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• In what way does this HEVC video not comply to Apples's requirements document ?

  16 novembre 2022, par Duke Dougal

  My goal is to work out why a given video file does not play on Macos/Safari/Quicktime.

  


  The background to this question is that it is possible to play HEVC videos with a transparent background/alpha channel on Safari/MacOS. To be playable, a video must meet the specific requirements set out by Apple in this document :

  


  https://developer.apple.com/av-foundation/HEVC-Video-with-Alpha-Interoperability-Profile.pdf

  


  The video that does not play on Apple/Safari/Quicktime is an HEVC video with an alpha transparency channel. Note that VLC for MacOS DOES play this file. Here it is :

  


  https://drive.google.com/file/d/1ZnXjcDbk-_YxTgRuH_D7RSR9SXdY_XTv/view?usp=share_link

  


  I have two example HEVC video files with a transparent background/alpha channel, and they both play fine using either Quicktime player or Safari :

  


  Working video #1 :

  


  https://drive.google.com/file/d/1PJAyg_sVKVvb-Py8PAu42c1qm8l2qCbh/view?usp=share_link

  


  Working video #2 :

  


  https://drive.google.com/file/d/1kk8ssUyT7qAaK15afp8VPR6mIWPFX8vQ/view?usp=sharing

  


  The first step is to work out in what way my non-working video ( https://drive.google.com/file/d/1ZnXjcDbk-_YxTgRuH_D7RSR9SXdY_XTv/view?usp=share_link ) does not comply with the specification.

  


  Once it is clear which requirements are not met by the non-working video then I can move onto the next phase, which is to try to formulate an ffmpeg command that will output a video meeting the requirements.

  


  I have read Apples requirements document and I am out of my depth in trying to analyse the non working video against the requirements - I don't know how to do it.

  


  Can anyone suggest a way to identify what is wrong with the video ?

  


  Additional context is that I am trying to find a way to create Apple/MacOS compatible alpha channel / transparent videos using ffmpeg with hevc_nvenc running on an Intel machine. I am aware that Apple hardware can create such videos, but for a wide variety of reasons it is not practical for me to use Apple hardware to do the job. I have spent many hours trying all sorts of ffmpeg and ffprobe commands to try to work out what is wrong and modify the video to fix it, but to be honest most of my attempts are guesswork.

  


• avformat/wavdec : Refuse to read chunks bigger than the filesize in w64_read_header()

  17 octobre 2020, par Michael Niedermayer

  avformat/wavdec : Refuse to read chunks bigger than the filesize in w64_read_header()
  Fixes : OOM
  
  Fixes : 26414/clusterfuzz-testcase-minimized-ffmpeg_dem_FWSE_fuzzer-5070632544632832
  
  Fixes : 26475/clusterfuzz-testcase-minimized-ffmpeg_dem_W64_fuzzer-5770207722995712
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/wavdec.c

• Mirrored Arabic Letters using TextClip Moviepy

  4 août 2020, par Sam

  I am trying to render the video which contains arabic letters. let's use مرحبا for the example. After video rendered the result is mirrored.

  


  background = mp.ColorClip(mobile_size, (255, 255, 255), duration=0.5) #float(audiolength.info.length)
text1 = mp.TextClip(english, fontsize=45, color=fcolor, font=Font, size= (mobile_size[0], 185), method = 'caption', align="south").set_duration(0.5) #float(audiolength.info.length)
text2 = mp.TextClip(formatChineseSentences(translated).encode("utf-8"), fontsize=45, color=fcolor2, font=Font, size= (mobile_size[0], 185), method = 'caption', align="north").set_duration(0.5) #float(audiolength.info.length)

clip1 = mp.CompositeVideoClip([background, text1.set_position(('center', "top")), text2.set_position(('center', "bottom"))])


  


  Expected Behavior

  


  

  


  Actual Behavior

  


  

  


  Steps to Reproduce the Problem

  


  Rendering TextClip with Arabic Characters. For this case we can use مرحبا.

  


  Specifications

  


  Python Version : Python 3.8.5
Moviepy Version : 1.0.3
Platform Name : Mac OS Catalina
Platform Version : 10.15.6