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--- ffmpeg:video:resize:maintain_aspect_ratio [2025/01/29 22:10] – created peter
+++ ffmpeg:video:resize:maintain_aspect_ratio [2025/01/29 22:18] (current) – peter
@@ Line 1: / Line 1: @@
 ====== ffmpeg - Video - Resize - Maintain aspect ratio ======
+<code bash>
+-vf scale=1920:-1
+-vf scale=-1:1080
+-vf scale=1920:-2
+-vf scale=-2:1080
+</code>
+<WRAP info>
+**NOTE:**
+  * **-1** for the width or height will keep it in ratio to the other specified dimension.
+  * **-2** will keep it in ratio to the other specified dimension, but, to ensure it is divisible by 2 (a requirement for certain encodings such as yuv420p) the width or height will be adjusted if necessary.
+</WRAP>
+----
+===== Example =====
+<code bash>
+ffmpeg -i input.mp4 -vf "scale=1920:-1" -c:a copy output.mp4
+</code>
+<WRAP info>
+**NOTE:**  The **-1** tells ffmpeg to automatically calculate the height while maintaining the aspect ratio after sizing to the new width.
+  * **-i input.mp4**: Specifies the input video file.
+  * **-vf "scale=1920:-1"**: Applies the scale filter to resize the video width to 1920 pixels, and the video height is calculated to ensure the aspect ratio is maintained.
+  * **-c:a copy**: Copies the media streams without re-encoding.
+  * **output.mp4**: Name of the output file.
+</WRAP>