Recherche avancée

Sur d’autres sites (14255)

• ffmpeg cross compiles nicely for aarch64, but when linking with my project, gives Relocations in generic ELF (EM : 62)

  29 août 2019, par Lucas Zanella

  Here’s how I’m configuring ffmpeg :

          ./configure \
  
          --prefix=${BUILD_DIR}/desktop/aarch64 \
  
          --disable-doc \
  
          --enable-cross-compile \
  
          --cross-prefix=aarch64-linux-gnu-\
  
          --target-os=linux \
  
          --arch=aarch64 \
  
          --extra-cflags="-O3 -fPIC" \
  
          --enable-shared \
  
          --disable-static \
  
          --disable-debug \
  
          --disable-runtime-cpudetect \
  
          --disable-programs \
  
          --disable-muxers \
  
          --disable-encoders \
  
          --disable-decoders \
  
          ${DECODERS_TO_ENABLE} \
  
          --disable-bsfs \
  
          --disable-pthreads \
  
          --disable-avdevice \
  
          --disable-network \
  
          --disable-postproc 
  
  
  
          make clean
  
          make -j$(nproc)
  
          make install

  It compiles fine. Then, when I try to link my project with this compiled ffmpeg, it gives me

  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  /usr/bin/ld: ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a(allcodecs.o): Relocations in generic ELF (EM: 62)
  
  ../../../deps/ffmpeg/build/desktop/aarch64/lib/libavcodec.a: error adding symbols: File in wrong format

  In this answer : https://stackoverflow.com/a/23185739/10116440 he says that CC is missing. I’m also not using CC but shouldn’t CC be the same as --cross-prefix ?

  I also found http://lakm.us/logit/2012/11/cross-compiling-ubuntu-arm-ffmpeg/ in where he says that I should use --cross-prefix=arm-linux-gnueabi-, in my case arm should be aarch64. However, there’s no aarch64-linux-gnueabi- toolchain, only aarch64-linux-gnu-. Can it be the problem ? I think no because eabi looks like its for 32 bits, I guess

  It’s worth noticing that I’m bulding ffmpeg on a amd64 but using the static library to build my project on a aarch64.

• Can't compile project with ffmpeg-light

  27 octobre 2016, par wowofbob

  Compilation of any project which uses openFile function from Codec.FFmpeg.Decode fails with error :

  Couldn't match type ‘GHC.IO.Exception.IOException’ with ‘[Char]’
           arising from a functional dependency between:
             constraint ‘mtl-2.2.1:Control.Monad.Error.Class.MonadError
                           String IO’
               arising from a use of ‘openFile’
             instance ‘mtl-2.2.1:Control.Monad.Error.Class.MonadError
                         GHC.IO.Exception.IOException IO’
               at <no location="location" info="info"></no>

  As an example, compilation of this fails :

  openVideoFile :: String -> IO ()
  
  openVideoFile filePath = do
  
  
  
    initFFmpeg
  
  
  
    avFmtCtx <- openFile filePath
  
  
  
    return ()

  I guess the reason is that there is no ready instance of MonadError String IO. But, when I add a dummy instance like this :

  instance MonadError String IO where
  
    throwError _   = undefined
  
    catchError _ _ = undefined

  I’m getting another error :

  Functional dependencies conflict between instance declarations:
 instance MonadError String IO
   -- Defined at src/Video/Play/Base.hs:20:10
 instance [safe] MonadError GHC.IO.Exception.IOException IO
   -- Defined in ‘Control.Monad.Error.Class’

  I don’t know how to force compiler to use MonadError String IO instace here.

  • Should I assure GHC that my instance is better ?
  • Do I have a wrong environment setup ? I’m using ffmpeg-light clone from here and resolver lts-7.2. Host OS is Ubuntu.
  • There is commit which replaces import of Control.Monad.Error.Class by Control.Monad.Except. But, Control.Monad.Error.Class is still used in Codec.FFmpeg.Common. First time I thought it caused a problem. But it turns out that Control.Monad.Except just re-exports MonadError class from Control.Monad.Error.Class. So, it’s not a problem.

• How to build + include FFMPEG into an existing Android project

  20 janvier 2015, par SteveEdson

  I’ve found multiple questions and tutorials regarding FFMPEG, but I don’t seem to understand most of them. All of the guides I have read, miss out large gaps and don’t tend to explain things.

  I have an existing Android app that streams audio using a third party library called AAC Decoder. For various reasons, I need to switch to use FFMPEG, but cannot figure out how. I have managed to follow guides to build FFMPEG, but then I don’t understand what I am supposed to do with the output.

  My app needs to stream audio only, from a remote URL. The streams can be in a variety of formats.

  If anyone could link me to some comprehensive, detailed guides, or provide me with instructions, it would be great.

  Thanks.