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• Processing .Raw images using ffmpeg or OpenCV

  23 février 2013, par Ahmed Kato

  After reading Wikipedia page of Raw image format which is the digital negative of any image.

  To be viewed or printed, the output from a camera's image sensor has
  to be processed, that is, converted to a photographic rendering of the
  scene, and then stored in a standard raster graphics format such as
  JPEG. This processing, whether done in-camera or later in a raw-file
  converter, involves a number of operations, typically including

  I have some .raw files grabbed from my Logitech c920 using v4l2 example but when I display the image it looks like this :
  a raw image where in other frames I can see my shadow

  Does anyone knows how to process such files to see the complete frame ?

  Here is a link to the original .raw file

• How to get time stamp of closet keyframe before a given timestamp with ffmpeg ?

  20 février 2013, par jAckOdE

  I want a ffmpeg seeking command that fast and accurate. I found this

  The solution is that we apply -ss for both input (fast seeking) and output (accurate seeking). The question is that if the input seeking is not accurate how can we be sure that the seeking position is accurate.

  For example : as the example used in the link, if we want to seek to 00:03:00, the command is something likes

  ffmpeg -ss 00:02:30 -i ... -ss 00:00:30
  As said, the first seeking will seek to somewhere else not 00:02:30, say 00:02:31. and after applying second seek, the final result would be 00:03:01- NOT what we want. Is that correct ?

  Where does fist seeking seek to ? Does it seek to k-frame that closet to 00:02:30 ?

  If so, here is my thought, correct me if i'm wrong : after first seeking, we get the timestamp of the result (in this example : 00:02:31), then we apply second seeking with appropriate time, in this case 00:00:29.

  Question is how do we get time stamp of first seeking's result ?

• How to get time stamp of closet k-frame before a given timestamp with ffmpeg ?

  20 février 2013, par jAckOdE

  I want a ffmpeg seeking command that fast and accurate. I found this

  The solution is that we apply -ss for both input (fast seeking) and output (accurate seeking). The question is that if the input seeking is not accurate how can we be sure that the seeking position is accurate.

  For example : as the example used in the link, if we want to seek to 00:03:00, the command is something likes

  ffmpeg -ss 00:02:30 -i ... -ss 00:00:30
  As said, the first seeking will seek to somewhere else not 00:02:30, say 00:02:31. and after applying second seek, the final result would be 00:03:01- NOT what we want. Is that correct ?

  Where does fist seeking seek to ? Does it seek to k-frame that closet to 00:02:30 ?

  If so, here is my thought, correct me if i'm wrong : after first seeking, we get the timestamp of the result (in this example : 00:02:31), then we apply second seeking with appropriate time, in this case 00:00:29.

  Question is how do we get time stamp of first seeking's result ?