Recherche avancée

Sur d’autres sites (7023)

• so Confused, why my build of libffmpeg.so > 17M ?

  24 février 2012, par ghost

  I did build ffmpeg for Android in winxp and scientific linux , ffmpeg is in dolphin player — an open source video player (http://code.google.com/p/dolphin-player/), and i just build the ffmpeg, its seems like the same as in rockplayer 1.7.0, they all use build_andriod.sh below， it worked in both winxp and linux,
  and all successfully got bin/ffmpeg (less than 5MB), but libffmpeg.so ( > 17MB)， when put libffmpeg.so in dolphin-player libs , player can't work, the size 17MB is too large, the original libffmpeg.so in olphin-player libs is less than 5MB, please give some advice.

  #!/bin/bash
  
  
  
  ######################################################
  
  # FFmpeg builds script for Android+ARM platform
  
  #
  
  # This script is released under term of 
  
  #   CDDL (http://www.opensource.org/licenses/cddl1) 
  
  # Wrote by pinxue (~@gmail.com) from RockPlayer.com
  
  #                                   2010-8 ~ 2011-4
  
  ######################################################
  
  
  
  ######################################################
  
  # Usage:
  
  #   put this script in top of FFmpeg source tree
  
  #   ./build_android
  
  #
  
  # It generates binary for following architectures:
  
  #     ARMv6 
  
  #     ARMv6+VFP 
  
  #     ARMv7+VFM-�d16 (Tegra2) 
  
  #     ARMv7+Neon (Cortex-A8)
  
  #
  
  # Customizing:
  
  # 1. Feel free to change ./configure parameters for more features
  
  # 2. To adapt other ARM variants
  
  #       set $CPU and $OPTIMIZE_CFLAGS 
  
  #       call build_one
  
  ######################################################
  
  
  
  export TMPDIR=D:/tmp/android
  
  export NDK=D:/android-ndk-r4
  
  
  
  #PLATFORM=$NDK/build/platforms/android-8/arch-arm/
  
  PLATFORM=$NDK/build/platforms/android-8/arch-arm
  
  #PREBUILT=$NDK/build/prebuilt/darwin-x86/arm-eabi-4.4.0
  
  PREBUILT=$NDK/build/prebuilt/windows/arm-eabi-4.4.0
  
  
  
  function build_one
  
  {
  
  
  
  # -fasm : required. Android header file uses asm keyword instead of __asm__ , but most of c dialect (like ansi,c99,gnu99) implies -fno-asm.
  
  #   ~/android/android-ndk-r4/build/platforms/android-5/arch-arm//usr/include/asm/byteorder.h: In function '___arch__swab32':
  
  #   ~/android/android-ndk-r4/build/platforms/android-5/arch-arm//usr/include/asm/byteorder.h:25: error: expected ')' before ':' token
  
  
  
  # -fno-short-enums : optimized.  Else FFmpeg obj will generate a huge number of warning for variable-size enums, 
  
  #   though we may suppress them by --no-enum-size-warning, it would be better to avoid it.
  
  #   .../ld: warning: cmdutils.o uses variable-size enums yet the output is to use 32-bit enums; use of enum values across objects may fail
  
  
  
  # --extra-libs="-lgcc" : required. Else cannot solve some runtime function symbols
  
  #   ... undefined reference to `__aeabi_f2uiz'
  
  
  
  # --enable-protocols : required. Without this option, the file open always fails mysteriously.
  
  #   FFmpeg's av_open_input_file will invoke file format probing functions, but because most of useful demuxers has flag of zero 
  
  #   which cause them are ignored during file format probling and fall to url stream parsing,
  
  #   if protocols are disabled, the file:// url cannot be opened as well.
  
  
  
  # $PREBUILT/bin/arm-eabi-ar d libavcodec/libavcodec.a inverse.o : required.
  
  #   FFmpeg includes two copies of inverse.c both in libavutil and libavcodec for performance consideration (not sure the benifit yet)
  
  #   Without this step, final ld of generating libffmpeg.so will fail silently, if invoke ld through gcc, gcc will collect more reasonable error message.
  
