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• How to capture a layered window with transparency background properly ? (using BitBlt)

  25 octobre 2016, par Mitra M

  I want to capture a WPF window (WPF layered window) with transparency background.

  To do that I tried FFmpeg, But :

  1 - If I set AllowTransparency (this is a property of WPF window) to false ,I can capture the window by gdigrab (this is an ffmpeg device), but output has black background.(I don’t want black background)

  2 - If I set AllowTransparency to true then gdigrab won’t work. (get black frame only)

  I have read David’s nice article, he has said :

  if you use BitBlt to do this, you could “or in” the CAPTUREBLT flag if
  you wanted to capture windows that are layered

  The gdigrab uses BitBlt, this is gdigrab.c code snippet :

  /* Blit screen grab */
  
      if (!BitBlt(dest_hdc, 0, 0,
  
                  clip_rect.right - clip_rect.left,
  
                  clip_rect.bottom - clip_rect.top,
  
                  source_hdc,
  
                  clip_rect.left, clip_rect.top, SRCCOPY | CAPTUREBLT)) {
  
          WIN32_API_ERROR("Failed to capture image");
  
          return AVERROR(EIO);
  
      }

  You can see the flags . (SRCCOPY | CAPTUREBLT).

  Please tell me :

  1- Why the gdigrab can not capture a WPF window properly ?

  2 - What changes in this code should be done to do this ?

  (Sorry for my English, I used translate.google)

  Thanks

• PKG_CONFIG_PATH can't be seen by configure

  23 mars 2019, par Hashim

  I’m using Cygwin to compile a MinGW version of FFmpeg (I already use Cygwin so it didn’t make sense to use anything else to build).

  I was originally getting an error that someone on the Doom9 forums suggested might be due to mixing MinGW-64 and Cygwin dependencies. I then compiled or sourced MinGW-64 versions of all of the required dependencies (as some dependencies could not be compiled with Cygwin alone), and FFmpeg still fails to configure, always with the same error.

  This error is always a variation of "package not found using pkg-config" - if libaom is enabled, I get :

  ERROR : aom >= 1.0.0 not found using pkg-config

  If I don’t add —enable-libaom in the configure script, I get :

  ERROR : libass not found using pkg-config

  I’m running the following on the command line, in a single shell, to compile FFmpeg :

  cd /ffmpeg_sources/ffmpeg && export PKG_CONFIG_PATH="/usr/local/lib/pkgconfig" && 
  
  ./configure --arch=x86_64 --cross-prefix=x86_64-w64-mingw32- --target-os=mingw32 \
  
  --prefix="/usr/local" \
  
  --extra-cflags="-I/usr/local/include -static" \
  
  --extra-ldflags="-L/usr/local/lib -static" \
  
  --pkg-config-flags="--static" \
  
  --extra-libs="-pthread -lm" \
  
  --enable-libaom \
  
  --enable-libass \
  
  --enable-libfdk-aac \
  
  --enable-libfreetype \
  
  --enable-libmp3lame \
  
  --enable-libopus \
  
  --enable-libvorbis \
  
  --enable-libvpx \
  
  --enable-libx264 \
  
  --enable-libx265 \
  
  --enable-gpl \
  
  --enable-nonfree \
  
  --enable-static  \
  
  --disable-shared && 
  
  make -j$(nproc) && 
  
  make install

  A similar question [here] indicates that it’s an issue with PKG_CONFIG_PATH not seeing the packages in /usr/local/lib/pkgconfig, but when I do :

  cd /ffmpeg_sources/ffmpeg && PKG_CONFIG_PATH="/usr/local/lib/pkgconfig" && pkg-config --exists --print-errors aom && echo $?

  ...it returns a 0, indicating aom.pc was found in the PKG_CONFIG_PATH - which either rules out an issue with PKG_CONFIG_PATH or makes it a very specific one in which only configure and make aren’t able to see PKG_CONFIG_PATH, despite being run from the same shell just a moment after.

  How can I resolve this ?

  ---

  EDIT

  I did some further investigation by looking into ffbuild/config.log, and noticed that it shows a warning :

  WARNING : x86_64-w64-mingw32-pkg-config not found, library detection
  may fail.

  However, doing apt-cyg search x86_64-w64-mingw32-pkg-config shows that particular package as being installed.

  Sure enough, in the /bin folder, there is an extensionless file called x86_64-w64-mingw32-pkg-config, with the following contents :

  #!/bin/sh
  
  exec pkgconf --personality=x86_64-w64-mingw32 $@

  I’ve also found the following related issues, in case they can help anyone else figure out what’s going on here :

  https://ffmpeg.org/pipermail/ffmpeg-devel/2012-June/126683.html

  Warning "i686-mingw32-pkg-config not found, library detection may fail" while cross compiling ffmpeg

  https://github.com/Microsoft/FFmpegInterop/issues/106

  https://gitlab.gnome.org/GNOME/librsvg/issues/239

  https://ffmpeg.zeranoe.com/forum/viewtopic.php?t=2041

• Stream to Azure Media Service from ffmpeg, stream can not be played

  24 juillet 2015, par Simon

  i try to send a stream from my RaspberryPI with debian wheezy to the AzureMediaService.
  I followed the instructions of this nice post.
  http://gtrifonov.com/2015/07/02/streaming-live-video-from-raspberrypi-to-azure-media-services/

  After a lot of trouble with the ffmpeg and libx264 builds i think i have it working now, to stream to the rtmp urls.

