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• How to crop and scale correctly with FFMPEG ?

  16 juin 2020, par Rivera A. Pablo

  I'm trying to remove the TOP AND BOTTOM black bars of a video.

  



  Image sample from video


  



  What i'm trying to achieve

  



  

  



  The video itself is 1280x720 16:9, but the portion that's image information is at 4:3 since it's been captured from a VHS. I want to somehow stretch it until the top bars disappear without deforming the image. I don't care about the left and right bars.

  



  I tried using crop and scale with no luck.

  



  By using this code the top and bottom black bars disappeared on VLC when on normal screen but when going Full Screen the bars appeared again.

  



  ffmpeg -i test.avi -filter:v "crop=1280:670" output_video.mp4


  



  I thought it had something to do with the Scale of the video but honestly every scale code I tried to use deformed the image a lot.

  



  I hope someone can help me, fairly new to FFMPEG but really enjoying it this far.

  


• Revision af660715c0 : Make coefficient skip condition an explicit RD choice. This commit replaces zru

  28 juin 2013, par Ronald S. Bultje

  Changed Paths :
   Modify /vp9/common/vp9_rtcd_defs.sh

  
   Modify /vp9/encoder/vp9_block.h

  
   Modify /vp9/encoder/vp9_onyx_int.h

  
   Modify /vp9/encoder/vp9_quantize.c

  
   Modify /vp9/encoder/vp9_rdopt.c

  
   Modify /vp9/encoder/x86/vp9_error_sse2.asm

  
  
  Make coefficient skip condition an explicit RD choice.

  This commit replaces zrun_zbin_boost, a method of biasing non-zero
  coefficients following runs of zero-coefficients to be rounded towards
  zero, with an explicit skip-block choice in the RD loop.

  The logic is basically that if individual coefficients should be rounded
  towards zero (from a RD point of view), the trellis/optimize loop should
  take care of it. If whole blocks should be zero (from a RD point of
  view), a single RD check is much more efficient than a complete
  serialization of the quantization loop.

  Quality change : derf +0.5% psnr, +1.6% ssim ; yt +0.6% psnr, +1.1% ssim.
  SIMD for quantize will follow in a separate patch. Results for other
  test sets pending.

  Change-Id : Ife5fa641163ac5150ac428011e87188f1937c1f4

• avcodec/smvjpegdec : Make decoder init-threadsafe

  27 novembre 2020, par Andreas Rheinhardt

  avcodec/smvjpegdec : Make decoder init-threadsafe
  The only thing that stands in the way of adding the
  
  FF_CODEC_CAP_INIT_THREADSAFE flag to the SMV JPEG decoder is its usage
  
  of ff_codec_open2_recursive() : This function requires its caller to hold
  
  the lock for the mutex that guards initialization of AVCodecContexts
  
  whose codecs have a non-threadsafe init function and only callers whose
  
  codec does not have the FF_CODEC_CAP_INIT_THREADSAFE flag set hold said
  
  lock (the others don't need to care about said lock). But one can set
  
  the flag if one switches to avcodec_open2() at the same time.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/smvjpegdec.c