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• H264 Encoding - Could not play video using VLC Player

  31 mars 2016, par bot1131357

  I am have trouble encoding an H264 video correctly using FFmpeg libav. I could not play the encoded video in VLC media player, and although I could play the video on MPC-HC the time shows 00:00/00:00. Clearly I’m missing something.

  The Media info from MPC-HC shows this :

  General
  Format : AVC
  Format/Info : Advanced Video Codec
  File size : 110 KiB
  Duration : 2s 400ms
  Overall bit rate : 375 Kbps
  Writing library : x264 core 148 r2665 a01e339
  Encoding settings : cabac=0 / ref=3 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=7 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=0 / keyint=12 / keyint_min=1 / scenecut=40 / intra_refresh=0 / rc_lookahead=12 / rc=abr / mbtree=1 / bitrate=2000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

  Video
  Format : AVC
  Format/Info : Advanced Video Codec
  Format profile : Baseline@L2.1
  Format settings, CABAC : No
  Format settings, ReFrames : 3 frames
  Format settings, GOP : M=1, N=12
  Duration : 2s 400ms
  Bit rate : 2 000 Kbps
  Width : 320 pixels
  Height : 240 pixels
  Display aspect ratio : 4:3
  Frame rate mode : Variable
  Frame rate : 20.833 fps
  Color space : YUV
  Chroma subsampling : 4:2:0
  Bit depth : 8 bits
  Scan type : Progressive
  Bits/(Pixel*Frame) : 1.250
  Stream size : 586 KiB
  Writing library : x264 core 148 r2665 a01e339
  Encoding settings : cabac=0 / ref=3 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=7 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=0 / keyint=12 / keyint_min=1 / scenecut=40 / intra_refresh=0 / rc_lookahead=12 / rc=abr / mbtree=1 / bitrate=2000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

  I noticed something odd in the above info :
   The frame rate is 20.833 fps, instead of the specified 10 fps.
   Duration of 2s 400ms did not seem right either, since the video played for more than 4s.

  Also, (AVFrame* picture)->pict_type is always set to AV_PICTURE_TYPE_NONE. I don’t think this is normal.

  The library that I’m using is ffmpeg-20160219-git-98a0053-win32-dev. I would really really appreciate if you could help me out of this confusion.

  /*
  
   * Video encoding example
  
   */
  
  char filename[] = "test.mp4";
  
  int main(int argc, char** argv)
  
  {
  
      AVCodec *codec = NULL;
  
      AVCodecContext *codecCtx= NULL;
  
      AVFormatContext *pFormatCtx = NULL;
  
      AVStream * pVideoStream = NULL;
  
      AVFrame *picture = NULL;
  
  
  
      int i, x, y,            //
  
          ret,                // Return value
  
          got_packet_ptr;     // Data encoded into packet
  
  
  
      printf("Video encoding\n");
  
  
  
      // Register all formats and codecs
  
      av_register_all();
  
  
  
      // allocate context
  
      pFormatCtx = avformat_alloc_context();
  
      memcpy(pFormatCtx->filename,filename,
  
          min(strlen(filename), sizeof(pFormatCtx->filename)));
  
  
  
      // guess format
  
      pFormatCtx->oformat = av_guess_format("h264", NULL, NULL);
  
      if (NULL==pFormatCtx->oformat)
  
      {
  
          cerr << "Could not guess output format" << endl;
  
          return -1;
  
      }   
  
  
  
      // Find the codec.
  
      codec = avcodec_find_encoder(pFormatCtx->oformat->video_codec);
  
      if (codec == NULL) {
  
          fprintf(stderr, "Codec not found\n");
  
          return -1;
  
      }
  
  
  
      // Set context
  
      int framerate = 10;
  
      codecCtx = avcodec_alloc_context3(codec);
  
      avcodec_get_context_defaults3(codecCtx, codec); 
  
      codecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
  
      codecCtx->profile = FF_PROFILE_H264_BASELINE; 
  
      // Resolution must be a multiple of two.
  
      codecCtx->width  = 320;
  
      codecCtx->height = 240;
  
  
  
      codecCtx->bit_rate = 2000000;
  
      codecCtx->time_base.den = framerate;
  
      codecCtx->time_base.num = 1;
  
      codecCtx->gop_size = 12; // emit one intra frame every twelve frames at most
  
  
  
      // Open the codec.  
  
      if (avcodec_open2(codecCtx, codec, NULL) < 0) 
  
      {
  
          printf("Cannot open video codec\n");
  
          return -1;
  
      }
  
  
  
      // Add stream to pFormatCtx
  
      pVideoStream = avformat_new_stream(pFormatCtx, codec);
  
      if (!pVideoStream) 
  
      {
  
          printf("Cannot add new video stream\n");
  
          return -1;
  
      }
  
      pVideoStream->codec = codecCtx;
  
      pVideoStream->time_base.den = framerate;
  
      pVideoStream->time_base.num = 1;
  
  
  
      if (avio_open2(&pFormatCtx->pb, filename, AVIO_FLAG_WRITE, NULL, NULL) < 0) 
  
      {
  
          printf("Cannot open file\n");
  
          return -1;
  
