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• How to detect the real orientation of a video recorded by mobile with "auto rotate" disabled

  28 octobre 2022, par FlamingMoe

  When you record a video, the rotation metadata has 4 possible values (0, 90, 180 and 270) and it stores how the device was held when starting the recording.

  


  But mobile phones has also a feature to enable or disable "auto rotation" of screen.

  


  It's very typical, nowadays, to have that feature disable, and many people record videos with the phone horizontally, but since the "auto rotation" is disable, the metadata stores like the video was recorded as vertically.

  


  How to handle this ?

  


• ffmpeg avfoundation (Mac OS X) capture second screen desktop

  1er août 2016, par user1706674

  I am use console ffmpeg, if I capture from first monitor, then all is well

  ./ffmpeg -video_size 640x480 -framerate 30 -f avfoundation -capture_cursor 1 -capture_mouse_clicks 1 -i 1:0 -c:v libx264 -qp 0 -preset ultrafast capture.mp4

  if try capture from the second monitor then process hangs

  ./ffmpeg -video_size 640x480 -framerate 30 -f avfoundation -capture_cursor 1 -capture_mouse_clicks 1 -i 2:0 -c:v libx264 -qp 0 -preset ultrafast capture.mp4

  My device list :

  AVFoundation input device @ 0x7fc74141a0c0] AVFoundation video devices:
  
  [AVFoundation input device @ 0x7fc74141a0c0] [0] HD-camera FaceTime (integrated)
  
  [AVFoundation input device @ 0x7fc74141a0c0] [1] Capture screen 0
  
  [AVFoundation input device @ 0x7fc74141a0c0] [2] Capture screen 1
  
  [AVFoundation input device @ 0x7fc74141a0c0] AVFoundation audio devices:
  
  [AVFoundation input device @ 0x7fc74141a0c0] [0] Built-in Input
  
  [AVFoundation input device @ 0x7fc74141a0c0] [1] Boom2Device

  But if I replace output format from mp4 to mkv then record is well on second monitor too ! How fix this bug ?

• Using GDIgrab in FFmpeg with dshow Audio produces black screen

  16 mars 2016, par Spreadys

  here is my command :

  ffmpeg -f gdigrab -framerate 25 -offset_x 10 -offset_y 10 -show_region 1 -draw_mouse 1 -video_size 1280x720 -i desktop -f dshow -i audio="Microphone (2- ATR USB microphone)" -r 25 -threads 4 -c:v libx264 -pix_fmt yuv422p -preset superfast -tune fastdecode -x264opts keyint=25:min-keyint=1 -crf 4 -c:a aac -profile:a aac_low -async 25 "C:\Users\david\Desktop\%output%.mp4"

  The gdigrab video works great when it is on its own (no audio). The audio works fine when it is on its own (no video). When I join the two commands to capture both together, as soon as I move a window within my capture area, the area goes black.

  In Windows 7, I used to get around this by stopping the desktop composition service prior to capture, (SC stop uxsms), but this is now not possible in Win10.

  I thought it may be something graphics card related.
  My main monitor is on an Nvidia card, with my second running from the onboard Intel. This is setup for Quicksync H264 playback and encoding with my NLE.

  I know that I could use a dshow screen capture driver such as UScreen but am trying to avoid that as I need the capture area to be specified each time from a simple batch.

  Any help appreciated to solve this black area problem- its driving me crazy !
  David