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• ffmpeg +libx264 iPhone -> 'avcodec_encode_video' return always 0 . please advice

  2 janvier 2014, par isaiah

                   av_register_all();

          AVCodec *codec ;
          AVCodecContext *c= NULL ;
          int  out_size, size, outbuf_size ;
          //FILE *f ;
          uint8_t *outbuf ;
          printf("Video encoding\n") ;
          /* find the mpeg video encoder */
  
          codec =avcodec_find_encoder(CODEC_ID_H264) ;//avcodec_find_encoder_by_name("libx264") ; //avcodec_find_encoder(CODEC_ID_H264) ;//CODEC_ID_H264) ;
  
          NSLog(@"codec = %i",codec) ;
  
          if (!codec) 
  
              fprintf(stderr, "codec not found\n") ;
  
              exit(1) ;
  
             
  
  c= avcodec_alloc_context() ;
          /* put sample parameters */
  
          c->bit_rate = 400000 ;
  
          c->bit_rate_tolerance = 10 ;
  
          c->me_method = 2 ;
  
          /* resolution must be a multiple of two */
  
          c->width = 352 ;//width ;//352 ;
  
          c->height = 288 ;//height ;//288 ;
  
          /* frames per second */
  
          c->time_base= (AVRational)1,25 ;
  
          c->gop_size = 10 ; /* emit one intra frame every ten frames */
  
          //c->max_b_frames=1 ;
  
          c->pix_fmt = PIX_FMT_YUV420P ;
          c ->me_range = 16 ;
  
          c ->max_qdiff = 4 ;
  
          c ->qmin = 10 ;
  
          c ->qmax = 51 ;
  
          c ->qcompress = 0.6f ;
  

  'avcodec_encode_video' is always 0 .

  I guess that because 'non-strictly-monotonic PTS' warning, do you konw same situation ?

• X264 encoding using Opencv

  29 novembre 2011, par user573193

  I am working with a high resolution camera : 4008x2672. I a writing a simple program which grabs frame from the camera and sends the frame to a avi file. For working with such a high resolution, I found only x264 codec that could do the trick (Suggestions welcome). I am using opencv for most of the image handling stuff. As mentioned in this post http://doom10.org/index.php?topic=1019.0 , I modified the AVCodecContext members as per ffmpeg presets for libx264 (Had to do this to avoid broken ffmpeg defaults settings error). This is output I am getting when I try to run the program

  libx264 @ 0x992d040]non-strictly-monotonic PTS 
  
  1294846981.526675 1 0 //Timestamp camera_no frame_no
  
  1294846981.621101 1 1
  
  1294846981.715521 1 2
  
  1294846981.809939 1 3
  
  1294846981.904360 1 4
  
  1294846981.998782 1 5
  
  1294846982.093203 1 6
  
      Last message repeated 7 times
  
  [avi @ 0x992beb0]st:0 error, non monotone timestamps 
  
  -614891469123651720 >= -614891469123651720
  
  
  
   OpenCV Error: Unspecified error (Error while writing video frame) in
  
   icv_av_write_frame_FFMPEG, file 
  
  /home/ajoshi/ext/OpenCV-2.2.0/modules/highgui/src/cap_ffmpeg.cpp, line 1034
  
  terminate called after throwing an instance of 'cv::Exception'
  
   what():  /home/ajoshi/ext/OpenCV-2.2.0/modules/highgui/src/cap_ffmpeg.cpp:1034:
  
  error: (-2) Error while writing video frame in function icv_av_write_frame_FFMPEG

  Aborted

  Modifications to the AVCodecContext are :

  if(codec_id == CODEC_ID_H264)
  
  {
  
      //fprintf(stderr, "Trying to parse a preset file for libx264\n");
  
      //Setting Values manually from medium preset
  
      c->me_method = 7;
  
      c->qcompress=0.6;
  
      c->qmin = 10;
  
      c->qmax = 51;
  
      c->max_qdiff = 4;
  
      c->i_quant_factor=0.71;
  
      c->max_b_frames=3;
  
      c->b_frame_strategy = 1;
  
      c->me_range = 16;<br />
  
      c->me_subpel_quality=7;
  
      c->coder_type = 1;
  
      c->scenechange_threshold=40;
  
      c->partitions = X264_PART_I8X8 | X264_PART_I4X4 | X264_PART_P8X8 | X264_PART_B8X8;
  
      c->flags = CODEC_FLAG_LOOP_FILTER;
  
      c->flags2 = CODEC_FLAG2_BPYRAMID | CODEC_FLAG2_MIXED_REFS | CODEC_FLAG2_WPRED | CODEC_FLAG2_8X8DCT | CODEC_FLAG2_FASTPSKIP;
  
      c->keyint_min = 25;
  
      c->refs = 3;
  
      c->trellis=1;
  
      c->directpred = 1;
  
      c->weighted_p_pred=2;
  
  }

  I am probably not setting the dts and pts values which I believed ffmpeg should be setting it for me.

  Any sugggestions welcome.
  Thanks in advance
  

• Mass Watermark Videos with Different Formats/Dimensions Programmatically

  17 septembre 2012, par ColorWP.com

  Is there a way to programmatically (using PHP) convert a directory full of videos with all kinds of formats (avi, mp4, mpeg, wmv) with different dimensions to a single format output (e.g. mp4) with the same dimensions as the input video and with a custom image watermark at the same position over the video (e.g. bottom left). Preferably, without lowering video quality and without making the watermark too large or too small for the resolution (maybe relative size to the video dimensions ?).