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• Haskell - Converting multiple images into a video file - ffmpeg-lights' frameWriter-function fails

  26 octobre 2017, par oRole

  Situation
  Currently I am working on an application for image-processing that uses ffmpeg-light to fetch all the frames of a given video-file so that the program afterwards can apply grayscaling, as well as edge detection alogrithms to each of the frames.

  With the help of friendly stackoverflowers I was able to set up a method capable of converting several images into one video file using ffmpeg-lights’ frameWriter function.

  Problem
  The application runs fine to the moment it hits the frameWriterfunction and I don’t really know why as there are no errors or exception-messages thrown. (OS : Win 10 64bit)

  What did I try ?
  I tried..
  
   different versions of ffmpeg (from 3.2 to 3.4).
  
   ffmpeg.exe using the command line to test if there are any codecs missing, but any conversion I tried worked.
  
   different EncodingParams-combinations : like.. EncodingParams width height fps (Nothing) (Nothing) "medium"
  

  Question
  Unfortunately, none of above worked and the web lacks on information to that specific case. Maybe I missed something essential (like ghc flags or something) or made a bigger mistake within my code. That is why I have to ask you : Do you have any suggestions/advice for me ?

  Haskell Packages
  
   ffmpeg-light-0.12.0
  
   JuicyPixels-3.2.8.3
  

  Code
  

  {--------------------------------------------------------------------------------------------
  
   Applies "juicyToFFmpeg'" and "getFPS" to a list of images and saves the output-video
  
   to a user defined location.
  
  ---------------------------------------------------------------------------------------------}     
  
  saveVideo :: String -> [Image PixelYA8] -> Int -> IO ()
  
  saveVideo path imgs fps = do
  
           -- program stops after hitting next line --
  
           frame <- frameWriter ep path
  
           ------------------------------------------------
  
           Prelude.mapM_ (frame . Just) ffmpegImgs 
  
           frame Nothing
  
           where ep = EncodingParams width height fps (Just avCodecIdMpeg4) (Just avPixFmtGray8a) "medium"
  
                 width      = toCInt $ imageWidth  $ head imgs
  
                 height     = toCInt $ imageHeight $ head imgs
  
                 ffmpegImgs = juicyToFFmpeg' imgs
  
                 toCInt x   = fromIntegral x :: CInt
  
  
  
  {--------------------------------------------------------------------------------------------
  
   Converts a single image from JuicyPixel-format to ffmpeg-light-format. 
  
  ---------------------------------------------------------------------------------------------}      
  
  juicyToFFmpeg :: Image PixelYA8 -> (AVPixelFormat, V2 CInt, Vector CUChar)
  
  juicyToFFmpeg img = (avPixFmtGray8a, V2 (toCInt width) (toCInt height), ffmpegData)
  
                    where toCInt   x   = fromIntegral x :: CInt
  
                          toCUChar x   = fromIntegral x :: CUChar
  
                          width        = imageWidth img
  
                          height       = imageHeight img
  
                          ffmpegData   = VS.map toCUChar (imageData img)
  
  
  
  {--------------------------------------------------------------------------------------------
  
   Converts a list of images from JuicyPixel-format to ffmpeg-light-format. 
  
  ---------------------------------------------------------------------------------------------}                        
  
  juicyToFFmpeg' :: [Image PixelYA8] -> [(AVPixelFormat, V2 CInt, Vector CUChar)]
  
  juicyToFFmpeg' imgs = Prelude.foldr (\i acc -> acc++[juicyToFFmpeg i]) [] imgs
  
  
  
  {--------------------------------------------------------------------------------------------
  
   Simply calculates the FPS for image-to-video conversion.
  
