  
          }
  
      }
  
      nanosleep(&nano_sleep_packet, 0);
  
  }
  
  close(transport_fd);
  
  close(sockfdstr);
  
  free(send_buf);
  
  printf("cleaning up\n");
  
  return 0;
  
  }

• ffmpeg command for overlaying a video onto am image with blend

  6 décembre 2022, par tebowner

  I have these requirements but cant seem to get this even close :

  


  

  • ffmpeg to produce a mp4 video

  


  • inputs : an image of varying size, an audio wav of X length, a video for the overlay such as particles or dust

  


  • create an mp4 with the image as the final video size, the overlay video light blended into the image using zoom/crop (no stretching of size), length of video is size of audio

  


  • assume the video overlay is bigger than the image as far as height and width