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• How to port signal() to sigaction() ?

  28 septembre 2016, par Shark

  due to recent problems discovered with NDK12 and NDK13b2, i’m thinking of ’porting’ libx264’s use of signal() (and missing bsd_signal() in ndk12) to use sigaction() instead.

  The problem is, I’m not quite sure what’s the simple&fastest way to replace signal() calls with sigaction() ones.

  For all i see, it’s mainly used in x264-snapshot/common/cpu.c in the following manner :

  using the following signal handler :

  static void sigill_handler( int sig )
  
  {
  
      if( !canjump )
  
      {
  
          signal( sig, SIG_DFL );
  
          raise( sig );
  
      }
  
  
  
      canjump = 0;
  
      siglongjmp( jmpbuf, 1 );
  
  }

  This is the problematic x264_cpu_detect function... currently, i’m guessing i only need to tackle the ARM version, but i’ ; ; still have to replace all occurances of signal() with sigaction() so i might just cover both of them to get the thing building...

  FYI - the NDK13 beta2 still has "unstable" libc and the build doesn’t fail on this part, but rather the first invocation of the rand() function somewhere else... So i’m out of luck and replacing the signal() calls might be better than just waiting for the official NDK13 release. I’m doing this to get rid of text-relocations so i can run the library (and doubango) on API 24 (Android N)

  the problematic part of function that invokes signal() :

  #elif SYS_LINUX
  
  
  
  uint32_t x264_cpu_detect( void )
  
  {
  
      static void (*oldsig)( int );
  
  
  
      oldsig = signal( SIGILL, sigill_handler );
  
      if( sigsetjmp( jmpbuf, 1 ) )
  
      {
  
          signal( SIGILL, oldsig );
  
          return 0;
  
      }
  
  
  
      canjump = 1;
  
      asm volatile( "mtspr 256, %0\n\t"
  
                    "vand 0, 0, 0\n\t"
  
                    :
  
                    : "r"(-1) );
  
      canjump = 0;
  
  
  
      signal( SIGILL, oldsig );
  
  
  
      return X264_CPU_ALTIVEC;
  
  }
  
  #endif
  
  
  
  #elif ARCH_ARM
  
  
  
  void x264_cpu_neon_test( void );
  
  int x264_cpu_fast_neon_mrc_test( void );
  
  
  
  uint32_t x264_cpu_detect( void )
  
  {
  
      int flags = 0;
  
  #if HAVE_ARMV6
  
      flags |= X264_CPU_ARMV6;
  
  
  
      // don't do this hack if compiled with -mfpu=neon
  
  #if !HAVE_NEON
  
      static void (* oldsig)( int );
  
      oldsig = signal( SIGILL, sigill_handler );
  
      if( sigsetjmp( jmpbuf, 1 ) )
  
      {
  
          signal( SIGILL, oldsig );
  
          return flags;
  
      }
  
  
  
      canjump = 1;
  
      x264_cpu_neon_test();
  
      canjump = 0;
  
      signal( SIGILL, oldsig );
  
  #endif
  
  
  
      flags |= X264_CPU_NEON;
  
  
  
      // fast neon -> arm (Cortex-A9) detection relies on user access to the
  
      // cycle counter; this assumes ARMv7 performance counters.
  
      // NEON requires at least ARMv7, ARMv8 may require changes here, but
  
      // hopefully this hacky detection method will have been replaced by then.
  
      // Note that there is potential for a race condition if another program or
  
      // x264 instance disables or reinits the counters while x264 is using them,
  
      // which may result in incorrect detection and the counters stuck enabled.
  
      // right now Apple does not seem to support performance counters for this test
  
  #ifndef __MACH__
  
      flags |= x264_cpu_fast_neon_mrc_test() ? X264_CPU_FAST_NEON_MRC : 0;
  
  #endif
  
      // TODO: write dual issue test? currently it's A8 (dual issue) vs. A9 (fast      mrc)
  
  #endif
  
      return flags;
  
  }
  
  
  
  #else
  
  
  
  uint32_t x264_cpu_detect( void )
  
  {
  
      return 0;
  
  }

  So the question is really this : what would be the quickest/easiest//fastest way to replace the signal() calls with sigaction() ones while preserving the current functionality ?

