Merge commit 'refs/pull/8619/head' of https://github.com/nexu-io/open-design into feat/motion-design-skill

apps/daemon/src/media/hyperframes-audio.ts

@@ -58,10 +58,17 @@ export function hyperFramesAudioEncodingArgs(tracks: HyperFramesAudioTrack[], du
   // Filters stay within FFmpeg 4.1 (the bundled Linux build): every track is
   // made stereo so one per-channel delay covers it (no `adelay all=1`), and
   // amix's input averaging is undone with a gain (no `amix normalize=0`).
+  // Each track fades out where it stops sounding: its own authored end or the
+  // film's end, whichever comes first. A track that already ends quietly is
+  // unchanged; one cut short (a remake made shorter than its music) no longer
+  // stops on a click.
   const filters = tracks.map((track, index) => {
     const delayMs = Math.round(track.start * 1000);
+    const audible = Math.min(track.duration, duration - track.start);
+    const fade = audible > 0 ? Math.min(0.6, audible / 4) : 0;
+    const fadeOut = fade > 0 ? `afade=t=out:st=${round(audible - fade)}:d=${round(fade)},` : '';
     return `[${index + 1}:a]atrim=duration=${track.duration},asetpts=PTS-STARTPTS,`
-      + `aformat=channel_layouts=stereo,volume=${track.volume},adelay=${delayMs}|${delayMs}[a${index}]`;
+      + `aformat=channel_layouts=stereo,${fadeOut}volume=${track.volume},adelay=${delayMs}|${delayMs}[a${index}]`;
   });
   const mixed = tracks.length === 1
     ? '[a0]'
@@ -70,3 +77,7 @@ export function hyperFramesAudioEncodingArgs(tracks: HyperFramesAudioTrack[], du
   filters.push(`${mixed}apad,atrim=duration=${duration}[audio]`);
   return ['-filter_complex', filters.join(';'), '-map', '0:v', '-map', '[audio]', '-c:a', 'aac', '-b:a', '192k'];
 }
+
+function round(seconds: number): number {
+  return Math.round(seconds * 1000) / 1000;
+}

apps/daemon/tests/media/hyperframes-audio.test.ts

@@ -2,7 +2,7 @@ import { mkdtemp, writeFile, rm, symlink } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
 import path from 'node:path';
 import { afterEach, beforeEach, expect, it } from 'vitest';
-import { prepareHyperFramesAudio } from '../../src/media/hyperframes-audio.js';
+import { hyperFramesAudioEncodingArgs, prepareHyperFramesAudio } from '../../src/media/hyperframes-audio.js';
 
 let root: string;
 beforeEach(async () => {
@@ -33,3 +33,17 @@ it.each(['data-start="intro + 2"', 'data-volume="2"', 'loop', 'data-media-start=
     await expect(prepareHyperFramesAudio(`<audio src="music.mp3" data-duration="3" ${attribute}></audio>`, root)).rejects.toThrow();
   },
 );
+
+it('fades each track out where it stops sounding, including a cut at the film end', () => {
+  const track = { file: 'music.mp3', format: 'mp3', volume: 1 };
+  const graph = (tracks: Parameters<typeof hyperFramesAudioEncodingArgs>[0], duration: number) =>
+    hyperFramesAudioEncodingArgs(tracks, duration)[1];
+  // Music authored for 15 s in a film cut to 10 s fades over the film's last 0.6 s.
+  expect(graph([{ ...track, start: 0, duration: 15 }], 10)).toContain('afade=t=out:st=9.4:d=0.6');
+  // A track that ends inside the film fades at its own end, offset by its start.
+  expect(graph([{ ...track, start: 2, duration: 4 }], 10)).toContain('afade=t=out:st=3.4:d=0.6');
+  // Short tracks keep most of their sound: the fade is at most a quarter of what plays.
+  expect(graph([{ ...track, start: 0, duration: 1 }], 10)).toContain('afade=t=out:st=0.75:d=0.25');
+  // A track that starts after the film ends contributes no fade.
+  expect(graph([{ ...track, start: 12, duration: 3 }], 10)).not.toContain('afade');
+});

docs/motion-template-sources.md

@@ -94,4 +94,8 @@ Every template carries an original procedural soundtrack in
 used and no audio-generation model was involved. HTML preview sound starts with
 the film; when the browser blocks autoplay, the first click or key press turns
 it on, and Sound off mutes it. Sound follows the master timeline. The desktop
-export path mixes the timed local audio into the MP4 with FFmpeg.
+export path mixes the timed local audio into the MP4 with FFmpeg and fades each
+track out where it stops, so a remake made shorter than its music ends cleanly.
+Make-same keeps the template's soundtrack by default, because the music is part
+of the look being remade; a brief that asks for no music or different music
+takes precedence.

