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• Run libFLAC++ through clang-tidy.

  29 août 2019, par Rosen Penev

  Run libFLAC++ through clang-tidy.
  Applied the following suggestions :
  modernize-deprecated-headers
  
  google-readability-casting
  
  google-readability-namespace-comments
  
  readability-else-after-return
  

  • [DH] src/libFLAC++/metadata.cpp
  • [DH] src/libFLAC++/stream_decoder.cpp
  • [DH] src/libFLAC++/stream_encoder.cpp

• avformat/http: add ff_http_do_new_request2 for options

  4 octobre 2019, par vectronic

  avformat/http: add ff_http_do_new_request2 for options
  add ff_http_do_new_request2() which supports options to be applied to
  
  HTTPContext after initialisation with the new uri
  Signed-off-by : Steven Liu <lq@onvideo.cn>
  
  Signed-off-by : vectronic <hello.vectronic@gmail.com>
  

  • [DH] libavformat/http.c
  • [DH] libavformat/http.h

• Is there a way to apply a curve bend in ffmpeg ?

  25 mars 2020, par stevendesu

  I have four cameras each feeding me a different portion of a basketball court. Due to the slight offset of the cameras physical locations and lens distortion around the edges of the camera, I cannot simply stitch the videos together without some kind of correction.

  I’ve looked into ffmpeg’s perspective filter, as well as the lenscorrection filter. In the former case it was only able to create a trapezoid, not the curved image I want. In the latter case using negative values to k1 and k2 seemed to be heading in the right direction, but it either disorted the top and bottom of the image to the point of being nonsensical noise, or it zoomed in to the image so much that I lost important details.

  For the sample picture below, ultimately I want the midcourt line (the blue vertical line on the right side) to be vertical, and I want the mess of wires on the white desk at the bottom to remain visible and identifiable.

  Given a video which looks like the following :

  

  I wish to produce something like the following :

  

  This image was made using the "Curve Bend" filter in GIMP, but I just eye-balled it - so it’s not perfect. Ideally once I get the exact parameters the midcourt line will be perfectly vertical

  When using the lenscorrection filter, no values for k1 and k2 seemed to get the effect I want :

  Negative k1, negative k2 :

  

  Negative k1, positive k2 :

  

  Positive k1, negative k2 :

  

  Positive k1, positive k2 :

  

  In general :

  • negative / negative distorted the image beyond recognition
  • negative / positive looked alright, but the midcourt line was off the screen and it wasn’t clear if any distortion had been applied
  • positive / negative looked the best, but while the top and bottom curved in the middle of the left and right actually bulged out, leaving the midcourt line distorted
  • positive / positive was the opposite of the desired effect