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• lavf/dump.c : Print mastering display metadata

  1er mars 2016, par Neil Birkbeck

  lavf/dump.c : Print mastering display metadata
  Signed-off-by : Neil Birkbeck <neil.birkbeck@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/dump.c

• alternative for ffmpeg without using ffmpeg

  24 mars 2016, par sanoj lawrence

  amusing following code to get image from video(snapshot)

  <?php
  
  $ffmpeg = 'ffmpeg\bin\ffmpeg.exe';
  
  $video  = 'upload/'.$location;
  
  $image  = 'upload/thumb/'.$random_name.'.jpg';
  
  $second = 1;
  
  $cmd = "$ffmpeg -i $video 2>&1";
  
  if (preg_match('/Duration: ((\d+):(\d+):(\d+))/s', `$cmd`, $time)) {
  
      $total = ($time[2] * 3600) + ($time[3] * 60) + $time[4];
  
      $second = rand(1, ($total - 1));
  
  }
  
  $cmd = "$ffmpeg -i $video -deinterlace -an -ss $second -t 00:00:01 -r 1 -y -vcodec mjpeg -f mjpeg $image 2>&1";
  
  $return = `$cmd`;
  
  ?>

  how do i get snapshot form video without using ffmpeg

  by using jquery or java is it possible like extraction snapshot and video duration for video

  because recently i found this using id3 detecting video duration etc.

• Why there is no AVFrame->data[2] data when decode h264 by ffmpeg use "h264_cuvid"

  27 juillet 2017, par Wu NL

  env : ubuntu 16.04 64 bit ; ffmpeg 3.3.2 build whih cuda cuvid libnpp...
  use ffmpeg cmd : ffmpeg -vsync 0 -c:v h264_cuvid -i test.264 -f rawvideo test.yuv works fine, the generated yuv file is ok.
  BUT When I decode this 264 file by my code use ’h264_cuvid’ decoder, something problem happens, this is my code :

  #include 
  
  
  
  #define __STDC_CONSTANT_MACROS
  
  
  
  #ifdef _WIN32
  
  //Windows
  
  extern "C"
  
  {
  
  #include "libavcodec/avcodec.h"
  
  };
  
  #else
  
  //Linux...
  
  #ifdef __cplusplus
  
  extern "C"
  
  {
  
  #endif
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #ifdef __cplusplus
  
  };
  
  #endif
  
  #endif
  
  
  
  
  
  //test different codec
  
  #define TEST_H264  1
  
  #define TEST_HEVC  0
  
  
  
  int main(int argc, char* argv[])
  
  {
  
      AVCodec *pCodec;
  
      AVCodecContext *pCodecCtx= NULL;
  
      AVCodecParserContext *pCodecParserCtx=NULL;
  
  
  
      FILE *fp_in;
  
      FILE *fp_out;
  
      AVFrame *pFrame;
  
  
  
      const int in_buffer_size=4096;
  
      unsigned char in_buffer[in_buffer_size + FF_INPUT_BUFFER_PADDING_SIZE]= {0};
  
      unsigned char *cur_ptr;
  
      int cur_size;
  
      AVPacket packet;
  
      int ret, got_picture;
  
  
  
  
  
  #if TEST_HEVC
  
      enum AVCodecID codec_id=AV_CODEC_ID_HEVC;
  
      char filepath_in[]="bigbuckbunny_480x272.hevc";
  
  #elif TEST_H264
  
      AVCodecID codec_id=AV_CODEC_ID_H264;
  
      char filepath_in[]="2_60_265to264.264";
  
  #else
  
      AVCodecID codec_id=AV_CODEC_ID_MPEG2VIDEO;
  
      char filepath_in[]="bigbuckbunny_480x272.m2v";
  
  #endif
  
  
  
      char filepath_out[]="mainSend.yuv";
  
      int first_time=1;
  
  
  
  
  
      //av_log_set_level(AV_LOG_DEBUG);
  
  
  
      avcodec_register_all();
  
  
  
  //    pCodec = avcodec_find_decoder(codec_id);
  
      pCodec = avcodec_find_decoder_by_name("h264_cuvid");
  
      if (!pCodec)
  
      {
  
          printf("Codec not found\n");
  
          return -1;
  
      }
  
      pCodecCtx = avcodec_alloc_context3(pCodec);
  
      if (!pCodecCtx)
  
      {
  
          printf("Could not allocate video codec context\n");
  
          return -1;
  
      }
  
  
  
      pCodecParserCtx=av_parser_init(pCodec->id);
  
      if (!pCodecParserCtx)
  
