Advanced search

On other websites (6457)

• Direct3d Color space conversion in GPU

  12 June 2019, by eruslu

  Creating direct3d surface inYV12 format and rendering video frames in yuv420 format causes a blur video. Seems like there is a smog on video. I think this is because yuv 420 color space format’s data range is in 16-235 for Y planes and 16-240 for U and V planes. They are not in range of 0-255.

  I changed color format to BGRA in CPU by using ffmpeg’s sws_scale() function and I created direct3d surface in BGRA format and then displayed video is OK. But cpu consumption is very high due to color space conversion. Is there any way to make color conversion in GPU or is there another way to have sharp video display?

  This is how I create YV12 surface

  m_pDirect3DDevice->CreateOffscreenPlainSurface(_srcWidth, _srcHeight, (D3DFORMAT)MAKEFOURCC('Y', 'V', '1', '2'), D3DPOOL_DEFAULT, &m_pDirect3DSurfaceRender, NULL);

  Here I copy yuv planes of camera’s video frames data to direct3d surface

          BYTE* pict = (BYTE*)d3d_rect.pBits;
  
          BYTE* Y = pY;
  
          BYTE* V = pV;
  
          BYTE* U = pU;
  
  
  
          for (int y = 0; y < _srcHeight; y++)
  
          {
  
              memcpy(pict, Y, p1);
  
              pict += d3d_rect.Pitch;
  
              Y += p1;
  
          }
  
          for (int y = 0; y < _srcHeight >> 1; y++)
  
          {
  
              memcpy(pict, V, p3);
  
              pict += d3d_rect.Pitch >> 1;
  
              V += p3;
  
          }
  
          for (int y = 0; y < _srcHeight >> 1; y++)
  
          {
  
              memcpy(pict, U, p2);
  
              pict += d3d_rect.Pitch >> 1;
  
              U += p2;
  
          }

  I appreciate your help, thank you.

• FFMpeg cuting AAC file but not accurate, append 100ms space to the end

  8 January 2018, by Pham Tuan Anh

  I used FFMPEG with this command:

  ffmpeg -ss 00:00:00 -i b1.aac -to 00:00:17.999 -c copy b2.aac

  output file (b2.aac) always contain around 100ms space An article has offered that here.

  How to remove exactly empty in output file or have any command to cut the aac(mp4) with exactly of the time as I want?

  Thank you.

  enter image description here

• avformat/matroskaenc: Don't fail if reserved Cues space doesn't suffice

  30 December 2019, by Andreas Rheinhardt

  avformat/matroskaenc: Don't fail if reserved Cues space doesn't suffice
  When the user opted to write the Cues at the beginning, the Cues were
  
  simply written without checking in advance whether enough space has been
  
  reserved for them. If it wasn't enough, the data following the space
  
  reserved for the Cues was simply overwritten, corrupting the file.
  This commit changes this by checking whether enough space has been
  
  reserved for the Cues before outputting anything. If it isn't enough,
  
  no Cues will be output at all and the file will be finalized normally,
  
  yet writing the trailer will nevertheless return an error to notify
  
  the user that his wish of having Cues at the front of the file hasn't
  
  been fulfilled.
  This change opens new usecases for this option: It is now safe to use
  
  this option to e.g. record live streams or to use it when muxing the
  
  output of an expensive encoding, because when the reserved space turns
  
  out to be insufficient, one ends up with a file that just lacks Cues
  
  but is otherwise fine.
  Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] doc/muxers.texi
  • [DH] libavformat/matroskaenc.c