  INGESTURI="rtmp://office-klokklokmediastream.channel.mediaservices.windows.net:1935/live/3e541bc149754ebd975b95ec3583c949/mystream1"
  
  ffmpeg -framerate 30 -r 30 -s 640x480 -i /dev/video0 -vcodec libx264 -preset ultrafast -acodec libfaac -ab 48k -b:v 500k -maxrate 500k -bufsize 500k -r 30 -g 60 -keyint_min 60 -sc_threshold 0 -f flv $INGESTURI

  But when i try to watch the link in azure portal publish link or with the azure amsmediaplayer it tells me (i have reseted the channel already) :

  "The video could not be loaded, either because the server or network failed or because the format is not supported."

  The public stream url is :

  http://klokklokmediastream.streaming.mediaservices.windows.net/30c3920e-420a-4d33-8938-e79d0db240ff/c9fd3479-0d4b-4643-a3f9-5fd5831985d0.ism/Manifest

  In the linux shell i see the following output while streaming, looks for me as send stream is working :

  "root@raspberrypi:/home/pi/klokklok# ./azure_ffmpeg
  
  ffmpeg version N-73894-g830d3a0 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.6 (Debian 4.6.3-14+rpi1)
  
    configuration: --arch=armel --target-os=linux --enable-gpl --enable-libx264 --enable-nonfree
  
    libavutil      54. 28.100 / 54. 28.100
  
    libavcodec     56. 50.101 / 56. 50.101
  
    libavformat    56. 40.101 / 56. 40.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 25.100 /  5. 25.100
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.101 /  1.  2.101
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, video4linux2,v4l2, from '/dev/video0':
  
    Duration: N/A, start: -140462028.282167, bitrate: 110592 kb/s
  
      Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 640x480, 110592 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
  
  [libx264 @ 0x3321920] using cpu capabilities: none!
  
  [libx264 @ 0x3321920] profile Constrained Baseline, level 3.0
  
  [libx264 @ 0x3321920] 264 - core 146 r2538 121396c - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=1 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=60 keyint_min=31 scenecut=0 intra_refresh=0 rc_lookahead=0 rc=cbr mbtree=0 bitrate=500 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=500 vbv_bufsize=500 nal_hrd=none filler=0 ip_ratio=1.40 aq=0
  
  Output #0, flv, to 'rtmp://office-klokklokmediastream.channel.mediaservices.windows.net:1935/live/3e501bc149754ebd975b95ec3583c949/mystream1':
  
    Metadata:
  
      encoder         : Lavf56.40.101
  
      Stream #0:0: Video: h264 (libx264) ([7][0][0][0] / 0x0007), yuv420p, 640x480, q=-1--1, 500 kb/s, 30 fps, 1k tbn, 30 tbc
  
      Metadata:
  
        encoder         : Lavc56.50.101 libx264
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  
  Press [q] to stop, [?] for help
  
  DTS 140462610481701, next:33333 st:0 invalid dropping
  
  PTS 140462610481701, next:33333 invalid dropping st:0
  
  DTS 140462610515017, next:66666 st:0 invalid dropping
  
  PTS 140462610515017, next:66666 invalid dropping st:0
  
  DTS 140462610548333, next:99999 st:0 invalid dropping
  
  PTS 140462610548333, next:99999 invalid dropping st:0
  
  frame=    4 fps=0.0 q=31.0 size=       7kB time=00:00:00.10 bitrate= 554.6kbits/DTS 140462610581650, next:133332 st:0 invalid dropping
  
  PTS 140462610581650, next:133332 invalid dropping st:0
  
  DTS 140462610614965, next:166665 st:0 invalid dropping
  
  PTS 140462610614965, next:166665 invalid dropping st:0
  
  frame=    6 fps=5.1 q=29.0 size=       9kB time=00:00:00.16 bitrate= 462.5kbits/DTS 140462610648281, next:199998 st:0 invalid dropping
  
  PTS 140462610648281, next:199998 invalid dropping st:0
  
  DTS 140462610681598, next:233331 st:0 invalid dropping
  
  PTS 140462610681598, next:233331 invalid dropping st:0
  
  DTS 140462610714914, next:266664 st:0 invalid dropping
  
  PTS 140462610714914, next:266664 invalid dropping st:0
  
  frame=   14 fps=4.6 q=23.0 size=      21kB time=00:00:00.43 bitrate= 396.0kbits/DTS 140462610914810, next:466662 st:0 invalid dropping
  
  PTS 140462610914810, next:466662 invalid dropping st:0
  
  [flv @ 0x3320ae0] Failed to update header with correct duration.
  
  [flv @ 0x3320ae0] Failed to update header with correct filesize.
  
  frame=   15 fps=3.9 q=22.0 Lsize=      25kB time=00:00:00.50 bitrate= 407.8kbits/s
  
  video:24kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.373589%
  
  [libx264 @ 0x3321920] frame I:1     Avg QP:31.00  size:  2777
  
  [libx264 @ 0x3321920] frame P:14    Avg QP:26.68  size:  1531
  
  [libx264 @ 0x3321920] mb I  I16..4: 100.0%  0.0%  0.0%
  
  [libx264 @ 0x3321920] mb P  I16..4: 12.4%  0.0%  0.0%  P16..4: 29.7%  0.0%  0.0%  0.0%  0.0%    skip:57.9%
  
  [libx264 @ 0x3321920] coded y,uvDC,uvAC intra: 6.3% 13.9% 0.5% inter: 5.7% 21.4% 0.1%
  
  [libx264 @ 0x3321920] i16 v,h,dc,p: 52% 17% 16% 14%
  
  [libx264 @ 0x3321920] i8c dc,h,v,p: 63% 14% 20%  3%
  
  [libx264 @ 0x3321920] kb/s:387.47
  
  Exiting normally, received signal 2.
  
  "

  I cant find a solution for that so thanks a lot for any advice.