Recherche avancée

Sur d’autres sites (4437)

• lavu : add support for Content Light Level side metadata

  3 avril 2017, par Steve Lhomme

  lavu : add support for Content Light Level side metadata
  As found in HEVC.
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] doc/APIchanges
  • [DH] libavutil/frame.c
  • [DH] libavutil/frame.h
  • [DH] libavutil/mastering_display_metadata.c
  • [DH] libavutil/mastering_display_metadata.h
  • [DH] libavutil/version.h

• 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.

• Install ffmpeg-light with cabal

  20 septembre 2016, par WirflBirfl

  I want to install the ffmpeg-light library from hackage via cabal on Windows 10 (64 bit). So I downloaded ffmpeg and extracted it to C :\FFmpeg.

  At first pkg-config was complaining that it could not find various packages. I solved this problem with .pc files.

  When I tried to use the command : cabal install ffmpeg-light cabal complained about missing C-libraries, being exactly those for which I created the .pc files.

  Then I tried the command : cabal install ffmpeg-light --extra-lib-dirs=C:\FFmpeg\lib. Now I have a different error message, which says :

  Enums.hsc:7:32: fatal error: libavcodec/avcodec.h: No such file or directory

  Edit :
  Then I tried the following command :

  cabal install ffmpeg-light --extra-lib-dirs=C:\FFmpeg\lib \
  
                             --extra-include-dirs=C:\FFmpeg\include

  Now first the compiler gives some warnings about deprecated functions in ffmpeg and redundant imports in ffmpeg-light, but compiles 11 of 11. But the build is still not successfull.

  In-place registering ffmpeg-light-0.11.1...
  
  setup-Simple-Cabal-1.22.5.0-x86_64-windows-ghc-7.10.3.exe:
  
  'C:\Haskell\bin\ghc-pkg.exe' exited with an error:
  
  ffmpeg-light-0.11.1: Warning: haddock-interfaces:
  
  C:\Users\HOLEYC~1\AppData\Local\Temp\cabal-tmp-2824\ffmpeg-light-0.11.1\dist\doc\html\ffmpeg-light\ffmpeg-light.haddock
  
  doesn't exist or isn't a file
  
  ffmpeg-light-0.11.1: Warning: haddock-html:
  
  C:\Users\HOLEYC~1\AppData\Local\Temp\cabal-tmp-2824\ffmpeg-light-0.11.1\dist\doc\html\ffmpeg-light
  
  doesn't exist or isn't a directory
  
  ffmpeg-light-0.11.1: library-dirs: C:FFmpeglib is a relative path which makes
  
  no sense (as there is nothing for it to be relative to). You can make paths
  
  relative to the package database itself by using ${pkgroot}. (use --force to
  
  override)
  
  ffmpeg-light-0.11.1: include-dirs: C:FFmpeginclude is a relative path which
  
  makes no sense (as there is nothing for it to be relative to). You can make
  
  paths relative to the package database itself by using ${pkgroot}. (use
  
  --force to override)
  
  cabal: Error: some packages failed to install:
  
  ffmpeg-light-0.11.1 failed during the building phase. The exception was:
  
  ExitFailure 1

  Some additional information :

  cabal version: cabal-install version 1.22.6.0
  
  using version 1.22.5.0 of the Cabal library
  
  gcc version of my installed Haskell platform: 5.2.0

  Example .pc file I used for pkg-config :

  Name: libavcodec
  
  Description: Library for ffmpeg
  
  Version: 57
  
  Cflags: -IC:\FFmpeg\include
  
  Libs: -LC:\FFmpeg\lib -llibavcodec