refactor(auto-thumbnail): [PKG-AUTO-THUMB-03] own hidden renderers and reject stale seeks

docs/compiled/artplayer-plugin-auto-thumbnail.js

@@ -4,4 +4,4 @@
  * (c) 2017-2026 Harvey Zhao
  * Released under the MIT License.
  */
-!function(e,t){"object"===typeof exports&&"undefined"!==typeof module?module.exports=t():"function"==typeof define&&define.amd?(e.artplayerPluginAutoThumbnail=t(),define(function(){return e.artplayerPluginAutoThumbnail})):(e="undefined"!==typeof globalThis?globalThis:e||self).artplayerPluginAutoThumbnail=t()}(this,function(){"use strict";function e(e,t){const i=document.createElement("video");e.own(()=>i.load()),e.own(()=>i.removeAttribute("src")),e.own(()=>i.pause());for(const n of["onloadedmetadata","onseeked","onerror"])e.own(()=>{i[n]=null});e.active()&&(i.crossOrigin="anonymous",i.onerror=e.guard(()=>{throw i.error||new Error("Auto-thumbnail media failed to load")}),i.onloadedmetadata=e.guard(()=>{i.onloadedmetadata=null;const n=i.duration,{height:r,canvasWidth:o,canvasHeight:a}=function(e,t){if(!Number.isFinite(t.duration)||t.duration<=0||!Number.isFinite(t.videoWidth)||t.videoWidth<=0||!Number.isFinite(t.videoHeight)||t.videoHeight<=0)throw new TypeError("Auto-thumbnail requires finite media duration and dimensions");const i=Math.floor(e.width*t.videoHeight/t.videoWidth),n=Math.trunc(10*e.width),r=Math.trunc(i*Math.ceil(e.number/10));if(![i,n,r].every(e=>Number.isSafeInteger(e)&&e>0&&e<=4294967295))throw new RangeError("Auto-thumbnail canvas dimensions are invalid");return{height:i,canvasWidth:n,canvasHeight:r}}(t,{duration:n,videoHeight:i.videoHeight,videoWidth:i.videoWidth});if(!e.active())return;const u=document.createElement("canvas");if(!e.active())return;u.width=o,u.height=a;const d=u.getContext("2d");if(!d)throw new Error("Auto-thumbnail canvas context is unavailable");if(!e.active())return;let c=0;const s=e.guard(()=>{c>=t.number?e.dispose():(i.onseeked=e.guard(()=>{if(i.onseeked=null,d.drawImage(i,c%10*t.width,Math.floor(c/10)*r,t.width,r),!e.active())return;let n=!1;u.toBlob(e.guard(i=>{n||(n=!0,e.publish(i,{height:r,column:10,number:t.number,width:t.width,scale:t.scale}),e.active()&&(c+=1,s()))}),"image/jpeg")}),e.active()&&(i.currentTime=n*c/t.number))});s()}),e.active()&&(i.src=t.url))}function t(e){let t,i=!1;for(const r of e)try{r()}catch(n){i||(i=!0,t=n)}return{failed:i,failure:t}}return function(i){return async n=>{const r=e=>console.warn("ArtPlayer auto-thumbnail failed:",e),o=function(e,i){let n,r,o=!1;const a=new Set;function u(e){a.delete(e)&&URL.revokeObjectURL(e)}function d(){const e=n;n=void 0,e?.dispose()}return{start:function(){if(o)return;const d=n,c=[];let s=!1;const l={active:()=>!o&&!s&&n===l,own(e){if(s){const n=t([e]);n.failed&&i(n.failure)}else c.push(e)},dispose(){if(s)return;s=!0,n===l&&(n=void 0);const e=t(c.splice(0).reverse());e.failed&&i(e.failure)},fail(e){l.active()&&(l.dispose(),i(e))},guard:e=>(...t)=>{if(l.active())try{return e(...t)}catch(i){l.fail(i)}},publish(n,o){if(!l.active())return;if(!n)throw new Error("Auto-thumbnail encoding returned no Blob");const d=URL.createObjectURL(n);if(a.add(d),!l.active())return void u(d);const c=r;r=d;try{e({url:d,...o})}catch(s){r===d&&(r=a.has(c)?c:void 0);const e=t([()=>u(d)]);throw e.failed&&i(e.failure),s}u(c)}};return n=l,d?.dispose(),l},cancel:d,destroy:function(){if(o)return;o=!0;const e=t([d,...