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• a lot of GREEN Color at YUV420p —> RGB in OpenGL 2.0 Shader on iOS

  25 octobre 2012, par 이형근

  I want to make a movie player for iOS using ffmpeg and OpenGL ES 2.0
  but I have some problem. Output RGB image has a lot of GREEN color.
  This is code and images

  • 480x320 width & height :
  • 512x512 Texture width & height

  I got a YUV420p row data from ffmpeg AVFrame.

      for (int i = 0, nDataLen = 0; i < 3; i++) {
  
          int nShift = (i == 0) ? 0 : 1;
  
          uint8_t *pYUVData = (uint8_t *)_frame->data[i];
  
          for (int j = 0; j < (mHeight >> nShift); j++) {
  
              memcpy(&pData->pOutBuffer[nDataLen], pYUVData, (mWidth >> nShift));
  
              pYUVData += _frame->linesize[i];
  
              nDataLen += (mWidth >> nShift);
  
          }
  
      }

  and prepare texture for Y, U & V channel.

  //: U Texture
  
      if (sampler1Texture) glDeleteTextures(1, &sampler1Texture);
  
  
  
      glActiveTexture(GL_TEXTURE1);
  
      glGenTextures(1, &sampler1Texture);
  
      glBindTexture(GL_TEXTURE_2D, sampler1Texture);
  
  
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
      // This is necessary for non-power-of-two textures
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  
      glEnable(GL_TEXTURE_2D);
  
  
  
      glTexImage2D(GL_TEXTURE_2D, 
  
                   0, 
  
                   GL_LUMINANCE, 
  
                   texW / 2, 
  
                   texH / 2, 
  
                   0, 
  
                   GL_LUMINANCE, 
  
                   GL_UNSIGNED_BYTE,
  
                   NULL);
  
  
  
      //: V Texture
  
      if (sampler2Texture) glDeleteTextures(1, &sampler2Texture);
  
  
  
      glActiveTexture(GL_TEXTURE2);
  
      glGenTextures(1, &sampler2Texture);
  
      glBindTexture(GL_TEXTURE_2D, sampler2Texture);
  
  
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
      // This is necessary for non-power-of-two textures
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  
      glEnable(GL_TEXTURE_2D);
  
  
  
      glTexImage2D(GL_TEXTURE_2D, 
  
                   0, 
  
                   GL_LUMINANCE, 
  
                   texW / 2, 
  
                   texH / 2, 
  
                   0, 
  
                   GL_LUMINANCE,
  
                   GL_UNSIGNED_BYTE,
  
                   NULL);
  
  
  
      //: Y Texture
  
      if (sampler0Texture) glDeleteTextures(1, &sampler0Texture);
  
  
  
      glActiveTexture(GL_TEXTURE0);
  
      glGenTextures(1, &sampler0Texture);
  
      glBindTexture(GL_TEXTURE_2D, sampler0Texture);
  
  
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
      // This is necessary for non-power-of-two textures
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  
      glEnable(GL_TEXTURE_2D);
  
  
  
      glTexImage2D(GL_TEXTURE_2D, 
  
                   0, 
  
                   GL_LUMINANCE, 
  
                   texW, 
  
                   texH, 
  
                   0, 
  
                   GL_LUMINANCE,
  
                   GL_UNSIGNED_BYTE, 
  
                   NULL);

  Rendering part is below.

  int _idxU = mFrameW * mFrameH;
  
  int _idxV = _idxU + (_idxU / 4);
  
  
  
  // U data
  
  glActiveTexture(GL_TEXTURE1);
  
  glBindTexture(GL_TEXTURE_2D, sampler1Texture);
  
  glUniform1i(sampler1Uniform, 1);
  
  
  
  glTexSubImage2D(
  
                  GL_TEXTURE_2D, 
  
                  0, 
  
                  0, 
  
                  0, 
  
                  mFrameW / 2,            // source width
  
                  mFrameH / 2,            // source height
  
                  GL_LUMINANCE,
  
                  GL_UNSIGNED_BYTE, 
  
                  &_frameData[_idxU]);
  
