--- name: polli-video description: Record terminal demo videos of the polli CLI using VHS (charmbracelet) with polli-generated voiceover and background music. Ships a working `example/demo.tape` + `example/render.sh` pipeline. Use when the user asks to make, record, or iterate on a polli demo video, LinkedIn/social clip of the CLI, or any terminal screencast for pollinations. allowed-tools: Bash(vhs *), Bash(ffmpeg *), Bash(ffprobe *), Bash(sox *), Bash(afplay *), Bash(polli *), Bash(open *), Bash(ls *), Bash(pkill *), Bash(rm *), Bash(cp *), Bash(mv *), Read, Write, Edit --- # polli-video — record polli CLI demos VHS records silent terminal video. Polli generates audio. ffmpeg merges. VHS cannot capture system audio — either capture it live via BlackHole, or overlay narration in post with `adelay`. ## When to use - Demo video for polli CLI, pollinations.ai, or terminal workflows - LinkedIn / social clip with voiceover and lofi background - Iterating on an existing `.tape` script ## Quick start ```bash mkdir -p temp/vhs-demo && cp .claude/skills/polli-video/example/* temp/vhs-demo/ cd temp/vhs-demo # Set system default output → BlackHole 2ch (see Pipeline A) ./render.sh ``` Produces `demo.mp4`. Edit `demo.tape` to change content. ## Pipeline A — BlackHole live capture (recommended) Single command, no `adelay` math, perfect sync. Requires [BlackHole 2ch](https://existential.audio/blackhole/) and default system output set to it (Option+click menu-bar speaker, or `SwitchAudioSource -s "BlackHole 2ch"`). See `example/render.sh` — archives old renders, captures while VHS runs, muxes trimmed to video length with a 5s audio pre-roll shift (ffmpeg startup + API roundtrip offset) and a 3s audio fade-out at the end. Copy and adapt. **Capture tool: `sox` over `ffmpeg avfoundation`.** ffmpeg dropped samples on long recordings (choppy audio) even with `-thread_queue_size 4096`, `-async 1`, `nice -20`. sox + coreaudio is stable end-to-end, addresses device by name ("BlackHole 2ch") instead of a flaky index, and needs no post-trim: ```bash AUDIODRIVER=coreaudio sox -q -c 2 -r 48000 -t coreaudio "BlackHole 2ch" \ -c 2 -r 48000 -b 16 captured.wav 2>/tmp/sox-capture.log & ``` Music gen must use `--play` so BlackHole captures it. Switch default output back to Speakers after. ## Pipeline B — post-hoc ffmpeg overlay (fallback) When BlackHole unavailable. Pre-generate narration + music, overlay with manual timestamps: ```bash vhs demo.tape # produces demo-silent.mp4 ffmpeg -y -i demo-silent.mp4 -i speech.mp3 -i music.mp3 \ -filter_complex "[1:a]adelay=16000|16000[narr]; \ [2:a]volume=0.18,atrim=end=75[bg]; \ [narr][bg]amix=inputs=2:duration=longest[a]" \ -map 0:v -map "[a]" -c:v copy -c:a aac demo.mp4 ``` `adelay=16000|16000` = ms, `left|right` (must be stereo pair). Tune to tape timestamp where narration should hit. Ducking: `0.12–0.20` under narration, `0.25–0.35` music-only. **Never pass `-shortest`** — truncates video to shortest audio. ## VHS tape conventions - **`Set Shell "bash"` is mandatory.** zsh + long `Type` lines triggers a VHS command-concatenation bug: two consecutive long commands get glued onto a single prompt line and the `Enter` between them is lost. Root cause is zsh's ZLE + VHS's wall-clock-timed CDP keystroke injection (no prompt-wait primitive). Bash's simpler line editor has no such race. Not fixable with `Wait+Line` (regex fails on colored prompts), `precmd` hooks ([VHS #691](https://github.com/charmbracelet/vhs/issues/691)), longer `Sleep`s, or `Ctrl+L` substitution. Just use bash. - 960×720 or 960×640, Menlo 16pt — reads on mobile, fits `polli gen text --model X "..."