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• Improve encoding speed on older Intel CPUs.

  4 décembre 2014, par Erik de Castro Lopo

  Improve encoding speed on older Intel CPUs.
  The commit http://git.xiph.org/?p=flac.git;a=commit;h=e9d805dd4374
  
  changed the that calculate autocorrelation. However, the new code
  
  worked slightly (about 4%) slower on Core 2, but with the new
  
  presets the speed decrease can reach 25%.
  This patch enables both old and new functions and chooses between
  
  them at runtime.
  Patch-from : lvqcl <lvqcl.mail@gmail.com>
  

  • [DH] src/libFLAC/cpu.c
  • [DH] src/libFLAC/ia32/lpc_asm.nasm
  • [DH] src/libFLAC/include/private/cpu.h
  • [DH] src/libFLAC/include/private/lpc.h
  • [DH] src/libFLAC/lpc_intrin_sse.c
  • [DH] src/libFLAC/stream_encoder.c

• Revision 8fd3f9a2fb : Enable non-rd mode coding on key frame, for speed 6. For key frame at speed 6 :

  12 novembre 2014, par Marco

  Changed Paths :
   Modify /test/vp9_avg_test.cc

  
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/encoder/vp9_avg.c

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_speed_features.c

  
   Modify /vp9/encoder/x86/vp9_avg_intrin_sse2.c

  
  
  Enable non-rd mode coding on key frame, for speed 6.

  For key frame at speed 6 : enable the non-rd mode selection in speed setting
  and use the (non-rd) variance_based partition.

  Adjust some logic/thresholds in variance partition selection for key frame only
  (no change to delta frames),
  mainly to bias to selecting smaller prediction blocks, and also set max tx size
  of 16x16.

  Loss in key frame quality ( 0.6-0.7dB) compared to rd coding,
  but speeds up key frame encoding by at least 6x.
  Average PNSR/SSIM metrics over RTC clips go down by 1-2% for speed 6.

  Change-Id : Ie4845e0127e876337b9c105aa37e93b286193405

• Using FFMPEG command to read the frame and show using the inshow function in opencv

  28 novembre 2024, par HARSH BHATNAGAR

  I am trying to get the frame using the ffmpeg command and show using the opencv function cv2.imshow(). This snippet gives the black and white image on the RTSP Stream link . Output is given below link [ output of FFmpeg link].
I have tried the ffplay command but it gives the direct image . i am not able to access the frame or apply the image processing.

  


  Output of FFMPEG

  


  import cv2
import subprocess as sp
command = [ 'C:/ffmpeg/ffmpeg.exe',
            '-i', 'rtsp://192.168.1.12/media/video2',
            '-f', 'image2pipe',
            '-pix_fmt', 'rgb24',
            '-vcodec', 'rawvideo', '-']


import numpy
pipe = sp.Popen(command, stdout = sp.PIPE, bufsize=10**8)
while True:
    raw_image = pipe.stdout.read(420*360*3)
   # transform the byte read into a numpy array
    image =  numpy.fromstring(raw_image, dtype='uint8')
    image = image.reshape((360,420,3))
    cv2.imshow('hello',image)
    cv2.waitKey(1)
    # throw away the data in the pipe's buffer.
    pipe.stdout.flush()