plugins/_official/examples/motion-energy-reel/SKILL.md

@@ -65,7 +65,12 @@ frame expensive and slow the MP4 export.
 ## Sound
 Carry `assets/soundtrack.mp3` with the reference files. It is an original
 procedural soundtrack authored for this example and timed to its beats; no
-audio from the source video is used. Keep the `<audio>` element inside the
+audio from the source video is used. The soundtrack is part of the look the
+user is remaking: keep it by default, and follow the brief when it asks for no
+music or different music. The music lands on this film's beats, so keep the
+film close to this length; when the brief changes the length, keep
+`data-duration` within the film, and the export fades the track out where it
+stops. Keep the `<audio>` element inside the
 composition root, with numeric `data-start`, `data-duration` and `data-volume`;
 the desktop exporter mixes that local file into the MP4. Preview sound
 starts with the film; when the browser blocks autoplay, the first click or key

plugins/_official/examples/motion-future/SKILL.md

@@ -68,7 +68,12 @@ frame expensive and slow the MP4 export.
 ## Sound
 Carry `assets/soundtrack.mp3` with the reference files. It is an original
 procedural soundtrack authored for this example and timed to its beats; no
-audio from the source video is used. Keep the `<audio>` element inside the
+audio from the source video is used. The soundtrack is part of the look the
+user is remaking: keep it by default, and follow the brief when it asks for no
+music or different music. The music lands on this film's beats, so keep the
+film close to this length; when the brief changes the length, keep
+`data-duration` within the film, and the export fades the track out where it
+stops. Keep the `<audio>` element inside the
 composition root, with numeric `data-start`, `data-duration` and `data-volume`;
 the desktop exporter mixes that local file into the MP4. Preview sound
 starts with the film; when the browser blocks autoplay, the first click or key

plugins/_official/examples/motion-pixel-wizard/SKILL.md

@@ -59,7 +59,12 @@ frame expensive and slow the MP4 export.
 ## Sound
 Carry `assets/soundtrack.mp3` with the reference files. It is an original
 procedural soundtrack authored for this example and timed to its beats; no
-audio from the source video is used. Keep the `<audio>` element inside the
+audio from the source video is used. The soundtrack is part of the look the
+user is remaking: keep it by default, and follow the brief when it asks for no
+music or different music. The music lands on this film's beats, so keep the
+film close to this length; when the brief changes the length, keep
+`data-duration` within the film, and the export fades the track out where it
+stops. Keep the `<audio>` element inside the
 composition root, with numeric `data-start`, `data-duration` and `data-volume`;
 the desktop exporter mixes that local file into the MP4. Preview sound
 starts with the film; when the browser blocks autoplay, the first click or key

plugins/_official/examples/motion-showreel/SKILL.md

@@ -66,7 +66,12 @@ frame expensive and slow the MP4 export.
 ## Sound
 Carry `assets/soundtrack.mp3` with the reference files. It is an original
 procedural soundtrack authored for this example and timed to its beats; no
-audio from the source video is used. Keep the `<audio>` element inside the
+audio from the source video is used. The soundtrack is part of the look the
+user is remaking: keep it by default, and follow the brief when it asks for no
+music or different music. The music lands on this film's beats, so keep the
+film close to this length; when the brief changes the length, keep
+`data-duration` within the film, and the export fades the track out where it
+stops. Keep the `<audio>` element inside the
 composition root, with numeric `data-start`, `data-duration` and `data-volume`;
 the desktop exporter mixes that local file into the MP4. Preview sound
 starts with the film; when the browser blocks autoplay, the first click or key

plugins/_official/examples/motion-ui-morph/SKILL.md

@@ -60,7 +60,12 @@ frame expensive and slow the MP4 export.
 ## Sound
 Carry `assets/soundtrack.mp3` with the reference files. It is an original
 procedural soundtrack authored for this example and timed to its beats; no
-audio from the source video is used. Keep the `<audio>` element inside the
+audio from the source video is used. The soundtrack is part of the look the
+user is remaking: keep it by default, and follow the brief when it asks for no
+music or different music. The music lands on this film's beats, so keep the
+film close to this length; when the brief changes the length, keep
+`data-duration` within the film, and the export fades the track out where it
+stops. Keep the `<audio>` element inside the
 composition root, with numeric `data-start`, `data-duration` and `data-volume`;
 the desktop exporter mixes that local file into the MP4. Preview sound
 starts with the film; when the browser blocks autoplay, the first click or key