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• AVCodecContext settings for H264 (1080i)

  23 septembre 2013, par moose

  I'm trying to configure x264 for 1080i capturing. Most of these settings below are found in different examples. However, compiled together they don't work. ffmpeg API reports no error, but avcodec_encode_video() always returns zero.

  Some of the numbers are strange to me... for example, gop_size. Isn't 250 too high ?

  Event you can't offer the final answer, I'm still interested in any kind of comment on this subject.

  pCodecContext->codec_type              = AVMEDIA_TYPE_VIDEO;
  
  pCodecContext->codec_id                = CODEC_ID_H264;
  
  
  
  pCodecContext->coder_type              = FF_CODER_TYPE_AC;
  
  pCodecContext->flags                  |= CODEC_FLAG_LOOP_FILTER | CODEC_FLAG_INTERLACED_ME | CODEC_FLAG_INTERLACED_DCT;
  
  pCodecContext->me_cmp                 |= 1;
  
  pCodecContext->partitions             |= X264_PART_I8X8 | X264_PART_I4X4 | X264_PART_P8X8 | X264_PART_B8X8;
  
  pCodecContext->me_method               = ME_UMH;
  
  pCodecContext->me_subpel_quality       = 8;
  
  pCodecContext->me_range                = 16;
  
  
  
  pCodecContext->bit_rate                = 10 * 1024 * 1024; // 10 Mbps??
  
  pCodecContext->width                   = 1920;
  
  pCodecContext->height                  = 1080;
  
  
  
  pCodecContext->time_base.num           = 1;    // 25 fps
  
  pCodecContext->time_base.den           = 25;   // 25 fps
  
  
  
  pCodecContext->gop_size                = 250; // 250
  
  pCodecContext->keyint_min              = 25;
  
  pCodecContext->scenechange_threshold   = 40;
  
  pCodecContext->i_quant_factor          = 0.71f;
  
  pCodecContext->b_frame_strategy        = 1;
  
  pCodecContext->qcompress               = 0.6f;
  
  pCodecContext->qmin                    = 10;
  
  pCodecContext->qmax                    = 51;
  
  pCodecContext->max_qdiff               = 4;
  
  pCodecContext->max_b_frames            = 3;
  
  pCodecContext->refs                    = 4;
  
  pCodecContext->directpred              = 3;
  
  pCodecContext->trellis                 = 1;
  
  pCodecContext->flags2                 |= CODEC_FLAG2_WPRED | CODEC_FLAG2_MIXED_REFS | CODEC_FLAG2_8X8DCT | CODEC_FLAG2_FASTPSKIP;  // wpred+mixed_refs+dct8x8+fastpskip
  
  pCodecContext->weighted_p_pred         = 2; // not implemented with interlaced ??
  
  pCodecContext->crf                     = 22;
  
  
  
  pCodecContext->pix_fmt                 = PIX_FMT_YUV420P;
  
  
  
  pCodecContext->thread_count            = 0;

• What is the meaning of the hexadecimal value that follows the avc1 in an m3u8 variant playlist

  16 février 2013, par Anand

  From this apple's sample variant playlist

  https://devimages.apple.com.edgekey.net/resources/http-streaming/examples/bipbop_4x3/bipbop_4x3_variant.m3u8

  i see hexadecimal numbers follow the av1 like avc1.4d4015,avc1.4d401e,avc1.4d401e,avc1.4d401f can anybody know what is the meaning of them

• FFMPEG in Java (runtime error)

  4 juillet 2012, par Eric

  I want to write a program that converts video into frames using FFMPEG. When I use it on the Ubuntu terminal, it works fine. But when I try to put it into the Java code, it gives me a runtime error. Did I make a mistake in my code below ?

  import java.util.*;
  
  import java.awt.*;
  
  import java.lang.*;
  
  import java.lang.Runtime;
  
  import java.io.*;
  
  import java.io.IOException;
  
  
  
  public class ConvertVideoToImage
  
  {
  
      private SingletonServer ss = null;
  
  
  
      public ConvertVideoToImage(SingletonServer ss)
  
      {
  
          this.ss = ss;
  
      }
  
  
  
      public void run()
  
      {
  
          convertVideo();
  
      }
  
  
  
      public void convertVideo()
  
      {
  
          try
  
          {
  
              Runtime rt = Runtime.getRunTime().exec("ffmpeg" + "-i" +         "display.wmv" + "image%d.jpg");
  
          }
  
          catch(Exception e){}
  
      }
  
  
  
  }

  Edit :

  I have changed the code like you suggested, but it also doesn't work. And when I Googled it, I found out that someone put the full path inside the executable and it became like this :

  Runtime.getRuntime().exec("/home/pc3/Documents/ffmpeg_temp/ffmpeg -i display.wmv image%d.jpg")

  BTW, thanks for the reply. I have another question. Is it possible to make a counter for FFMPEG ? I used this command in the Ubuntu terminal to make it convert a video to 30 frames/1seconds :

  ffmpeg -i display.wmv image%d.jpg

  This will automatically generate numbers like image1.jpg, image2.jpg, to image901.jpg. Is it possible to make a counter for this ? Because I need to count the files and control the number.

  Thanks in advance.