[...a].map(e=>()=>u(e))]);r=void 0,e.failed&&i(e.failure)},get closed(){return o}}}(e=>{n.thumbnails=e},r),a=[],u=()=>{const t=o.start();t&&t.guard(()=>{const r=function(e,t){const i={url:e.url||t(),width:e.width||160,number:e.number||100,scale:e.scale||1};if(!Number.isFinite(Number(i.width))||i.width<=0||!Number.isFinite(Number(i.number))||i.number<=0)throw new TypeError("Auto-thumbnail width and number must be finite positive numbers");return i}(i,()=>n.option.url);t.active()&&e(t,r)})()},d=()=>{const e=a.splice(0),i=t([o.destroy,...e]);i.failed&&r(i.failure)};try{for(const[e,t]of[["destroy",d],["restart",o.cancel],["video:loadedmetadata",u]]){if(o.closed)break;a.push(()=>n.off(e,t)),n.on(e,t),o.closed&&n.off(e,t)}}catch(c){throw d(),c}return{name:"artplayerPluginAutoThumbnail"}}}});
+!function(e,t){"object"===typeof exports&&"undefined"!==typeof module?module.exports=t():"function"==typeof define&&define.amd?(e.artplayerPluginAutoThumbnail=t(),define(function(){return e.artplayerPluginAutoThumbnail})):(e="undefined"!==typeof globalThis?globalThis:e||self).artplayerPluginAutoThumbnail=t()}(this,function(){"use strict";function e(e,t){const i=function(e){const t=document.createElement("video");e.own(()=>t.remove()),e.own(()=>t.load()),e.own(()=>t.removeAttribute("src")),e.own(()=>t.pause());for(const i of["onloadedmetadata","onseeked","onerror"])e.own(()=>{t[i]=null});return e.active()?(t.crossOrigin="anonymous",t.muted=!0,t.playsInline=!0,t.tabIndex=-1,t.setAttribute("aria-hidden","true"),t.style.cssText="position:fixed;left:0;top:0;visibility:hidden;pointer-events:none;display:block;width:auto;height:auto;max-width:none;max-height:none",document.documentElement.appendChild(t),e.active()||t.remove(),t):t}(e);e.active()&&(i.onerror=e.guard(()=>{throw i.error||new Error("Auto-thumbnail media failed to load")}),i.onloadedmetadata=e.guard(()=>{i.onloadedmetadata=null;const n=i.duration,r=i.videoHeight,o=i.videoWidth,{height:a,canvasWidth:u,canvasHeight:d}=function(e,t){if(!Number.isFinite(t.duration)||t.duration<=0||!Number.isFinite(t.videoWidth)||t.videoWidth<=0||!Number.isFinite(t.videoHeight)||t.videoHeight<=0)throw new TypeError("Auto-thumbnail requires finite media duration and dimensions");const i=Math.floor(e.width*t.videoHeight/t.videoWidth),n=Math.trunc(10*e.width),r=Math.trunc(i*Math.ceil(e.number/10));if(![i,n,r].every(e=>Number.isSafeInteger(e)&&e>0&&e<=4294967295))throw new RangeError("Auto-thumbnail canvas dimensions are invalid");return{height:i,canvasWidth:n,canvasHeight:r}}(t,{duration:n,videoHeight:r,videoWidth:o});if(!e.active())return;i.width=o,i.height=r,i.style.width=`${o}px`,i.style.height=`${r}px`;const