In those examples, “-c:a copy” means the audio will just be copied, not re-encoded, a wise choice when dealing with lossy compression. Putting all this together, we might end up with a command that looks like:įfmpeg -i Video.mkv -vf subtitles=Video.mkv:original_size=1280x720 -c:v libx264 -profile:v high -level 4.1 -preset veryslow -tune film -crf 22 -c:a copy Final.mp4įfmpeg -i Video.mp4 -vf subtitles=English.ass:original_size=1920x1080 -c:v libx265 -preset slow -crf 26 -c:a copy Final.mp4įfmpeg -i Video.mp4 -vf subtitles='English SDH.srt':original_size=1920x1080 -c:v libaom-av1 -cpu-used 5 -crf 26 -b:v 0 -c:a copy Final.mp4 Of note, too, is the “-preset” parameter, which controls encoding speed and compression (try medium, slow, slower, or veryslow). For example, you might want to set “-tune film” if it is live-action, or “-tune animation” if anime. See the other article for a fuller discussion of this and other x264 parameters. Lower values: higher quality and bigger files. Higher values lead to lower quality and smaller files. “-crf” controls the quality of the encoding and can be set to a value of your choice (0–51). If that is the case, the command-line would run something like this:įfmpeg -i Video.mkv -vf subtitles=Video.mkv:original_size=1280x720 -c:v libx264 -crf 22 -c:a copy Final.mp4 Many Matroska files have subtitles stored inside them. You can use the Windows command-line instead, but batch files are easier to correct, edit, and re-use. And note that “original_size” must be set to the size of the video. Replace “Video.mp4” and “English.srt” with the names of your files, and then save the text file, using the “.bat” extension, perhaps calling it “ffmpeg.bat” or something similar. Also, this process re-encodes the video, which leads to further loss of quality.įirstly, download the latest Git build of FFmpeg and extract the zip file to a folder of your choice (trying to avoid a path with spaces).ġ) Copy your video and its subtitle file to the “bin” directory of FFmpeg.Ģ) Assuming a simple MP4 video and SRT subtitle file, open Notepad and type the following:įfmpeg -i Video.mp4 -vf subtitles=English.srt:original_size=1280x720 -c:v libx264 -crf 22 -c:a copy Final.mp4 Once burnt in, they will be part of the picture for good, so keep the originals if you can. What if one needs to burn the subtitles into the video itself, so that it becomes part of the picture? FFmpeg can do this quite easily-it is useful if a device cannot read subtitles or if they cannot be turned on for some reason.

In the other article, I wrote about combining (or muxing) video and subtitles into a single file.

Ffmpeg copy subtitles