      }
  
  
  
      // Write file header.
  
      avformat_write_header(pFormatCtx, NULL);
  
  
  
      // Create frame
  
      picture= av_frame_alloc();
  
      picture->format = codecCtx->pix_fmt;
  
      picture->width  = codecCtx->width;
  
      picture->height = codecCtx->height;
  
  
  
      int bufferImgSize = av_image_get_buffer_size(codecCtx->pix_fmt, codecCtx->width,
  
                      codecCtx->height,1);    
  
      av_image_alloc(picture->data, picture->linesize, codecCtx->width, codecCtx->height,                 codecCtx->pix_fmt, 32);
  
  
  
      AVPacket avpkt;
  
  
  
      /* encode 1 second of video */
  
      for(i=0;i<50;i++) 
  
      {
  
          /* prepare a dummy image */
  
          /* Y */
  
          for(y=0;yheight;y++)
  
          {
  
              for(x=0;xwidth;x++) 
  
              {
  
                  picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
  
              }
  
          }
  
          /* Cb and Cr */
  
          for(y=0;yheight/2;y++) 
  
          {
  
              for(x=0;xwidth/2;x++) 
  
              {
  
                  picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
  
                  picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
  
              }
  
          }
  
  
  
          // Get timestamp
  
          picture->pts = (float) i * (1000.0/(float)(codecCtx->time_base.den)) * 90; 
  
  
  
          // Encode frame to packet
  
          av_init_packet(&avpkt);
  
          got_packet_ptr = 0;
  
          int error = avcodec_encode_video2(codecCtx, &avpkt, picture, &got_packet_ptr);
  
          if (!error && got_packet_ptr > 0) 
  
          {
  
              // Write packet with frame.
  
              ret = (av_interleaved_write_frame(pFormatCtx, &avpkt) == 0);        
  
          }   
  
          av_packet_unref(&avpkt); 
  
      }
  
  
  
      // Flush remaining encoded data
  
      while(1)
  
      {
  
          av_init_packet(&avpkt);
  
          got_packet_ptr = 0;
  
          // Encode frame to packet.
  
          int error = avcodec_encode_video2(codecCtx, &avpkt, NULL, &got_packet_ptr);
  
          if (!error && got_packet_ptr > 0) 
  
          {
  
              // Write packet with frame.
  
              ret = (av_interleaved_write_frame(pFormatCtx, &avpkt) == 0);        
  
          } 
  
          else 
  
          {
  
              break;
  
          }
  
          av_packet_unref(&avpkt); 
  
      }
  
      av_write_trailer(pFormatCtx);
  
  
  
      av_packet_unref(&avpkt);
  
      av_frame_free(&picture);
  
  
  
      avcodec_close(codecCtx);
  
      av_free(codecCtx);
  
  
  
      cin.get();
  
  }

• Fix min/max validation. Closes gh-666. Fixes #648

  20 mars 2013, par ekonijn

  Fix min/max validation. Closes gh-666. Fixes #648
  In 1.10.0, min/max validation was supported for input type="text",
  
  where min/max were interpreted as numbers.  This means min/max
  
  for date would not work : min="2012-02-13" was interpreted as min="Not a Number".
  In 1.11.0, min/max were no longer converted to numbers.  This means
  
  min/max for dates worked, but min/max for numbers failed :
  
  "50" < "150" < "1000" does not hold.
  For an example, see http://jsbin.com/awokex/3
  This commit makes the behaviour of min/max dependent on input type :
   * input type=text (or not type attribute) has numeric min/max, as in 1.10.0
  
   * input type=date has working min/max for type date ;
  
     on mobile browsers you also get a date picker,
  
     plus the browser may reject invalid dates before
  
     javascript gets a chance to complain.
  
   * input type=number or range get numeric min/max,
  
     plus numeric keypad or slider on mobile browsers,
  
     plus browser may reject invalid input before javascript
  
     gets a chance to complain
  Allowing use of min/max with type=number/range/date is important
  
  for mobile browsers, where the numeric keypad or date picker
  
  make the input much easier to use than a generic text input field.
  
  In this situation jquery-validate remains necessary to support
  
  older browsers that do not do input validation based on type
  
  and min/max.
  For situations where numeric input should be validated by jquery
  
  without giving the browser a chance to validate the input format,
  
  input type=text in combination with min/max can be used, as in 1.10.0.
  

• Writing an MP4 file on the Mac with OpenCV ffmpeg

  13 janvier 2015, par Sameer Parekh

  I am using OpenCV with ffmpeg on a mac to write video. I’ve been able to successfully write .avi files using the codec/fourcc code, FMP4. I would like to write .mp4 files, however. When I try to write an .mp4 file using fourcc FMP4 I get this error :

  [mp4 @ 0x100b4ec00] Tag FMP4/0x34504d46 incompatible with output codec id '13' ( [0][0][0])

  When I use AVC1 I get the following error :

  [libx264 @ 0x104003000] broken ffmpeg default settings detected
  
  [libx264 @ 0x104003000] use an encoding preset (e.g. -vpre medium)
  
  [libx264 @ 0x104003000] preset usage: -vpre <speed> -vpre <profile>
  
  [libx264 @ 0x104003000] speed presets are listed in x264 --help
  
  [libx264 @ 0x104003000] profile is optional; x264 defaults to high
  
  Could not open codec 'libx264': Unspecified error
  
  </profile></speed>

  Does anyone here know the right codec to use with OpenCV and ffmpeg to write to an MP4 container on the Mac ?

