Recherche avancée

Sur d’autres sites (9797)

• ffmpeg overlay png on video has color issue

  9 janvier 2023, par Richard

  Im trying a simple overlay command to put a logo on a black video, but find the color a little different in output, the original RGB value of green part of the logo is (0,220,90), but changed to (0,191,88) in output. Looks like the color gets mixed with the black background, any ideas ?

  


  original logo rgb :

  


  

  


  rgb after logo overlayed on video :

  


  

  


  the command to overlay :

  


  ffmpeg -i video.mp4 -i logo.png -filter_complex "[1:v]format=rgba[s],[0:v][s]overlay=240:1275:format=auto" output.mp4


  


  the logo and video :

  


  ▶ ffmpeg -i logo.png               
ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100                                                                                                                                            
Input #0, png_pipe, from 'logo.png':
  Duration: N/A, bitrate: N/A
  Stream #0:0: Video: png, rgba(pc), 601x81 [SAR 2834:2834 DAR 601:81], 25 fps, 25 tbr, 25 tbn, 25 tbc

▶ ffmpeg -i video.mp4                                                                                                   
ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.76.100
  Duration: 00:00:02.00, start: 0.000000, bitrate: 24 kb/s
  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1080x1920, 18 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]


  


• FFmpeg programming : assign color transfer characteristics

  8 juillet 2017, par Francis Tesla

  When using ffmpeg library to load an EXR file it appears to dark.

  This seems to be the same problem as this one :

  ffmpeg - getting a dark output when converting .exr sequence to .mp4

  The EXR decoder has a parameter to assign color transfer
  characteristics.

  For sRGB, it is

  ffmpeg -apply_trc iec61966_2_1 -start_frame 1100 -i input.$04d.exr
  output.mp4

  But how to achieve the same result programmatically ?

  Here is my code :

  AVFrame *frame = av_frame_alloc();
  
  avcodec_decode_video2(codecCtx, frame, &frameFinished, &packet);
  
  
  
  ... 
  
  
  
  AVPicture       picture;
  
  avpicture_alloc(&picture, dest_format, dest_width, dest_height);
  
  
  
  SwsContext *swsCtx = NULL;
  
  
  
  swsCtx = sws_getContext(source_width, source_height, source_format, dest_width, dest_height, dest_format, SWS_POINT, NULL, NULL, NULL);
  
  
  
  if (swsCtx == NULL) {
  
      qDebug() << "error calling sws_getContext";
  
  }
  
  
  
  sws_scale(swsCtx, frame->data, frame->linesize, 0, frame->height, picture.data, picture.linesize);
  
  
  
  QImage image(dest_width, dest_height, QImage::Format_ARGB32);
  
  
  
  for (int y = 0; y < dest_height; ++y) {
  
      memcpy(image.scanLine(y), picture.data[0] + y * picture.linesize[0], picture.linesize[0]);
  
  }
  
  
  
  av_frame_free(&frame);
  
  sws_freeContext(swsCtx);

  Thank you,
  Francis

• Revision 41eb20d1e9 : Add encoder control for setting color space This commit adds encoder side contr

  13 janvier 2015, par Yaowu Xu

  Changed Paths :
   Modify /vp9/common/vp9_enums.h

  
   Modify /vp9/common/vp9_onyxc_int.h

  
   Modify /vp9/decoder/vp9_decodeframe.c

  
   Modify /vp9/encoder/vp9_bitstream.c

  
   Modify /vp9/encoder/vp9_encoder.c

  
   Modify /vp9/encoder/vp9_encoder.h

  
   Modify /vp9/vp9_cx_iface.c

  
   Modify /vpx/vp8cx.h

  
   Modify /vpxenc.c

  
  
  Add encoder control for setting color space

  This commit adds encoder side control for vp9 to set color space info
  in the output compressed bitstream.

  It also amends the "vp9_encoder_params_get_to_decoder" test to verify
  the correct color space information is passed from the encoder end to
  decoder end.

  Change-Id : Ibf5fba2edcb2a8dc37557f6fae5c7816efa52650
  (cherry picked from commit e94b415c3479129944a69fafbeacf550fb9237b7)