Recherche avancée

Sur d’autres sites (11395)

• Encoding frames to video with ffmpeg

  5 septembre 2017, par Mher Didaryan

  I am trying to encode a video in Unreal Engine 4 with C++. I have access to the separate frames. Below is the code which reads viewport's displayed pixels and stores in buffer.

  //Safely get render target resource.
  
  FRenderTarget* RenderTarget = TextureRenderTarget->GameThread_GetRenderTargetResource();
  
  FIntPoint Size = RenderTarget->GetSizeXY();
  
  auto ImageBytes = Size.X* Size.Y * static_cast<int32>(sizeof(FColor));
  
  TArray<uint8> RawData;
  
  RawData.AddUninitialized(ImageBytes);
  
  
  
  //Get image raw data.
  
  if (!RenderTarget->ReadPixelsPtr((FColor*)RawData.GetData()))
  
  {
  
      RawData.Empty();
  
      UE_LOG(ExportRenderTargetBPFLibrary, Error, TEXT("ExportRenderTargetAsImage: Failed to get raw data."));
  
      return false;
  
  }
  
  
  
  Buffer::getInstance().add(RawData);
  
  </uint8></int32>

  Unreal Engine has IImageWrapperModule with which you can get an image from frame, but noting for video encoding. What I want is to encode frames in real time basis for live streaming service.

  I found this post Encoding a screenshot into a video using FFMPEG which is kind of what I want, but I have problems adapting this solution for my case. The code is outdated (for example avcodec_encode_video changed to avcodec_encode_video2 with different parameters).

  Bellow is the code of encoder.

  void Compressor::DoWork()
  
  {
  
  AVCodec* codec;
  
  AVCodecContext* c = NULL;
  
  //uint8_t* outbuf;
  
  //int /*i, out_size,*/ outbuf_size;
  
  
  
  UE_LOG(LogTemp, Warning, TEXT("encoding"));
  
  
  
  codec = avcodec_find_encoder(AV_CODEC_ID_MPEG1VIDEO);            // finding the H264 encoder
  
  if (!codec) {
  
      UE_LOG(LogTemp, Warning, TEXT("codec not found"));
  
      exit(1);
  
  }
  
  else UE_LOG(LogTemp, Warning, TEXT("codec found"));
  
  
  
  c = avcodec_alloc_context3(codec);
  
  c->bit_rate = 400000;
  
  c->width = 1280;                                        // resolution must be a multiple of two (1280x720),(1900x1080),(720x480)
  
  c->height = 720;
  
  c->time_base.num = 1;                                   // framerate numerator
  
  c->time_base.den = 25;                                  // framerate denominator
  
  c->gop_size = 10;                                       // emit one intra frame every ten frames
  
  c->max_b_frames = 1;                                    // maximum number of b-frames between non b-frames
  
  c->keyint_min = 1;                                      // minimum GOP size
  
  c->i_quant_factor = (float)0.71;                        // qscale factor between P and I frames
  
  //c->b_frame_strategy = 20;                               ///// find out exactly what this does
  
  c->qcompress = (float)0.6;                              ///// find out exactly what this does
  
  c->qmin = 20;                                           // minimum quantizer
  
  c->qmax = 51;                                           // maximum quantizer
  
  c->max_qdiff = 4;                                       // maximum quantizer difference between frames
  
  c->refs = 4;                                            // number of reference frames
  
  c->trellis = 1;                                         // trellis RD Quantization
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;                           // universal pixel format for video encoding
  
  c->codec_id = AV_CODEC_ID_MPEG1VIDEO;
  
  c->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  if (avcodec_open2(c, codec, NULL) < 0) {
  
      UE_LOG(LogTemp, Warning, TEXT("could not open codec"));         // opening the codec
  
      //exit(1);
  
  }
  
  else UE_LOG(LogTemp, Warning, TEXT("codec oppened"));
  
  
  
  FString FinalFilename = FString("C:/Screen/sample.mpg");
  
  auto &PlatformFile = FPlatformFileManager::Get().GetPlatformFile();
  
  auto FileHandle = PlatformFile.OpenWrite(*FinalFilename, true);
  
  
  
  if (FileHandle)
  
  {
  
      delete FileHandle; // remove when ready
  
      UE_LOG(LogTemp, Warning, TEXT("file opened"));
  
      while (true)
  
      {
  
          UE_LOG(LogTemp, Warning, TEXT("removing from buffer"));
  
  
  
          int nbytes = avpicture_get_size(AV_PIX_FMT_YUV420P, c->width, c->height);                                      // allocating outbuffer
  
          uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes * sizeof(uint8_t));
  
  
  
          AVFrame* inpic = av_frame_alloc();
  
