| 40 | } |
| 41 | |
| 42 | function ffprobe(path: string): Promise<Probe> { |
| 43 | return new Promise((resolve, reject) => { |
| 44 | const p = spawn("ffprobe", [ |
| 45 | "-v", "error", "-select_streams", "v:0", |
| 46 | "-show_entries", "stream=width,height,r_frame_rate,nb_read_frames:format=duration", |
| 47 | "-count_frames", "-of", "json", path, |
| 48 | ]); |
| 49 | let out = ""; |
| 50 | p.stdout.on("data", (c) => (out += c)); |
| 51 | p.on("error", reject); |
| 52 | p.on("close", () => { |
| 53 | try { |
| 54 | const j = JSON.parse(out); |
| 55 | const s = j.streams[0]; |
| 56 | const [n, d] = String(s.r_frame_rate).split("/").map(Number); |
| 57 | resolve({ |
| 58 | width: s.width, |
| 59 | height: s.height, |
| 60 | fps: d ? n / d : 30, |
| 61 | frames: Number(s.nb_read_frames) || 0, |
| 62 | duration: Number(j.format?.duration) || 0, |
| 63 | }); |
| 64 | } catch (e) { |
| 65 | reject(e); |
| 66 | } |
| 67 | }); |
| 68 | }); |
| 69 | } |
| 70 | |
| 71 | /** Track the plane (frame fractions) across the clip via motion compensation. */ |
| 72 | function detectTrack(path: string): Promise<({ cx: number; cy: number } | null)[]> { |