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• Portable YUV Drawing Context

  1er juin 2017, par Leif Andersen

  I have a stream of YUV data (from a video file) that I want to stream to a screen in real time. (Basically, I want to write a program that plays the video in real time.)

  As such, I am looking for a portable way to send YUV data to the screen. I would ideally like to use something portable so I don’t have to reimplement it for every major platform.

  I have found a few options, but all of them seem to have significant issues. They are :

  1. Use OpenGL directly, converting the YUV data to RGB. (And using the single quad for the whole screen trick.)

  This obviously won’t work because converting RGB to YUV on the CPU is going to be too slow for displaying images in real time.

  2. Use OpenGL, but use a shader to convert the YUV stream to RGB.

  This option is a bit better. Although the problem here is that (afaict), this will involve making two streams and splicing them together. It might work, but may have issues with larger resolutions.

  3. Instead use SDL, which has the option of creating a YUV context directly.

  The problem with this is I already am using a cross platform widget library for other aspects of my program (such as playback controls). As far as I can tell, SDL only opens up in its on (possibly borderless) window. I would ideally like my controls and drawing context to be in the same window. Which I can do with opengl, but not SDL.

  4. Use SDL, and also use something like Qt for the on screen widgets, use a message passing protocol to communicate between the two libraries. Have the (borderless) SDL window constantly move itself on top of the opengl window.

  While this approach is clever, it seems like the two windows could get out of sink easily making the user experience sub-optimal.

  5. Forget a cross platform library, do thinks OS specific, making use of hardware acceleration if present.

  This is a fine solution although its not cross platform.

  As such, is there any good way to draw YUV data to a screen that ideally is :

  1. Portable (at least to the major platforms).
  2. Fast enough to be real time.
  3. Allows other widgets in the same window.

• FFmpeg On iOS can’t find delogo

  8 mai 2018, par Y.Y.Doe

  I integrated FFmpeg on iOS，and use “delogo” to clean watermark，but it does not work.
  And it logs :

  No such filter:delogo

  I don’t know why,and I need help

  it’s my iOS code to use FFmpeg

  dispatch_async(dispatch_get_global_queue(0, 0), ^{
  
      char *outPic = (char *)[DocumentPath(@"delogo.mp4") UTF8String];
  
      char *movie = (char *)[BundlePath(@"logo.mp4") UTF8String];
  
      char *a[] = {
  
          "ffmpeg",
  
          "-i",
  
          movie,
  
          "-vf",
  
          "delogo=x=10:y=10:w=250:h=120:show=1",
  
          outPic
  
      };
  
      ffmpeg_main(sizeof(a)/sizeof(*a),a);
  
  });

