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• using ffmpeg to automate splitting video into quarters and stacking

  11 février 2014, par user3297049

  I need to create a quick FFMPEG batch file that takes a very wide video file and splits it into quaters (dimension wise not time wise), then outputting a file where each quarter is under the previous.

  E.g.

  A B C D

  would become
  A
  B
  C
  D
  

  I know this should be possible with crop and pad commands, and through research I've found that someone divided into quarters and put the top left and bottom right next to each other horizontally using :

  "% dp0\ffmpeg.exe" -i %1 -filter_complex "[0:0]crop=iw/2:ih/2:0:0,pad=iw*2:ih:0:0[tl] ;[0:0]crop=iw/2:ih:iw/2:ih/2[br] ;[tl][br]overlay=W/2" -b:v 32000k -b:a 128k %1_2.avi

  Can anyone help as the command line is beyond me.
  Thanks
  Steve

• link error Xcode libx264.a ARM

  19 novembre 2013, par user1558688

  I'm trying to build libx264.a to run on my iphone 4s ( running iOS 6.1.3 )

  I'm building it using the MACOSX 10.9 Terminal application :

  CC=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang ./configure 
  
  --host=arm-apple-darwin 
  
  --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk 
  
  --prefix=armv7 
  
  --extra-cflags='-no-integrated-as -arch armv7' 
  
  --extra-ldflags="-L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/usr/lib/system -arch armv7" 
  
  --enable-pic --enable-static

  Which guives me the output :

  platform:      ARM
  
  system:        MACOSX
  
  cli:           yes
  
  libx264:       internal
  
  shared:        no
  
  static:        yes
  
  asm:           yes
  
  interlaced:    yes
  
  avs:           avxsynth
  
  lavf:          no
  
  ffms:          no
  
  mp4:           no
  
  gpl:           yes
  
  thread:        posix
  
  opencl:        yes
  
  filters:       crop select_every 
  
  debug:         no
  
  gprof:         no
  
  strip:         no
  
  PIC:           yes
  
  bit depth:     8
  
  chroma format: all

  Then I run 'make' and it generates a libx264.a archive.

  So far, so good.

  On my Xcode (Version 5.0.2 (5A3005)) application I set :

  1) Build Settings -> Header Search Path -> x264 parent directory (../x264 )
  2) Build Phases -> Link Library with Binaries -> Add Other... ( ../x264/libx264.a )
  3) Build Settings -> Other Linker Flags : -ObjC

  In my AppDelegate.mm :

  #import "AppDelegate.h"
  
  #import "x264.h"
  
  
  
  @implementation AppDelegate
  
  
  
  - (BOOL)application:(UIApplication *)application 
  
  didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
  
  {    
  
      x264_param_t x264param;
  
      x264_param_default(&x264param);
  
  
  
      // Override point for customization after application launch.
  
      return YES;
  
  }
  
  
  
  ...

  When i try to run it on the device I get the error :

  Undefined symbols for architecture armv7:
  
    "x264_param_default(x264_param_t*)", referenced from:
  
    -[AppDelegate application:didFinishLaunchingWithOptions:] in AppDelegate.o
  
  ld: symbol(s) not found for architecture armv7
  
  clang: error: linker command failed with exit code 1 
  
  (use -v to see invocation)

  Here is the command invoked by xcode :

  Ld /Users/danieldantas/Library/Developer/Xcode/DerivedData/testingCpp-bvawshyhjcybwvadwwwjqxuomjts/Build/Products/Debug-iphoneos/testingCpp.app/testingCpp normal armv7
  
  cd /Users/danieldantas/Desktop/projects/testingCpp
  
  setenv IPHONEOS_DEPLOYMENT_TARGET 6.0
  
  setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
  
  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -arch armv7 -isysroot 
  
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk 
  
  -L/Users/danieldantas/Library/Developer/Xcode/DerivedData/testingCpp-bvawshyhjcybwvadwwwjqxuomjts/Build/Products/Debug-iphoneos 
  
  -L/Users/danieldantas/Desktop/projects/testingCpp -L/Users/danieldantas/Desktop/projects/x264 
  
  -F/Users/danieldantas/Library/Developer/Xcode/DerivedData/testingCpp-bvawshyhjcybwvadwwwjqxuomjts/Build/Products/Debug-iphoneos 
  
  -filelist /Users/danieldantas/Library/Developer/Xcode/DerivedData/testingCpp-bvawshyhjcybwvadwwwjqxuomjts/Build/Intermediates/testingCpp.build/Debug-iphoneos/testingCpp.build/Objects-normal/armv7/testingCpp.LinkFileList 
  
  -dead_strip -ObjC -stdlib=libc++ -fobjc-arc -fobjc-link-runtime -miphoneos-version-min=6.0 -lx264 -framework CoreGraphics -framework UIKit -framework Foundation -Xlinker -dependency_info -Xlinker 
  
  /Users/danieldantas/Library/Developer/Xcode/DerivedData/testingCpp-bvawshyhjcybwvadwwwjqxuomjts/Build/Intermediates/testingCpp.build/Debug-iphoneos/testingCpp.build/Objects-normal/armv7/testingCpp_dependency_info.dat -o 
  
  /Users/danieldantas/Library/Developer/Xcode/DerivedData/testingCpp-bvawshyhjcybwvadwwwjqxuomjts/Build/Products/Debug-iphoneos/testingCpp.app/testingCpp

  Any idea how to fix this ?

  Thanks

• Transcoding and Streaming a video file for Android

  2 août 2013, par Yaron Budowski

  I'm trying to encode a local/static input file (can MP4, for example) into a smaller video file (either by resizing, lesser quality video, etc.) and stream it in parallel (i.e. I can't wait for the encoding process to finish before streaming it back), so it can be played by an Android client (the standard Android video player).

  So I've tried using ffmpeg as follows :

  ffmpeg -re -i input.mp4 -g 52 -acodec libvo_aacenc -ab 64k -vcodec libx264 -vb 448k -f mp4 -movflags frag_keyframe+empty_moov -

  Notice I'm using stdout as the output so I can run ffmpeg and stream its output on the fly

  However, such methods (and other similar methods) don't seem to work on Android - it can't simply play it once it receives "non-standard" files (such as a fragmented MP4s) - it seems like the empty moov atom messes it up.

  I also tried other container formats, such as 3GPP and WebM.

  I'd love to hear any kind of input on this issue...

  Thanks