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• Setting a timeout for av_read_frame

  20 décembre 2014, par user3663917

  I am new to FFMPEG and was trying to do HLS streaming using FFMPEG. When i tried using the function "av_read_frame" it returns a negative value whenever data is not available. Is there some method to make this function wait till some data is received or to make this function wait till a timeout is reached ?

• FFMPEG Video loop from images files

  27 février 2020, par Nesan Mano

  I am trying to make a video from a bundle of image files and then apply a an overlay on top of it.Another requirement is to make the video loop 3x. It is simply not working.

  The first three paths are pointing toward the same image bundle. (A folder containing images like the following DSC0001_0013.jpg,DSC0002_0013.jpg,etc)

  Observed symptoms :

  The script runs infinitely.I produces a video file of 0 KB.I have to abort script using CTRL+C

  This is my script.

  ffmpeg 
  
  -start_number 1 -framerate 3/1 
  
  -i "C:\Users\xxx\AppData\Local\xxx\xxx\xxx\xxx\xxx\xxx\xxx\963d9d9b8e1\DSC%04d_0013.jpg"
  
  
  
  -i "C:\Users\xxx\AppData\Local\xxx\xxx\projects\xxx\xxx\xxx\xxx\963d9d9b8e1\DSC%04d_0013.jpg"
  
  
  
  -i "C:\Users\xxx\AppData\Local\xxx\xxx\projects\xxx\xxx\xxx\xxx\963d9d9b8e1\DSC%04d_0013.jpg"
  
  
  
  -i "C:\Users\xxx\AppData\Local\xxx\xxx\projects\1237\1138\overlay.png" 
  
  -i "C:\Users\xxx\AppData\Local\xxx\xxx\projects\1237\1138\overlay.png" 
  
  -i "C:\Users\xxx\AppData\Local\xxx\xxx\projects\1237\1138\overlay.png" 
  
  -filter_complex " [0:v]scale=600x900[scaled1]; [1:v]scale=600x900[scaled2]; [2:v]scale=600x900[scaled3]; [scaled1][3:v]overlay[tmp1]; [scaled2][4:v]overlay[tmp2]; [scaled3][5:v]overlay[tmp3]; [tmp1][tmp2][tmp3]concat=n=3[scaled] "
  
  -map [scaled] -r 10 -vcodec libx264  -pix_fmt yuv420p -crf 23  "C:\Users\xxx\Documents\Projets\2020\xxx\video test ffmpeg\test.mp4"

• lavd/v4l2 : produce a 0 byte packet when a dequeued buffer's size is unexpected

  5 juin 2019, par Stephan Hilb

  lavd/v4l2 : produce a 0 byte packet when a dequeued buffer's size is unexpected
  Behave like we do for V4L2_BUF_FLAG_ERROR, implemented in commit 28f20d2ff4 .
  For some devices (probably also related to the V4L driver implementation)
  
  it happens that when invoking the ioctl DQBUF, the returned buffer is not
  
  of the expected size. Here are two examples for such occurrences :
      [video4linux2,v4l2 @ 0x258b440] Dequeued v4l2 buffer contains 609596 bytes, but 614400 were expected. Flags : 0x00000001.
  
      /dev/video1 : Invalid data found when processing input
      [video4linux2,v4l2 @ 0x225f440] Dequeued v4l2 buffer contains 609508 bytes, but 614400 were expected. Flags : 0x00000001.
  
      /dev/video1 : Invalid data found when processing input
  For the ffmpeg CLI tool this means it will stop capturing and exit.
  The described behaviour was observed at least with one OmniVision USB
  
  web cam and with some stk1160 devices.
  If you search the web for the error message, you will find quite a few
  
  instances of this problem. Some of them experienced on other devices.
  Probably fixes ticket #4795
  Signed-off-by : Alexander Strasser <eclipse7@gmx.net>
  

  • [DH] libavdevice/v4l2.c