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• Theatrical quality ffmpeg/x264 encoding of a high-motion 1080p video

  2 décembre 2011, par Ian

  I've been struggling with encoding videos using FFMPEG and x264. The output stutters when played back in Quicktime, while in VLC it shows a lot of compression artifacts at the same places Quicktime stutters. So it seems like Quicktime is stuttering because it's trying to suppress the corruption/artifacts.

  The videos have a lot of random motion in them, including frames where 75% of the pixels will change at a random interval (the video is software generated so it's truly pseudo-random). The compression seems to be choking in these places where it's likely detecting a "scene cut" incorrectly. It also seems to choke at regular intervals where I guess it's doing a keyframe.

  I've based my encoding preset off of the x264-hq preset that comes with FFMPEG. I've tried turning off scene cut detection, and playing with the keyint/g and keyint_min options. Setting g to 1 makes it work, but blows out the filesize. I've tried the lossless presets, but they won't playback at all in Quicktime. Oddly, I haven't had any problems when working with a lower-resolution test video (1440x810).

  Here's the preset I have right now, which works, but yields a file that's approximately 60% larger than the (non-working) hq preset yields. Is there any way to improve upon this ? The filesize doesn't matter much, I just want something that will playback anywhere and be very high quality.

  coder=1
  flags=+loop
  cmp=+chroma
  partitions=+parti8x8+parti4x4+partp8x8+partp4x4+partb8x8
  me_method=umh
  subq=8
  me_range=16
  g=1
  keyint_min=1
  sc_threshold=0
  i_qfactor=0.71
  b_strategy=1crf=20
  qcomp=0.6
  qmin=20
  qmax=51
  qdiff=4
  bf=16
  refs=4
  trellis=1
  flags2=+dct8x8+wpred+bpyramid+mixed_refs
  wpredp=2
  

  Here's the command :

  ffmpeg \
    -r 60 -i "frame-%06d.tiff" \
    -vcodec libx264 -vpre my_preset \
    -threads 0 \
    -r 60 -an -f out.mp4
  

• Restrict bandwidth usage in cloud game server

  13 décembre 2012, par Nandy

  I am working on cloud game server development.

  During the testing of some games, there is a spike observed of around 10 MBps. Normally game consumes 4 6 MBps network bandwidth.

  Is there any way to keep consumed bandwidth <5 MBps without much affecting video quality ?

  720p resolution is being used. We are using x264 encoder, are there any params of this encoder which may help me out to achieve expected o/p ?

• full screen preview in javacv RecordActivity

  14 avril 2016, par mghaffari

  I use the RecordActivity sample 
  how to set initialize full screen with correct ratio and best resolution in any device and camera ?
  I tested any typical solution for android, but non of them gave me the outcome I wanted. Some of them caused the phone to go heated, and some of them caused the app to stop. 
  If you have any ideas or solutions using which I can use to solve my problem in RecordActivity class, it would be very kind of you to share it with me. Thanks in advance.

  https://github.com/bytedeco/javacv/blob/master/samples/RecordActivity.java