feat(player): add volume slider and wheel control for video preview

frontend/src/main.ts

@@ -18,6 +18,7 @@ interface State {
   loopTrim: boolean;
   previewMixAudio: boolean;
   mutedPreview: boolean;
+  previewVolume: number;
   usingProxy: boolean;
   encoder: string;
   hwDecode: string;
@@ -53,6 +54,7 @@ const state: State = {
   loopTrim: true,
   previewMixAudio: false,
   mutedPreview: false,
+  previewVolume: Number(localStorage.getItem('convert_preview_volume') ?? 1),
   usingProxy: false,
   encoder: 'libx264',
   hwDecode: 'none',
@@ -188,7 +190,11 @@ function renderShell() {
             <button id="setEndBtn" disabled>${tr.setEnd} ⏭</button>
             <button id="loopBtn" class="pill-active">🔁 ${tr.loopTrim}</button>
             <button id="previewMixBtn" class="hidden">🎧 ${tr.previewMix}</button>
-            <button id="mutePreviewBtn">🔊</button>
+            <div class="volume-box">
+              <button id="mutePreviewBtn" title="Звук">🔊</button>
+              <input type="range" id="volumeRange" min="0" max="1" step="0.05" value="1" title="Громкость" />
+              <span id="volumeVal" class="mono volume-val">100%</span>
+            </div>
           </div>
         </div>
 
@@ -567,6 +573,37 @@ function updatePlayhead(currentTime: number) {
   el<'span'>('timeReadout').textContent = `${formatTimecode(currentTime, true)} / ${formatTimecode(dur, true)}`;
 }
 
+function updateVolumeUI() {
+  const video = el<'video'>('videoEl');
+  const btn = el<'button'>('mutePreviewBtn');
+  const rng = el<'input'>('volumeRange');
+  const val = el<'span'>('volumeVal');
+  if (!btn || !rng || !val) return;
+
+  const vol = Math.max(0, Math.min(1, state.previewVolume));
+  if (video) {
+    video.volume = vol;
+    video.muted = state.mutedPreview;
+  }
+
+  rng.value = String(vol);
+  val.textContent = state.mutedPreview ? 'Mute' : `${Math.round(vol * 100)}%`;
+
+  if (state.mutedPreview || vol === 0) {
+    btn.textContent = '🔇';
+    btn.title = 'Включить звук';
+  } else if (vol < 0.4) {
+    btn.textContent = '🔈';
+    btn.title = 'Выключить звук';
+  } else if (vol < 0.8) {
+    btn.textContent = '🔉';
+    btn.title = 'Выключить звук';
+  } else {
+    btn.textContent = '🔊';
+    btn.title = 'Выключить звук';
+  }
+}
+
 function buildRequest(): ConvertRequest {
   return {
     inputPath: state.loaded?.info.path ?? '',
@@ -679,7 +716,7 @@ function applyLoadedUI(
   const mixBtn = el<'button'>('previewMixBtn');
   mixBtn.classList.toggle('hidden', res.info.audioStreams.length < 2);
   mixBtn.classList.toggle('pill-active', state.previewMixAudio);
-  el<'button'>('mutePreviewBtn').textContent = state.mutedPreview ? '🔇' : '🔊';
+  updateVolumeUI();
 
   el<'pre'>('cliBox').classList.toggle('hidden', !state.cliExpanded);
   el<'button'>('copyCliBtn').classList.toggle('hidden', !state.cliExpanded);
@@ -727,6 +764,7 @@ function setPlayerSource(
 
   const rate = Math.max(0.25, Math.min(8, state.speed));
   video.muted = state.mutedPreview;
+  video.volume = Math.max(0, Math.min(1, state.previewVolume));
   video.defaultPlaybackRate = rate;
   video.playbackRate = rate;
 
@@ -740,6 +778,7 @@ function setPlayerSource(
       video.defaultPlaybackRate = r;
       video.playbackRate = r;
       video.muted = state.mutedPreview;
+      video.volume = Math.max(0, Math.min(1, state.previewVolume));
       fitVideoStage();
       if (seekSec > 0 && Number.isFinite(seekSec)) {
         video.currentTime = Math.min(seekSec, res.info.duration || seekSec);
@@ -1058,8 +1097,20 @@ function bindEvents() {
   });
   el<'button'>('mutePreviewBtn').addEventListener('click', () => {
     state.mutedPreview = !state.mutedPreview;
-    video.muted = state.mutedPreview;
-    el<'button'>('mutePreviewBtn').textContent = state.mutedPreview ? '🔇' : '🔊';
+    if (!state.mutedPreview && state.previewVolume === 0) {
+      state.previewVolume = 0.5;
+      localStorage.setItem('convert_preview_volume', '0.5');
+    }
+    updateVolumeUI();
+  });
+  el<'input'>('volumeRange').addEventListener('input', (e) => {
+    const v = Number((e.target as HTMLInputElement).value);
+    state.previewVolume = v;
+    if (v > 0) {
+      state.mutedPreview = false;
+    }
+    localStorage.setItem('convert_preview_volume', String(v));
+    updateVolumeUI();
   });
 
   // Timeline drag (handles + seek)