One film, four doors

Each day ended as several files from one master: a long YouTube episode, a vertical trailer for Reels, a file for the family chat, and the whole day joined as-is for a private archive. Everything went up from the Mac; my phone had no free space, which is how the Instagram upload ended up on the API too.

Codecs, measured

• The master is HEVC on the Mac’s hardware encoder: a 36-minute film is 1.6 GB, against 3.2 GB for x264 at crf 18.

  ffmpeg -i film.mov -c:v hevc_videotoolbox -q:v 62 -tag:v hvc1 -c:a aac -b:a 256k -movflags +faststart film.mp4
  

• Upload to YouTube in 1440p, even from 1080p footage. YouTube serves a 1080p upload at about 3.5 Mbps AVC, while the 1440p tier gets VP9 or AV1 and more bits. The upscale adds no detail; it buys the viewer a better transcode.
• Telegram stays h264. Some Android phones have no HEVC decoder, and a file there downloads whole. 1080p at crf 21 fits about 40 minutes into the 2 GB limit.
• Swapping audio never re-encodes the picture: -map 0:v -c:v copy.

Vertical

Phone clips shot vertical go to Reels untouched. For a horizontal day there are three options: the whole frame over a blurred copy, a fixed centre crop, or a 9:16 window that follows faces. On a 20-second clip with the face off-centre, following kept 31 faces of 37, the centre crop 5. The window moves slowly and stays put when nobody is in frame; a jumpy window is more visible than an imperfect composition. Subtitles are burned in here and only here: the feed plays muted.

What the machine does not pick

• The hook. The first ten seconds of a long film are a mini trailer. The automatic pick goes for sharp and colourful, which is a clean empty path through trees, exactly what people scroll past. Fire, water, neon, night, something moving at the camera, a face with an expression: chosen by eye from a contact sheet of candidates.
• The cover. Best frame, a big title, and the city and region as badges on the image: on YouTube that is search.

Small things that saved confusion

• The real shooting date in every description. A week in, I could not tell which day was which, and neither could viewers.
• A short Life2Film card at the end of every file, appended without re-encoding the film.
• Upload private, watch on the phone, then publish. Related videos are linked by hand in Studio: the API accepts that field and does not save it.
• Archive after the films are out, never during. Sources and outputs of finished days moved to iCloud (4 TB free there, the laptop disk was running out). The analysis files travel with them, so a month-long film later needs no re-analysis.

How the cut itself was made: creative-video-agent-cut. Sound: creative-video-sound. Every recipe here was re-run before publishing and lives in the solo:video-edit skill (solo-factory, references/delivery.md).

A UGC talk at LA Tech Week put numbers on the first frame: 0.1 seconds for Gen Z, 0.5 for millennials, 1 to 2 for boomers, by the speaker’s own count (la-tech-week-video-agents-live-worlds-2026).