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• ffmpeg scale/forcing fixed video resolution issue

  31 janvier 2018, par Massimo Vantaggio

  I try to be sure that the video comes out with a resolution of 1920 x1080,
  If not the encoding must force this resolution.
  I need this to create fine adaption set from a video input with standard resolution (HD).

  Im unable to get always this resolution, for example with a movie of
  1920 x 1040 i get 1993 x 1080

  , below my ffmpeg command line :

  ffmpeg -y -i $name -i logo1080.png -c:a aac -b:a 256k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -r $FPSC -b:v 2400k -maxrate 2400k -bufsize 1200k -profile:v main -t $FDUR -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:10,scale=1920:1080" format1080.mp4

  I tried every possibility that the ffmpeg scale page tells, without understand how to fix it.
  I think i need some help,
  Thanks,
  Massimo

• Intel IPP RGBToYUV420 function is getting IppStsSizeErr result code

  6 février 2018, par yesilcimen.ahmet

  I am using IPP 2017.0.3(r55431) and Delphi 10.2, I am trying convert RGB to YUV420P, but I am getting IppStsSizeErr result code.

  I have m_dst_picture, m_src_picture: AVPicture structure created by FFMPEG.

  { allocate the encoded raw picture }
  
  
  
   ret := avpicture_alloc(@m_dst_picture, AV_PIX_FMT_YUV420P, c^.width, c^.height);
  
  
  
   if (ret < 0) then
  
      Exit(False);
  
  
  
   { allocate BGR frame that we can pass to the YUV frame }
  
   ret := avpicture_alloc(@m_src_picture, AV_PIX_FMT_BGR24, c^.width, c^.height);
  
   if (ret < 0) then
  
     Exit(False);
  
   //It works fine.
  
   { convert BGR frame (m_src_picture) to and YUV frame (m_dst_picture) }
  
   sws_scale(sws_ctx, @m_src_picture.data[0], @m_src_picture.linesize, 0, c^.height, @m_dst_picture.data[0], @m_dst_picture.linesize);

  I want to convert the RGB buffer directly to YUV420P. The original code first loads RGB into the AVPicture then convert RGB to YUV420P with sws_scale and it causes slowness.

  Here I copy the BGR buffer to m_src_picture of FFMPEG. But this leads to performance loss, so I want to convert it directly to YUV420P using Intel IPP.

  procedure WriteFrameBGR24(frame: PByte);
  
  var
  
    y: Integer;
  
  begin
  
    for y := 0 to m_c^.height - 1 do
  
      Move(PByte(frame - (y * dstStep))^, PByte(m_src_picture.data[0] + (y * m_src_picture.linesize[0]))^, dstStep);
  
  end;

  In the code below I am trying to convert using Intel IPP.

  { Converting RGB to YUV420P. }
  
  
  
  **roiSize is 1920 and 1080
  
  
  
  **The values created by FFMPEG for YUV420P in m_dst_picture.linesize are [0]=1920,[1]=960,[2]=960 respectively.

  Do I need to convert the values of the linesize to another value ?

  **The reason why the srcStep parameter is a minus sign is the Bottom-Up Bitmap and the frame pointer indicates the Bmp.ScanLine[0] address, which indicates the highest pointer address.

  srcStep := (((width * (3 * 8)) + 31) and not 31) div 8; //for 24 bitmap
  
  
  
  { Swap of BGR channels to RGB. }
  
  //It works fine    
  
  st := ippiSwapChannels_8u_C3IR(frame, -srcStep, roiSize, @BGRToRGBArray[0]); 
  
  
  
  { Convert RGB to YUV420P. }
  
  //IppStsSizeErr  
  
  st := ippiRGBToYUV420_8u_C3P3R(frame, -srcStep, @m_dst_picture.data[0], @m_dst_picture.linesize[0], roiSize);

  How do I solve this problem ?

  Thank you.

• FFMPEG, resize and pad a video by and odd number of pixels ?

  18 février 2018, par Jules

  I’m trying to resize and pad a video from 1917 x 1080 to 1920 x 1080.

  I’ve tried various syntax, which works but doesn’t change the size.

  ffmpeg -i input.mp4 -filter:v scale=1920:1080,pad=1920:1080 -c:a copy output.mp4

  However, I have go to this point by resize, joint audio and rotate. The initial size is 640 x 1136, I believe this is the source of the problem.

  ffmpeg -i input.mp4 -filter:v scale=900:1200 -c:a copy output.mp4
  
  
  
  ffmpeg \
  
  -i input.m4a \
  
  -i resize.mp4 -acodec copy -vcodec copy -shortest \
  
  output.mp4
  
  
  
  ffmpeg -i input.mp4" -vf "transpose=2" output/mp4

  So I’m wondering if I should do something different earlier