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• Revision ed2dc59c1b : Integral projection based motion estimation This commit introduces a new block

  13 février 2015, par Jingning Han

  Changed Paths :
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/encoder/vp9_avg.c

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/x86/vp9_avg_intrin_sse2.c

  
  
  Integral projection based motion estimation

  This commit introduces a new block match motion estimation
  using integral projection measurement. The 2-D block and the nearby
  region is projected onto the horizontal and vertical 1-D vectors,
  respectively. It then runs vector match, instead of block match,
  over the two separate 1-D vectors to locate the motion compensated
  reference block.

  This process is run per 64x64 block to align the reference before
  choosing partitioning in speed 6. The overall CPU cycle cost due
  to this additional 64x64 block match (SSE2 version) takes around 2%
  at low bit-rate rtc speed 6. When strong motion activities exist in
  the video sequence, it substantially improves the partition
  selection accuracy, thereby achieving better compression performance
  and lower CPU cycles.

  The experiments were tested in RTC speed -6 setting :
  cloud 1080p 500 kbps
  17006 b/f, 37.086 dB, 5386 ms ->
  16669 b/f, 37.970 dB, 5085 ms (>0.9dB gain and 6% faster)

  pedestrian_area 1080p 500 kbps
  53537 b/f, 36.771 dB, 18706 ms ->
  51897 b/f, 36.792 dB, 18585 ms (4% bit-rate savings)

  blue_sky 1080p 500 kbps
  70214 b/f, 33.600 dB, 13979 ms ->
  53885 b/f, 33.645 dB, 10878 ms (30% bit-rate savings, 25% faster)

  jimred 400 kbps
  13380 b/f, 36.014 dB, 5723 ms ->
  13377 b/f, 36.087 dB, 5831 ms (2% bit-rate savings, 2% slower)

  Change-Id : Iffdb6ea5b16b77016bfa3dd3904d284168ae649c

• Codec issue ? Mp4 video flashing during play via JW Player (and same issue with mac computer)

  19 décembre 2017, par janosdupai

  I have a linux based server online. It has Mp4 videos. I try to play these video with JW Player. I had any problems with them, but some files has the following problem : https://www.video.match-meeting.com/drive/5a350a6700bc4.mp4

  If I download this file to a windows computer, it plays without problem. Is that a codec problem with my server (and on my mac) ?

• c Can you use variables from other files without using include ?

  2 juin 2021, par aszswaz

  I am reading the code of the ffmpeg project.In the fftools/ffmpeg.c file of this project, there is a piece of code on line 519 :

  


  519         if (do_benchmark) {
520             int maxrss = getmaxrss() / 1024;
521             av_log(NULL, AV_LOG_INFO, "bench: maxrss=%ikB\n", maxrss);
522         }


  


  I use gdb to find the definition location of the do_benchmark variable :

  


  (gdb) info variables do_benchmark
All variables matching regular expression "do_benchmark":

File fftools/ffmpeg_opt.c:
159:    int do_benchmark;
160:    int do_benchmark_all;


  


  However, I cannot find a statement like include fftools/ffmpeg_opt.c in the fftools/ffmpeg.c file.I use find + grep to no avail.

  


  $ find . -type f | xargs grep 'ffmpeg_opt'
grep: ./.git/objects/pack/pack-c2a6a6b1765b632f6fa88814ec92d3b0e4c11dad.pack：Match to binary file
grep: ./.git/index：Match to binary file
grep: ./ffmpeg：Match to binary file
./fftools/ffmpeg_opt.d:fftools/ffmpeg_opt.o: fftools/ffmpeg_opt.c fftools/ffmpeg.h config.h \
grep: ./fftools/ffmpeg_opt.o：Match to binary file
./fftools/Makefile:OBJS-ffmpeg                        += fftools/ffmpeg_opt.o fftools/ffmpeg_filter.o fftools/ffmpeg_hw.o
grep: ./ffmpeg_g：Match to binary file


  


  I wanted to try a similar approach, but failed.

  


  demo-01.c

  


  #include "stdio.h"

int main(void){
    fptintf(stdout, "demo: %d", demo);
    return 0;
}


  


  demo-02.c

  


  int demo = 0;


  


  $ gcc demo-01.c demo-02.c -o demo
demo-01.c: In the function ‘main’:
demo-01.c:4:33: Error: ‘demo’ is not declared (first use in this function)
    4 |     fprintf(stdout, "demo: %d", demo);
      |                                 ^~~~
demo-01.c:4:33: Note: Each undeclared identifier is only reported once in the function in which it appears.


  


  why is that ?