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• Android SIGSEGV code1 vs code2

  24 janvier 2014, par nmxprime

  As of i've seen, SIGSEGV (code 2) comes during memory access not own by the process, i.e., accessing a buffer of size 10 at 11th location. [Please correct if my observation is wrong]. What SIGSEGV (code 1) means ??

  I have this during the execution of ffmpeg(with neon enabled).

  avcodec_decode_video2(ctx, frame, &got_picture, avpkt);
  
  if(got_picture) {
  
  fprintf(stderr,"Got-Picture = %d",got_picture);
  
  }

  So how to resolve this code 1 Segment fault ? Any insight into this issue ??[i wish to better understand why it occurs, possibly in general]

• Android ffmpeg apply video effects take time

  2 février 2016, par PrvN

  I am using below command to apply effect,its take 6-8 minutes to apply effect for 2min video.
  Please help me to improve effective time for ffmpeg commands.

  String commandStr = "ffmpeg -y -i "
  
              + mVideoData.getPath()
  
              + " -strict experimental -vf curves=vintage -s 640x480 -r 30 -aspect 4:3 -ab 48000 -ac 2 -ar 22050 -b 2097k -vcodec mpeg4 /sdcard/videokit/curve.mp4";

  Thanks in advance.

• How to discover framebuffer format on android ?

  18 mars 2013, par Guilherme Torres Castro

  i'm capturing framebuffer on my android device, but each device has a different frame buffer pixel format. How can i get the this format for each device ?

  I found i can get the bbp and screen resoution using :

  ioctl -rl 28 /dev/graphics/fb0 17920

  This command return :

  return buf : f0 00 00 00 40 01 00 00 f0 00 00 00 80 02 00 00 00 00 00 00 00 00 00 00 20 00 00 00

  In little-endian format i have :

  • The last four bytes (20) is the number of bbp 32.
  • The first four bytes is the screen width 0xF0 = 240
  • Bytes 5 to 8 is the screen height 0x0140 = 320

  I tried to decode the fb (Galaxy 5) using the folowing command :

  ./ffmpeg -vframes 1 -vcodec rawvideo -f rawvideo -pix_fmt rgb32 -s 240x320 -i fb0 -f image2 -vcodec png image%d.png

  And i got this warning :

  Invalid buffer size, packet size 40960 < expected length 307200 Error
  while decoding stream #0:0 : Invalid argument

  and this two images :

  
  

  I think what's is wrong is the pix_fmt param.