  
  
  # -llog: debug only, FFmpeg itself doesn't require it at all.
  
  #   With this option, we may simply includes "utils/Log.h" and use LOGx() to observe FFmpeg's behavior
  
  #   PS, it seems the toolchain implies -DNDEBUG somewhere, it would be safer to use following syntax
  
  #    #ifdef NDEBUG
  
  #        #undef NDEBUG
  
  #        #define HAVE_NDEBUG
  
  #    #endif
  
  #    #include "utils/Log.h"
  
  #    #ifdef HAVE_NDEBUG
  
  #        #define NDEBUG
  
  #        #undef HAVE_NDEBUG
  
  #    #endif
  
  
  
  # --whole-archive : required. Else ld generate a small .so file (about 15k)
  
  
  
  # --no-stdlib : required. Android doesn't use standard c runtime but invited its own wheal (bionic libc) because of license consideration.
  
  
  
  # space before \ of configure lines: required for some options. Else next line will be merged into previous lines's content and cause problem.
  
  #   Especially the --extra-cflags, the next line will pass to gcc in this case and configure will say gcc cannot create executable.
  
  
  
  # many options mentioned by articles over internet are implied by -O2 or -O3 already, need not repeat at all.
  
  
  
  # two or three common optimization cflags are omitted because not sure about the trade off yet. invoke NDK build system with V=1 to find them.
  
  
  
  # -Wl,-T,$PREBUILT/arm-eabi/lib/ldscripts/armelf.x mentioned by almost every articles over internet, but it is not required to specify at all.
  
  
  
  # -Dipv6mr_interface=ipv6mr_ifindex : required. Android inet header doesn't use ipv6mr_interface which is required by rfc, seems it generate this user space header file directly from kernel header file, but Linux kernel has decided to keep its own name for ever and ask user space header to use rfc name.
  
  
  
  # HAVE_SYS_UIO_H : required. Else:
  
  # In file included from ~/android/android-ndk-r4/build/platforms/android-5/arch-arm//usr/include/linux/socket.h:29,
  
  #                 from ~/android/android-ndk-r4/build/platforms/android-5/arch-arm//usr/include/sys/socket.h:33,
  
  #                 from libavformat/network.h:35,
  
  #                 from libavformat/utils.c:46:
  
  #~/android/android-ndk-r4/build/platforms/android-5/arch-arm//usr/include/linux/uio.h:19: error: redefinition of 'struct iovec'
  
  #
  
  
  
  # --disable-doc : required because of strange bug of toolchain.
  
  #
  
  
  
  #
  
  #--extra-ldflags=-Wl,-T,$PREBUILT/arm-eabi/lib/ldscripts/armelf.x -Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib $PREBUILT/lib/gcc/arm-eabi/4.4.0/crtbegin.o $PREBUILT/lib/gcc/arm-eabi/4.4.0/crtend.o -lc -lm -ldl"
  
  #
  
  
  
  ./configure --target-os=linux \
  
      --prefix=$PREFIX \
  
      --enable-cross-compile \
  
      --extra-libs="-lgcc" \
  
      --arch=arm \
  
      --cc=$PREBUILT/bin/arm-eabi-gcc \
  
      --cross-prefix=$PREBUILT/bin/arm-eabi- \
  
      --nm=$PREBUILT/bin/arm-eabi-nm \
  
      --sysroot=$PLATFORM \
  
     --extra-cflags=" -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums  -fno-strict-aliasing -finline-limit=300 $OPTIMIZE_CFLAGS " \
  
      --disable-shared \
  
      --enable-static \
  
      --extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -nostdlib -lc -lm -ldl -llog" \
  
      --enable-parsers \
  
      --disable-encoders  \
  
      --enable-decoders \
  
      --disable-muxers \
  
      --enable-demuxers \
  
      --enable-swscale  \
  
      --disable-ffplay \
  
      --disable-ffprobe \
  
      --disable-ffserver \
  
      --enable-network \
  
      --enable-indevs \
  
      --disable-bsfs \
  
      --disable-filters \
  
      --enable-protocols  \
  
      --enable-asm \
  
      --disable-doc \
  
      $ADDITIONAL_CONFIGURE_FLAG
  
  
  
  ##make clean
  
  make  -j4 install
  
  
  
  
  
  $PREBUILT/bin/arm-eabi-ar d libavcodec/libavcodec.a inverse.o
  
  
  
