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• Compiling ffmpeg for use in Android (ndk) for x86 architecture

  26 septembre 2012, par Ankur22

  I am trying to compile ffmpeg for Android but for the x86 architecture. I've successfully compiled an arm .so and it all works, and I though that by replacing arm with x86 in the relevant places within the build script would have done the trick. Unfortunately that's not the case and I get some strange things occurring.

  First I get this while it's compiling ffmpeg :

  /home/ankur/android-ndk-r8/platforms/android-8/arch-arm//usr/include/strings.h:49: warning: redundant redeclaration of 'index'

  Notice the arch-arm instead of arch-x86. Finally I get this :

  /home/ankur/android-ndk-r8/toolchains/x86-4.4.3/prebuilt/linux-x86/bin/i686-android-linux-ld: libavcodec/libavcodec.a(4xm.o): Relocations in generic ELF (EM: 40)
  
  /home/ankur/android-ndk-r8/toolchains/x86-4.4.3/prebuilt/linux-x86/bin/i686-android-linux-ld: libavcodec/libavcodec.a(4xm.o): Relocations in generic ELF (EM: 40)
  
  /home/ankur/android-ndk-r8/toolchains/x86-4.4.3/prebuilt/linux-x86/bin/i686-android-linux-ld: libavcodec/libavcodec.a(4xm.o): Relocations in generic ELF (EM: 40)
  
  libavcodec/libavcodec.a(4xm.o): could not read symbols: File in wrong format

  The build script I've created looks like this :

  #!/bin/bash
  
  
  
  NDK=~/android-ndk-r8
  
  PLATFORM=$NDK/platforms/android-8/arch-x86/
  
  PREBUILT=$NDK/toolchains/x86-4.4.3/prebuilt/linux-x86
  
  function build_one_r8
  
  {
  
  ./configure \
  
      --disable-shared \
  
      --enable-static \
  
      --enable-gpl \
  
      --enable-version3 \
  
      --enable-nonfree \
  
      --disable-doc \
  
      --disable-ffmpeg \
  
      --disable-ffplay \
  
      --disable-ffprobe \
  
      --disable-ffserver \
  
      --disable-avdevice \
  
      --disable-avfilter \
  
      --disable-postproc \
  
      --enable-small \
  
      --cross-prefix=$PREBUILT/bin/i686-android-linux- \
  
      --enable-cross-compile \
  
      --target-os=linux \
  
      --extra-cflags="-I$PLATFORM/usr/include" \
  
      --arch=x86 \
  
      --disable-symver \
  
      --disable-debug \
  
      --disable-stripping \
  
      $ADDITIONAL_CONFIGURE_FLAG
  
  sed -i 's/HAVE_LRINT 0/HAVE_LRINT 1/g' config.h
  
  sed -i 's/HAVE_LRINTF 0/HAVE_LRINTF 1/g' config.h
  
  sed -i 's/HAVE_ROUND 0/HAVE_ROUND 1/g' config.h
  
  sed -i 's/HAVE_ROUNDF 0/HAVE_ROUNDF 1/g' config.h
  
  sed -i 's/HAVE_TRUNC 0/HAVE_TRUNC 1/g' config.h
  
  sed -i 's/HAVE_TRUNCF 0/HAVE_TRUNCF 1/g' config.h
  
  make clean
  
  make  -j4 install
  
  $PREBUILT/bin/i686-android-linux-ar d libavcodec/libavcodec.a inverse.o
  
  $PREBUILT/bin/i686-android-linux-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog  --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/i686-android-linux/4.4.3/libgcc.a
  
  }
  
  function build_one_r8_2
  
  {
  
  $PREBUILT/bin/i686-android-linux-ar d libavcodec/libavcodec.a inverse.o
  
  $PREBUILT/bin/i686-android-linux-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog  --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/i686-android-linux/4.4.3/libgcc.a
  
  }
  
  #x86
  
  CPU=x86
  
  OPTIMIZE_CFLAGS="-march=$CPU "
  
  PREFIX=./android/$CPU
  
  ADDITIONAL_CONFIGURE_FLAG=
  
  build_one_r8

  I hope I'm doing something wrong rather than this not being possible.

  Thanks !

• mpegts : Support running the write_trailer function without an AVIOContext

  19 décembre 2014, par Martin Storsjö

  mpegts : Support running the write_trailer function without an AVIOContext
  If opening and closing dynamic buffers as AVIOContext, we may
  
  not have any AVIOContext available when wanting to close and
  
  deallocate the muxer. Allow calling write_trailer despite this.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/mpegtsenc.c

• lavu/riscv : use Zbb REV8 at run-time

  30 mai 2024, par Rémi Denis-Courmont

  lavu/riscv : use Zbb REV8 at run-time
  This adds runtime support to use Zbb REV8 for 32- and 64-bit byte-wise
  
  swaps. The result is about five times slower than if targetting Zbb
  
  statically, but still a lot faster than the default bespoke C code or a
  
  call to GCC run-time functions.
  For 16-bit swap, this is however unsurprisingly a lot worse, and so this
  
  sticks to the baseline. In fact, even using REV8 statically does not
  
  seem to be beneficial in that case.
           Zbb static    Zbb dynamic   I baseline
  
  bswap16 :  0.668184765   3.340764069   0.668029012
  
  bswap32 :  0.668174014   3.340763319   9.353855435
  
  bswap64 :  0.668221765   3.340496313  14.698672283
  
  (seconds for 1 billion iterations on a SiFive-U74 core)
  

  • [DH] libavutil/riscv/bswap.h