[FFmpeg-user] Question about tmix filter
astroelectronic at t-online.de
Wed Mar 6 22:39:53 EET 2019
Am 06.03.2019 um 20:45 schrieb Paul B Mahol:
>>>> Your interpretation of test results is invalid.
>>>> You should count frames.
>>> Well, I did run the video in VLC and measure the duration with a
>>> stopwatch, and it is 5 seconds. Below is the FFprobe output.
>>> How can I count the frames?
>> Old fashioned way - by hand.
> -f null -
> AKA null muxer counts frames for you.
ok, it's 76 frames and 5 seconds. Lesson learned, don't trust the video
Next question. I want to make a dark subtract for my videos of the night
sky. I capture a few seconds of video with the cap on the lens. From
this video I want to average 100 frames and extract the result as a PNG
image, which will then be subtracted from the video of the night sky.
Do you think this is the correct command for extracting the average of
the first 100 frames?
ffmpeg -i dark.mov -vf tmix=frames=100 -frames 1 dark.png
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