Cecil Westerhof via ffmpeg-user <ffmpeg-user@ffmpeg.org> writes: > I have to cut out a part of a video, crop it and blackout two parts. > I do this with: > ffmpeg -y \ > -ss 00:19:49 \ > -i 2021-03-25ToastmastersClubAvond.mp4 \ > -to 442 \ > -vf " > crop = 1440:1080:240:0 > , > drawbox=enable='between(t, 0, 2)' : > color = black : > w = in_w : > h = in_h : > thickness = fill > , > drawbox=enable='between(t, 339, 342)' : > color = black : > w = in_w : > h = in_h : > thickness = fill > " \ > -acodec copy \ > -vcodec libx264 \ > -crf 23 \ > speechClean2.mp4
With the help of this mailing list I changed it to: ffmpeg -y \ -ss 00:19:49 \ -i 2021-03-25ToastmastersClubAvond.mp4 \ -to 442 \ -vf " crop = 1440:1080:240:0 , drawbox=enable='bitor(between(t, 0, 2),between(t, 339, 342))' : color = black : w = in_w : h = in_h : thickness = fill " \ -acodec copy \ -vcodec libx264 \ -preset veryfast \ -crf 28 \ speechClean3.mp4 The input quality is probably poor, that is why I switched to crf 28. I do not see a difference in quality. I use veryfast because that probably gives (counter-intuitively) the smallest size. > The reason I do -to in the output is that in this way the metadata > concerning the video length is less out of whack. > > I was wondering if this is a good way, or that it could be done > better? > Also, beside the timestamps the parameters for drawbox are the same. > Is there a way that I do not have to repeat them? > > I started the crf with 16, then 20 and lastly 23. > > The input file has: > Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1920x1080, 2070 kb/s, 25 fps, 25 tbr, 30k tbn, 60k tbc (default) > > With crf 16 I get: > Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 5541 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) > > With crf 20 I get: > Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 3538 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) > > And with crf 23 I get: > Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 2444 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) With crf 28 and preset veryfast I get: Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1440x1080, 1056 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) When I have better quality video I should maybe change crf back to 23. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".