Burning Multiple SRT Subtitles Tracks into Video using ffmpeg -filter-complex

Introduction

In this article, we will discuss how to burn multiple SRT subtitle tracks into a video using the ffmpeg filter-complex. Subtitles are an essential component of multimedia content, especially for audiences who prefer to watch videos with captions or have hearing impairments. FFmpeg is a versatile multimedia framework that can handle various tasks, including merging multiple SRT subtitle tracks into a single video.

Background: What are SRT Subtitle Files?

SRT (SubRip) is a popular subtitle file format that contains timing and text information. It is widely used due to its simplicity and compatibility with various media players. SRT files consist of plain text and are easy to edit using a text editor. Each line in an SRT file represents a single subtitle, including the start time, end time, and the text content.

Burning Subtitles into a Video

To burn subtitles into a video using ffmpeg, you can use the filter-complex with the 'subtitles' filter. This filter allows you to specify one or more subtitle files and their respective positions on the screen. In this article, we will focus on merging multiple SRT subtitle tracks into a single video.

Command Line Example

Let's consider an example where we have two SRT subtitle files named "subtitle1.srt" and "subtitle2.srt". We will merge these subtitle files into a video named "output.mp4".

In the above command, we used the 'subtitles' filter twice to merge both subtitle files. The 'force_style' option is used to customize the appearance of the subtitles, including the font, color, and background.

Understanding the Command Line Options

Let's break down the command line options used in the previous example:

• -i input.mp4: This option specifies the input video file.
• -vf: This option is used to apply video filters. In our case, we will apply the 'subtitles' filter twice.
• "subtitles=subtitle1.srt:force_style='...': This option specifies the first subtitle file and its corresponding filter settings.
• "subtitles=subtitle2.srt:force_style='...': This option specifies the second subtitle file and its corresponding filter settings.
• output.mp4: This option specifies the output video file name.

In this article, we learned how to merge multiple SRT subtitle tracks into a single video using the ffmpeg filter-complex. We discussed the background of SRT subtitle files and provided a command line example to demonstrate the process. By following these steps, you can easily create a video with multiple subtitle tracks.