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• Saving frames from a network camera (RTSP) to a mp4 file

  24 novembre 2015, par Dídac Pérez

  I am quite confused about how to save a video stream into a mp4 file. I am using ffmpeg. Let me explain the problem :

  1. I connect to a network camera via RTSP (H.264 stream) with avformat_open_input(), avformat_find_stream_info(), av_read_play(), and I get frames with av_read_frame().
  2. Each time I get a frame with av_read_frame(), I store the corresponding AVPacket in a circular buffer.
  3. In some points in my application, a range of this circular buffer is selected. I find a key frame used to start from.
  4. Once I have a list of AVPacket’s starting from a key frame, I write header, frames, and tail, as I described below in the code.

  The problem is that the resulting mp4 video has artifacts if I try to watch it using VLC, Windows Media Player, or another one.

  I have also realized that the pts of that packets are not continuous, while dts are continuous. I know about B frames, but is this a problem in my case ?

  // Prepare the output
  
  AVFormatContext* oc = avformat_alloc_context();
  
  oc->oformat = av_guess_format(NULL, "video.mp4", NULL);
  
  
  
  // Must write header, packets, and trailing
  
  avio_open2(&oc->pb, "video.mp4", AVIO_FLAG_WRITE, NULL, NULL);
  
  
  
  // Write header
  
  AVStream* stream = avformat_new_stream(oc, (AVCodec*) 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;
  
  avformat_write_header(oc, NULL);
  
  
  
  // FOR EACH FRAME...
  
  ... av_write_frame(oc, circular[k]); ...
  
  
  
  // Write trailer and close the file
  
  av_write_trailer(oc);
  
  avcodec_close(stream->codec);
  
  avio_close(oc->pb);
  
  avformat_free_context(oc);

  Thank you so much,

• ffmepg always get broken video streaming from rtsp protocol [on hold]

  6 janvier 2014, par poc

  I'm trying to capture rtsp streaming from Ip Camera by the command

  ffmpeg -t 10 -i  rtsp://172.19.1.42/live.sdp  -ss 00:00:02.500  -c:v copy download.mp4

  However I always get the broken streaming, but if I used the VLC or Qucicktime to watch the RTSP streaming, it worked fine , there was no broken streaming.

  Is there any setting or options for ffmpeg can improve the streaming quality ? Thanks

  [rtsp @ 0x7f9a84017c00] Estimating duration from bitrate, this may be inaccurate
  
  Input #0, rtsp, from 'rtsp://172.19.1.42/live.sdp':
  
    Metadata:
  
      title           : RTSP server
  
    Duration: N/A, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: h264 (Main), yuv420p, 2048x1536, 13.33 tbr, 90k tbn, 180k tbc
  
  -t is not an input option, keeping it for the next output; consider fixing your command line.
  
  Output #0, mp4, to 'c0_s1_h264_1920x1536_10_cbr_500_6000000_imagequality.mp4':
  
    Metadata:
  
      title           : RTSP server
  
      encoder         : Lavf54.63.104
  
      Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 2048x1536, q=2-31, 90k tbn, 90k tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  [NULL @ 0x7f9a83805200] RTP: missed 3 packets
  
      Last message repeated 1 times
  
  RTP: missed 3 packets=-1.0 size=     521kB time=00:00:00.80 bitrate=5303.8kbits/s
  
  [NULL @ 0x7f9a83805200] RTP: missed 3 packets
  
  RTP: missed 3 packets=-1.0 size=     895kB time=00:00:01.40 bitrate=5224.0kbits/s
  
  [NULL @ 0x7f9a83805200] RTP: missed 3 packets
  
  RTP: missed 3 packets=-1.0 size=    1271kB time=00:00:02.00 bitrate=5192.3kbits/s
  
  [NULL @ 0x7f9a83805200] RTP: missed 3 packets
  
  RTP: missed 3 packets=-1.0 size=    1646kB time=00:00:02.60 bitrate=5175.1kbits/s
  
  RTP: missed 2 packets=-1.0 size=    2029kB time=00:00:03.20 bitrate=5183.5kbits/s
  
  RTP: missed 3 packets=-1.0 size=    2420kB time=00:00:03.80 bitrate=5207.3kbits/s
  
  RTP: missed 2 packets=-1.0 size=    2801kB time=00:00:04.40 bitrate=5206.0kbits/s
  
  [NULL @ 0x7f9a83805200] RTP: missed 3 packets
  
  RTP: missed 2 packets=-1.0 size=    3180kB time=00:00:05.00 bitrate=5201.6kbits/s
  
  [NULL @ 0x7f9a83805200] RTP: missed 3 packets
  
  RTP: missed 3 packets=-1.0 size=    4708kB time=00:00:07.41 bitrate=5204.6kbits/s
  
  RTP: missed 2 packets=-1.0 size=    5088kB time=00:00:08.01 bitrate=5202.7kbits/s
  
  RTP: missed 2 packets=-1.0 size=    5857kB time=00:00:09.21 bitrate=5207.3kbits/s
  
  [NULL @ 0x7f9a83805200] RTP: missed 2 packets
  
  frame=  100 fps= 10 q=-1.0 Lsize=    6382kB time=00:00:09.96 bitrate=5246.4kbits/s

• Displaying text on video while recording and if saved then also(add text to video when start recording)

  25 novembre 2017, par J4GD33P 51NGH

  i’m using this android project from git hub and now want to add text to video when start recording. text should also there if we watch saved video later. can anyone suggest me an idea to do this.