  
  
  // V data
  
  glActiveTexture(GL_TEXTURE2);
  
  glBindTexture(GL_TEXTURE_2D, sampler2Texture);
  
  glUniform1i(sampler2Texture, 2);
  
  
  
  glTexSubImage2D(
  
                  GL_TEXTURE_2D, 
  
                  0, 
  
                  0, 
  
                  0, 
  
                  mFrameW / 2,            // source width
  
                  mFrameH / 2,            // source height
  
                  GL_LUMINANCE,
  
                  GL_UNSIGNED_BYTE,
  
                  &_frameData[_idxV]);
  
  
  
  // Y data
  
  glActiveTexture(GL_TEXTURE0);
  
  glBindTexture(GL_TEXTURE_2D, sampler0Texture);
  
  glUniform1i(sampler0Uniform, 0);
  
  
  
  glTexSubImage2D(
  
                  GL_TEXTURE_2D, 
  
                  0, 
  
                  0, 
  
                  0, 
  
                  mFrameW,            // source width
  
                  mFrameH,            // source height
  
                  GL_LUMINANCE,
  
                  GL_UNSIGNED_BYTE,
  
                  _frameData);

  Vertex Shader & Fragment Shader is below.

  attribute vec4 Position;
  
  attribute vec2 TexCoordIn;
  
  
  
  varying vec2 TexCoordOut;
  
  varying vec2 TexCoordOut_UV;
  
  
  
  uniform mat4 Projection;
  
  uniform mat4 Modelview;
  
  
  
  void main()
  
  {
  
      gl_Position = Projection * Modelview * Position;
  
      TexCoordOut = TexCoordIn;
  
  }
  
  
  
  
  
  
  
  uniform sampler2D sampler0; // Y Texture Sampler
  
  uniform sampler2D sampler1; // U Texture Sampler
  
  uniform sampler2D sampler2; // V Texture Sampler
  
  
  
  varying highp vec2 TexCoordOut;
  
  
  
  void main()
  
  {
  
      highp float y = texture2D(sampler0, TexCoordOut).r;
  
      highp float u = texture2D(sampler2, TexCoordOut).r - 0.5;
  
      highp float v = texture2D(sampler1, TexCoordOut).r - 0.5;
  
  
  
      //y = 0.0;
  
      //u = 0.0;
  
      //v = 0.0;
  
  
  
      highp float r = y + 1.13983 * v;
  
      highp float g = y - 0.39465 * u - 0.58060 * v;
  
      highp float b = y + 2.03211 * u;
  
  
  
      gl_FragColor = vec4(r, g, b, 1.0);
  
  }

  Y Texture (Grayscale) is correct but U & V has a lot of Green Color.
  So final RGB image (Y+U+V) has a lot of GREEN Color.
  What's the problem ?

  Please help.
  thanks.

• Fragmented MP4 has wrong duration in Windows Media Player

  3 février 2020, par Expressingx

  I’m streaming video from a camera to a file using ffmpeg. The case to use Fragmented MP4 is that there can be sudden power off and lose the video. I’ve configured the fragments to be at least 30 secs and this is how much the Windows Media Player reports for the duration even if its 2 hours long, after that it keeps streaming the video but is not seekable after the 30th second. How can be that fixed ?

  ffmpeg -c copy -movflags frag_keyframe+separate_moof+omit_tfhd_offset -min_frag_duration 30000000 -bsf:a aac_adtstoasc \ out.mp4

  If I use -movflags frag_keyframe+empty_moov then the video is not seekable at all and no duration reported.

  I aim for seekable video with correct duration both on VLC/Windows Media Player

  Version of ffmpeg : 3.3.4

• FFMpeg Command work in command line, but not in python script. (Semi Solved)

  20 février 2015, par Fooldj

  Okay, kind of a weird problem. But I’m not sure whether it’s python, ffmpeg, or some stupid thing I’m doing wrong.