`. - Absolute path in `Hide`-block `cd`; relative path in `Output` (parser splits on `/`). - Always `export FORCE_COLOR=1` in `Hide` — VHS pty fails `isTTY`, chalk strips colors otherwise. - Scene titles via ANSI from shell (no VHS primitive). `\033[1;38;5;141m` = polli purple. - `announce()` pattern: one function that prints the bold title AND fires backgrounded TTS. Every later scene is a one-liner. See `example/demo.tape`. **Canonical bash `Hide` block** (copy verbatim — fixes job notices, heredoc prompts, prompt trailing-line): ``` Set Shell "bash" Hide Type "cd /absolute/path/to/working/dir" Enter Type "export FORCE_COLOR=1" Enter Type "export PS1='» '" Enter Type "export PS2='» '" Enter Type "PROMPT_COMMAND='echo'" Enter Type "set +m" Enter Type "clear" Enter Show ``` - `PS2='» '` — hides heredoc/continuation `>` prompts that leak on wrapped `Type` lines. - `PROMPT_COMMAND='echo'` — trailing blank line between scenes so output doesn't crash into the next prompt. - `set +m` — disables job-control, suppresses `[1] 12345` notices from `&` backgrounding. - Wrap backgrounded commands in a subshell anyway: `( cmd & )` never prints a PID even in interactive shells. ## The `announce` function One-liner per scene: prints a bold purple title AND fires backgrounded TTS. The `sed` strip removes ElevenLabs emotion cues (`[whispers]`, `[excited]`, …) from the *printed* title while keeping them in the *spoken* audio. ```bash announce() { printf '\n\033[1;38;5;141m»» %s\033[0m\n\n' "$(sed -E 's/\[[^]]*\] *//g' <<< "$1")" ( polli gen audio --play --output /tmp/narr-$$-$RANDOM.mp3 "$1" >/dev/null 2>&1 & ) } ``` Usage: ``` Type `announce "[excited] first — we need some backing music"` Enter ``` **ElevenLabs emotion cues** (must use ElevenLabs-backed voice, e.g. default `sage`): `[whispers]`, `[excited]`, `[confident]`, `[curious]`, `[sighs]`, `[laughs]`. Place inline — the TTS engine interprets them; the sed strip keeps the on-screen text clean. **Why subshell `( cmd & )`, not bare `&` or `disown`:** - Bare `&` in a non-interactive bash (VHS) still prints `[1] 12345` — even with `set +m`, occasional leakage. - `disown` after `&` still shows the job-start notice. - `( cmd & )` spawns the background job inside a subshell that exits immediately, so no job record is ever attached to the parent shell — nothing to print. ## Gotchas | Symptom | Cause | Fix | |---|---|---| | Two commands merge on one line, `Enter` eaten | zsh + long `Type` (ZLE race) | `Set Shell "bash"` | | `heredoc>` or `>` prompts visible | Wrapped line, zsh/bash PROMPT2 | `export PS2='» '` | | `[1] 12345` leaks on screen | Bash job-control notice | `set +m` + `( cmd & )` subshell | | Scene collides with previous output | No trailing newline | `PROMPT_COMMAND='echo'` | | Nested `temp/vhs-demo/temp/vhs-demo/` | Absolute path in `Output` | Use relative; `cd` in `Hide` | | Typing takes forever | Default TypingSpeed 50ms | Set `12–20ms` | | Colors stripped | VHS pty, no FORCE_COLOR | `export FORCE_COLOR=1` | | Font renders wrong | JetBrains Mono not on macOS | Use `Menlo` | | FontSize >18 wraps prompts | 960 width | Stick with 16 | | BG output corrupts next command | `&` with stdout live | `cmd >/dev/null 2>&1 &` | | `↑` / multibyte char eats adjacent chars | VHS `Type` + Unicode edge case | Drop the arrow; use plain ASCII | | Choppy/dropped audio in long capture | ffmpeg avfoundation | Use `sox -t coreaudio "BlackHole 2ch"` | | Video only 2s long | `-shortest` on ffmpeg | Drop `-shortest` | | No sound in final mp4 | Missing audio map | `-map 0:v -map "[a]"` | | BlackHole not found by ffmpeg | Wrong device index | Use sox + device name instead | | Disk fills during capture | Uncompressed wav, forgot to trap | `trap "kill $FFPID" EXIT` | | Final MP4 narration lands too late | ffmpeg startup + API pre-roll | In mux: `ffmpeg -ss 5 -i captured.wav …` (tune 3–6s) | | Music cuts abruptly at end | No fade filter | Add `-af "afade=t=out:st=$((VID_DUR-3)):d=3"` | | `afade` filter errors `No option name near '3'` on `st=66,36` | Locale uses comma for decimals | Wrap the `awk` computing `FADE_START` with `LC_ALL=C` | | Punctuation/wording cached across renders | Pollinations text cache keys on exact string | Change a character (swap `·` ↔ `;` ↔ `,`, add `!