          AVFrame* outpic = av_frame_alloc();
  
  
  
          outpic->pts = (int64_t)((float)1 * (1000.0 / ((float)(c->time_base.den))) * 90);                              // setting frame pts
  
          avpicture_fill((AVPicture*)inpic, (uint8_t*)Buffer::getInstance().remove().GetData(),
  
              AV_PIX_FMT_PAL8, c->width, c->height); // fill image with input screenshot
  
          avpicture_fill((AVPicture*)outpic, outbuffer, AV_PIX_FMT_YUV420P, c->width, c->height);                        // clear output picture for buffer copy
  
          av_image_alloc(outpic->data, outpic->linesize, c->width, c->height, c->pix_fmt, 1);
  
  
  
          /* 
  
          inpic->data[0] += inpic->linesize[0]*(screenHeight-1);                                                      
  
          // flipping frame
  
          inpic->linesize[0] = -inpic->linesize[0];                                                                   
  
          // flipping frame
  
  
  
          struct SwsContext* fooContext = sws_getContext(screenWidth, screenHeight, PIX_FMT_RGB32, c->width, c->height, PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
          sws_scale(fooContext, inpic->data, inpic->linesize, 0, c->height, outpic->data, outpic->linesize);          // converting frame size and format
  
  
  
          out_size = avcodec_encode_video(c, outbuf, outbuf_size, outpic);                                            
  
          // save in file
  
  
  
          */
  
  
  
      }
  
      delete FileHandle;
  
  }
  
  else
  
  {
  
      UE_LOG(LogTemp, Warning, TEXT("Can't open file"));
  
  }
  
  }

  Can someone explain flipping frame part (why it’s done ?) and how to use avcodec_encode_video2 function instead of avcodec_encode_video ?

• FFmpeg : Multiple x265-params are not recognized

  13 septembre 2022, par zinon

  I'm using ffmpeg in x265 and I want to use multiple x265-params in one encoding.

  



  When I use more than one parameter, ffmpeg does not recognize them.

  



  My script is :

  



  ffmpeg -s:v 1440x1080 -r 25 -i incident_10d_1440x1080_25.yuv -c:v rawvideo \
-pix_fmt yuv420p -c:v libx265 -x265-params "--qp=16:--preset=medium:--psnr" \
out_1440x1080_qp16.mp4


  



  I set quantization parameter value equal to 16.

  



  But my output in terminal contains the following :

  



  x265 [info]: Main profile, Level-4 (Main tier)
x265 [info]: Thread pool created using 4 threads
x265 [info]: Slices                              : 1
x265 [info]: frame threads / pool features       : 2 / wpp(17 rows)
x265 [info]: Coding QT: max CU size, min CU size : 64 / 8
x265 [info]: Residual QT: max TU size, max depth : 32 / 1 inter / 1 intra
x265 [info]: ME / range / subpel / merge         : hex / 57 / 2 / 2
x265 [info]: Keyframe min / max / scenecut / bias: 25 / 250 / 40 / 5.00
x265 [info]: Lookahead / bframes / badapt        : 20 / 4 / 2
x265 [info]: b-pyramid / weightp / weightb       : 1 / 1 / 0
x265 [info]: References / ref-limit  cu / depth  : 3 / on / on
x265 [info]: AQ: mode / str / qg-size / cu-tree  : 1 / 1.0 / 32 / 1
x265 [info]: Rate Control / qCompress            : CRF-28.0 / 0.60


  



  As can be seen I get Rate Control / qCompress : CRF-28.0 / 0.60.

  



  The correct one must be x265 [info]: Rate Control : CQP-16.

  



  When I have only this parameter in x265-params like -x265-params "--qp=16" it's working properly.

  


• SIMD opus pvq_search implementation

  8 juin 2017, par Ivan Kalvachev

  SIMD opus pvq_search implementation
  Explanation on the workings and methods used by the
  
  Pyramid Vector Quantization Search function
  
  could be found in the following Work-In-Progress mail threads :
  
  http://ffmpeg.org/pipermail/ffmpeg-devel/2017-June/212146.html
  
  http://ffmpeg.org/pipermail/ffmpeg-devel/2017-June/212816.html
  
  http://ffmpeg.org/pipermail/ffmpeg-devel/2017-July/213030.html
  
  http://ffmpeg.org/pipermail/ffmpeg-devel/2017-July/213436.html
  Signed-off-by : Ivan Kalvachev <ikalvachev@gmail.com>
  

  • [DH] libavcodec/opus_pvq.c
  • [DH] libavcodec/opus_pvq.h
  • [DH] libavcodec/x86/Makefile
  • [DH] libavcodec/x86/opus_dsp_init.c
  • [DH] libavcodec/x86/opus_pvq_search.asm