Differences

This shows you the differences between two versions of the page.

--- lwc:multimedia_and_graphics [2022/10/23 21:57] – John Harrison
+++ lwc:multimedia_and_graphics [2023/08/18 08:22] (current) – John Harrison
@@ Line 1: / Line 1: @@
   * [[http://stackoverflow.com/questions/12336401/creating-icon-fonts-with-vector-software-i-e-inkscape-and-fontforge|How to create a ttf]]
-  * crossfade example with ffmpeg (audio and video):
+==== Crossfade with ffmpeg ====
+=== crossfade example with ffmpeg (audio and video) ===
 <code>
 /opt/ffmpeg/bin/ffmpeg -i 1.mov -i 2.mov -f lavfi -i color=black -filter_complex \
@@ Line 29: / Line 31: @@
 [over1][va1]overlay=format=yuv420[outv]" \
 -vcodec libx264 -preset ultrafast -qp 0 -aspect 1.778 -map [outv] -map [outa] -acodec libvorbis -qscale:a 10 -ss 00:00:02 -t 5 out.mp4
+</code>
+=== crossfade using ffmpeg and xfade ===
+<code>
+ffmpeg -i first.mp4 -i second.mp4 -filter_complex "xfade=transition=fade:offset=60:duration=1" out.mp4
+<code>
+// from https://superuser.com/questions/778762/crossfade-between-2-videos-using-ffmpeg //
 </code>
   * compress video with ffmpeg:
@@ Line 35: / Line 43: @@
   * convert video to a sequence of pngs: ''ffmpeg -i <FILENAME1> <FILENAME2>_%03d.png''
   * [[https://superuser.com/questions/810471/remove-mp4-video-top-and-bottom-black-bars-using-ffmpeg|remove letterboxing with ffmpeg]]
+  * slow down video but keep smoothness by using optical flow (sometimes called motion interpolation): ''ffmpeg -i input.mkv -filter:v "minterpolate='mi_mode=mci:mc_mode=aobmc:vsbmc=1:fps=120'" output.mkv'' where ''fps'' is the output fps (independent of input fps)
+  * change speed video is played (fps) without changing anything else. No frames are harmed with this cmd: ''ffmpeg -itsscale 2 -i input.mp4 -c copy -an output.mp4'' # slow to 2x slower