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--- appwiki:ffmpeg [2021/06/18 19:14] – [Common Convertion] ying
+++ appwiki:ffmpeg [2021/12/08 20:16] – [Common Convertion] ying
@@ Line 1: / Line 1: @@
-====== REF ======
-  * about -ss before -i and after -i  difference, which can make cut video works or not works
-  * https://ottverse.com/trim-cut-video-using-start-endtime-reencoding-ffmpeg/
 ====== FFmpeg - the core command app of open source transcoder ======
@@ Line 55: / Line 52: @@
   * copy portion of video <code>
+# about -ss before -i and after -i  difference, which can make cut video works or not works
+# ref: https://ottverse.com/trim-cut-video-using-start-endtime-reencoding-ffmpeg/
 ffmpeg.exe -i video.mp4 -c copy -ss 00:00:09 -to 00:00:21 video_cut.mp4
-# for some video start time need to be infront
+# -ss in front means: start time (from 9s), duration time (21s)
 ffmpeg.exe -ss 00:00:09 -i video.mp4 -c copy -to 00:00:21 video_cut.mp4
 </code>
+  * combine list of videos into 1 video
+    * ref: https://stackoverflow.com/questions/7333232/how-to-concatenate-two-mp4-files-using-ffmpeg
   * gif maker <code>
@@ Line 69: / Line 72: @@
 </code>
+  * image to square size (like convert image to texture size format) <code>
+ffmpeg -i image.jpg -vf "scale=1024:1024:force_original_aspect_ratio=decrease,pad=1024:1024:-1:-1:color=white" -q:v 1 tex_image.jpg
+# longest side, so basically original size with padding to square
+ffmpeg -i image.jpg -vf "scale=max(iw\,ih):max(iw\,ih):force_original_aspect_ratio=decrease,pad=max(iw\,ih):max(iw\,ih):-1:-1:color=white" -q:v 1 tex_image.jpg
+</code>