How to Use Font Attachment and Burn Subtitles in MKV Container

In this article, we will explore how to use font attachment burn subtitles in MKV container format. We will cover key concepts related to subtitles and how to use the dump_attachment feature of ffmpeg to burn subtitles into the video.

What are Subtitles?

Subtitles are textual versions of a video's audio content that are displayed on the screen. They are commonly used to provide translations for foreign language films or to assist those who are deaf or hard of hearing. Subtitles can be either hardcoded or softcoded. Hardcoded subtitles are permanently burned into the video, while softcoded subtitles are separate from the video and can be turned on or off by the viewer.

Font Attachment Burn Subtitles

Font attachment burn subtitles refer to hardcoded subtitles that are burned into the video using a specific font. This method ensures that the subtitles are always displayed, regardless of the viewer's software or settings. It is commonly used for distributing videos with subtitles in languages other than the original audio.

Using ffmpeg to Burn Subtitles

ffmpeg is a powerful, open-source multimedia processing tool that can be used to burn subtitles into videos. To burn subtitles using ffmpeg, we can use the -vf flag to specify the video filter and the subtitles filter to specify the subtitle file. However, there is a limitation with this method: the subtitle font is not embedded in the video.

Using dump_attachment Feature

To overcome the limitation of the previous method, we can use the dump_attachment feature of ffmpeg. This feature allows us to extract the subtitle track from the MKV container and save it as a separate file. We can then embed the subtitle track back into the video using the -i flag to specify the subtitle file.

ffmpeg -i input.mkv -vf "dump_attachment:subtitles=subtitle_Track_ID" -map 0:v -c:v copy -map 0:a -c:a copy -map "[subtitles]" -c:s copy output.mkv
 

In the above command, input.mkv is the input video file, subtitle_Track_ID is the ID of the subtitle track to extract, and output.mkv is the output video file with the embedded subtitle track. The -c:s copy flag is used to ensure that the subtitle font is embedded in the output video.

• Subtitles are textual versions of a video's audio content that are displayed on the screen.
• Font attachment burn subtitles refer to hardcoded subtitles that are burned into the video using a specific font.
• The ffmpeg multimedia processing tool can be used to burn subtitles into videos.
• The dump_attachment feature of ffmpeg allows us to extract and embed subtitle tracks, ensuring that the subtitle font is embedded in the output video.

References

• FFmpeg Documentation: https://ffmpeg.org/documentation.html
• MKVToolNix Documentation: https://mkvtoolnix.download/doc/mkvmerge.html