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• FFMPEG encoding is rotating portrait images uploaded from the iPhone

  27 juillet 2017, par Kevin J

  I’m trying to figure out why FFMPEG is rotating my thumbnail image when a portrait video is uploaded from an iphone.

  Here is my command line test :

  ffmpeg -i video/test.mp4 -c:v libx264 -profile:v high -level 5 -crf 18 -preset medium -maxrate 10M -bufsize 16M -pix_fmt yuv420p -vf "scale=iw*sar:ih, scale=\'if(gt(iw,ih),min(1920,iw),-1)\':\'if(gt(iw,ih),-1,min(1080,ih))\'" -x264opts bframes=3:cabac=1 -movflags faststart -b:a 320k -y video/test.mp4 -vcodec mjpeg -vframes 1 -an -f rawvideo -s 410x231 video/testthumb.jpg 2>&1

  Then the portrait image is rotated 90 degrees to be made a landscape image, but the video stays portrait. How can I keep the orientation the same ?

• (IOS) Streaming raw h.264 video from and iphone to a RTSP

  10 octobre 2015, par Eric Jovenitti

  Ok so i’m new to video encoding and decoding and RTSP, but I need to take a third party component video stream i.e. (A quad copter drone) and output that stream to a RTSP. The stream is in raw h.264. The stream comes from the drones sdk i.e.,

  -(void) camera:(DJICamera*)camera didReceivedVideoData:(uint8_t*)videoBuffer length:(int)length{
  
  uint8_t* pBuffer = (uint8_t*)malloc(length);
  
  memcpy(pBuffer, videoBuffer, length);
  
  [[[VideoPreviewer instance] dataQueue] push:pBuffer length:length];

  }

  As you can see the raw video comes in from camera in the uint8_t.
  To my understanding this a decoded raw h.264 stream with Nalu’s an a IDR frame.

  So I want to stream this video to a RTSP so it can be watch on VLC .

  Does anyone know of tutorials or demo code to stream this video via a RTSP ?

  Additionally I found this demo : http://www.gdcl.co.uk/2013/02/20/iOS-Video-Encoding.html

  This sends the iphone camera’s video out to a RTSP and it work well.
  But i can’t figure out how to inject the drones streaming video into this demo RTSP app.

  This demo uses
  AVCaptureDevice to capture the cameras streaming data.

  So my questions from this demo are :
  Is there anyway to make my drones stream an AVCAptureDevice ?
  If not, can i just inject the drones raw data into the where the iphones camera data would be and just use the same properties that the iphome camera already configured ?

  if i can’t do those options can I just use the demos RTSP part ?
  If that’s possible, i can that the iphone camera data is being encoded. Does this mean i would need to encode the drones stream ? if so, how would i go about doing this ? The drones SKD uses FFmpeg to output the video so it can be seen in real time on the iphones screen.

  Thanks so much for the help !

• How to deal ffplay being too slow playing iPhone's videos ?

  8 janvier 2020, par Mikhail T.

  Trying to play a 3840x2160 video recorded by an iPhone 7 (@30fps), I get frequent pauses — in the video, music keeps playing.

  



  This happens both in firefox and when ffplay is invoked to play the file directly — from command-line. The CPU is a dual E6700 @3.20GHz — not super fast, but it should be able to play smoothly, shouldn't it ? Video is Intel's "series 4" integrated chipset — again, not a speed-daemon, but it should be adequate... Support for Intel's VA API is included.

  



  I build ffmpeg-4.1 from source using FreeBSD port. As you can see, the port has a maddening amount of options — including several different ones for the 264-codec.

  



  Any suggestions for improving the decoding speed to the point, where it is watchable by a human ? Thank you !