Differences

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--- fuss:ffmpeg [2017/11/29 08:15] – [Install a Full FFmpeg Distribution on Debian] office
+++ fuss:ffmpeg [2019/01/04 19:24] – [Convert Video to GIF Animation] office
@@ Line 304: / Line 304: @@
 ffmpeg -i dump.gif -vf "setpts=0.25*PTS" -r 7 final.gif
 </code>
-  * ''setpts=0.25*PTS'' will set the speed as 4 times the current speed,
+  * ''setpts=0.25*PTS'' will set the speed as $4$ times the current speed,
-  * ''-r 1'' will drop or duplicate frames to achieve 7 frames per second
+  * ''-r 1'' will drop or duplicate frames to achieve $7$ frames per second
 Achieving an acceptable GIF is a games of push and pull between the value of ''-r'' and the value of ''setpts''.
+Other very useful filters are:
+  * ''decimate'' - will merge / drop duplicate frames hence lowering the GIF size,
+  * ''deflicker'' - will attempt to stabilize the video,
+  * ''scale'' - will scale the movie (down) and hence can be used to lower the file size
+In one pass:
+<code bash>
+ffmpeg -i a.gif -vf "deflicker, decimate=cycle=4, fps=8, setpts=0.35*PTS, scale=360:trunc(ow/a/2)*2" b.gif
+</code>
+the actions performed will be:
+  * ''deflicker'' - attempt to deflicker / stabilize the video,
+  * ''decimate=cycle=4'' - crop duplicate frames at a rate of $1$ duplicate frame out of $4$,
+  * ''fps=8'' - attempt to set the framerate to $8$ frames per second,
+  * ''setpts=0.35*PTS'' - speed up the movie by $0.35$ of the original speed.
+====== Lowest Common Denominator Settings Compatible with All Sites ======
+The settings produce an output file with the ''faststart'' flag such that the video can be sought through without having to buffer the entire file.
+<code bash>
+ffmpeg -i $INPUT_FILE \
+  -c:v libx264 -crf 23 -profile:v baseline -level 3.0 -pix_fmt yuv420p \
+  -c:a aac -ac 2 -b:a 128k \
+  -movflags faststart \
+  output.mp4
+</code>