55 lines
1.9 KiB
TypeScript
55 lines
1.9 KiB
TypeScript
import { execSync } from 'node:child_process';
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import { renameSync, statSync } from 'node:fs';
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import { LEAD_IN_S } from './config.js';
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import { viewportFor, type Storyboard } from './script.js';
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export function trimRecording(
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rawPath: string,
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trimmedPath: string,
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storyboard: Storyboard,
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times: { recordStartMs: number; sceneStartMs: number; sceneEndMs: number }
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) {
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const sceneSpan = (times.sceneEndMs - times.sceneStartMs) / 1000;
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const trimStart = Math.max(
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0,
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(times.sceneStartMs - times.recordStartMs) / 1000 - LEAD_IN_S
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);
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const trimEnd = (times.sceneEndMs - times.recordStartMs) / 1000;
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const wallDuration = trimEnd - trimStart;
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const finalDuration = wallDuration;
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const { outputFps, webmBitrate, maxDurationS } = storyboard.video;
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const viewport = viewportFor(storyboard.video);
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if (finalDuration > maxDurationS) {
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console.log(
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`[${storyboard.name}] Scene output duration is ${finalDuration.toFixed(2)}s ` +
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`(guard ${maxDurationS.toFixed(2)}s); keeping the full take.`
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);
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}
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const filter =
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`trim=start=${trimStart.toFixed(3)}:duration=${wallDuration.toFixed(3)},` +
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`setpts=PTS-STARTPTS,fps=${outputFps},` +
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`trim=duration=${finalDuration.toFixed(3)},setpts=PTS-STARTPTS`;
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// Keep trimming inside the filter graph: it is frame-accurate for WebM
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// without the keyframe leakage of input seeking.
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execSync(
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`ffmpeg -y -i "${rawPath}" -vf "${filter}" ` +
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`-fps_mode cfr -r ${outputFps} -c:v libvpx -b:v ${webmBitrate} -deadline good -cpu-used 5 ` +
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`"${trimmedPath}"`,
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{ stdio: 'inherit' }
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);
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try {
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statSync(rawPath);
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renameSync(rawPath, rawPath + '.untrimmed');
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} catch {
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/* ignore */
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}
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console.log(
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`[${storyboard.name}] Wrote ${trimmedPath} (${finalDuration.toFixed(2)}s, scene=${sceneSpan.toFixed(2)}s, capture=${viewport.width}x${viewport.height})`
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);
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}
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