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• Ffmpeg gdigrab records black window when capturing graphics-intensive flight simulator

  23 mars 2021, par iter

  I am trying to capture video from XPlane, a popular flight simulator. I'm running on Windows.

  



  Normally, I can capture individual windows using gdigrab, but when I use it on an XPlane window like so...

  



  ffmpeg -f gdigrab -framerate 30 -i "X-System" -b:v 300K capture.mp4


  



  ...I get a video file that's the right dimensions but is all black. I imagine this may have something to do with how XPlane talks directly to the GPU. I should add that if I capture the entire desktop like so...

  



  ffmpeg -f gdigrab -framerate 30 -i desktop -b:v 300K capture.mp4


  



  ...I get everything including the simulator window, but naturally with unrelated windows in the capture, including windows sitting on top of the simulator window.

  



  Is there a way for gdigrab to capture video this GPU-intensive window alone ? Is there a different tool I can use ?

  


• gstreamer vaapih264enc generated ts segment dont play on AVPlayer

  21 juin 2022, par Guru Govindan

  I have a pipeline that transcodes an rtsp stream into hls segments. The manifest is playable in browsers(with hlsjs) and ffplay and VLC. However when I play the stream or individual ts segments in Quicktime player or my IOS App that uses avplayer, it doesnt work.

  


  This seems to be an issue only with vaapih264enc. When I try the same with software encode like x264enc it works fine.

  


  The following is a simple pipeline where this is reproducible.

  


  GST_DEBUG=3 gst-launch-1.0 rtspsrc location='rtsp://user:pass@10.10.10.12:554/' name=rtpsrc0 \
 rtpsrc0. ! rtph264depay ! queue ! decodebin ! vaapih264enc ! mpegtsmux name=mux ! filesink location=mymux.ts \
 rtpsrc0. ! decodebin ! queue ! fdkaacenc ! mux.


  


  when I run the following command to copy the encoded stream as is from the generated ts segment it works

  


  ffmpeg -i mymux.ts -c copy mymux_ffmpeg.ts


  


  Is the ffmpeg adding some additional header information that the quicktime player is happy with ?

  


  I appreciate any help with this.

  


• Best Web Video Encoding Practices for IOS (FFMpeg)

  21 juin 2012, par MagicMushroom

  I am working on an online video repository system for a client, written mostly in PHP. At the moment I am building a mobile version of our desktop website. Our desktop site allows users to watch videos in the browser, much like YouTube.

  My client uploads videos through the manager interface I have created, and my application uses FFmpeg on the server to transcode his videos into several resolutions and bitrates. I am no expert on FFmpeg, and while I do not know the ins and outs of each individual setting, I do understand how it works as a whole. Right now, we are using the mp4 container format with the h.264 codec to encode our videos. Our command looks like :

  ffmpeg -y -i "INPUT FILE.mov" -f mp4 -s 640x480 -vcodec libx264 -preset fast -maxrate 1500 -bitrate 1000 -bufsize 4096 -acodec libfaac -ab 192 -ac 2 "OUTPUT_FILE.mp4" >> "FILE.log" 2>&1 &

  I'm hoping to gain information about best practices with encoding video for web streaming on IOS and other mobile devices using FFmpeg. What resolutions and settings make for good mobile streaming video ? How can I ensure maximum compatibility across the sea of Android devices ?