s=document.createElement("canvas");if(!e.active())return;s.width=u,s.height=d;const c=s.getContext("2d");if(!c)throw new Error("Auto-thumbnail canvas context is unavailable");if(!e.active())return;let l=0;const h=e.guard(()=>{if(l>=t.number)return void e.dispose();const r=n*l/t.number;let o=0;i.onseeked=e.guard(()=>{if(i.seeking)return;const n=i.currentTime;if(!e.active())return;if(!Number.isFinite(n)||Math.abs(n-r)>.05){if(++o>3)throw new Error("Auto-thumbnail seek did not reach the requested time");return void(i.currentTime=r)}if(i.onseeked=null,c.drawImage(i,l%10*t.width,Math.floor(l/10)*a,t.width,a),!e.active())return;let u=!1;s.toBlob(e.guard(i=>{u||(u=!0,e.publish(i,{height:a,column:10,number:t.number,width:t.width,scale:t.scale}),e.active()&&(l+=1,h()))}),"image/jpeg")}),e.active()&&(i.currentTime=r)});h()}),e.active()&&(i.src=t.url))}function t(e){let t,i=!1;for(const r of e)try{r()}catch(n){i||(i=!0,t=n)}return{failed:i,failure:t}}return function(i){return async n=>{const r=e=>console.warn("ArtPlayer auto-thumbnail failed:",e),o=function(e,i){let n,r,o=!1;const a=new Set;function u(e){a.delete(e)&&URL.revokeObjectURL(e)}function d(){const e=n;n=void 0,e?.dispose()}return{start:function(){if(o)return;const d=n,s=[];let c=!1;const l={active:()=>!o&&!c&&n===l,own(e){if(c){const n=t([e]);n.failed&&i(n.failure)}else s.push(e)},dispose(){if(c)return;c=!0,n===l&&(n=void 0);const e=t(s.splice(0).reverse());e.failed&&i(e.failure)},fail(e){l.active()&&(l.dispose(),i(e))},guard:e=>(...t)=>{if(l.active())try{return e(...t)}catch(i){l.fail(i)}},publish(n,o){if(!l.active())return;if(!n)throw new Error("Auto-thumbnail encoding returned no Blob");const d=URL.createObjectURL(n);if(a.add(d),!l.active())return void u(d);const s=r;r=d;try{e({url:d,...o})}catch(c){r===d&&(r=a.has(s)?s:void 0);const e=t([()=>u(d)]);throw e.failed&&i(e.failure),c}u(s)}};return n=l,d?.dispose(),l},cancel:d,destroy:function(){if(o)return;o=!0;const e=t([d,...[...a].map(e=>()=>u(e))]);r=void 0,e.failed&&i(e.failure)},get closed(){return o}}}(e=>{n.thumbnails=e},r),a=[],u=()=>{const t=o.start();t&&t.guard(()=>{const r=function(e,t){const i={url:e.url||t(),width:e.width||160,number:e.number||100,scale:e.scale||1};if(!Number.isFinite(Number(i.width))||i.width<=0||!Number.isFinite(Number(i.number))||i.number<=0)throw new TypeError("Auto-thumbnail width and number must be finite positive numbers");return i}(i,()=>n.option.url);t.active()&&e(t,r)})()},d=()=>{const e=a.splice(0),i=t([o.destroy,...e]);i.failed&&r(i.failure)};try{for(const[e,t]of[["destroy",d],["restart",o.cancel],["video:loadedmetadata",u]]){if(o.closed)break;a.push(()=>n.off(e,t)),n.on(e,t),o.closed&&n.off(e,t)}}catch(s){throw d(),s}return{name:"artplayerPluginAutoThumbnail"}}}});

docs/compiled/artplayer-plugin-auto-thumbnail.legacy.js

@@ -4,4 +4,4 @@
  * (c) 2017-2026 Harvey Zhao
  * Released under the MIT License.
