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--- howto:convert-images [2024/07/28 12:56] – Wulf Rajek
+++ howto:convert-images [2025/01/05 18:28] (current) – Wulf Rajek
@@ Line 26: / Line 26: @@
 find . -name '*.png' -type f -exec bash -c 'cwebp -z 9 "$0" -o "${0%.png}.webp"' {} \;
 #find . -type f -name '*.png' -delete
+</code>
+===== lossy conversion of png to jpg =====
+Converts all png files in the directory recursively to jpg
+<code>
+find . -iname '*.png' | while read i; do mogrify -format jpg "$i" && rm "$i"; echo "Converted $i to ${i%.*}.jpg"; done
 </code>
@@ Line 45: / Line 51: @@
 ===== high quality conversion to mp4 =====
+<code>
 #High quality non-mp4 to mp4 conversion
 find . -type f \( -iname "*.mpg" -o -iname "*.asf" -o -iname "*.wmv" -o -iname "*.mpg" -o -iname "*.mpeg" -o -iname "*.avi" -o -iname "*.divx" -o -iname "*.rmvb" -o -iname "*.rm" -o -iname "*.m4v" -o -iname "*.flv" \) | while read f; do
     ffmpeg -nostdin -i "$f" -vcodec libx264 -acodec aac "${f%.*}.mp4"
 done
+</code>
 ===== find all non-mp4 files =====
 <code>
@@ Line 198: / Line 204: @@
 </code>
+===== 3D VR SBS to 2D =====
+https://blog.interstellar.co.jp/en/2022/06/21/converting-vr180-videos-to-2d-videos-with-ffmpeg/
+<code>
+ffmpeg -i input.mp4 -vf v360=input=equirect:output=flat:ih_fov=180:iv_fov=180:h_fov=93:v_fov=121:in_stereo=sbs:w=960:h=640 -codec:v h264 output.mp4
+</code>
+https://video.stackexchange.com/questions/21084/how-to-convert-a-3d-movie-to-2d-using-ffmpeg
+<code>
+ffmpeg -i input.mkv -vf stereo3d=sbsl:ml -metadata:s:v:0 stereo_mode="mono" output.mkv
+</code>
+Use sbsl2:ml or  -aspect 16:9 if the aspect ratio is wrong
+https://stackoverflow.com/questions/66960003/unwarping-180-vr-footage-with-ffmpeg-v360-filter
+https://github.com/paulpaul999/vr-video-notes/blob/main/vr-to-flat/README.md
+<code>
+ffmpeg -i equirectangular.mp4 -filter:v "v360=input=hequirect:output=flat:in_stereo=sbs:out_stereo=2d:d_fov=125:w=1920:h=1080:pitch=+5" -map 0 -c copy -c:v h264 -pix_fmt yuv420p flat.mp4
+</code>