  I’m trying to take a video, and take 1 frame a second, and output that frame to an image. Right now, if i use the command line with ffmpeg :

  ffmpeg -i test.avi -r 1 -f image2 image-%3d.jpeg -pix_fmt rgb24 -vcodec rawrvideo

  It outputs about 10 images, the images look fine, awesome. Now I have this code (right now some code from some github, as I wanted stuff that i was relatively sure would work, and mine is allll convoluted)

  import subprocess as sp
  
  import numpy as np
  
  import re
  
  import cv2
  
  import time
  
  
  
  FFMPEG_BIN = r'ffmpeg.exe'
  
  INPUT_VID = 'test.avi'
  
  
  
  def getInfo():
  
      command = [FFMPEG_BIN,'-i', INPUT_VID, '-']
  
      pipe = sp.Popen(command, stdout=sp.PIPE, stderr=sp.PIPE)
  
      pipe.stdout.readline()
  
      pipe.terminate()
  
      infos = pipe.stderr.read()
  
      infos_list = infos.split('\r\n')
  
      res = re.search(' \d+x\d+ ',infos)
  
      res = [int(x) for x in res.group(0).split('x')]
  
      return res
  
  res = getInfo()
  
  command = [ FFMPEG_BIN,
  
          '-i', INPUT_VID,
  
          '-f', 'image2pipe',
  
          '-pix_fmt', 'rgb24',
  
          '-vcodec', 'rawvideo', '-']
  
  pipe = sp.Popen(command, stdout = sp.PIPE, bufsize=10**8)
  
  n = 0
  
  im2 = []
  
  try:
  
      mog = cv2.BackgroundSubtractorMOG2(120,2,True)
  
      while True:
  
          raw_image = pipe.stdout.read(res[0]*res[1]*3)
  
          # transform the byte read into a numpy array
  
          image =  np.fromstring(raw_image, dtype='uint8')
  
          image = image.reshape((res[1],res[0],3))
  
          rgbImg = image.copy()
  
  
  
          fname = ('_tmp%03d.png'%time.time())
  
          cv2.imwrite(fname, rgbImg)
  
          # throw away the data in the pipe's buffer.
  
          #pipe.stdout.flush()
  
          n += 1
  
          print n
  
  except:
  
      print 'done',n
  
      pipe.kill()
  
      cv2.destroyAllWindows()

  When I run this, I get 10 images, but they all have a Blue Tint ! I cannot for the life of me figure out why. I’ve done tons of searches, I’ve tried quite a few different codecs (usually just messes things up worse). The media info for the video file is here :

   General
  
   Complete name                            : test.avi
  
  Format                                   : AVI
  
  Format/Info                              : Audio Video Interleave
  
  File size                                : 85.0 KiB
  
  Duration                                 : 133ms
  
  Overall bit rate                         : 5 235 Kbps
  
  
  
  Video
  
  ID                                       : 0
  
  Format                                   : JPEG
  
  Codec ID                                 : MJPG
  
  Duration                                 : 133ms
  
  Bit rate                                 : 1 240 Kbps
  
  Width                                    : 640 pixels
  
  Height                                   : 480 pixels
  
  Display aspect ratio                     : 4:3
  
  Frame rate                               : 30.000 fps
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:2
  
  Bit depth                                : 8 bits
  
  Compression mode                         : Lossy
  
  Bits/(Pixel*Frame)                       : 0.135
  
  Stream size                              : 20.1 KiB (24%)

  Any suggestions ? It seems like it should be an RGB mixup...just not sure where at...

  EDIT : So I fixed the problem by switching the blue and red channels with this code :
  bChannel = rgbImg[ :, :,0]
  rChannel = rgbImg[ :, :,2]
  gChannel = rgbImg[ :, :,1]

              rgbArray = np.zeros((res[1],res[0],3), 'uint8')
  
              rgbArray[...,0] = rChannel
  
              rgbArray[...,1] = gChannel
  
              rgbArray[...,2] = bChannel

  So I guess this is now a question of, why is python mixing up these channels ? Is it a problem with python, or ffmpeg, the codec ?

  Thanks !