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• Writing a series of images into a video file using libavcodec (ffmpeg)

  19 novembre 2013, par user2978372

  Requirements :

  I have a bunch of images (to be more specific they are 1024x768, 24bpp RGB PNG files) that I want to encode into a video files.

  And I need to use 'libavcodec' library, not 'ffmpeg' tool. (well I know they are basically same in the origin, I am emphasizing because someone may answer to use 'ffmpeg' tool, but that's not a solution what I am looking for)

  I am using h264 encoder.

  Target :
  A high quality video with equal resolution (1024 x 768), YUV420P
  each image has a duration of 1 second.
  24 fps

  Problems :
  i've tried with many different (but same resolution and bits) png images, and all have failed to output a good video.

  For some series of images, only the frames of first second was shown in a good shape, but the remaining frames was distorted and color changed (lighter).

  For some series of images, it seemed the images were zoomed-in and distorted again.

  and etc.

  Question :
  I am a total AV newbie and I need someone to verify my steps for encoding. I am total AV newbie.

  1) av_register_all()

  2) avcodec_register_all()

  3) avcodec_find_encoder()

  4) avcodec_alloc_context3()

  5) sets codec configuraton to context.

  6) avcodec_open2()

  7) opens a output file using fopen_s()

  8)

  for(int second=1; second<=10; ++seconds)
  
  {
  
  
  
    Read a image from local using Gdiplus
  
  
  
    Create a gdiplus bitmap and draw the image onto this bitmap
  
  
  
    Get the raw byte data using LockBits
  
  
  
    Transfer this RGB raw byte into YUV420 frame using 'swscontext', 'sws_scale'
  
  
  
    for(int f=0; f<24; ++f)
  
    {
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;
  
      pkt.size = 0;
  
  
  
      pFrame->pts = f;
  
      ret = avcodec_encode_video2(pContext, &pkt, pFrame, &got_output);
  
  
  
      if(got_output)
  
      {
  
          fwrite(pkt.data, 1, pkt.size, outputFile);
  
          av_free_packet(&pkt);
  
      }
  
    }
  
  }
  
  
  
  /* get the delayed frames */
  
  for (got_output = 1; got_output; i++) {
  
      fflush(stdout);
  
  
  
      ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
  
      if (ret < 0) {
  
          fprintf(stderr, "Error encoding frame\n");
  
          exit(1);
  
      }
  
  
  
      if (got_output) {
  
          printf("Write frame %3d (size=%5d)\n", i, pkt.size);
  
          fwrite(pkt.data, 1, pkt.size, f);
  
          av_free_packet(&pkt);
  
      }
  
  }
  
  
  
  close everything required

  I am sure that I misunderstood some steps using ffmpeg api. The above pseudo codes are based on the 'encoding' example of ffmpeg. which part am I doing wrong ? please can someone help me ?

  p.s sorry about broken english. english is not my natvie language. I tried my best =P

• converting audio bytes[] array to RTSP stream using ffmpeg

  19 février 2016, par suresh

  Thanks in adv,

  I am creating a windows application where the goal is to receive bytes array from the stethoscope as input and convert them at runtime to RTSP stream
  ffmpeg seems like the right tool for the conversion, but every command line
  example I have seen takes a file as an input and converting into stream.my aim is I have an input of a byte array , and get an output of a
  RTSP stream. Is it possible to convert byte array to an RTSP stream through ffmpeg.

• RTP Streaming with ffmpeg : server streaming, client failing

  27 novembre 2013, par Christoph Kuhr

  I compiled ffmpeg and x264 myself.

  x264 version :

   #define X264_REV 2377
  
   #define X264_REV_DIFF 0
  
   #define X264_VERSION " r2377 1ca7bb9"
  
   #define X264_POINTVER "0.140.2377 1ca7bb9"

  ffmpeg version : 0.11.4
  ffmpeg configuration :

   --enable-x11grab --enable-pthreads --enable-libfaac --enable-libxvid --enable-libx264 --enable-libv4l2 --enable-libmp3lame --enable-libpulse --enable-gpl --enable-nonfree --disable-yasm

  streaming server call :

  ffmpeg -f x11grab -s 1600x900 -framerate 50 -i :0.0 -vcodec libx264 -threads 4 -preset ultrafast -crf 0 -q:v 1 -b:v 8M -an -f rtp rtp://192.168.188.30:8710
  
  
  
  ...
  
  
  
   Output #0, rtp, to 'rtp://192.168.188.30:8710':
  
    Metadata:
  
      encoder         : Lavf54.6.100
  
      Stream #0:0: Video: h264, yuv420p, 1600x900, q=-1--1, 8000 kb/s, 90k tbn, 50 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo -> libx264)
  
  SDP:
  
  v=0
  
  o=- 0 0 IN IP4 127.0.0.1
  
  s=No Name
  
  c=IN IP4 192.168.188.30
  
  t=0 0
  
  a=tool:libavformat 54.6.100
  
  m=video 8710 RTP/AVP 96
  
  b=AS:8000
  
  a=rtpmap:96 H264/90000
  
  a=fmtp:96 packetization-mode=1

  Everything looks good so far...

  Now the problem.
  I create foo.sdp from the SDP output of the server and try to playback the stream with ffmpeg ffplay foo.sdp. ffplay fails with the following error :

   [sdp @ 0x7f5e0c0008c0] decoding for stream 0 failed
  
   [sdp @ 0x7f5e0c0008c0] Could not find codec parameters (Video: h264)
  
   [sdp @ 0x7f5e0c0008c0] Estimating duration from bitrate, this may be inaccurate
  
   gameserver.sdp: could not find codec parameters

  If I try the same with VLC, it also fails, but with the different error :

    [0x7f3278c045b8] live555 demux error: no data received in 10s, aborting

  Look like different reasons. But I could not solve either. Does anyone have a clue ?