Video EditingAdvanced

How to Burn an SRT into a Video with FFmpeg

Use FFmpeg to hardcode a subtitle file into a video from the command line, with styling control.

9 minAdvanced

Once you have a corrected SRT from Submagic or VEED, you do not always need to re-render inside those tools. FFmpeg can burn the subtitles into any video from the command line, which is ideal for automation and precise control. This guide covers the real commands.

FFmpeg installed (verify with ffmpeg -version)
A video file and a matching .srt in the same folder
Comfort with a terminal

Step 1: Confirm FFmpeg is installed

Check the version first. On macOS you can install it with Homebrew if it is missing.

zsh - ffmpeg

$ffmpeg -version

If not found, install it:

$brew install ffmpeg

Step 2: Burn the SRT with one command

The subtitles filter draws the SRT onto each frame. This re-encodes the video, so it permanently bakes the captions in. The audio is copied through untouched.

burn-basic.sh

ffmpeg -i input.mp4 -vf "subtitles=captions.srt" -c:a copy output.mp4

Step 3: Control the look with force_style

You can override font, size, color, outline, and position using force_style, which takes ASS style keys. Colors are in &HBBGGRR hex order, which is reversed from normal RGB, so white is &HFFFFFF and yellow is &H00FFFF.

burn-styled.sh

ffmpeg -i input.mp4 -vf "subtitles=captions.srt:force_style='FontName=Arial,Fontsize=24,PrimaryColour=&H00FFFFFF,OutlineColour=&H00000000,Outline=2,Alignment=2,MarginV=60'" -c:a copy output.mp4

Terminal - Encoding Progress

frame= 1480 fps= 92 q=24.0 size= 10240kB time=00:00:49.33

bitrate=1700.2kbits/s speed=3.06x

video:9800kB audio:430kB muxing overhead 0.1%

done.

FFmpeg reports frame count and speed while it renders.

BGR color order

force_style colors are &HAABBGGRR, not RGB. If your red comes out blue, you have the byte order reversed. PrimaryColour=&H000000FF is red, not blue.

Step 4: Keep a soft subtitle track instead

If you want toggleable captions inside an MP4 rather than burned-in pixels, mux the SRT as a soft track with mov_text. Players that support it can switch captions on and off.

soft-subs.sh

ffmpeg -i input.mp4 -i captions.srt -c copy -c:s mov_text -metadata:s:s:0 language=eng output.mp4

Step 5: Batch a whole folder

For many clips, loop over files that share a base name with their SRT. This is where the command line beats clicking through a GUI.

batch-burn.sh

for f in *.mp4; do
  base="${f%.mp4}"
  if [ -f "${base}.srt" ]; then
    ffmpeg -i "$f" -vf "subtitles=${base}.srt" -c:a copy "out_${base}.mp4"
  fi
done

Result: a folder of clips with matching SRTs is burned with consistent styling in a single scripted run, no editor required.