From 06d384ba33658c01b2fe2e8598208efe76d7dee2 Mon Sep 17 00:00:00 2001 From: Malin Freeborn Date: Mon, 20 Dec 2021 15:57:16 +0000 Subject: [PATCH] make ffmpeg file --- vision/ffmpeg.md | 136 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 135 insertions(+), 1 deletion(-) mode change 120000 => 100644 vision/ffmpeg.md diff --git a/vision/ffmpeg.md b/vision/ffmpeg.md deleted file mode 120000 index 36a2a55..0000000 --- a/vision/ffmpeg.md +++ /dev/null @@ -1 +0,0 @@ -../sound/ffmpeg.md \ No newline at end of file diff --git a/vision/ffmpeg.md b/vision/ffmpeg.md new file mode 100644 index 0000000..19e1b51 --- /dev/null +++ b/vision/ffmpeg.md @@ -0,0 +1,135 @@ +# Basics + +ffmpeg -i [input file] output_file.mkv + +The input file might be a device, such as a camera. + +Play video: + +> ffplay file.mp4 + +#Record screen +Take the format as 'grab the x11 screen'. + +> ffmpeg -f x11grab -s [screensize] -i :0.0 out.mkv + +Get screensize with + +> xrandr -q + +or maybe just... + +> ffmpeg -f x11grab -s "$(xdpyinfo | grep dimensions | awk '{print $2}')" -i :1.0 out.mkv + +#Add default pulse audio +> ffmpeg -f x11grab -s [screensize] -i :0.0 -f alsa -i default out.mkv + +For problems, see pavucontrol. + +# Random online suggestion + ffmpeg -video_size "$(xdpyinfo | grep dimensions | awk '{print $2}')" -f x11grab -i :0.0 -f pulse -ac 2 -i default ~/out.mkv + +# Rotate + +> ffmpeg -i in.mov -vf "transpose=1" out.mov + +0 = 90 Counterclockwise and verfical flip (default) +1 = 90 Clockwise +2 = 90 CounterClockwise +3 = 90Clockwise and vertical flip + +# Lower Video Quality +A crf quality of 18 is high, while 24 is low quality. + +ffmpeg -i input.mp4 -vcodec libx264 -crf 20 output.mp4 + +# convert + +Check for supported formats: + +> ffmpeg -formats + +To convert from mkv to mp4 we can use a codec rather than proper conversion. Both are wrappers around other formats, so this conversion loses less quality than other conversion types. + +> ffmpeg -i LostInTranslation.mkv -codec copy LostInTranslation.mp4 + +Opus to mp3 + +> ffmpeg -i song.opus song.mp3 + +> ffmpeg -i video.flv video.mpeg + +> ffmpeg -i input.webm -qscale 0 output.mp4 + +# Video to Audio + +> ffmpeg -i input.mp4 -vn output.mp3 + + +# Convert all mkv files to mp4 + +> for i in *.mkv; do + + > ffmpeg -i "$i" -codec copy "${i%.*}.mp4" + +> done + + +# Change resolution + +> ffmpeg -i input.mp4 -filter:v scale=1280:720 -c:a copy output.mp4 + +Or just crop: + +> ffmpeg -i input.mp4 -filter:v "crop=w:h:x:y" output.mp4 + +Or aspect ratio: + +> ffmpeg -i input.mp4 -aspect 16:9 output.mp4 + +Or trim to start and stop times: + +> ffmpeg -i input.mp4 -ss 00:00:50 -codec copy -t 50 output.mp4 + +Indicate start times with -ss and time with -t in seconds. + +Or split a video into parts: + +> ffmpeg -i input.mp4 -t 00:00:30 -c copy part1.mp4 -ss 00:00:30 -codec copy part2.mp4 + + +# Compress Video + +> ffmpeg -i input.mp4 -vf scale=1280:-1 -c:v libx264 -preset veryslow -crf 24 output.mp4 + +# Extract Images from Video + +-r sets the frame rate, and -f selects the format. + +> ffmpeg -i input.mp4 -r 1 -f image2 image-%2d.png + +# Add Images to Audio + +> $ ffmpeg -loop 1 -i inputimage.jpg -i inputaudio.mp3 -c:v libx264 -c:a aac -strict experimental -b:a 192k -shortest output.mp4 + +# Create a Video from Multiple Parts + +First make a text file indicating all the parts, e.g. + +``` + +file /home/sk/myvideos/part1.mp4 +file /home/sk/myvideos/part2.mp4 +file /home/sk/myvideos/part3.mp4 +file /home/sk/myvideos/part4.mp4 + +``` + +Then join with: + +> ffmpeg -f concat -i join.txt -c copy output.mp4 + +# Add Subtitles + +> fmpeg -i input.mp4 -i subtitle.srt -map 0 -map 1 -c copy -c:v libx264 -crf 23 -preset veryfast output.mp4 +