  */
-!function(e,t){"object"===typeof exports&&"undefined"!==typeof module?module.exports=t():"function"==typeof define&&define.amd?(e.artplayerPluginAutoThumbnail=t(),define(function(){return e.artplayerPluginAutoThumbnail})):(e="undefined"!==typeof globalThis?globalThis:e||self).artplayerPluginAutoThumbnail=t()}(this,function(){"use strict";var e=Object.defineProperty,t=Object.getOwnPropertySymbols,r=Object.prototype.hasOwnProperty,n=Object.prototype.propertyIsEnumerable,i=(t,r,n)=>r in t?e(t,r,{enumerable:!0,configurable:!0,writable:!0,value:n}):t[r]=n;function o(e,t){const r=document.createElement("video");e.own(()=>r.load()),e.own(()=>r.removeAttribute("src")),e.own(()=>r.pause());for(const n of["onloadedmetadata","onseeked","onerror"])e.own(()=>{r[n]=null});e.active()&&(r.crossOrigin="anonymous",r.onerror=e.guard(()=>{throw r.error||new Error("Auto-thumbnail media failed to load")}),r.onloadedmetadata=e.guard(()=>{r.onloadedmetadata=null;const n=r.duration,{height:i,canvasWidth:o,canvasHeight:a}=function(e,t){if(!Number.isFinite(t.duration)||t.duration<=0||!Number.isFinite(t.videoWidth)||t.videoWidth<=0||!Number.isFinite(t.videoHeight)||t.videoHeight<=0)throw new TypeError("Auto-thumbnail requires finite media duration and dimensions");const r=Math.floor(e.width*t.videoHeight/t.videoWidth),n=Math.trunc(10*e.width),i=Math.trunc(r*Math.ceil(e.number/10));if(![r,n,i].every(e=>Number.isSafeInteger(e)&&e>0&&e<=4294967295))throw new RangeError("Auto-thumbnail canvas dimensions are invalid");return{height:r,canvasWidth:n,canvasHeight:i}}(t,{duration:n,videoHeight:r.videoHeight,videoWidth:r.videoWidth});if(!e.active())return;const u=document.createElement("canvas");if(!e.active())return;u.width=o,u.height=a;const d=u.getContext("2d");if(!d)throw new Error("Auto-thumbnail canvas context is unavailable");if(!e.active())return;let c=0;const l=e.guard(()=>{c>=t.number?e.dispose():(r.onseeked=e.guard(()=>{if(r.onseeked=null,d.drawImage(r,c%10*t.width,Math.floor(c/10)*i,t.width,i),!e.active())return;let n=!1;u.toBlob(e.guard(r=>{n||(n=!0,e.publish(r,{height:i,column:10,number:t.number,width:t.width,scale:t.scale}),e.active()&&(c+=1,l()))}),"image/jpeg")}),e.active()&&(r.currentTime=n*c/t.number))});l()}),e.active()&&(r.src=t.url))}function a(e){let t,r=!1;for(const i of e)try{i()}catch(n){r||(r=!0,t=n)}return{failed:r,failure:t}}function u(e,o){let u,d,c=!1;const l=new Set;function s(e){l.delete(e)&&URL.revokeObjectURL(e)}function f(){const e=u;u=void 0,null==e||e.dispose()}return{start:function(){if(c)return;const f=u,h=[];let m=!1;const v={active:()=>!c&&!m&&u===v,own(e){if(m){const t=a([e]);t.failed&&o(t.failure)}else h.push(e)},dispose(){if(m)return;m=!0,u===v&&(u=void 0);const e=a(h.splice(0).reverse());e.failed&&o(e.failure)},fail(e){v.active()&&(v.dispose(),o(e))},guard:e=>(...t)=>{if(v.active())try{return e(...t)}catch(r){v.fail(r)}},publish(u,c){if(!v.active())return;if(!u)throw new Error("Auto-thumbnail encoding returned no Blob");const f=URL.createObjectURL(u);if(l.add(f),!v.active())return void s(f);const h=d;d=f;try{e(((e,o)=>{for(var a in o||(o={}))r.call(o,a)&&i(e,a,o[a]);if(t)for(var a of t(o))n.call(o,a)&&i(e,a,o[a]);return e})({url:f},c))}catch(m){d===f&&(d=l.has(h)?h:void 0);const e=a([()=>s(f)]);throw e.failed&&o(e.failure),m}s(h)}};return u=v,null==f||f.dispose(),v},cancel:f,destroy:function(){if(c)return;c=!0;const e=a([f,...