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• Missing piece between libjpeg-turbo & h264 ffmpeg C/C++

  15 octobre 2022, par Nelstaar

  On the left side I have a buffer with decoded pixels that I can get in two formats :

  


  RGB interleaved/packed where bytes in buffer are R0G0B0R1G1B1....

  


  or

  


  YUV444 interleaved/packed where bytes in buffer are Y0U0V0Y1U1V1...

  


  (JCS_RGB or JCS_YCbCr in jpeglib.h)

  


  (Please note that I use libjpeg-turbo because I need to decompress a cropped region of the image. (jpeg_crop_scanline()))

  


  On the right side I have x264 codec via ffmpeg that support only planar pixel formats :

  


  yuv420p, yuvj420p, yuv422p, yuvj422p, yuv444p, yuvj444p, nv12, nv16, nv21, yuv420p10le, yuv422p10le, yuv444p10le, nv20le

  


  yuv444p where bytes in buffer are Y0Y1Y2...U0U1...V0V1...

  


  according to ffmpeg -h encoder=libx264

  


  I have some ideas already :

  


  

  • Decompress Jpeg to RBG888 in buffer 1 then libswscale to yuv420p in buffer 2 and encoding. (copy)

  


  • Decompress Jpeg to YUV444 interleaved in buffer 1 then SSSE3 magic in buffer 1 to yuv444p and encoding. (no copy)

  


  • or else.

  


  


  What would be the most effective fastest way ?

  


  I which to avoid buffer copy.

  


  Movie have the same width & height than Jpegs.

  


• Store a videostream from webcam but as 1s long files that can later be merged together [duplicate]

  17 février 2018, par Jennifer R

  This question is an exact duplicate of :

  • How to segment a video and then concatenate back into original one with ffmpeg
    
    1 answer
    

  I’m trying to store a videostream from a webcam but need it to be 1s long files. I have never worked with storing videofiles so i’m not sure if and how i should use opencv and how those videofiles need to be contained that i can merge them together. I tried the old windows cmd code

  copy /b *.avi combined.avi

  but since avi is sort of a container type i only got as far as the first file. I’m guessing since there’s some container data limiting the first file and i can’t watch it.

  I need help in both questions. How can i store a video stream and how do i merge those videos ? Do i use ffmpeg for the latter and is it possible to edit the container data to the correct length ?

• Ubuntu 16.04 python installing 3rd party module ffmpeg-3.0.2

  3 juin 2016, par vanoccupanther

  Have tried installing this package multiple times. Initially I installed it to a directory where I am running scripts that call it but I get an error message "ImportError : No module named ’ffmpeg’".

  I then tried putting it in one of my python paths listed in sys.path and again I got the same message.

  I then opened .bashrc and added the home directory path and still got the same error message when I ran my script.

  import sys
  
  import pandas as pd
  
  import numpy as np
  
  import matplotlib.pyplot as plt
  
  import ffmpeg
  
  
  
  from PIL import Image
  
  
  
  img = sys.argv[1] # ignore this
  
  
  
  im = Image.open(img) # ignore this
  
  imarray = np.array(im) # ignore this
  
  
  
  ffmpeg -i ('flame.avi') -f image2 -c:v mjpeg ('image-%d.jpg')
  
  avconv -i ('flame.avi') -vsync ('1') -r ('100') ('image%03d.tif')

  I’m really not sure where to go, what are my options here ? And what am I doing that is glaringly wrong ?