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• Tainted canvas may not be exported. When trying to send it via ajax to php file

  6 décembre 2015, par romikette F

  I am trying to capture an image from a local video so I can make a thumb out of it. I am trying to avoid using video conversions (like ffmpeg) to save server resources and keep my videos in theyr original format.
  I’we been reading about tainted canvases and I understand I am trying to breach the browsers security protocols. But this article https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image#What_is_a_tainted_canvas said that I could pull an image if it were from a different source (something something).
  So far I have this :

  <video src="http://www.w3schools.com/html/mov_bbb.mp4" type="video/mp4" controls="controls"></video><br />
  
  <button>Capture</button> <br /><br />
  
  <div></div>
  
  <canvas></canvas> <br /><br />

  and :

  function capture(){
  
  var canvas = document.getElementById('mYcanvas');
  
  var video = document.getElementById('video');
  
  canvas.getContext('2d').drawImage(video, 0, 0, video.videoWidth, video.videoHeight);
  
  
  
  function getBase64() {
  
  var img = document.getElementById("mYcanvas");
  
  var canvas = document.createElement("canvas");
  
  canvas.width = img.width;
  
  canvas.height = img.width;
  
  var ctx = canvas.getContext("2d");
  
  ctx.drawImage(img, 0, 0);
  
  var dataURL = canvas.toDataURL("image/png");
  
  alert(dataURL.replace(/^data:image\/(png|jpg);base64,/, "")); 
  
  
  
  $.ajax({
  
      url: 'submit_image.php',
  
      type: 'POST',
  
      data: {
  
          imgdata: dataURL
  
      },
  
      success: function (res) {
  
              document.getElementById("response").innerHTML = res;
  
          }
  
  });
  
  }
  
  getBase64();
  
  
  
  }

  Never mind the php. It dose not receive anything.

• FFMPEG, MPV, SVP 4 Pro : not converting as original resolution problem, yuv420p10 -> p010 [closed]

  12 août 2023, par LeeShey

  I am using SVP4 Pro(Frame rate conversion).
The SVP 4 Pro setting :
RIFE AI engine setting
encoder commands
Transcoding 4K(3840x2160) video exports 3840x2144 resolution.
I think converting yuv420p10 -> p010 causes video height loss.

  


  I did transcoding FHD video(just for test), but it worked lossless.
Problems to 4K, but not FHD ??

  


  Here's the log :

  


  19:36:05.942: ===== Starting mpv ======
19:36:05.942: Command line: C:\Program Files (x86)\SVP 4\mpv64\mpv.exe D:/Candy/prob3.mov --o=D:/Candy/prob3.SVP.VO.mov --no-audio --no-sub --no-sub-auto --input-ipc-server=mpvencodepipe --input-media-keys=no --no-msg-color --vf=lavfi=[yadif=send_frame],vapoursynth:[C:\Users\????\AppData\Roaming\SVP4\scripts\ffff.py]:4:16 --ovc=hevc_nvenc --ovcopts=preset=lossless,time_base=1000/120000,threads=16
19:36:05.982: (+) Video --vid=1 (*) (prores 3840x2160 60.000fps)
19:36:05.982: Audio --aid=1 --alang=eng (*) (pcm_s16le 2ch 48000Hz)
19:36:06.277: vstrt: TensorRT version mismatch, built with 2135 but loaded with 2136; continue but fingers crossed...
19:36:06.856: CUDA lazy loading is not enabled. Enabling it can significantly reduce device memory usage. See `CUDA_MODULE_LOADING` in https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#env-vars
19:36:06.930: CUDA lazy loading is not enabled. Enabling it can significantly reduce device memory usage. See `CUDA_MODULE_LOADING` in https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#env-vars
19:36:07.005: CUDA lazy loading is not enabled. Enabling it can significantly reduce device memory usage. See `CUDA_MODULE_LOADING` in https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#env-vars
19:36:07.079: CUDA lazy loading is not enabled. Enabling it can significantly reduce device memory usage. See `CUDA_MODULE_LOADING` in https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#env-vars
19:36:09.683: [autoconvert] Converting yuv420p10 -> p010
19:36:09.693: VO: [lavc] 3840x2144 p010
19:36:09.693: [vo/lavc] Opening encoder: NVIDIA NVENC hevc encoder [hevc_nvenc]
19:36:09.695: [ffmpeg] hevc_nvenc: The selected preset is deprecated. Use p1 to p7 + -tune or fast/medium/slow.
19:36:10.130: [encode] Opening output file: D:/Candy/prob3.movprob3.SVP.VO.mov
19:36:10.131: [encode] Opening muxer: QuickTime / MOV [mov]
19:36:10.131: [ffmpeg] mov: WARNING codec timebase is very high. If duration is too long,
19:36:10.131: [ffmpeg] file may not be playable by quicktime. Specify a shorter timebase
19:36:10.131: [ffmpeg] or choose different container.
19:36:10.136: [autoconvert] Converting yuv420p10 -> p010
19:36:10.145: V: 00:00:00 / 00:00:15 (0%) {0.0min 0.0MB}
19:36:11.087: -- PAUSED --



  


• opencv3.1 python VideoCapture black screen

  3 mai 2017, par alex

  i’m trying to use opencv3.1 with python3.5
  following this official)tutorial
  http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_gui/py_video_display/py_video_display.html#display-video

  the camera led is "on" but the window doesn’t show any image (black)

  my current enviroment :
   windows 10
   python 3.5.2 (32bit)
   numpy 1.12.0b1 (32bit) binaries downloaded from : http://www.lfd.uci.edu/ gohlke/pythonlibs/
   opencv 3.1.0 (32bit) binaries downloaded from : http://www.lfd.uci.edu/ gohlke/pythonlibs/

  they seem installed correctly !

  as the tutorial says :

  Note Make sure proper versions of ffmpeg or gstreamer is installed. Sometimes, it is a headache to work with Video Capture mostly due to wrong installation of ffmpeg/gstreamer.

  i’ve no ffmpeg installed !!! so i suppose this is the cause of my problem
  so the questions are :
  1) which version of ffmpeg is needed ?
  2) how install ffmpeg on windows ? it seems a setup doesn’t exist(there is a binary section with a zip file ? how to use it after unzipped ?)
  3) is possible to see(in some way) if the opencv binaries(that i’ve downloaded) were compiled with ffmpeg support(flag ?)

  PS : i’ve tried to add the ffmpeg folder path the the PATH enviroment variable but nothing change