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• Evolution #4727 : Des pictos / icônes symboliques pour tout le monde

  13 avril 2021, par nicod _

  Comme je disais, en SCSS j’ai une mixin qui me permet des trucs comme ça, ce qui transforme :

  .machin 
      position : relative ;
      &:after 
          content :’’ ;
          position : absolute ;
          right : -1em ;
          top : 50% ;
          transform : translateY(-50%) ;
          width : 7px ;
          height : 7px ;
          background : svg-url(’’) center no-repeat ;
      
  
  

  mais bon, on va peut être pas mettre scssphp dans la dist...

• FFMpeg - Trimming out the video after removing duplicate frames

  29 avril 2021, par MarianD

  I removed many duplicate frames from video (and completely removed audio) by this command

  



  ffmpeg -i scene.mkv -vf mpdecimate,setpts=N/FRAME_RATE/TB -map:v 0  scene3.mp4


  



  (by an Mulvya's answer, thanks again).

  



  The resulting video is OK but the total duration will not change - the last frame of original video is frozen to fill the remaining time (when playing back the video).

  



  Is there some way to trim the video so that it will finish at this last frame ?

  


• File encoded as FFV1 with ffmpeg is unplayable

  18 novembre 2016, par Ali Alidoust

  I’m using the following code to encode a series of frames into an mkv or avi file with FFV1 encoding :

  HRESULT Session::createContext(LPCSTR filepath, UINT width, UINT height, UINT fps_num, UINT fps_den) {
  
      LOG(filepath);
  
  
  
      this->codec = avcodec_find_encoder(AV_CODEC_ID_FFV1);
  
      RET_IF_NULL(this->codec, "Could not create codec", E_FAIL);
  
  
  
      this->oformat = av_guess_format(NULL, filepath, NULL);
  
      RET_IF_NULL(this->oformat, "Could not create format", E_FAIL);
  
      this->oformat->video_codec = AV_CODEC_ID_FFV1;
  
      this->width = width;
  
      this->height = height;
  
      this->context = avcodec_alloc_context3(this->codec);
  
      RET_IF_NULL(this->context, "Could not allocate context for the codec", E_FAIL);
  
  
  
      this->context->codec = this->codec;
  
      this->context->codec_id = AV_CODEC_ID_FFV1;
  
      this->context->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
      this->context->pix_fmt = AV_PIX_FMT_YUV420P;
  
      this->context->width = this->width;
  
      this->context->height = this->height;
  
      this->context->time_base.num = fps_num;
  
      this->context->time_base.den = fps_den;
  
  
  
      this->context->gop_size = 1;
  
  
  
      av_opt_set_int(this->context->priv_data, "coder", 0, 0);
  
      av_opt_set_int(this->context->priv_data, "context", 1, 0);
  
      av_opt_set_int(this->context->priv_data, "slicecrc", 1, 0);
  
  
  
      avformat_alloc_output_context2(&fmtContext, NULL, NULL, filepath);
  
  
  
      this->fmtContext->oformat = this->oformat;
  
      this->fmtContext->video_codec_id = AV_CODEC_ID_FFV1;
  
  
  
      this->stream = avformat_new_stream(this->fmtContext, this->codec);
  
      RET_IF_NULL(this->fmtContext, "Could not create new stream", E_FAIL);
  
      avcodec_parameters_from_context(this->stream->codecpar, this->context);
  
      this->stream->codecpar->level = 3;
  
  
  
      /*if (this->fmtContext->oformat->flags & AVFMT_GLOBALHEADER)
  
      {*/
  
          this->context->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
      /*}*/
  
  
  
      RET_IF_FAILED_AV(avcodec_open2(this->context, this->codec, NULL), "Could not open codec", E_FAIL);
  
      RET_IF_FAILED_AV(avio_open(&this->fmtContext->pb, filepath, AVIO_FLAG_READ_WRITE), "Could not open output file", E_FAIL);
  
      RET_IF_NULL(this->fmtContext->pb, "Could not open output file", E_FAIL);
  
      RET_IF_FAILED_AV(avformat_write_header(this->fmtContext, NULL), "Could not write header", E_FAIL);
  
