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• Connect external cameras to iOS and decompress to a usable form

  27 septembre 2017, par Ping Chen

  I want to create a 2 camera setup which can send 1 of the camera views out as an RTMP stream depending on the motion intensity detected. The chosen camera view can change if motion intensity on the views changes.

  I imagine that I could use an iPhone/iPad as encoding/streaming hub as well as 1 of the cameras. And connect a WiFi camera to the iPad/iPhone to feed the 2nd camera view.

  My goals for the iOS side are :

  1. Connect with a WiFi camera on the local network
  2. Decode the data and run motion intensity detection on the WiFi camera feed AND the iPhone/iPad’s own camera feed with Brad Larson’s GPUImage framework https://github.com/BradLarson/GPUImage
  3. Stream out the chosen camera view. depending on motion detected

  Larson’s GPUImage framework works with an AVCaptureSession subclass. I’m only familiar with AVFoundation objects, but am a complete noob with it comes to VideoToolbox and some of the lower level iOS video stuff. Through googling, I kind of know that VTDecompressionSession is what I’d get from the WiFi camera. I have no clue how I can manipulate that to a usable form for my purposes.

  I’ve dug through stackoverflow answers such as : https://stackoverflow.com/a/29525001/7097455

  Very informative, but maybe I don’t even know to ask the correct questions

• FFMPEG iOS 7 Library

  15 septembre 2017, par Destiny Dawn

  I’ve tried reading many tutorials.
  I’ve spent hours on google, and stackoverflow trying answer.
  So far I’ve read : Trying to compile the FFMPEG libraries for iPhoneOS platform with armv6 and arv7 architecture FFMPEG integration on iphone/ ipad project and https://github.com/lajos/iFrameExtractor few of the many.

  I’m trying to build this library for iOS 7/Xcode 5 compatibility but it’s not working.
  A common error I’d get is :

  Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
  
  yasm/nasm not found or too old. Use --disable-yasm for a crippled build.
  
  
  
  If you think configure made a mistake, make sure you are using the latest
  
  version from Git.  If the latest version fails, report the problem to the
  
  ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
  
  Include the log file "config.log" produced by configure as this will help
  
  solving the problem.

  I’d also get many more once that is finished. Such as :

  rm: illegal option -- .
  
  usage: rm [-f | -i] [-dPRrvW] file ...
  
         unlink file
  
  make: *** [clean] Error 64

  I’ve mostly tried using this command to start, but it always crashes on "make clean" :

  ./configure \
  
  --cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc \
  
  --as='/usr/local/bin/gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc' \
  
  --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk \
  
  --target-os=darwin \
  
  --arch=arm \
  
  --cpu=cortex-a8 \
  
  --extra-cflags='-arch armv7' \
  
  --extra-ldflags='-arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk' \
  
  --prefix=compiled/armv7 \
  
  --enable-cross-compile \
  
  --enable-nonfree \
  
  --enable-gpl \
  
  --disable-armv5te \
  
  --disable-swscale-alpha \
  
  --disable-doc \
  
  --disable-ffmpeg \
  
  --disable-ffplay \
  
  --disable-ffprobe \
  
  --disable-ffserver \
  
  --disable-asm \
  
  --disable-debug

• How to open a HEIF (.heic) image ?

  14 décembre 2022, par Jean-Milost Reymond

  For a c++ project, I need to open and show a HEIF (.heic) image. What I know (if I'm right) is that the HEIF images are based on the ffmpeg standard, and requires a H265 codec to be read.

  



  I found several open-source H265 codecs :

  



  

  • OpenHEVC (https://github.com/OpenHEVC/openHEVC)

  


  • x265 (https://bitbucket.org/multicoreware/x265/downloads/)

  


  • libde265 (https://github.com/strukturag/libde265)

  


  



  I can open and show H265 encoded video files with each of them, but I'm unable to simply open, show or convert a .heic image. All of them return an error, or just do nothing.

  



  To be honest I'm a little puzzled, because the HEIF standard seem to be a well kept secret. I'm unable to find a relevant info that could allow me to walk to a solution. Those I found are just tricks and workarounds, like e.g. forcing the device (I'm speaking here about the Apple iPhone using the new iOS11) to generate a jpg image instead of a heic, or using a third party application like dr.fone. Of course these solutions are irrelevant for me.

  



  So, somebody can tell me which codec I should use with a .heif image, and how I can use it to open it ? Or are there open source libraries or examples that allow to manipulate this type of image file ? Somebody can point me to the good direction ?