  my total log

  ffmpeg version 3.0 Copyright (c) 2000-2016 the FFmpeg developers
 built with Apple LLVM version 7.3.0 (clang-703.0.31)
 configuration: --target-os=darwin --arch=arm64 --cc='xcrun -sdk iphoneos clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch arm64 -mios-version-min=6.0 -fembed-bitcode' --extra-ldflags='-arch arm64 -mios-version-min=6.0 -fembed-bitcode' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/arm64
 WARNING: library configuration mismatch
 avutil      configuration: --target-os=darwin --arch=x86_64 --cc='xcrun -sdk iphonesimulator clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch x86_64 -mios-simulator-version-min=6.0' --extra-ldflags='-arch x86_64 -mios-simulator-version-min=6.0' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/x86_64
 avcodec     configuration: --target-os=darwin --arch=x86_64 --cc='xcrun -sdk iphonesimulator clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch x86_64 -mios-simulator-version-min=6.0' --extra-ldflags='-arch x86_64 -mios-simulator-version-min=6.0' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/x86_64
 avformat    configuration: --target-os=darwin --arch=x86_64 --cc='xcrun -sdk iphonesimulator clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch x86_64 -mios-simulator-version-min=6.0' --extra-ldflags='-arch x86_64 -mios-simulator-version-min=6.0' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/x86_64
 avdevice    configuration: --target-os=darwin --arch=x86_64 --cc='xcrun -sdk iphonesimulator clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch x86_64 -mios-simulator-version-min=6.0' --extra-ldflags='-arch x86_64 -mios-simulator-version-min=6.0' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/x86_64
 avfilter    configuration: --target-os=darwin --arch=x86_64 --cc='xcrun -sdk iphonesimulator clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch x86_64 -mios-simulator-version-min=6.0' --extra-ldflags='-arch x86_64 -mios-simulator-version-min=6.0' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/x86_64
 swscale     configuration: --target-os=darwin --arch=x86_64 --cc='xcrun -sdk iphonesimulator clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch x86_64 -mios-simulator-version-min=6.0' --extra-ldflags='-arch x86_64 -mios-simulator-version-min=6.0' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/x86_64
 swresample  configuration: --target-os=darwin --arch=x86_64 --cc='xcrun -sdk iphonesimulator clang' --enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic --extra-cflags='-arch x86_64 -mios-simulator-version-min=6.0' --extra-ldflags='-arch x86_64 -mios-simulator-version-min=6.0' --prefix=/Users/lxh/Desktop/FFmpeg-iOS-build-script-master/thin/x86_64
 libavutil      55. 17.103 / 55. 17.103
 libavcodec     57. 24.102 / 57. 24.102
 libavformat    57. 25.100 / 57. 25.100
 libavdevice    57.  0.101 / 57.  0.101
 libavfilter     6. 31.100 /  6. 31.100
 libswscale      4.  0.100 /  4.  0.100
 libswresample   2.  0.101 /  2.  0.101
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/daiyangyang/Library/Developer/CoreSimulator/Devices/02A8BC3F-5E46-453A-A3B4-A42563C518EA/data/Containers/Bundle/Application/4E0BB47F-5D3E-42A3-BC76-2D7D03657870/去水印.app/logo.mp4':
 Metadata:
   major_brand     : isom
   minor_version   : 512
   compatible_brands: isomiso2mp41
   encoder         : Lavf57.25.100
 Duration: 00:02:31.37, start: 0.023220, bitrate: 472 kb/s
   Stream #0:0(und): Video: mpeg4 (Simple Profile) (mp4v / 0x7634706D), yuv420p, 640x352 [SAR 1:1 DAR 20:11], 338 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 24k tbc (default)
   Metadata:
     handler_name    : VideoHandler
   Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 129 kb/s (default)
   Metadata:
     handler_name    : SoundHandler
[AVFilterGraph @ 0x7fbabb519e00] No such filter: 'delogo'
Error opening filters!

  I integrated FFmpeg by "FFmpeg-iOS-build-script"(https://github.com/kewlbear/FFmpeg-iOS-build-script)

• Android Ndk & FFMPEG - Not able to compile on ubuntu x86

  18 février 2015, par Palak Darji

  I am following this :
  roman10’s android ndk r9d - ffmpeg tutorial
  I am able to run build_android.sh script.. but its not creating that ‘android’ folder in my source/ffmpeg folder !!
  what should I do ? Plz help me.

  Another Doubt : The thing ‘arm’ in that .sh file is supposed to be changed according to machine env ???? If that is the case, can you guide us for x86 ???

  my build_android.sh file :

  #!/bin/bash
  
  NDK=/home/NDK/android-ndk-r9d
  
  SYSROOT=$NDK/platforms/android-19/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-arm
  
  function build_one
  
  {
  
  sudo ./configure \
  
      --target-os=linux \
  
      --prefix=$PREFIX \
  
      --enable-shared \
  
      --disable-static \
  
      --disable-doc \
  
      --disable-ffmpeg \
  
      --disable-ffplay \
  
      --disable-ffprobe \
  
      --disable-ffserver \
  
      --disable-avdevice \
  
      --disable-doc \
  
      --disable-symver \
  
      --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
      --arch=arm \
  
      --enable-cross-compile \
  
      --sysroot=$SYSROOT \
  
      --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
  
      --extra-ldflags="$ADDI_LDFLAGS" \
  
      $ADDITIONAL_CONFIGURE_FLAG
  
  make clean
  
  make
  
  make install
  
  }
  
  CPU=i686
  
  PREFIX=$(pwd)/android/$CPU 
  
  ADDI_CFLAGS="-marm"
  
  build_one

  I am using Ndk r10, ffmpeg 2.5.4, ubuntu x86.

  Thanks for ur time.

  Palak.