[...l].map(e=>()=>s(e))]);d=void 0,e.failed&&o(e.failure)},get closed(){return c}}}return function(e){return t=>{return r=null,n=null,i=function*(){const r=e=>console.warn("ArtPlayer auto-thumbnail failed:",e),n=u(e=>{t.thumbnails=e},r),i=[],d=()=>{const r=n.start();r&&r.guard(()=>{const n=function(e,t){const r={url:e.url||t(),width:e.width||160,number:e.number||100,scale:e.scale||1};if(!Number.isFinite(Number(r.width))||r.width<=0||!Number.isFinite(Number(r.number))||r.number<=0)throw new TypeError("Auto-thumbnail width and number must be finite positive numbers");return r}(e,()=>t.option.url);r.active()&&o(r,n)})()},c=()=>{const e=i.splice(0),t=a([n.destroy,...e]);t.failed&&r(t.failure)};try{for(const[e,r]of[["destroy",c],["restart",n.cancel],["video:loadedmetadata",d]]){if(n.closed)break;i.push(()=>t.off(e,r)),t.on(e,r),n.closed&&t.off(e,r)}}catch(l){throw c(),l}return{name:"artplayerPluginAutoThumbnail"}},new Promise((e,t)=>{var o=e=>{try{u(i.next(e))}catch(r){t(r)}},a=e=>{try{u(i.throw(e))}catch(r){t(r)}},u=t=>t.done?e(t.value):Promise.resolve(t.value).then(o,a);u((i=i.apply(r,n)).next())});var r,n,i}}});
+!function(e,t){"object"===typeof exports&&"undefined"!==typeof module?module.exports=t():"function"==typeof define&&define.amd?(e.artplayerPluginAutoThumbnail=t(),define(function(){return e.artplayerPluginAutoThumbnail})):(e="undefined"!==typeof globalThis?globalThis:e||self).artplayerPluginAutoThumbnail=t()}(this,function(){"use strict";var e=Object.defineProperty,t=Object.getOwnPropertySymbols,i=Object.prototype.hasOwnProperty,n=Object.prototype.propertyIsEnumerable,r=(t,i,n)=>i in t?e(t,i,{enumerable:!0,configurable:!0,writable:!0,value:n}):t[i]=n;function o(e,t){const i=function(e){const t=document.createElement("video");e.own(()=>t.remove()),e.own(()=>t.load()),e.own(()=>t.removeAttribute("src")),e.own(()=>t.pause());for(const i of["onloadedmetadata","onseeked","onerror"])e.own(()=>{t[i]=null});return e.active()?(t.crossOrigin="anonymous",t.muted=!0,t.playsInline=!0,t.tabIndex=-1,t.setAttribute("aria-hidden","true"),t.style.cssText="position:fixed;left:0;top:0;visibility:hidden;pointer-events:none;display:block;width:auto;height:auto;max-width:none;max-height:none",document.documentElement.appendChild(t),e.active()||t.remove(),t):t}(e);e.active()&&(i.onerror=e.guard(()=>{throw i.error||new Error("Auto-thumbnail media failed to load")}),i.onloadedmetadata=e.guard(()=>{i.onloadedmetadata=null;const n=i.duration,r=i.videoHeight,o=i.videoWidth,{height:a,canvasWidth:u,canvasHeight:d}=function(e,t){if(!Number.isFinite(t.duration)||t.duration<=0||!Number.isFinite(t.videoWidth)||t.videoWidth<=0||!Number.isFinite(t.videoHeight)||t.videoHeight<=0)throw new TypeError("Auto-thumbnail requires finite media duration and dimensions");const i=Math.floor(e.width*t.videoHeight/t.videoWidth),n=Math.trunc(10*e.width),r=Math.trunc(i*Math.ceil(e.number/10));if(![i,n,r].every(e=>Number.isSafeInteger(e)&&e>0&&e<=4294967295))throw