Does vlc use 10 bit or 8 bit build? Doubt it used 10bit Sent from my iPhone
> On Sep 20, 2020, at 8:20 PM, Michael Koch <[email protected]> wrote: > > Am 19.09.2020 um 17:01 schrieb Paul B Mahol: >>> On Sat, Sep 19, 2020 at 12:10 PM Michael Koch <[email protected]> >>> wrote: >>> >>> Hello all, >>> >>> I want to create a 10-bit VLog test video which contains 18 levels of >>> gray, according to Panasonic's VLog curve. >>> The curve is documented here: >>> >>> https://pro-av.panasonic.net/en/cinema_camera_varicam_eva/support/pdf/VARICAM_V-Log_V-Gamut.pdf >>> >>> I want the leftmost bar to be black (128) and the other 17 bars are for >>> -8 to +8 stops, so that the rightmost bar is at level 1023. I'm using >>> this command line and the console output is copied below: >>> >>> ffmpeg -f lavfi -i nullsrc=s=svga,format=gray16 -lavfi >>> geq=lum='st(0,trunc(18*X/W));64*(128*eq(ld(0),0)+132*eq(ld(0),1)+136*eq(ld(0),2)+144*eq(ld(0),3)+160*eq(ld(0),4)+192*eq(ld(0),5)+240*eq(ld(0),6)+298*eq(ld(0),7)+363*eq(ld(0),8)+433*eq(ld(0),9)+505*eq(ld(0),10)+578*eq(ld(0),11)+652*eq(ld(0),12)+726*eq(ld(0),13)+800*eq(ld(0),14)+874*eq(ld(0),15)+949*eq(ld(0),16)+1023*eq(ld(0),17))' >>> >>> -pix_fmt yuv444p10le -crf 10 -c:v h264 -t 5 -y VLog_10bit.mov >>> >>> The video looks perfect when played with FFplay. The leftmost bars are >>> indistinguishable on a 8-bit monitor because the levels are too close >>> together, but the rightmost bars look as expected. >>> >>> However when I play the same video with VLC, the two brightest bars at >>> the right side have the same shade of gray. I don't understand why. Is >>> this a problem in my video, or is it a problem in VLC? >>> >>> When I extraxt a 16-bit PNG image from the video, this looks as expected >>> with 18 levels of gray. >>> ffmpeg -i VLog_10bit.mov -frames 1 -y out.png >>> >>> Unrelated: I did try to add the oscilloscope filter at the end of the >>> filter chain, but it seems it doesn't work with 16-bit data. There >>> should be a warning or an error message. oscilloscope=tw=1:s=1 >>> >> That happened only with gray>8 formats and have been fixed already. > > Thanks, oscilloscope works fine now. > Do you have any idea why the brightest bar looks correct in FFplay and wrong > in VLC? > Is the problem reproducible on other computers? > > 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".
