FFMPEG - extract srts from all .m4v files in a directory.

gistfile1.txt

//THE ONE-LINER-COMBO-MAGIC (updated 20230807)
for FILENM in *; do ffmpeg -i $FILENM -vn -an -codec:s srt ${FILENM/.m4v/}.srt; ffmpeg -i $FILENM -c copy ${FILENM/.m4v/}.mp4; done;

//convert all the videos to a low bandwidth version and place alongside the original video. 
//source: https://addpipe.com/blog/flv-to-mp4/
for FILENM in *; do ffmpeg -i $FILENM -crf 45 -movflags faststart -profile:v baseline -level 3.1 ${FILENM/.mp4/}_3play.mp4; done;
//*** make sure the original video doesn't have spaces in the file name.  

//MACOS UNIX
//Extract all the .srt files
xxxxxxx$ for FILENM in *; do ffmpeg -i $FILENM -vn -an -codec:s srt ${FILENM/.m4v/}.srt; done;

//Convert the .m4v files to .mp4 files while keeping the existing audio and video codecs(h.264).
xxxxxxx$ for FILENM in *.m4v; do ffmpeg -i $FILENM -c copy ${FILENM/.m4v/}.mp4; done;

//Convert the .m4v files to .mp4 file and keep the existing codec + add faststart.
for FILENM in *.m4v; do ffmpeg -i $FILENM -c copy -movflags faststart ${FILENM/.m4v/}.mp4; done;


//EXPLANATION
//$FILENM -- each file in the directory
//${FILENM/.m4v/}.srt -- strip off the .m4v extension and add .srt.
//-vn -an -codec:s srt -- no video stream, no audio stream, codec stuff (see source below).

//SOURCE:
//Extracting an embedded subtitle from a video file using FFMPEG
//http://guns.buffout.org/blog/extracting-an-embedded-subtitle-from-a-video-file-using-ffmpeg/ (404)
//How to extract subtitle from video using ffmpeg?
https://superuser.com/questions/583393/how-to-extract-subtitle-from-video-using-ffmpeg

//REFERENCE:
//Easily renaming multiple files.
//http://www.debian-administration.org/articles/150