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--- ffmpeg [2022/04/15 11:12] – [Editing] Better croppign example rjt
+++ ffmpeg [2025/07/22 01:10] (current) – [Editing] Rotation rjt
@@ Line 9: / Line 9: @@
 Most of the time I just use---
-<code>ffmpeg -i input.ext output.ext</code>
+<code>ffmpeg -i [input.ext] [output.ext]</code>
 ---and it usually works fine leaving it to just use defaults.
@@ Line 15: / Line 15: @@
 This gives good results (and a smaller file size) converting MP3 to OGG though:
-<code>ffmpeg -i input.mp3 -c:a libvorbis -q:a 4 output.ogg</code>
+<code>ffmpeg -i [input].mp3 -c:a libvorbis -q:a 4 [output].ogg</code>
+Fuck-off those .WEBMs. ''copy'' here copies those streams, so they're no reencoded, it's just changing the container:
+<code>ffmpeg -i [input].webm -acodec copy -vcodec copy [output].mkv</code>
+A more compact way is to use ''-c'', which will copy over all streams (there's also ''-c:a'' (audio) ''-c:v'' (video) ''-c:s'' (subtitles)…:
+<code>ffmpeg -i [input].webm -c copy [output].mkv</code>
+So if you wanted to copy the video stream and just reencode/change the audio, for example:
+<code>ffmpeg -i [input].[ext] -acodec aac -vcodec copy [output].[ext]</code>
 === Multiple ===
@@ Line 21: / Line 33: @@
 For doing a whole directory I use this one-liner I got from Stack Exchange.
-<code>for i in *.ext; do ffmpeg -i "$i" "${i%.*}.ext"; done</code>
+<code>for i in *.[ext]; do ffmpeg -i "$i" "${i%.*}.[ext]"; done</code>
 For converting files for my [[m-u-s-u-c]] blog I also strip out the cover images: ''-map a'' tells it to take only the audio stream.
@@ Line 27: / Line 39: @@
 <code>for i in *.mp3; do ffmpeg -i "$i" -c:a libvorbis -q:a 4 -map a "${i%.*}.ogg"; done</code>
-You can use the wildcard ''*'' in the file extension to, so if you've got a mix of .mkv and .mp4 files from Youtube you can do. say:
+You can use the wildcard ''*'' in the file extension too, so if you've got a mix of .mkv and .mp4 files from Youtube you can do. say:
 <code>for i in *.m*; do ffmpeg -i "$i" "${i%.*}.ogv"; done</code>
@@ Line 33: / Line 45: @@
 If you want to put the new videos into a subdirectory, first create it, then simply add it to the output part:
-<code>for i in *.ext; do ffmpeg -i "$i" "directory/${i%.*}.ext"; done</code>
+<code>for i in *.[ext]; do ffmpeg -i "$i" "directory/${i%.*}.[ext]"; done</code>
-For converting a directory of .FLAC files to .MP3. ''[-qscale:a 0|-b:a 320k]'' is your choice between VBR with the best quality (0) or a CBR of 320k. VBR is generally just as good, though sometimes you need CBR.
+For converting a directory of .FLAC files to .MP3. ''[-q:a 0|-b:a 320k]'' is your choice between VBR with the best quality (0) or a CBR of 320k. VBR is generally just as good, though sometimes you need CBR.
-<code>for a in ./*.flac; do ffmpeg -i "$a" [-qscale:a 0|-b:a 320k] "${a[@]/%flac/mp3}"; done</code>
+<code>for i in *.flac; do ffmpeg -i "$i" [-q:a 0|-b:a 320k] "${i%*}.mp3"; done</code>
 ==== Editing ====
@@ Line 78: / Line 90: @@
 === Rotation ===
-Rotate 90°.
+Rotate 90°. This will reencode the video.
 <code>ffmpeg -i inputfile.ext -vf "transpose=1" outputfile.ext</code>
+To rotate -90° is ''transpose=2''.
+(The easiest, tidiest way to rotate a phone video is to just edit the metadata with [[exiftool]])
 === Trimming ===
@@ Line 130: / Line 146: @@
 Just had an .AVI file throwing error messages about a busted index. Copying the file seemed to fix it.
 <code>ffmpeg -i "inputfile.avi" -c:v copy -c:a copy "outputfile.avi"</code>
+===== Frontends =====
+  * [[https://ffmpeg.lav.io/|FFmpeg Explorer]] - Browser-based GUI with a node-based interface for changing parameters.
 ===== See Also =====