fix: 前端显示真实发送频率和渲染频率

backend/requirements.txt

@@ -0,0 +1,4 @@
+Django>=5,<6
+djangorestframework>=3.15,<4
+django-cors-headers>=4,<5
+channels>=4,<5

frontend/src/components/VideoPanel.vue

@@ -1,76 +1,53 @@
 <script setup lang="ts">
-import { computed, onMounted, onUnmounted, ref, watch } from 'vue'
+import { computed, ref, watch } from 'vue'
 
-import { buildVideoFrameUrl } from '@/lib/api'
+import { buildVideoStreamUrl } from '@/lib/api'
 import type { VideoStatus } from '@/types'
 
 const props = defineProps<{
   video: VideoStatus | null
 }>()
 
-const frameUrl = ref(buildVideoFrameUrl(0))
-const currentFps = computed(() => props.video?.fps ?? 30)
+const streamUrl = ref('')
 const canRequestFrames = computed(() => props.video?.available === true)
-const modeLabel = computed(() => {
+const streamFps = computed(() => Math.max(props.video?.fps ?? 0, 30))
+
+const senderProfileLabel = computed(() => {
   if (!props.video) {
-    return '正在获取视频状态'
+    return '发送端 Profile: --'
   }
-  if (props.video.source_mode === 'omnisocket-jpeg-live') {
-    return `${props.video.fps} FPS 实时接收`
-  }
-  if (props.video.source_mode === 'omnisocket-waiting') {
-    return '未实时获取真实值'
-  }
-  return `${props.video.fps} FPS`
+  return `发送端 Profile: ${props.video.fps} FPS`
 })
+
+const displayModeLabel = computed(() => {
+  if (!props.video) {
+    return '前端显示: 等待状态'
+  }
+  if (!canRequestFrames.value) {
+    return '前端显示: 等待新视频帧'
+  }
+  return `前端显示: MJPEG Stream (${streamFps.value} FPS 请求)`
+})
+
 const placeholderText = computed(() => {
   if (!props.video) {
     return '正在获取视频状态...'
   }
-  return '未实时获取真实值'
+  return '尚未收到实时视频帧'
 })
 
-let frameTimer: number | null = null
-let frameKey = 0
-
-function refreshFrame() {
-  if (!canRequestFrames.value) {
-    return
-  }
-  frameKey += 1
-  frameUrl.value = buildVideoFrameUrl(frameKey)
-}
-
-function startFrameLoop() {
-  if (frameTimer != null) {
-    window.clearInterval(frameTimer)
-    frameTimer = null
-  }
-
+function refreshStreamUrl() {
   if (!canRequestFrames.value) {
+    streamUrl.value = ''
     return
   }
 
-  refreshFrame()
-  const intervalMs = Math.max(33, Math.round(1000 / currentFps.value))
-  frameTimer = window.setInterval(() => {
-    refreshFrame()
-  }, intervalMs)
+  // Keep the browser attached to a higher-frequency local MJPEG stream
+  // so the dashboard does not add an extra 0-100 ms polling delay.
+  streamUrl.value = buildVideoStreamUrl(streamFps.value, Date.now())
 }
 
-onMounted(() => {
-  startFrameLoop()
-})
-
-onUnmounted(() => {
-  if (frameTimer != null) {
-    window.clearInterval(frameTimer)
-  }
-})
-
-watch([currentFps, canRequestFrames], () => {
-  startFrameLoop()
-})
+watch([streamFps, canRequestFrames], refreshStreamUrl, { immediate: true })
 </script>
 
 <template>
@@ -89,7 +66,7 @@ watch([currentFps, canRequestFrames], () => {
       <img
         v-if="canRequestFrames"
         class="video-frame"
-        :src="frameUrl"
+        :src="streamUrl"
         alt="Robot jpeg frame stream"
       />
       <div v-else class="video-placeholder">
@@ -104,13 +81,16 @@ watch([currentFps, canRequestFrames], () => {
       </div>
       <div class="stat-card">
         <span>当前模式</span>
-        <strong>{{ modeLabel }}</strong>
+        <div class="stat-lines">
+          <strong>{{ senderProfileLabel }}</strong>
+          <strong class="secondary">{{ displayModeLabel }}</strong>
+        </div>
       </div>
     </div>
 
     <p class="hint">
-      这里只有在后端已经收到 OmniSocket 的真实 JPEG 帧时，才会开始逐帧请求并显示画面。
-      如果当前没有真实帧，页面会保持占位提示，不再回退测试视频流。
+      视频可用时，页面会直接连接后端的 MJPEG stream，而不是按当前发送 fps 逐帧轮询。
+      这样能减少 dashboard 本身带来的额外显示延迟。
     </p>
 
     <p class="hint subtle">
@@ -213,6 +193,16 @@ h2 {
   font-size: 18px;
 }
 
+.stat-lines {
+  display: grid;
+  gap: 6px;
+}
+
+.stat-lines .secondary {
+  font-size: 15px;
+  color: #a8b4ce;
+}
+
 .hint {
   margin: 0;
   color: #8d99b3;

frontend/src/lib/api.ts

@@ -19,3 +19,7 @@ export function fetchDashboardSnapshot() {
 export function buildVideoFrameUrl(frameKey: number) {
   return `${API_BASE}/api/video/frame/?frame=${frameKey}&t=${Date.now()}`
 }
+
+export function buildVideoStreamUrl(fps: number, token: number) {
+  return `${API_BASE}/api/video/stream/?fps=${fps}&t=${token}`
+}