add-intro-outro

Add the intro and outro

The stings are short MP4s with their own jingle, one pair per orientation, listed in preferences. This skill normalises everything to one format, joins intro, video and outro with short cross-fades (video and audio), and renders the result.

Preferences

remote-video-editing/preferences.json (lookup order as in clean-voice-sidon):

Key	Meaning
stings	{"intro_16x9": url, "outro_16x9": url, "intro_9x16": url, "outro_9x16": url}; URLs or local paths
sting_fade_s	Cross-fade length, default 0.5
render_notes	Where to run long encodes (e.g. a server rather than a laptop). Follow them.

If stings is not set, ask for the files. The plugin does not ship any brand assets.

Orientation

Read the displayed orientation, not the coded size: phones store portrait video as 1920x1080 with a rotation tag. Check with ffprobe -v error -select_streams v:0 -show_entries stream=width,height:stream_side_data=rotation -of compact IN. A rotation of 90 or -90 swaps width and height. ffmpeg applies the rotation automatically when it decodes.

• Portrait (9:16) video: use intro_9x16 / outro_9x16, canvas 1080x1920.
• Landscape: use the 16:9 pair, canvas 1920x1080.
• 16:9 cut of a portrait video (for YouTube's main feed): canvas 1920x1080, the video scaled to 1080 high in the centre, over a blurred, darkened, zoomed copy of itself; use the 16:9 stings. The [v1] chain below becomes:

  [1:v]fps=30,split[a][b];
  [a]scale=1920:1080:force_original_aspect_ratio=increase,crop=1920:1080,scale=480:270,boxblur=20:2,scale=1920:1080,eq=brightness=-0.06:saturation=0.9[bg];
  [b]scale=-2:1080[fg];[bg][fg]overlay=(W-w)/2:0,setsar=1,format=yuv420p[v1]
  

  Test it on an 8-second cut (-ss 60 -t 8) and show a frame before rendering the whole thing.

Render

W:H is the canvas, F the fade (0.5), DI the intro duration, DV the video duration (ffprobe format=duration). Offsets: first fade at DI-F; second at DI+DV-2*F.

ffmpeg -y -i intro.mp4 -i main.mp4 -i outro.mp4 -filter_complex "
 [0:v]fps=30,scale=W:H,setsar=1,format=yuv420p[v0];
 [1:v]fps=30,scale=W:H:force_original_aspect_ratio=decrease,pad=W:H:(ow-iw)/2:(oh-ih)/2,setsar=1,format=yuv420p[v1];
 [2:v]fps=30,scale=W:H,setsar=1,format=yuv420p[v2];
 [0:a]aresample=48000,aformat=channel_layouts=stereo[a0];
 [1:a]aresample=48000,aformat=channel_layouts=stereo[a1];
 [2:a]aresample=48000,aformat=channel_layouts=stereo[a2];
 [v0][v1]xfade=transition=fade:duration=F:offset=DI-F[v01];
 [v01][v2]xfade=transition=fade:duration=F:offset=DI+DV-2*F[v];
 [a0][a1]acrossfade=d=F[a01];[a01][a2]acrossfade=d=F[a]" \
 -map "[v]" -map "[a]" -c:v libx264 -preset medium -crf 20 -maxrate 10M -bufsize 20M -c:a aac -b:a 192k -movflags +faststart out.mp4

• Several source clips: join them first (same filter pattern, or the concat demuxer if they share a codec), then treat the result as main.mp4.
• This is a full re-encode: minutes of every core for a 10-minute 1080p video. Run it on Modal, not locally and not on a home server: put the arguments after the inputs (from -filter_complex to +faststart) one per line in render.args, then $MODAL run "${CLAUDE_PLUGIN_ROOT}/scripts/ffmpeg_modal.py" --inputs intro.mp4,main.mp4,outro.mp4 --args-file render.args --out out.mp4 (modal_command and run_notes from preferences say where Modal runs). Join several clips in the same graph (concat filter) rather than as a separate pass. Delete the job's folder in volume video-editing-work afterwards.
• xfade needs both inputs on the same timebase: put fps=30,settb=1/30 on every video branch (including after a concat), or ffmpeg fails with "First input link main timebase (1/30) do not match".
• Bitrate: keep the cap (-crf 20 -maxrate 10M -bufsize 20M). Plain CRF 18 on noisy phone footage came out at 24 Mbps, about 2 GB for 11 minutes (2026-11-13). YouTube re-encodes anyway and suggests 8-12 Mbps for 1080p uploads.
• Verify: output duration is about DI + DV + DO - 2*F, and check frames at DI-F/2 (mid-fade), the middle and the end.

Handheld footage: stabilise in the same render

Phone videos shot handheld benefit from light stabilisation (the user, 2026-11-13, after the first Hebrish weekend update went out without it). Use ffmpeg's vid.stab (libvidstab; Debian's ffmpeg, which the Modal image installs, has it; check with ffmpeg -filters | grep vidstab). Two passes, both on Modal:

1. Detect (fast, analysis only, writes a transforms file), per source clip: ffmpeg -i main.mp4 -vf vidstabdetect=shakiness=5:accuracy=15:result=main.trf -f null - Run it as its own ffmpeg_modal.py job (args -vf / vidstabdetect=...:result=/work/<job>/main.trf / -f / null, output -), or add a detect step to the script. The .trf must sit beside the input in the volume.
2. Transform inside the main render, first thing on that clip's video branch, before grade and scale: vidstabtransform=input=main.trf:smoothing=20:zoom=2:optzoom=0,unsharp=5:5:0.4 smoothing around 15-30 (frames) keeps natural motion; a fixed zoom=2 (percent) hides the moving borders without the pumping optzoom=1 causes on a talking head. The light unsharp offsets the resampling softness.

Test on an 8-second cut first and compare a still and a short clip with the user before the full render. If libvidstab is missing, deshake is a one-pass fallback (weaker). AI stabilisers are not needed for this.

Making stings

The stings in use were rendered from the brand SVGs with a small Pillow script plus a generated jingle. Find it with find-script (tags logo, sting, intro), and don't regenerate the logo with a video model: video models distort letterforms.