Sur d’autres sites (9247)

• NDK r8c warning for asm objects regarding "Cortex-A8 erratum" - should I be worried ?

  7 décembre 2012, par Alex Cohn

  Question : What is the meaning of this warning ? If there are no real-life consequences, I can live with it for a while... But I am concerned with what will happen if our program gets loaded on one of the faulty chips.

  Background : With NDK r8c, linking of X264 encoder issues warnings :

  cannot scan executable section 1 of libx264.a(dct-a.o) for Cortex-A8 erratum because it has no mapping symbols

  ... same warning for all assembly files in libx264.

  libx264.a itself was cross-compiled on the same machine with the same 4.6 toolchain taken from NDK.

  Here are the instructions to easily reproduce the problem (Ubuntu or MacOS) :

  1. Download x264-snapshot-20121203-2245 from ftp://ftp.videolan.org/pub/x264/snapshots/last_x264.tar.bz2

  2. Run ./configure --enable-pic --enable-strip --enable-static --cross-prefix=~/android-ndk-r8c/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86/bin/arm-linux-androideabi- --sysroot=~/android-ndk-r8c/platforms/android-14/arch-arm --host=arm-linux

  3. Run ~/android-ndk-r8c/prebuilt/linux-x86/bin/make

  It will build the static library, and after that display the Cortex-A8 warning while linking the x265 executable. I am not worried about the compiler warnings, because building libx264.a is done offline, it is not part of our official daily build.

  I have reported this as http://code.google.com/p/android/issues/detail?id=40794.

  I tried to add the mapping symbols manually to dct-a.S following the ARM.com instructions, but this had no effect.

• How to run FFMPEG with —enable-libfontconfig on Amazon Linux 2

  22 avril 2024, par Adrien Kaczmarek

  Problem

  


  I want to run FFmpeg on AWS Lambda (Amazon Linux 2) with the configuration --enable-libfontconfig enable.

  


  Situation

  


  I already have FFmpeg running on AWS Lambda without the configuration --enable-libfontconfig.

  


  Here is the step I took to run FFmpeg on AWS Lambda (see official guide) :

  


  

  • Connect to Amazon EC2 running on AL2 (environment used by Lambda for Python 3.11)

  


  • Download and package FFmpeg from John Van Sickle

  


  • Create a Lambda Layer with FFmpeg

  


  


  Unfortunately, the version built by John Van Sickle doesn't have the configuration --enable-libfontconfig enabled.

  


  Unsuccessful Trials

  


  I tried to rebuilt it from scratch following the installation guide but without success (and the guide doesn't install font related dependencies)

  


  I tried to install it with brew but the command brew install ffmpeg didn't succeed on AL2.

  


  I tried to install ffmpeg from ffmpeg-master-latest-linux64-gpl.tar.xz. Unfortunately, this build of ffmpeg doesn't run on AL2 :

  


  ffmpeg: /lib64/libm.so.6: version `GLIBC_2.27' not found (required by ffmpeg)
ffmpeg: /lib64/libpthread.so.0: version `GLIBC_2.28' not found (required by ffmpeg)
ffmpeg: /lib64/libc.so.6: version `GLIBC_2.27' not found (required by ffmpeg)
ffmpeg: /lib64/libc.so.6: version `GLIBC_2.28' not found (required by ffmpeg)


  


  Any help would be greatly appreciated,

  


  Please make sure your answer is up to date and tested. Too many answers out there are auto-generated, too generic, or simple redirect without context.

  


  Thank you

  


• Swift framework project with internal C module - Undefined symbols for architecture arm64

  29 mars 2020, par Phạm Phi Phúc

  I’m creating Swift framework project using FFmpeg module internally.

  Steps are :

  1. Download source of FFmpeg from official website.
  2. Build it by build script here : https://github.com/kewlbear/FFmpeg-iOS-build-script
  3. Copy built file to project
  4. Create file module.modulemap, it’s content is :

  module FFmpeg [system][extern_c] {
  
  
  
      header "include/libavcodec/avcodec.h"
  
      header "include/libavdevice/avdevice.h"
  
      header "include/libavfilter/avfilter.h"
  
      header "include/libavformat/avformat.h"
  
      header "include/libavutil/avutil.h"
  
      header "include/libswresample/swresample.h"
  
      header "include/libswscale/swscale.h"
  
  
  
      export *
  
  }

  Project tree is :

  

  5. Set Import paths for both project settings and target settings to
     $(SRCROOT)/MediaToolkit/Libraries/FFmpeg/**
  6. My source code is :

  import Foundation
  
  import FFmpeg
  
  
  
  public class MediaToolkit {
  
      public init(){}
  
  
  
      public func hello() {
  
          print("AVFMT_NOFILE: \(AVFMT_NOFILE)")
  
          avformat_network_init()
  
      }
  
  }

  When I build it, I received error

  Undefined symbols for architecture arm64:
  
    "_avformat_network_init", referenced from:
  
        MediaToolkit.MediaToolkit.hello(Swift.String) -> () in MediaToolkit.o
  
  ld: symbol(s) not found for architecture arm64
  
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

  If I remove line avformat_network_init(), it will print AVFMT_NOFILE: 1