ffmpeg -i video.mp4 -ss 240 -filter_complex
"select='between(t,240,600)*not(mod(n,240))',subtitles=video.en.srt,scale=640:-1,tile=layout=2x2:padding=4"
-vframes 1 -q:v 2
Most tools install FFMPEG (like Subtitle-Edit, etc.)
So this should work everywhere.
Params explained:
-ss 120 -to 1800 → limit the clip to 120–1800 seconds, but we only need "-ss" in this example
select='between(t,119.5,120.5)+...' → four exact time windows (with ±0.5s tolerance so FFmpeg actually finds a frame at those timestamps)
subtitles=... → render subtitles in sync with the original video timeline
scale=640:-1 → fix the width to 640 pixels, scale height proportionally
tile=2x2:padding=4 → build a collage of 4 images, arranged in a 2×2 grid, with 4-pixel spacing
-vframes 1 → output only a single image (the collage)
-q:v 2 → good JPEG quality
If you don't have FFMPEG:
