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• Get blur effect inside a drawn box using ass format

  18 septembre 2024, par Armen Sanoyan

  I have Nodejs application which generates subtitles file for video editing. The editing is done by ffmpeg. For each word I also generate a backdrop with rounded corners using drawing command. Example of dialog for backdrop.

  


  Dialogue: 0,00:00:38.60,00:00:42.10,Default,,0,0,0,,{\p1\1a&HD8&\c&HE27FA4&\pos(341.07421875,517.5)\an4}  {\p1}m 15 0 b 1202.8515625 .... {\p0}


  


  Now I want to make the backdrop blur.
(Text backdrop by ass formatting)

  


  I have tried to use \blur or \be, but they are for other purpose. Below is reference from the doc

  


  Enable or disable a subtle softening-effect for the edges of the text

  


  Is there any other way to achieve the blurred backdrop. I am ready even to mix ffmpeg commands like boxblur and ass file. I mean separately paint the backdrops and then apply ass subtitles file. Here is an experiment to explain the idea.

  


  [0:v]split=3[base][blur1_in][blur2_in];

[blur1_in]crop=w=100:h=100:x=20:y=40[region1];
[region1]boxblur=luma_radius=10:luma_power=1[blurred_region1];
[base][blurred_region1]overlay=x=20:y=40:enable='between(t,0,5)'[tmp1];

[blur2_in]crop=w=30:h=30:x=20:y=40[region2];
[region2]boxblur=luma_radius=5:luma_power=1[blurred_region2];
[tmp1][blurred_region2]overlay=x=20:y=40:enable='between(t,5,10)'[tmp2];

[tmp2]ass=../logs/ass.ass:fontsdir=../fonts/Audiowide-Regular.ttf[final_video]


  


  The problem in this case is that the corners are not rounded. Could anyone explain to me what is the easiest way to get backdrop with rounded corners an blurred inside

  


• cuvid : Implement flush to support seeking in media players

  4 septembre 2016, par Philip Langdale

  cuvid : Implement flush to support seeking in media players
  Right now, if we attempt to use cuvid in a media player and then
  
  try to seek, the decoder will happily pass out whatever frames were
  
  already in flight before the seek.
  There is both the output queue in our code and some number of frames
  
  within the cuvid decoder that need to be accounted for.
  cuvid doesn’t support flush, so our only choice is to do a brute-force
  
  re-creation of the decoder, which also implies re-creating the parser,
  
  but this is fine.
  The only subtlty is that there is sanity check code in decoder
  
  initialisation that wants to make sure the HWContextFrame hasn’t already
  
  been initialised. This is a fair check to do at the beginning but not
  
  after a flush, so it has to be made conditional.
  Signed-off-by : Philip Langdale <philipl@overt.org>
  
  Signed-off-by : Timo Rothenpieler <timo@rothenpieler.org>
  

  • [DH] libavcodec/cuvid.c
  • [DH] libavcodec/version.h

• Video encoding green screen

  22 août 2016, par Mohammad Abu Musa

  I am building a screen recorder, the input stream is formatted with PP_VIDEOFRAME_FORMAT_I420 and the output is formatted with AV_PIX_FMT_YUV420P below is the code I use to do the conversion

  const uint8_t* data = static_cast<const>(frame.GetDataBuffer());
  
      pp::Size size;
  
      frame.GetSize(&amp;size);
  
      uint32_t buffersize = frame.GetDataBufferSize();
  
  
  
  
  
      if (is_recording_) {
  
          vpx_codec_iter_t iter = NULL;
  
          const vpx_codec_cx_pkt_t *pkt;
  
          // copy the pixels into our "raw input" container.
  
          int bytes_filled = avpicture_fill(&amp;pic_raw, data, AV_PIX_FMT_YUV420P, out_width, out_height);
  
          if(!bytes_filled) {
  
              Logger::Log("Cannot fill the raw input buffer");
  
              return;
  
          }
  
  
  
          if(vpx_codec_encode(&amp;codec, &amp;raw, frame_cnt, 1, flags, VPX_DL_REALTIME))
  
                die_codec(&amp;codec, "Failed to encode frame");
  
  
  
          while( (pkt = vpx_codec_get_cx_data(&amp;codec, &amp;iter)) ) {
  
              switch(pkt->kind) {
  
                  case VPX_CODEC_CX_FRAME_PKT:
  
                      glb_app_thread.message_loop().PostWork(callback_factory_.NewCallback(&amp;EncoderInstance::write_ivf_frame_header, pkt));
  
                      glb_app_thread.message_loop().PostWork(callback_factory_.NewCallback(&amp;EncoderInstance::WriteFile, pkt));
  
                      break;
  
                  default:break;
  
              }
  
          }
  
  
  
          frame_cnt++;
  
  </const>

  I have three questions :

  1- Is the conversion is done correctly ? do I have to investigate image formats more ? are data channels mapped correctly.

  2- What causes the green screen to show ? what does it mean ?

  3- Is this a thread issue ? I mean is data passed correctly and the conversion is done correctly but the threads are racing