      {
  
          printf("Could not allocate video parser context\n");
  
          return -1;
  
      }
  
  
  
      if (avcodec_open2(pCodecCtx, pCodec, NULL) &lt; 0)
  
      {
  
          printf("Could not open codec\n");
  
          return -1;
  
      }
  
      //Input File
  
      fp_in = fopen(filepath_in, "rb");
  
      if (!fp_in)
  
      {
  
          printf("Could not open input stream\n");
  
          return -1;
  
      }
  
      //Output File
  
      fp_out = fopen(filepath_out, "wb");
  
      if (!fp_out)
  
      {
  
          printf("Could not open output YUV file\n");
  
          return -1;
  
      }
  
  
  
      pFrame = av_frame_alloc();
  
      av_init_packet(&amp;packet);
  
  
  
      while (1)
  
      {
  
  
  
          cur_size = fread(in_buffer, 1, in_buffer_size, fp_in);
  
          if (cur_size == 0)
  
              break;
  
          cur_ptr=in_buffer;
  
  
  
          while (cur_size>0)
  
          {
  
  
  
              int len = av_parser_parse2(
  
                            pCodecParserCtx, pCodecCtx,
  
                            &amp;packet.data, &amp;packet.size,
  
                            cur_ptr, cur_size,
  
                            AV_NOPTS_VALUE, AV_NOPTS_VALUE, AV_NOPTS_VALUE);
  
  
  
              cur_ptr += len;
  
              cur_size -= len;
  
  
  
              if(packet.size==0)
  
                  continue;
  
  
  
              //Some Info from AVCodecParserContext
  
              printf("[Packet]Size:%6d\t",packet.size);
  
              switch(pCodecParserCtx->pict_type)
  
              {
  
              case AV_PICTURE_TYPE_I:
  
                  printf("Type:I\tNumber:%4d\n",pCodecParserCtx->output_picture_number);
  
                  break;
  
              case AV_PICTURE_TYPE_P:
  
                  printf("Type:P\t");
  
                  break;
  
              case AV_PICTURE_TYPE_B:
  
                  printf("Type:B\t");
  
                  break;
  
              default:
  
                  printf("Type:Other\t");
  
                  break;
  
              }
  
              printf("Number:%4d\n",pCodecParserCtx->output_picture_number);
  
              AVFrame* myFrame = av_frame_alloc();
  
              ret = avcodec_decode_video2(pCodecCtx, myFrame, &amp;got_picture, &amp;packet);
  
              if (ret &lt; 0)
  
              {
  
                  printf("Decode Error.\n");
  
                  return ret;
  
              }
  
              if (got_picture)
  
              {
  
                  if(first_time)
  
                  {
  
                      printf("\nCodec Full Name:%s\n",pCodecCtx->codec->long_name);
  
                      printf("width:%d\nheight:%d\n\n",pCodecCtx->width,pCodecCtx->height);
  
                      first_time=0;
  
                  }
  
                  //Y, U, V
  
                  for(int i=0; iheight; i++)
  
                  {
  
                      fwrite(myFrame->data[0]+myFrag-g>linesize[0]*i,1,myFrame->width,fp_out);
  
                  }
  
                  for(int i=0; iheight/2; i++)
  
                  {
  
                      fwrite(myFrame->data[1]+myFrag-g>linesize[1]*i,1,myFrame->width/2,fp_out);
  
                  }
  
                  for(int i=0; iheight/2; i++)
  
                  {
  
                      fwrite(myFrame->data[2]+myFrag-g>linesize[2]*i,1,myFrame->width/2,fp_out);
  
                  }
  
  //                printf("pframe's width height %d %d\t key frame %d\n",myFrame->width,myFrame->height,myFrame->key_frame);
  
                  printf("Succeed to decode 1 frame!\n");
  
                  av_frame_free(&amp;myFrame);
  
              }
  
          }
  
  
  
      }
  
  
  
      fclose(fp_in);
  
      fclose(fp_out);
  
  
  
  
  
      av_parser_close(pCodecParserCtx);
  
  
  
      av_frame_free(&amp;pFrame);
  
      avcodec_close(pCodecCtx);
  
      av_free(pCodecCtx);
  
  
  
      return 0;
  
  }

  In this demo code, I call h264_cuvid by vcodec_find_decoder_by_name("h264_cuvid");
  BUT the code crash at fwrite(myFrame->data[2]+myFrag-g>linesize[2]*i,1,myFrame->width/2,fp_out);
  So after debug with codeblocks, I found that there is no data in myFrame->data[2] codeblocks watching window

  Any suggestion ? thanks !