  EDIT :
  The reason i’m trying to get rid of signal() are these build errors :

  /home/devshark/SCRATCH/doubango/thirdparties/android/armv5te/lib/dist/libx264.a(cpu.o):cpu.c:function sigill_handler: error: undefined reference to 'bsd_signal'
  
  
  
  /home/devshark/SCRATCH/doubango/thirdparties/android/armv5te/lib/dist/libx264.a(cpu.o):cpu.c:function x264_cpu_detect: error: undefined reference to 'bsd_signal'
  
  /home/devshark/SCRATCH/doubango/thirdparties/android/armv5te/lib/dist/libx264.a(cpu.o):cpu.c:function x264_cpu_detect: error: undefined reference to 'bsd_signal'
  
  
  
  /home/devshark/SCRATCH/doubango/thirdparties/android/armv5te/lib/dist/libx264.a(cpu.o):cpu.c:function x264_cpu_detect: error: undefined reference to 'bsd_signal'

  I already know that this is a known NDK12 problem, that might be solved by bringing bsd_signal back to the libc in NDK13. However, in it’ beta state with it’s unstable libc - it’s currently missing the rand() function and simply waiting for it might not do the trick. But in the worst-case scenario, i guess i’ll just have to wait for it and retry after it’s release.

  But as it currently is, the prebuilt version of the library i want to use has text-relocations and is being rejected by phones running newer API / version of the android OS.

  EDIT2 :
  I also know that signal() usually works by using sigaction() under the hood, but maybe i won’t get bsd_signal related build-errors... since i’m suspecting that this one isn’t using it. It’s obviously using bsd_signal, which may or may not be the same underlying thing :/

• Why does javaFx run converted mp4 but not original ?

  20 février 2020, par brat

  Simply put, I have this issue where I have a mp4 file with a video. If I run it directly in the code posted here, the window opens but its white/blank. No movie showing.
  But if I run the original movie through ffmpeg it works.

  ffmpeg -i original.mp4 -s hd720 converted.mp4

  Note that Im converting from mp4 to mp4, I just change the size to hd720.
  So, the question is, why do I need to do that ?

  My code :

  package mypack;
  
  
  
  import javafx.application.Application;
  
  import javafx.scene.Group;
  
  import javafx.scene.Scene;
  
  import javafx.scene.layout.BorderPane;
  
  import javafx.scene.media.Media;
  
  import javafx.scene.media.MediaPlayer;
  
  import javafx.scene.media.MediaView;
  
  import javafx.stage.Stage;
  
  
  
  public class MyPlayer extends Application{
  
  
  
      public static void main(String[] args) {
  
          launch(args);
  
      }
  
  
  
  
  
      public void start(Stage primaryStage) throws Exception {
  
          BorderPane content = new BorderPane();
  
  
  
           Scene scene = new Scene(content, 540, 209);
  
           primaryStage.setScene(scene);
  
           primaryStage.setScene(scene);
  
  
  
           primaryStage.setTitle("Hello Media");
  
  
  
           String source;
  
           source = "file:///C:/Users/Noob/Desktop/Movies/original.mp4";
  
  //       source = "file:///C:/Users/Noob/Desktop/Movies/converted.mp4";
  
  
  
  
  
           Media media = new Media(source);
  
  
  
           MediaPlayer mediaPlayer = new MediaPlayer(media);
  
           mediaPlayer.setAutoPlay(true);
  
  
  
           MediaView mediaView = new MediaView(mediaPlayer);
  
           ((BorderPane) scene.getRoot()).getChildren().add(mediaView);
  
           primaryStage.show();
  
  
  
      }
  
  
  
  }

  For those audio/video afficionados/ffmpeg pros out there. This is what gets output from the original.

  ffprobe -i original.mp4

  ffprobe version 4.2.2 Copyright (c) 2007-2019 the FFmpeg developers
  
    built with gcc 9.2.1 (GCC) 20200122
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  
    libavutil      56. 31.100 / 56. 31.100
  
    libavcodec     58. 54.100 / 58. 54.100
  
    libavformat    58. 29.100 / 58. 29.100
  
    libavdevice    58.  8.100 / 58.  8.100
  
    libavfilter     7. 57.100 /  7. 57.100
  
    libswscale      5.  5.100 /  5.  5.100
  
    libswresample   3.  5.100 /  3.  5.100
  
    libpostproc    55.  5.100 / 55.  5.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0000029bc02bc540] st: 0 edit list: 1 Missing key frame while searching for timestamp: 0
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0000029bc02bc540] st: 0 edit list 1 Cannot find an index entry before timestamp: 0.
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'original.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42mp41
  
      creation_time   : 2020-02-18T17:09:21.000000Z
  
    Duration: 00:00:22.56, start: 0.000000, bitrate: 1631 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 1624 kb/s, 29.97 fps, 29.97 tbr, 29970 tbn, 59.94 tbc (default)
  
      Metadata:
  
        creation_time   : 2020-02-18T17:09:21.000000Z
  
        handler_name    : Mainconcept MP4 Video Media Handler
  
        encoder         : AVC Coding

  Could it have to do with size ? To big ? Since it sayes 3840x2160 in the original ? And Im making it smaller with hd720 ?
  If so, I would expect at least a corner of the movie showing, instead of a totally blank window.
  Im new at this, so if you also give some good link to ffmpeg (excluding official manpages) and/or a good tutorial/info page on video formatting pointed towards beginners it would be much appreciated. My understanding this far is there are containers which hold streams and each stream can have different codecs depending on the container.