   -> frame :: (Double, DynamicImage) where Double is a timestamp of when it got extracted 
  
  ---------------------------------------------------------------------------------------------}
  
  getFPS :: [(Double, DynamicImage)] -> Int
  
  getFPS frames = div (ceiling $ lastTimestamp - firstTimestamp) frameCount :: Int
  
                where firstTimestamp = fst $ head frames
  
                      lastTimestamp  = fst $ last frames
  
                      frameCount     = length frames

• avcodec/vc1 : fix mquant calculation for interlace field pictures

  18 mai 2018, par Jerome Borsboom

  avcodec/vc1 : fix mquant calculation for interlace field pictures
  For interlace field pictures s->mb_height indicates the height of the full
  
  picture in MBs, i.e. the two fields combined. A single field is half this
  
  size. When calculating mquant for interlace field pictures, the bottom edge
  
  is the last MB row of the field.
  Signed-off-by : Jerome Borsboom <jerome.borsboom@carpalis.nl>
  

  • [DH] libavcodec/vc1_block.c

• Chrome struggles to play videos

  11 décembre 2017, par Cameron

  I have some video files I want to display on a webpage using the HTML5 video player. The videos were sent to me at 1920x1080 in H.254 MP4 format.

  Using FFMPEG I have converted them so I have a smaller Mp4 file, an OGV file, and a WebM file using the following commands :

  ffmpeg -i FILE.mp4 -vcodec h264 FILE.mp4
  
  
  
  ffmpeg -i FILE.mp4 -acodec libvorbis -vcodec libtheora -f ogv FILE.ogv
  
  
  
  ffmpeg -i FILE.mp4 -c:v libvpx -crf 10 -b:v 1M -c:a libvorbis FILE.webm

  And then the video is embedded into the page like so :

  <video preload="metadata" crossorigin="anonymous" poster="poster.jpg" controls="controls" playsinline="playsinline">
  
      <source src="FILE.webm" type="video/webm">
  
      <source src="FILE.ogv" type="video/ogv">
  
      <source src="FILE.mp4" type="video/mp4">
  
  </source></source></source></video>

  However when I click to play the video in Chrome, it stops after a few seconds and then if I click play again it restarts. If I right click and open the video in a new tab I just see a tiny player and not the video e.g.
  

  The same happens for all three formats. But if I refresh the browser enough times I can get the MP4 file to show up in the new tab though it still suffers from the aforementioned bug of playing for a few seconds before failing.

  I have tested this in Firefox and Safari and it works fine ! In fact it even works in IE and Edge :D And I can also play the videos in a player on the machine itself... e.g. QuickTime.

  Any ideas why Chrome is acting this way ? Or any resolutions ? I’m seeing the same behaviour on Chrome for Windows and Mac. Is the way I have converted the videos using FFMPEG in anyway a cause that could affect Chrome but not other browsers ?

  Chrome version tested on : Version 63.0.3239.84 (Official Build) (64-bit)

  Output from ffprobe as per the comments on the one of the webm files :

  ffprobe version 3.4 Copyright (c) 2007-2017 the FFmpeg developers
  
    built with Apple LLVM version 7.3.0 (clang-703.0.31)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-ffplay --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --enable-openssl --disable-lzma --enable-libopenjpeg --disable-decoder=jpeg2000 --extra-cflags=-I/usr/local/Cellar/openjpeg/2.3.0/include/openjpeg-2.3 --enable-nonfree
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libavresample   3.  7.  0 /  3.  7.  0
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  Input #0, matroska,webm, from 'FILE.webm':
  
    Metadata:
  
      COMPATIBLE_BRANDS: mp42mp41
  
      MAJOR_BRAND     : mp42
  
      MINOR_VERSION   : 0
  
      ENCODER         : Lavf57.83.100
  
    Duration: 00:00:52.57, start: 0.000000, bitrate: 910 kb/s
  
      Stream #0:0(eng): Video: vp8, yuv420p(progressive), 1920x1080, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        HANDLER_NAME    : Alias Data Handler
  
        ENCODER         : Lavc57.107.100 libvpx
  
        DURATION        : 00:00:52.563000000
  
      Stream #0:1(eng): Audio: vorbis, 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        HANDLER_NAME    : Alias Data Handler
  
        ENCODER         : Lavc57.107.100 libvorbis
  
        DURATION        : 00:00:52.568000000