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• How to use hardware acceleration with ffmpeg

  16 juin 2014, par ixSci

  I need to have ffmpeg decode my video(e.g. h264) using hardware acceleration. I’m using the usual way of decoding frames : read packet -> decode frame. And I’d like to have ffmpeg speed up decoding. So I’ve built it with --enable-vaapi and --enable-hwaccel=h264. But I don’t really know what should I do next. I’ve tried to use avcodec_find_decoder_by_name("h264_vaapi") but it returns nullptr.
  Anyway, I might want to use others API and not just VA API. How one is supposed to speed up ffmpeg decoding ?

  P.S. I didn’t find any examples on Internet which uses ffmpeg with hwaccel.

• av_find_stream_info works OK with file, not with pipe

  14 décembre 2016, par Aliza

  I have the following code :

  av_register_all();
  
  pFormatCtx = avformat_alloc_context();
  
  const char* input = "pipe:";
  
  AVInputFormat* iFormat = av_find_input_format("mpegts");
  
  if ( avformat_open_input(&pFormatCtx, input, iFormat, NULL) != 0 )
  
           return -1;
  
  int res = av_find_stream_info(pFormatCtx);

  when my input is a regular file, this works nicely and pFormatCtx is populated with the streams in the file. However, when i set input to "pipe :", av_find_stream_info returns with -1.

  I am using the same file and piping it by running
  cat mpeg.ts | myApp

  Any ideas ?

  Thanks,
  Aliza

• ftp upload then loop

  23 juillet 2012, par thevoipman

  I have a minor bash script loop I'm trying to learn and accomplish but it's giving me a hard time to comprehend with all the readings I've done.

  I am uploading to a ftp server, then I want to check to see if the upload went through successfully by using wget spider method. If it returns OK then we're good, if not then I want to redo the ftp upload once more.

  The code I have below are based on my research and learning from here. If I could be doing this better, please help me revise it so I can learn from it.

  Thanks again in advance :

  for ((i = 0 ; i < 1 ; i++ )); 
  
  do 
  
      wget_output=$(wget -q --spider "http://$FTP_HOST/test.jpg")
  
      if [ $? -ne 0 ]; 
  
      then
  
  
  
          ftp -in $FTP_HOST &lt;<endftp user="user" binary="binary" put="put" bye="bye" endftp="endftp" else="else" echo="echo" code="code" fi="fi" done="done"></endftp>code>

  My errors when executing is :

  line 28: syntax error: unexpected end of file