# Basic Transcoding (MP4 to MKV)
ffmpeg -i input.mp4 output.mkv

# Change Video Codec (to H.265/HEVC)
ffmpeg -i input.mp4 -c:v libx265 -crf 28 -c:a copy output.mp4

# Extract Audio (No Video)
ffmpeg -i input.mp4 -vn -c:a libmp3lame -q:a 2 output.mp3

# Resize/Scale Video
ffmpeg -i input.mp4 -vf "scale=1280:720" output.mp4

# Cut Video (Start at 10s, Duration 30s)
ffmpeg -i input.mp4 -ss 00:00:10 -t 00:00:30 -c copy output.mp4

# Fast Precise Cut (Re-encoding only the cut points is complex, so standard re-encoding is safer for precision)
ffmpeg -ss 00:00:10 -i input.mp4 -to 00:00:40 -c:v libx264 -crf 23 -c:a aac output.mp4

# Concatenate Files (using demuxer)
# Create filelist.txt: file 'part1.mp4' \n file 'part2.mp4'
ffmpeg -f concat -safe 0 -i filelist.txt -c copy output.mp4

# Speed Up/Slow Down Video (2x speed)
ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" -map "[v]" -map "[a]" output.mp4

# Example: Adding a watermark at the bottom right
ffmpeg -i input.mp4 -i watermark.png -filter_complex "overlay=main_w-overlay_w-10:main_h-overlay_h-10" output.mp4

# Example: Vertical Stack (2 videos)
ffmpeg -i top.mp4 -i bottom.mp4 -filter_complex "vstack=inputs=2" output.mp4

# Example: Side-by-Side (2 videos)
ffmpeg -i left.mp4 -i right.mp4 -filter_complex "hstack=inputs=2" output.mp4

# Example: Grid (4 videos 2x2)
ffmpeg -i v1.mp4 -i v2.mp4 -i v3.mp4 -i v4.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[top];[2:v][3:v]hstack=inputs=2[bottom];[top][bottom]vstack=inputs=2" output.mp4

# Example: Fade Transition (Simple crossfade between two clips)
# Requires manual offset calculation, using xfade is better
ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "xfade=transition=fade:duration=1:offset=9" output.mp4

ffmpeg -i input.mp4 -vf "fps=15,scale=480:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" output.gif

ffmpeg -i voice.mp4 -i bgm.mp3 -filter_complex "[1:a]volume=0.3[bg];[0:a][bg]amix=inputs=2:duration=first" -c:v copy output.mp4

# Pass 1: Analyze
ffmpeg -i shaky.mp4 -vf vidstabdetect -f null -
# Pass 2: Transform
ffmpeg -i shaky.mp4 -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 output.mp4

# brightness=0.05, contrast=1.1, saturation=1.2
ffmpeg -i input.mp4 -vf "eq=brightness=0.05:contrast=1.1:saturation=1.2" output.mp4

ffmpeg -i input.mp4 -vf "select='not(mod(n,100))',scale=320:-1,tile=3x3" -frames:v 1 preview.png

ffmpeg -i input.mp4 -af silenceremove=start_periods=1:start_silence=0.1:start_threshold=-50dB:stop_periods=1:stop_silence=0.1:stop_threshold=-50dB output.mp4

# Burn SRT
ffmpeg -i input.mp4 -vf "subtitles=subs.srt" output.mp4
# Burn ASS (supports advanced styling)
ffmpeg -i input.mp4 -vf "ass=subs.ass" output.mp4

# Bitrate = (TargetSize_in_bits) / (Duration_in_seconds)
# 50MB = 400,000 bits. For 60s, bitrate ≈ 6600k
ffmpeg -i input.mp4 -b:v 6000k -maxrate 6000k -bufsize 12000k -c:a aac -b:a 128k output.mp4

ffmpeg -i input.mp4 -filter_complex "select='gt(scene,0.4)',metadata=print:file=scenes.txt" -vsync vfr scene_%03d.png

ffmpeg -i input.mp4 -vf "fps=1/5" img_%03d.jpg

for f in *.mov; do ffmpeg -i "$f" "${f%.mov}.mp4"; done

ffmpeg -re -i input.mp4 -c:v libx264 -preset veryfast -b:v 3000k -maxrate 3000k -bufsize 6000k -pix_fmt yuv420p -g 60 -c:a aac -b:a 128k -f flv rtmp://a.rtmp.youtube.com/live2/YOUR_STREAM_KEY