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• FFmpeg Convert to JPEG works in VLC but not in Mac Preview ?

  24 juillet 2019, par Evan Keeton

  I’m trying to convert a PNG image to a JPEG image using ffmpeg. As far as I can tell, it’s working fine, but it doesn’t display properly in Mac Preview.

  I’m running the following :

  $ ffmpeg -i foo.png foo.jpg

  And it produces the following output :

  ffmpeg version 4.1.3 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.3_1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  Input #0, png_pipe, from 'foo.png':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: png, rgba(pc), 200x231, 25 tbr, 25 tbn, 25 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (png (native) -> mjpeg (native))
  
  Press [q] to stop, [?] for help
  
  [swscaler @ 0x7ffeaf00ae00] deprecated pixel format used, make sure you did set range correctly
  
  Output #0, image2, to 'foo.jpg':
  
    Metadata:
  
      encoder         : Lavf58.20.100
  
      Stream #0:0: Video: mjpeg, yuvj444p(pc), 200x231, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
  
      Metadata:
  
        encoder         : Lavc58.35.100 mjpeg
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
  
  frame=    1 fps=0.0 q=3.7 Lsize=N/A time=00:00:00.04 bitrate=N/A speed= 4.7x    
  
  video:12kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

  When I open foo.jpg in most applications, such as VLC or Google Chrome, I get exactly what I expected : an image that looks exactly the same as foo.png, the input.

  
  

  However, this is what is displayed in the Finder preview, and the same this is displayed when I open up the file in "Preview."

  

   I wonder if this has something to do with the deprecated pixel format used, make sure you did set range correctly error, but I’m not sure, especially since the image is fine, the problem seems to be elsewhere. 

  It seems the deprecated pixel format error is not the issue (that’s an internal thing), so I guess I just need to specify pixel formats properly.

• Anomalie #4369 (En cours) : YQL n’est plus actif

  7 août 2019, par Ybbet SPIP

  Bonjour tout le monde,

  J’ai envoyé un message sur la liste SPIP-Dev. Je crée un ticket pour traçabilité.

  SPIP offre depuis la boucle DATA la source YQL. Cf. code ici : https://core.spip.net/projects/spip/repository/entry/spip/ecrire/iterateur/data.php#L642
  Malheureusement, le service est fermé depuis le 3 janvier 2019. cf. https://news.ycombinator.com/item?id=18785255

  Je n’ai pas trouvé de solutions alternatives équivalentes en ligne. Que du Desktop "freemium" quand une solution existe.
  Il existe https://vespa.ai/ qui est à installer sur une machine.
  Autre élément trouvé https://www.pipes.digital/
  Je ne suis pas sûr qu’on retrouve une souplesse telle que l’était YQL.

  Bien à vous,

• How to mark TIME on each h.264 frames [duplicate]

  22 août 2019, par kylesong

  This question already has an answer here :

  • FFmpeg for marking time video based on a reference date
    
    1 answer
    

  I want to create python script to make time shown in video(h.264) file.
  There’s unixtime(in hex) in each frame header, so I want to use this time value to put in the video.

  In video.h264 binary file, there’s unix time written like below.
  frame header

  004D195D (offset 0x12)
  
  => 2019-07-01 00:00:00(UTC0)

  What I’ve tried is, parse unixtime and convert to 2019-07-01 00:00:00 format using datetime module.

  unixtime = int.from_bytes(fh.read(4), byteorder='little')
  
  timestring = datetime.utcfromtimestamp(unixtime).strftime('%Y-%m-%d %H:%M:%S')

  However, I’m stuck to express time in video frame.

  I attached sample video files(video.h264), and some screenshots.

  Any possible way to make this thing work ?
  original.png possible_result.png

  And you can download sample video, always welcome to test and play wih it.
  https://drive.google.com/open?id=1Csn7RdvUifSGIGjhTFUJbkRru5J2uDFd

  if you want to see the sample video(video.h264) that I’ve attached, use "ffplay" command like below.

  ffplay.exe video.h264

  To convert to AVI,

  ffmpeg.exe -i video.h264 video.avi