• How to prevent gray overlays, transparency issues, and similar shader defects when using gl-transition filters

  29 janvier 2021, par Soren Wray

  I compiled and installed a local build of ffmpeg with support for gl-transition adapted from the official guide for Ubuntu. The build is configured with all relevant packages and seems to be working as intended. See the code samples at the end.

  


  I know the gl-transition filter is installed due to ./ffmpeg -v 0 -filters | grep gltransition, which outputs :

  


  T.. gltransition      VV->V      OpenGL blend transitions

  


  All sources were tested with the custom command string : ./ffmpeg -i ~/PATH/TO/INPUT1.mp4 -i ~/PATH/TO/INPUT2.mp4 -filter_complex "gltransition=duration=3:offset=1:source=/PATH/TO/EFFECT.glsl" -y ~/PATH/TO/OUTPUT.mp4, which is for a 3 second transition effect (duration=3), starting at 1 second (offset=1).

  


  I've been testing the code sources for various transition effects listed in the gl-transition gallery and have encountered some unusual gray overlays at the transition points, likely having to do with alpha channel transparency. In many cases, there are also shader or animation defects, e.g. with windowslice.glsl rendering only 1 slice when there are supposed to be 10, or again with WaterDrop.glsl, which simply fades out the clip in place of the intended ripple effect. Most complex animations seem to default to this monotonous gray overlay. I provide a gif example below for the GlitchedMemories.glsl transition.

  


  Example of Glitched Memories

  


  I couldn't locate any other reports of this particular issue online. The documentation for gl-transitions is sorely lacking and the Stack Exchange network has very little information about this custom filter. I don't know how to fix the problem. It could have something to do with the codec or pixel format used, or some quirk of my build, but the technical details are beyond me.

  


  Please note my compilation and configuration steps, perhaps the error is there :

  


  sudo apt-get update -qq && sudo apt-get -y install autoconf automake build-essential cmake git-core libass-dev libfreetype6-dev libgnutls28-dev libsdl2-dev libtool libunistring-dev libva-dev libvdpau-dev libvorbis-dev libxcb1-dev libxcb-shm0-dev libxcb-xfixes0-dev pkg-config texinfo wget yasm zlib1g-dev

mkdir -p ~/ffmpeg_sources ~/bin

sudo apt-get install nasm libx264-dev libx265-dev libnuma-dev libvpx-dev libfdk-aac-dev libmp3lame-dev libopus-dev

cd ~/ffmpeg_sources && wget -O ffmpeg-snapshot.tar.bz2 https://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2 && tar xjvf ffmpeg-snapshot.tar.bz2

cd ~/ && git clone https://github.com/transitive-bullshit/ffmpeg-gl-transition.git


  


  Open ~/ffmpeg-gl-transition/vf_gltransition.c in an editor and delete line : # define GL_TRANSITION_USING_EGL // remove this line if you don't want to use EGL

  


  cd ~/ffmpeg_sources/ffmpeg && cp ~/ffmpeg-gl-transition/vf_gltransition.c libavfilter/

git apply ~/ffmpeg-gl-transition/ffmpeg.diff

PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure \
    --prefix="$HOME/ffmpeg_build" \
    --pkg-config-flags="--static" \
    --extra-cflags="-I$HOME/ffmpeg_build/include" \
    --extra-ldflags="-L$HOME/ffmpeg_build/lib" \
    --extra-libs="-lpthread -lm" \
    --bindir="$HOME/bin" \
    --enable-gpl \
    --enable-opengl \
    --enable-gnutls \
    --enable-libass \
    --enable-libfdk-aac \
    --enable-libfreetype \
    --enable-libmp3lame \
    --enable-libopus \
    --enable-libvorbis \
    --enable-libvpx \
    --enable-libx264 \
    --enable-libx265 \
    --disable-shared \
    --enable-static \
    --enable-runtime-cpudetect \
    --enable-filter=gltransition \
    --extra-libs='-lGLEW -lglfw' \
    --enable-nonfree && \
PATH="$HOME/bin:$PATH" make

source ~/.profile