`) each re-render | ## Voice selection Default: `sage`. Others: `fin`, `callum`, `onyx`, `rachel`. Preview: ```bash polli gen audio --voice --output sample.mp3 "test line" && afplay sample.mp3 ``` Full list: `polli models --type audio --json | jq '.[].voices'`. ## Music (elevenmusic) Deterministic cache — same prompt+duration = same bytes. Always `--instrumental`. Match duration to `ffprobe demo-silent.mp4`. Example prompt: `"lofi instrumental hip hop, warm analog, jazzy bass"`. ## Demo design principles - Open silent with `polli --help` — orients without narration. - One audio moment per scene, not many. - Hold scenes: help ~4s, streaming text 10–20s, ASCII outro 15–17s. - Payoff produces something reusable (the post, an image, a doc). - Streaming > buffered — lean into polli's default streaming reveal (drop `--no-stream` when used in a recorded tape so the audience sees generation happening live). - End with a punchy ASCII wordmark outro (see "Streaming outros" section). - 960×720 or 960×640 beats 1920×1080 on mobile feeds. ## Brand voice for generated content See `operations/social/prompts/posts/linkedin/tone.md`, `operations/social/prompts/brand/about.md`. - Dry, information-dense, anti-corporate. - No "excited to announce", "game-changing", hashtag spam. - Plain text for LinkedIn (markdown renders raw). ## Generating the announcement post (lessons) **Model selection (ranked for this task):** - `claude-fast` — **pick this for live demos.** Consistent ~4s latency, never leaks scaffolding in this prompt shape. Voice slightly flatter than glm but reliability wins when a `Sleep 30000ms` hold has to cover the call. - `glm` — best voice quality when it works. But latency is wildly variable (12s first call → 31s next → sometimes >60s); not safe behind a fixed `Sleep` budget. Use for offline one-shots, not live-tape renders. - `kimi` — strong rhythm, hacker-genz feel. Solid backup. - `openai` — leaks prompt scaffolding verbatim (e.g. `sign-off:`, `110w`, `your own line-1 hook`), overshoots word count. Avoid. - `gemini-search` / `perplexity-fast` — web-search adds citation markers `[1][2]`; hallucinate features, inflate corpo voice. Avoid for this. **Call flags:** - Use `--no-stream`. Streaming + `> file` hangs on long prompts; `--no-stream` returns in 3–5s. - Never wrap polli in `timeout N` — it breaks the stdout flush and always kills the call. **Input context (what to pipe in):** - `polli --help` only — leanest, forces the model to describe the command surface without repackaging README bullet points. - Feeding the README causes models to repeat README-specific phrases ("humans, AI agents, and everything in between") and hallucinate flags (`--budget` etc). - `--help` limitation: doesn't expose npm package name → model guesses `polli-cli`. Patch install line manually. **Prompt shape (compressed, declarative, no imperative wordiness):** - State the task (`announce polli on LinkedIn`), not a procedure. - Voice in 1 line with `·` separators. Let the model interpret rather than listing banned phrases. - Don't put counted claims in the prompt (`7-verb CLI`) — every model echoes them. Just list the verbs. - Don't say "scroll-stopper" or "your own line-1 hook" — models paste those labels literally. - Keep `no md · no 🚀 · no corpo` as the only negative constraints. More bans → defensive, boring output. - Ask for `sign-off` not `CTA`. **Final prompt used (LinkedIn launch post):** ``` ↑ polli --help for polli CLI. task: announce polli on LinkedIn. reformat this into a post. voice: hacker-genz .nfo irc-drop · dry · emojis 🐝💾⚡🔮🧪👁️🌀 scattered 100-130w · sharp sign-off · no md · no 🚀 · no corpo ``` Pipe in via: `polli --help | polli gen text --model claude-fast --no-stream ""`. **For live tape renders** (where a `Sleep Xms` must cover the call): use `claude-fast` — ~4s predictable. For offline post generation without timing constraints, `glm` gives slightly better voice but `polli --help | polli gen text --model glm --no-stream …` may take 10–60s. **Parallel batching gotcha:** 3+ concurrent calls to the same model hit Cloudflare 520. Run sequentially for reliable batches. ## Streaming outros (ASCII demoscene) `polli gen text` streams by default — no `animate` helper or frame splitter needed. Pipe straight to the terminal and the characters appear as generated: ``` Type "clear" Enter Sleep 400ms Type `polli gen text --model claude "ascii frame 50×20; spell POLLI big block letters centered. organic evolving mycelium decor — demoscene."` Enter Sleep 17000ms # hold long enough for full generation + read time ``` **Prompt engineering notes for ASCII wordmarks:** - Small prompts work best. Every added constraint (CA rules, 6 frames, palette, emoji) pushes the model away from the actual word. Keep it one sentence. - Strict letter constraints ("P O L L I — two L's") drift anyway with claude-fast. Use `claude` (non-fast) for final renders; `claude-fast` often outputs "POLL" / "PELL" / random block shapes. - Canvas 50×20 is the sweet spot for 960-wide terminals at FontSize 16. 60×40 overflows vertically. - No color/palette mentions — ASCII is monochrome. Confuses the model. - One keyword for "evolving" (e.g. `mycelium`, `cellular automaton`) > a full description. But `cellular automaton` sometimes confuses the model into abandoning the word entirely — `mycelium` is more reliable. ## Layered emotion cues in announce() ElevenLabs handles multiple `[cue]` markers in one line, changing tone mid-sentence. Useful for punchy payoff lines: ``` announce "[playful] confused? just ask your agent to [whispers] install me... [curious] install me? [excited] install me!!" ``` The `sed` strip removes all cues from the printed text, so the screen just shows `»» confused? just ask your agent to install me... install me? install me!!` while the audio layers whisper → curious → excited across three repetitions. The `...` and `?` / `!!` punctuation gives ElevenLabs natural beats to change register. ## Files - `example/demo.tape` — canonical working tape (polli launch demo, 5 scenes incl. streaming ASCII outro, bash, `claude`) - `example/render.sh` — canonical pipeline (sox BlackHole capture + mux with 5s audio pre-roll + 3s fade-out) - `example/.gitignore` — ignores `*.mp4`, `*.wav`, `music.mp3`, `speech.mp3`, `.DS_Store`, timestamped archives Render artifacts (regenerable, gitignored): `demo.mp4`, `demo-silent.mp4`, `captured.wav`, `music.mp3`, `speech.mp3`. Previous renders are auto-archived to `-vHHMM.` by `render.sh`. --- Source attribution: pollinations Original project: https://github.com/pollinations/pollinations/blob/60d4074d1047a887b9ed7ed01f4bd75cb6122834/.claude/skills/polli-video/SKILL.md License: MIT License information: https://opensource.org/license/mit Original upstream instructions; downloaded from Dave AI. ## Upstream license notice MIT License Copyright (c) 2026 pollinations.ai Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Dave AI resource metadata Creator / publisher: pollinations Original project: https://github.com/pollinations/pollinations/blob/60d4074d1047a887b9ed7ed01f4bd75cb6122834/.claude/skills/polli-video/SKILL.md Attribution basis: Source repository record Fields of work: Content & Media, Marketing Roles: Content Marketer, Social Media Manager, Video Producer Specialties: Specialty not specified Tools: Blackhole, Ffmpeg, Sox Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: 30ee1ce4ac919c4856c425be29a397796828b33d6e7090558e7d1320caf90c94