new RangeError("Auto-thumbnail canvas dimensions are invalid");return{height:i,canvasWidth:n,canvasHeight:r}}(t,{duration:n,videoHeight:r,videoWidth:o});if(!e.active())return;i.width=o,i.height=r,i.style.width=`${o}px`,i.style.height=`${r}px`;const c=document.createElement("canvas");if(!e.active())return;c.width=u,c.height=d;const l=c.getContext("2d");if(!l)throw new Error("Auto-thumbnail canvas context is unavailable");if(!e.active())return;let s=0;const h=e.guard(()=>{if(s>=t.number)return void e.dispose();const r=n*s/t.number;let o=0;i.onseeked=e.guard(()=>{if(i.seeking)return;const n=i.currentTime;if(!e.active())return;if(!Number.isFinite(n)||Math.abs(n-r)>.05){if(++o>3)throw new Error("Auto-thumbnail seek did not reach the requested time");return void(i.currentTime=r)}if(i.onseeked=null,l.drawImage(i,s%10*t.width,Math.floor(s/10)*a,t.width,a),!e.active())return;let u=!1;c.toBlob(e.guard(i=>{u||(u=!0,e.publish(i,{height:a,column:10,number:t.number,width:t.width,scale:t.scale}),e.active()&&(s+=1,h()))}),"image/jpeg")}),e.active()&&(i.currentTime=r)});h()}),e.active()&&(i.src=t.url))}function a(e){let t,i=!1;for(const r of e)try{r()}catch(n){i||(i=!0,t=n)}return{failed:i,failure:t}}function u(e,o){let u,d,c=!1;const l=new Set;function s(e){l.delete(e)&&URL.revokeObjectURL(e)}function h(){const e=u;u=void 0,null==e||e.dispose()}return{start:function(){if(c)return;const h=u,f=[];let m=!1;const v={active:()=>!c&&!m&&u===v,own(e){if(m){const t=a([e]);t.failed&&o(t.failure)}else f.push(e)},dispose(){if(m)return;m=!0,u===v&&(u=void 0);const e=a(f.splice(0).reverse());e.failed&&o(e.failure)},fail(e){v.active()&&(v.dispose(),o(e))},guard:e=>(...t)=>{if(v.active())try{return e(...t)}catch(i){v.fail(i)}},publish(u,c){if(!v.active())return;if(!u)throw new Error("Auto-thumbnail encoding returned no Blob");const h=URL.createObjectURL(u);if(l.add(h),!v.active())return void s(h);const f=d;d=h;try{e(((e,o)=>{for(var a in o||(o={}))i.call(o,a)&&r(e,a,o[a]);if(t)for(var a of t(o))n.call(o,a)&&r(e,a,o[a]);return e})({url:h},c))}catch(m){d===h&&(d=l.has(f)?f:void 0);const e=a([()=>s(h)]);throw e.failed&&o(e.failure),m}s(f)}};return u=v,null==h||h.dispose(),v},cancel:h,destroy:function(){if(c)return;c=!0;const e=a([h,...[...l].map(e=>()=>s(e))]);d=void 0,e.failed&&o(e.failure)},get closed(){return c}}}return function(e){return t=>{return i=null,n=null,r=function*(){const i=e=>console.warn("ArtPlayer auto-thumbnail failed:",e),n=u(e=>{t.thumbnails=e},i),r=[],d=()=>{const i=n.start();i&&i.guard(()=>{const n=function(e,t){const i={url:e.url||t(),width:e.width||160,number:e.number||100,scale:e.scale||1};if(!Number.isFinite(Number(i.width))||i.width<=0||!Number.isFinite(Number(i.number))||i.number<=0)throw new TypeError("Auto-thumbnail width and number must be finite positive numbers");return i}(e,()=>t.option.url);i.active()&&o(i,n)})()},c=()=>{const e=r.splice(0),t=a([n.destroy,...e]);t.failed&&i(t.failure)};try{for(const[e,i]of[["destroy",c],["restart",n.cancel],["video:loadedmetadata",d]]){if(n.closed)break;r.push(()=>t.off(e,i)),t.on(e,i),n.closed&&t.off(e,i)}}catch(l){throw c(),l}return{name:"artplayerPluginAutoThumbLine truncated