  
  
      frame = av_frame_alloc();
  
      RET_IF_NULL(frame, "Could not allocate frame", E_FAIL);
  
      frame->format = this->context->pix_fmt;
  
      frame->width = width;
  
      frame->height = height;
  
      // RET_IF_FAILED(av_image_alloc(frame->data, frame->linesize, context->width, context->height, context->pix_fmt, 32), "Could not allocate image", E_FAIL);
  
      return S_OK;
  
  }
  
  
  
  HRESULT Session::writeFrame(IMFSample * pSample) {
  
      IMFMediaBuffer *mediaBuffer = NULL;
  
      BYTE *pData = NULL;
  
      DWORD length;
  
  
  
      RET_IF_FAILED(pSample->ConvertToContiguousBuffer(&mediaBuffer), "Could not convert IMFSample to contagiuous buffer", E_FAIL);
  
      RET_IF_FAILED(mediaBuffer->GetCurrentLength(&length), "Could not get buffer length", E_FAIL);
  
      RET_IF_FAILED(mediaBuffer->Lock(&pData, NULL, NULL), "Could not lock the buffer", E_FAIL);
  
      RET_IF_FAILED(av_image_fill_arrays(frame->data, frame->linesize, pData, AV_PIX_FMT_YUV420P, this->width, this->height, 1), "Could not fill the frame with data from the buffer", E_FAIL);
  
      LOG_IF_FAILED(mediaBuffer->Unlock(), "Could not unlock the buffer");
  
  
  
      frame->pts = this->pts++;
  
  
  
      AVPacket pkt;
  
  
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;
  
      pkt.size = 0;
  
  
  
      RET_IF_FAILED_AV(avcodec_send_frame(this->context, frame), "Could not send the frame to the encoder", E_FAIL);
  
      if (SUCCEEDED(avcodec_receive_packet(this->context, &pkt))) {
  
          RET_IF_FAILED_AV(av_interleaved_write_frame(this->fmtContext, &pkt), "Could not write the received packet.", E_FAIL);
  
      }
  
  
  
      av_packet_unref(&pkt);
  
  
  
      return S_OK;
  
  }
  
  
  
  HRESULT Session::endSession() {
  
      LOG("Ending session...");
  
      LOG("Closing files...");
  
      av_write_trailer(this->fmtContext);
  
      avio_close(this->fmtContext->pb);
  
      avcodec_close(this->context);
  
      av_free(this->context);
  
      //fclose(this->file);
  
      LOG("Done.");
  
      return S_OK;
  
  }

  The problem is that the generated file is not playable in either VLC or MPC-HC. However, MPC-HC reports following info in file properties :

  General
  
  Unique ID                      : 202978442142665779317960161865934977227 (0x98B439D9BE859109BD5EC00A62A238CB)
  
  Complete name                  : T:\Test.mkv
  
  Format                         : Matroska
  
  Format version                 : Version 4 / Version 2
  
  File size                      : 24.6 MiB
  
  Duration                       : 147ms
  
  Overall bit rate               : 1 401 Mbps
  
  Writing application            : Lavf57.57.100
  
  Writing library                : Lavf57.57.100
  
  
  
  Video
  
  ID                             : 1
  
  Format                         : FFV1
  
  Format version                 : Version 0
  
  Codec ID                       : V_MS/VFW/FOURCC / FFV1
  
  Duration                       : 147ms
  
  Width                          : 1 280 pixels
  
  Height                         : 720 pixels
  
  Display aspect ratio           : 16:9
  
  Frame rate mode                : Constant
  
  Frame rate                     : 1 000.000 fps
  
  Color space                    : YUV
  
  Chroma subsampling             : 4:2:0
  
  Bit depth                      : 8 bits
  
  Compression mode               : Lossless
  
  Default                        : Yes
  
  Forced                         : No
  
  DURATION                       : 00:00:00.147000000
  
  coder_type                     : Golomb Rice

  Something to note is that it reports 1000 FPS which is weird since I’ve set AVCodecContext::time_base in the code.