Am 02.10.2020 um 10:10 schrieb Paul B Mahol:
On Thu, Oct 01, 2020 at 11:40:57PM +0200, Michael Koch wrote:
Am 01.10.2020 um 22:11 schrieb Paul B Mahol:
On Tue, Sep 29, 2020 at 10:54:54PM +0200, Michael Koch wrote:
Hello all,
I've programmed a C# workaround for stabilization of 360° videos. The
procedure is as follows:
1. FFmpeg: From each frame of the equirectangular input video, extract two
small images which are 90° apart in the input video. I call them A and B
images.
2. C# code: Analyze the x and y image shift from subsequent A and B images.
Calculate how the equirectangular frames must be rotated (yaw, pitch, roll)
to compensate the image shifts. This part wasn't easy. Two rotation matrices
and one matrix multiplication are required. Write the results to a *.cmd
file.
3. FFmpeg: Read the *.cmd file and apply the rotations with the v360 filter.
The output video is stabilized.
For details and source code please have a look at chapter 2.78 in my book:
http://www.astro-electronic.de/FFmpeg_Book.pdf
If anyone wants to implement this in FFmpeg, please feel free to do it.
Better upload DNG files that do not decode with FFmpeg.
In this message
http://ffmpeg.org/pipermail/ffmpeg-user/2020-August/049681.html
you find a link to many DNG images which FFmpeg can't decode correctly.
There is no error message, but the result is much too dark with low
saturation.
Use correct player like mpv, which does not ignore color_trc.
A player? The output is a jpg image and it's too dark.
ffmpeg -i input.dng output.jpg
I did convert a RAW image from a Canon 6D to DNG with Adobe DNG Converter
V12.4. FFmpeg is unable to decode this DNG image. See this message for
details:
http://ffmpeg.org/pipermail/ffmpeg-user/2020-August/049738.html
You can download the DNG image here (I will delete it from my webspace in a
few days):
www.astro-electronic.de/IMG_3459.dng
I did also try a RAW image from a Canon 5D-MK4 with the same negative
result.
A friend gave me a DNG image that was written by his Pentax K5 camera. Same
negative result.
Summary: I did try DNG images from 4 different sources and in 4 of 4 cases
In my testcases, 30 out of 30 DNGs decoded just fine.
Did any of your 30 DNGs come from Adobe DNG converter V12.4, or from a
Pentax K5 camera?
Michael
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