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• sidxindex : Remove parsing that isn’t necessary any longer

  28 novembre 2014, par Martin Storsjö

  sidxindex : Remove parsing that isn’t necessary any longer
  When we don’t adjust the Period start time, we don’t need to
  
  parse the earliest_presentation_time from the sidx boxes either.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] tools/sidxindex.c

• Android - merge videos taken with front and back cameras

  3 mai 2023, par Raz Leshem

  I am having an orientation problem when merging videos taken with front and back cameras in portrait, recorded using Android CameraX.

  


  This issue is explained here, but I am yet to find a working solution. I have tried multiple solutions, such as using mp4parser as suggested in the issue explanation, but the result is a that every alternate camera video is upside down.
I also tried using FFmpeg for android - mobile-ffmpeg.
Using ffmpeg Concat demuxer resulted in the same result as mp4parser did.

  


  Concat demuxer command I used : ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4

  


  I also tried changing the rotation metadata of the videos to match before concatenating, similar to how it's done here, but that did not seem to have any effect on the end result.

  


  Lastly, I used ffmpeg Concat filter. That solution took longer obviously because of the re-encoding of the video but it did fix the problem of the orientation of the videos, but the output video quality was poor.

  


  Concat filter command :

  


  ffmpeg -i front1.mp4 -i rear1.mp4 -i front2.mp4 \
-filter_complex "[0:v] [0:a] [1:v] [1:a] [2:v] [2:a] \
concat=n=3:v=1:a=1 [v] [a]" \
-map "[v]" -map "[a]" output.mp4


  


  Has anyone found a solution on how to fix the orientation problem in android ? or maybe how can I keep the videos quality as much as possible when using the FFmpeg Concat filter to merge the videos ?

  


• avutil/hwcontext_mediacodec : fix backward compatibility

  11 janvier 2023, par Zhao Zhili

  avutil/hwcontext_mediacodec : fix backward compatibility
  AVMediaCodecDeviceContext without surface or native_window is
  
  useless, it shouldn't be created at all. Such dummy AVHWDeviceContext
  
  is allowed before, and it's used by mpv player. Creating a ANativeWindow
  
  automatically breaks such usecases.
  So disable creating a ANativeWindow by default. It can be enabled
  
  via the create_window flag, or by set the AVDictionary of
  
  av_hwdevice_ctx_create(). The downside is that
  ffmpeg -hwaccel mediacodec -i input.mp4 \
  
  	-c:a copy -c:v hevc_mediacodec output.mp4
  use ByteBuffer mode which isn't as efficient as before. The upside
  
  is libavfilter works now, which should be less surprise.
  To enable create_window on ffmpeg command line, use
  
  ffmpeg -hwaccel mediacodec \
  
  	-init_hw_device mediacodec=mediacodec,create_window=1 \
  
  	-i input.mp4 -c:a copy -c:v hevc_mediacodec output.mp4
  Users should know what it is to enable create_window. It should
  
  be OK to take sometime to figure out the option. And there are comments
  
  inside hwcontext_mediacodec.h to help user figure it out.
  Signed-off-by : Zhao Zhili <zhilizhao@tencent.com>
  

  • [DH] libavutil/hwcontext_mediacodec.c
  • [DH] libavutil/hwcontext_mediacodec.h