Assuming you have:
# 1️⃣ Install needed tools (Ubuntu/Debian example)
sudo apt-get update
sudo apt-get install -y ffmpeg python3-pip
pip3 install autosub
# 2️⃣ Generate timestamps automatically (autosub uses Whisper under the hood)
autosub -i movie.mp4 -S en -D en -o fjin046engsub.srt
# 3️⃣ Clean up line length (using subtitle-edit's command‑line mode)
# (You need Java for Subtitle Edit)
java -jar SubtitleEdit.jar -c -fixoverlaps -maxlen 42 -maxlines 2 fjin046engsub.srt
# 4️⃣ Validate and export to VTT
ffmpeg -i fjin046engsub.srt fjin046engsub.vtt
Result: fjin046engsub.vtt – a tidy, time‑coded subtitle file ready for upload to YouTube, Vimeo, etc. fjin046engsub convert020136 min better
ffmpeg -i fjin046engsub.mkv -map 0 -c:v libx265 -preset slow -crf 23 \
-x265-params "zones=7260k,7260k,b=1.2" \
-c:a libopus -b:a 96k -c:s copy output_fjin046_optimized.mkv
Breakdown:
Let’s compute: 02:01:36 in seconds = 2*60 + 1 + 36/100 = 121.36 seconds.
At 30 fps, that’s ~3640 frames. But if video is 23.976 fps, use frame number: 121.36 * 23.976 ≈ 2910.
Better to use time-based zones in newer FFmpeg: Assuming you have:
- x265-params "zones=2910,2910,b=1.5"
This boosts bitrate around that scene by 50% to prevent artifacts. # 1️⃣ Install needed tools (Ubuntu/Debian example) sudo
Most casual users rely on HandBrake or FFmpeg presets. However, problematic scenes (high motion, fades, or complex subtitle overlays) often appear around timestamps like 02:01:36. Standard encoding allocates bits evenly, causing:
To make it “better,” you need scene-aware encoding.