  If AVC1 is the right codec, how do I install ffmpeg + OpenCV correctly ? I did

  brew install gpac
  
  brew install ffmpeg
  
  brew install opencv

  The call I am using to open the videowriter :

  fourcc = cv2.cv.CV_FOURCC('A', 'V', 'C', '1')   
  
  video_out = cv2.VideoWriter(
  
      filename=output_filename,
  
      fourcc=fourcc,
  
      fps=video_fps,
  
      frameSize=(video_width,video_height),
  
      isColor=1)

  When I run x264 --help I get

  % x264 --help
  
  x264 core:125
  
  Syntax: x264 [options] -o outfile infile
  
  
  
  Infile can be raw (in which case resolution is required),
  
    or YUV4MPEG (*.y4m),
  
    or Avisynth if compiled with support (no).
  
    or libav* formats if compiled with lavf support (no) or ffms support (no).
  
  Outfile type is selected by filename:
  
   .264 -> Raw bytestream
  
   .mkv -> Matroska
  
   .flv -> Flash Video
  
   .mp4 -> MP4 if compiled with GPAC support (no)
  
  Output bit depth: 8 (configured at compile time)
  
  
  
  Options:
  
  
  
    -h, --help                  List basic options
  
        --longhelp              List more options
  
        --fullhelp              List all options
  
  
  
  Example usage:
  
  
  
        Constant quality mode:
  
              x264 --crf 24 -o <output> <input />
  
  
  
        Two-pass with a bitrate of 1000kbps:
  
              x264 --pass 1 --bitrate 1000 -o <output> <input />
  
              x264 --pass 2 --bitrate 1000 -o <output> <input />
  
  
  
        Lossless:
  
              x264 --qp 0 -o <output> <input />
  
  
  
        Maximum PSNR at the cost of speed and visual quality:
  
              x264 --preset placebo --tune psnr -o <output> <input />
  
  
  
        Constant bitrate at 1000kbps with a 2 second-buffer:
  
              x264 --vbv-bufsize 2000 --bitrate 1000 -o <output> <input />
  
  
  
  Presets:
  
  
  
        --profile <string>      Force the limits of an H.264 profile
  
                                    Overrides all settings.
  
                                    - baseline,main,high,high10,high422,high444
  
        --preset <string>       Use a preset to select encoding settings [medium]
  
                                    Overridden by user settings.
  
                                    - ultrafast,superfast,veryfast,faster,fast
  
                                    - medium,slow,slower,veryslow,placebo
  
        --tune <string>         Tune the settings for a particular type of source
  
                                or situation
  
                                    Overridden by user settings.
  
                                    Multiple tunings are separated by commas.
  
                                    Only one psy tuning can be used at a time.
  
                                    - psy tunings: film,animation,grain,
  
                                                   stillimage,psnr,ssim
  
                                    - other tunings: fastdecode,zerolatency
  
  
  
  Frame-type options:
  
  
  
    -I, --keyint <integer or="or"> Maximum GOP size [250]
  
        --tff                   Enable interlaced mode (top field first)
  
        --bff                   Enable interlaced mode (bottom field first)
  
        --pulldown <string>     Use soft pulldown to change frame rate
  
                                    - none, 22, 32, 64, double, triple, euro (requires cfr input)
  
  
  
  Ratecontrol:
  
  
  
    -B, --bitrate <integer>     Set bitrate (kbit/s)
  
        --crf <float>           Quality-based VBR (0-51) [23.0]
  
        --vbv-maxrate <integer> Max local bitrate (kbit/s) [0]
  
        --vbv-bufsize <integer> Set size of the VBV buffer (kbit) [0]
  
    -p, --pass <integer>        Enable multipass ratecontrol
  
                                    - 1: First pass, creates stats file
  
                                    - 2: Last pass, does not overwrite stats file
  
  
  
  Input/Output:
  
  
  
    -o, --output <string>       Specify output file
  
        --sar width:height      Specify Sample Aspect Ratio
  
        --fps   Specify framerate
  
        --seek <integer>        First frame to encode
  
        --frames <integer>      Maximum number of frames to encode
  
        --level <string>        Specify level (as defined by Annex A)
  
        --quiet                 Quiet Mode
  
  
  
  Filtering:
  
  
  
        --vf, --video-filter <filter0>/<filter1>/... Apply video filtering to the input file
  
  
  
        Filter options may be specified in <filter>:<option>=<value> format.
  
  
  
        Available filters:
  
        crop:left,top,right,bottom
  
        select_every:step,offset1[,...]
  
  </value></option></filter></filter1></filter0></string></integer></integer></string></integer></integer></integer></float></integer></string></integer></string></string></string></output></output></output></output></output></output>

  Thanks,
   s