Arabic Words Showing Square Boxes: Fix Subtitles in FFmpeg

FFmpeg is a powerful, open-source tool used for handling multimedia files, including videos and subtitles. However, sometimes you may encounter issues when displaying Arabic subtitles, as they appear as square boxes instead of actual text. This article will guide you through a detailed explanation of the problem and provide a step-by-step solution using FFmpeg.

Understanding the Issue

Arabic words showing square boxes are usually caused by encoding issues. In most cases, the subtitle file is in a different encoding than the video file or the video player. This discrepancy prevents Arabic characters from being displayed correctly.

Common Subtitle Formats

There are several subtitle formats, but the most common and widely supported ones are SubRip (SRT) and Advanced SubStation Alpha (ASS/SSA). Other formats include MicroDVD and SubViewer. However, ASS/SSA provides more advanced features, such as styling and timing options.

Character Encoding: The Root Cause

Character encoding determines how characters are stored and displayed. Incompatible character encoding can result in Arabic subtitles appearing as square boxes. In FFmpeg, the default encoding used for subtitles is UTF-8, which supports most languages, including Arabic.

Incorrect Encoding in ASS Files

When converting ASS files to another format, the encoding might be changed if not specified. This conversion can lead to incorrect Arabic subtitle rendering, resulting in square boxes.

Fixing Arabic Subtitles with FFmpeg

To resolve the Arabic word square box issue in your subtitles, you can follow these steps using FFmpeg:

1. Identify the encoding format of your video file and your subtitle file using tools like ffprobe.
2. Convert the subtitle file to the required format using FFmpeg, making sure to specify the correct encoding.
3. Add the converted subtitle file to your video using FFmpeg, with a codec that supports Arabic characters.

Step 1: Identify Encoding Formats

To check the encoding format, use the following ffprobe commands:

$ ffprobe video_file.mp4
 $ ffprobe subtitle_file.ass
 

Look for the "format" section in the output, which will contain information on the encoding format.

Step 2: Convert Subtitle File

To convert an ASS file to an SRT file while preserving UTF-8 encoding, you can use the following FFmpeg command:

$ ffmpeg -i subtitle_file.ass -c:s srt -encoding utf8 fixed_subtitle_file.srt
 

Step 3: Attach Subtitle File to Video

Finally, you can attach the fixed subtitle file to the video with the correct codec (e.g., MOV\_TEXT or UTF8) using FFmpeg:

$ ffmpeg -i video_file.mp4 -vf "subtitles=fixed_subtitle_file.srt:force_style='Fontsize=24'" -c:a copy output_video_file.mp4
 

• Arabic words appearing as square boxes in subtitles can be caused by encoding issues.
• Use FFmpeg to convert subtitle files to the correct format and encoding.
• Add fixed subtitle files to video using FFmpeg with the correct codec.

References

• FFmpeg official site
• FFprobe documentation
• Changing Font Size in Subtitle using FFmpeg