openclaw - 💡(How to fix) Fix Podcast clip videos are black — ffmpeg uses soft-subs instead of hard-burned subtitles [1 participants]

Fix Plan

To fix the issue, we need to modify the ffmpeg command to hard-burn subtitles onto the video stream. We can use the subtitles filter for this purpose.

Step-by-Step Solution

1. Install the required ffmpeg filters: Ensure that you have the subtitles filter installed and available in your ffmpeg setup.
2. Modify the ffmpeg command: Update the ffmpeg command to use the subtitles filter. Here's an example:

ffmpeg -i input.mp4 -vf "subtitles=input.srt:force_style='FontSize=24'" output.mp4

   Replace `input.mp4` with your input audio file, `input.srt` with your subtitle file, and `output.mp4` with the desired output file name.
3. **Add a non-black background**: To add a non-black background, you can use the `color` filter to generate a background color or image, and then overlay the subtitles on top of it. Here's an example:
   ```bash
ffmpeg -i input.mp4 -filter_complex "color=c=white:s=1280x720:r=30, subtitles=input.srt:force_style='FontSize=24'" output.mp4

This will generate a white background with the subtitles overlaid on top. 4. Use a waveform visualization or podcast artwork: To use a waveform visualization or podcast artwork as the background, you can use the movie filter to overlay an image or video on top of the subtitles. Here's an example:

ffmpeg -i input.mp4 -filter_complex "movie=background.png [bg]; [bg][input] overlay, subtitles=input.srt:force_style='FontSize=24'" output.mp4

Replace background.png with your background image file.

Verification

To verify that the fix worked, you can check the output video file using a media player that supports subtitles, such as VLC. The subtitles should be hard-burned onto the video stream and visible in all video players, including Telegram.

Extra Tips

• Make sure to adjust the font size and style of the subtitles according to your requirements.
• You can also use other filters, such as ass or libx264, to customize the subtitle rendering.
• If you're using a programming language to generate the ffmpeg command, make sure to escape any special characters in the command to avoid errors.