docs/compiled/artplayer-plugin-auto-thumbnail.mjs

@@ -25,8 +25,9 @@ function sheetSize(config, video) {
     throw new RangeError("Auto-thumbnail canvas dimensions are invalid");
   return { height, canvasWidth, canvasHeight };
 }
-function extract(job, config) {
+function createVideo(job) {
   const video = document.createElement("video");
+  job.own(() => video.remove());
   job.own(() => video.load());
   job.own(() => video.removeAttribute("src"));
   job.own(() => video.pause());
@@ -35,21 +36,41 @@ function extract(job, config) {
       video[property] = null;
     });
   if (!job.active())
-    return;
+    return video;
   video.crossOrigin = "anonymous";
+  video.muted = true;
+  video.playsInline = true;
+  video.tabIndex = -1;
+  video.setAttribute("aria-hidden", "true");
+  video.style.cssText = "position:fixed;left:0;top:0;visibility:hidden;pointer-events:none;display:block;width:auto;height:auto;max-width:none;max-height:none";
+  document.documentElement.appendChild(video);
+  if (!job.active())
+    video.remove();
+  return video;
+}
+function extract(job, config) {
+  const video = createVideo(job);
+  if (!job.active())
+    return;
   video.onerror = job.guard(() => {
     throw video.error || new Error("Auto-thumbnail media failed to load");
   });
   video.onloadedmetadata = job.guard(() => {
     video.onloadedmetadata = null;
     const duration = video.duration;
+    const videoHeight = video.videoHeight;
+    const videoWidth = video.videoWidth;
     const { height, canvasWidth, canvasHeight } = sheetSize(config, {
       duration,
-      videoHeight: video.videoHeight,
-      videoWidth: video.videoWidth
+      videoHeight,
+      videoWidth
     });
     if (!job.active())
       return;
+    video.width = videoWidth;
+    video.height = videoHeight;
+    video.style.width = `${videoWidth}px`;
+    video.style.height = `${videoHeight}px`;
     const canvas = document.createElement("canvas");
     if (!job.active())
       return;
@@ -66,7 +87,20 @@ function extract(job, config) {
         job.dispose();
         return;
       }
+      const target = duration * index / config.number;
+      let retries = 0;
       video.onseeked = job.guard(() => {
+        if (video.seeking)
+          return;
+        const time = video.currentTime;
+        if (!job.active())
+          return;
+        if (!Number.isFinite(time) || Math.abs(time - target) > 0.05) {
+          if (++retries > 3)
+            throw new Error("Auto-thumbnail seek did not reach the requested time");
+          video.currentTime = target;
+          return;
+        }
         video.onseeked = null;
         ctx.drawImage(video, index % 10 * config.width, Math.floor(index / 10) * height, config.width, height);
         if (!job.active())
@@ -84,7 +118,7 @@ function extract(job, config) {
         }), "image/jpeg");
       });
       if (job.active())
-        video.currentTime = duration * index / config.number;
+        video.currentTime = target;
     });
     seek();
   });