Am 03.03.2020 um 10:52 schrieb Paul B Mahol:
Hi,
On 3/3/20, Michael Koch <[email protected]> wrote:
I'd like to stitch two fisheye videos together to an equirectangular
video. The input videos have larger than 180° field of view, so that
there is an overlap region and I want to use the maskedmerge filter for
merging the videos.
My first (successful) test is with png images:
First create the mask file for maskedmerge:
ffmpeg -f lavfi -i nullsrc=size=640x640 -vf
"format=gray8,geq='clip(128-128/10*(180-191.5/(640/2)*hypot(X-640/2,Y-640/2)),0,255)',v360=fisheye:e:ih_fov=191.5:iv_fov=191.5,format=rgb24"
-frames 1 -y mergemap.png
The pixel values in this image are 0 for one fisheye region, 255 for the
other fisheye region and a 0-255 ramp in the overlap region.
Now create two fisheye inputs (one is red and the other is green) and
transform them to equirectangular:
ffmpeg -f lavfi -i color=red:size=640x640 -lavfi
"drawbox=w=1:h=1:color=black,v360=input=fisheye:output=e:ih_fov=191.5:iv_fov=191.5"
-frames 1 -y eq1.png
ffmpeg -f lavfi -i color=green:size=640x640 -lavfi
"drawbox=w=1:h=1:color=black,v360=input=fisheye:output=e:ih_fov=191.5:iv_fov=191.5:yaw=180"
-frames 1 -y eq2.png
Now merge the two images with maskedmerge:
ffmpeg -i eq1.png -i eq2.png -i mergemap.png -lavfi "maskedmerge"
-frames 1 -y out.png
Up to this point, everything did work as expected. The output image
looks correct. As the next step, I want to do the same thing with
videos. I replace the file extensions by *.mp4, I replace "-frames 1" by
"-t 5", and I add "-loop 1" for the third input file (which is the same
as before):
ffmpeg -f lavfi -i color=red:size=640x640 -lavfi
"drawbox=w=1:h=1:color=black,v360=input=fisheye:output=e:ih_fov=191.5:iv_fov=191.5"
-t 5 -y eq1.mp4
ffmpeg -f lavfi -i color=green:size=640x640 -lavfi
"drawbox=w=1:h=1:color=black,v360=input=fisheye:output=e:ih_fov=191.5:iv_fov=191.5:yaw=180"
-t 5 -y eq2.mp4
ffmpeg -i eq1.mp4 -i eq2.mp4 -loop 1 -i mergemap.png -lavfi
"maskedmerge" -t 5 -y out.mp4
The intermediate videos eq1.mp4 and eq2.mp4 look correct, but the output
video is wrong.
I did already try many format conversions, but I haven't yet figured out
what's going wrong here.
Below is the console output for the last command line.
ffmpeg -i eq1.mp4 -i eq2.mp4 -loop 1 -i mergemap.png -lavfi
"[0:v]format=gbrp[a],[1:v]format=gbrp[b],[2:v]format=gbrp[c],[a][b][c]maskedmerge,format=gbrp"
-t 5 -y out.mp4
yes, this works. The trick is to use the format filter after
maskedmerge. Then it also works with rgb24.
I did expect that the output of maskedmerge is in the same format as the
three inputs (I did already test with three rgb24 inputs). Apparently
this is not the case and another format=rgb24 is required after
maskedmerge. There should be a warning in the documentation that
maskedmerge has a different output format, even if all three inputs are
rgb24.
Thanks,
Michael
_______________________________________________
ffmpeg-user mailing list
[email protected]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
[email protected] with subject "unsubscribe".
