On 3/6/19, Michael Koch <[email protected]> wrote: > 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 > length. > > 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
Only first frame will be average of first 100 frames. > > 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". _______________________________________________ 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".