  $PREBUILT/bin/arm-eabi-ld -rpath-link=$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  -lc -lm -lz -ldl -llog  --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-eabi/4.4.0/libgcc.a
  
  
  
  }
  
  
  
  
  
  #arm v6
  
  CPU=armv6
  
  OPTIMIZE_CFLAGS="-marm -march=$CPU"
  
  PREFIX=./android/$CPU 
  
  ADDITIONAL_CONFIGURE_FLAG=
  
  build_one
  
  
  
  #arm v7vfpv3
  
  CPU=armv7-a
  
  OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=$CPU "
  
  PREFIX=./android/$CPU 
  
  ADDITIONAL_CONFIGURE_FLAG=
  
  build_one
  
  
  
  #arm v7vfp
  
  CPU=armv7-a
  
  OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU "
  
  PREFIX=./android/$CPU-vfp
  
  ADDITIONAL_CONFIGURE_FLAG=
  
  build_one
  
  
  
  #arm v7n
  
  CPU=armv7-a
  
  OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -march=$CPU -mtune=cortex-a8"
  
  PREFIX=./android/$CPU-neon 
  
  ADDITIONAL_CONFIGURE_FLAG=--enable-neon
  
  build_one
  
  
  
  #arm v6+vfp
  
  CPU=armv6
  
  OPTIMIZE_CFLAGS="-DCMP_HAVE_VFP -mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU"
  
  PREFIX=./android/${CPU}_vfp 
  
  ADDITIONAL_CONFIGURE_FLAG=
  
  build_one

• Wo can tell me the difference and relation between ffmpeg 、libav and avconv

  28 février 2012, par why

  when I run ffmpeg on ubuntu, it shows :

  ffmpeg 
  
  ffmpeg version v0.8, Copyright (c) 2000-2011 the Libav developers
  
    built on Feb 28 2012 13:27:36 with gcc 4.6.1
  
  This program is not developed anymore and is only provided for compatibility. Use avconv instead (see Changelog for the list of incompatible changes).
  
  Hyper fast Audio and Video encoder
  
  usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
  
  
  
  Use -h to get full help or, even better, run 'man ffmpeg'

  I found avconv on http://libav.org, I am just perplexed by them

• Internecine Legal Threats

  1er juin 2011, par Multimedia Mike — Legal/Ethical

  FFmpeg and associated open source multimedia projects such as xine, MPlayer, and VLC have long had a rebel mystique about them ; a bunch of hackers playing fast and loose with IP law in order to give the world the free multimedia experience it deserved. We figured out the algorithms using any tools available, including the feared technique of binary reverse engineering. When I gave a presentation about FFmpeg at Linuxtag in 2007, I created this image illustrating said mystique :

  
  
  

  It garnered laughs. But I made the point that we multimedia hackers just press on, doing our thing while ignoring legal threats. The policy has historically worked out famously for us– to date, I seem to be the only person on the receiving end of a sort-of legal threat from the outside world.

  Who would have thought that the most credible legal threat to an open source multimedia project would emanate from a fork of that very project ? Because that’s exactly what has transpired :

  
  
  Click for full threat
  

  So it came to pass that Michael Niedermayer — the leader of the FFmpeg project — received a bona fide legal nastygram from Mans Rullgard, a representative of the FFmpeg-forked Libav project. The subject of dispute is a scorched-earth matter involving the somewhat iconic FFmpeg zigzag logo :

  Original 2D logo		enhanced 3D logo

  To think of all those years we spent worrying about legal threats from organizations outside the community. I’m reminded of that time-honored horror trope/urban legend staple : Get out ! The legal threats are coming from inside the house !

  I’m interested to see how this all plays out, particularly regarding jurisdiction, as we have a U.K. resident engaging an Italian lawyer outfit to deliver a legal threat to an Austrian citizen regarding an image hosted on a server in Hungary. I suspect I know why that law firm was chosen, but it’s still a curious jurisdictional setup.

  People often used to ask me if we multimedia hackers would get sued to death for doing what we do. My response was always, “There’s only one way to know for sure,” by which I meant that we would just have to engage in said shady activities and determine empirically if lawsuits resulted. So I’m a strong advocate for experimentation to push the limits. Kudos to Michael and Mans for volunteering to push the legal limits.