feat(frontend/vditor): 实现基于 FFmpeg.wasm 的视频压缩功能

- 添加视频压缩相关配置和工具函数
- 实现 FFmpeg.wasm 初始化和视频压缩功能
- 优化文件上传流程，支持视频文件压缩

frontend_nuxt/utils/ffmpegVideoCompressor.js

@@ -0,0 +1,327 @@
+/**
+ * FFmpeg.wasm 视频压缩器
+ *
+ * 用法：
+ *   const { $ffmpeg } = useNuxtApp()
+ *   const ff = await $ffmpeg() // 插件里已完成 ffmpeg.load()
+ *   const out = await compressVideoWithFFmpeg(ff, file, { onProgress, strictSize: false })
+ *
+ * 设计要点：
+ *  - 本文件不再负责加载/初始化，只负责转码逻辑；和 Nuxt 插件解耦。
+ *  - 针对【同一个 ffmpeg 实例】做串行队列，避免并发 exec 踩内存文件系统。
+ *  - 使用 nanoid 生成唯一文件名；日志环形缓冲；默认 CRF+VBV，可选 strictSize（two-pass）。
+ *  - 体积明显小于目标时直通返回，减少无谓重编码。
+ */
+
+import { fetchFile } from '@ffmpeg/util'
+import { nanoid } from 'nanoid'
+import { UPLOAD_CONFIG } from '../config/uploadConfig.js'
+
+/*************************
+ * 每实例一个串行队列     *
+ *************************/
+// WeakMap<FFmpeg, { q: (()=>Promise<any>)[], running: boolean, resolvers: {res,rej}[] }>
+const queues = new WeakMap()
+
+function enqueueOn(instance, taskFn) {
+  return new Promise((res, rej) => {
+    let st = queues.get(instance)
+    if (!st) {
+      st = { q: [], running: false, resolvers: [] }
+      queues.set(instance, st)
+    }
+    st.q.push(taskFn)
+    st.resolvers.push({ res, rej })
+    drain(instance)
+  })
+}
+
+async function drain(instance) {
+  const st = queues.get(instance)
+  if (!st || st.running) return
+  st.running = true
+  try {
+    while (st.q.length) {
+      const task = st.q.shift()
+      const rr = st.resolvers.shift()
+      try {
+        rr.res(await task())
+      } catch (e) {
+        rr.rej(e)
+      }
+    }
+  } finally {
+    st.running = false
+  }
+}
+
+/*****************
+ * 工具函数       *
+ *****************/
+function decideScale(widthHint) {
+  if (!widthHint) return { filter: null, width: null }
+  const evenW = widthHint % 2 === 0 ? widthHint : widthHint - 1
+  return { filter: `scale=${evenW}:-2:flags=bicubic,setsar=1`, width: evenW }
+}
+
+function calculateParamsByRatio(originalSize, targetSize) {
+  const ratio = Math.min(targetSize / originalSize, 1)
+  const crf = ratio < 0.35 ? 29 : ratio < 0.5 ? 27 : ratio < 0.7 ? 25 : 23
+  const preset = ratio < 0.35 ? 'slow' : ratio < 0.5 ? 'medium' : 'veryfast'
+  const s =
+    ratio < 0.35
+      ? decideScale(720)
+      : ratio < 0.6
+        ? decideScale(960)
+        : ratio < 0.8
+          ? decideScale(1280)
+          : { filter: null, width: null }
+  const audioBitrateK = ratio < 0.5 ? 96 : ratio < 0.7 ? 128 : 160
+  const profile = s.width && s.width <= 1280 ? 'main' : 'high'
+  return { crf, preset, scaleFilter: s.filter, scaleWidth: s.width, audioBitrateK, profile }
+}
+
+function makeRingLogger(capBytes = 4000) {
+  const buf = []
+  let total = 0
+  function push(s) {
+    if (!s) return
+    buf.push(s)
+    total += s.length
+    while (total > capBytes) total -= buf.shift().length
+  }
+  return { push, dump: () => buf.slice() }
+}
+
+function parseDurationFromLogs(logs) {
+  // 避免正则：查找 Duration: 后的 00:00:00.xx
+  const text = logs.join(' ')
+  const idx = text.indexOf('Duration:')
+  if (idx === -1) return null
+  let i = idx + 'Duration:'.length
+  while (i < text.length && text[i] === ' ') i++
+  function read2(start) {
+    const a = text.charCodeAt(start) - 48
+    const b = text.charCodeAt(start + 1) - 48
+    if (a < 0 || a > 9 || b < 0 || b > 9) return null
+    return a * 10 + b
+  }
+  const hh = read2(i)
+  if (hh === null) return null
+  i += 2
+  if (text[i++] !== ':') return null
+  const mm = read2(i)
+  if (mm === null) return null
+  i += 2
+  if (text[i++] !== ':') return null
+  const s1 = read2(i)
+  if (s1 === null) return null
+  i += 2
+  if (text[i++] !== '.') return null
+  let j = i
+  while (j < text.length && text.charCodeAt(j) >= 48 && text.charCodeAt(j) <= 57) j++
+  const frac = parseFloat('0.' + text.slice(i, j) || '0')
+  return hh * 3600 + mm * 60 + s1 + frac
+}
+
+export function isFFmpegSupported() {
+  return typeof WebAssembly !== 'undefined' && typeof Worker !== 'undefined'
+}
+
+/**
+ * 读取 ffmpeg 核心版本（通过 -version），会进入队列避免并发冲突
+ */
+export async function getFFmpegInfo(ffmpegInstance) {
+  return enqueueOn(ffmpegInstance, async () => {
+    const logs = []
+    const onLog = ({ type, message }) => {
+      if (type === 'info' || type === 'fferr') logs.push(message)
+    }
+    ffmpegInstance.on('log', onLog)
+    try {
+      await ffmpegInstance.exec(['-version'])
+    } finally {
+      ffmpegInstance.off('log', onLog)
+    }
+    const line = logs.find((l) => l.toLowerCase().includes('ffmpeg version')) || ''
+    const parts = line.trim().split(' ').filter(Boolean)
+    const version = parts.length > 2 ? parts[2] : parts[1] || null
+    return { version }
+  })
+}
+
+/**
+ * 压缩：接受一个已经 load() 完成的 ffmpeg 实例
+ * @param {*} ffmpegInstance 已初始化的 FFmpeg 实例（来自 Nuxt 插件）
+ * @param {File|Blob} file 输入文件
+ * @param {{ onProgress?:(p:{stage:string,progress:number})=>void, signal?:AbortSignal, strictSize?:boolean, targetSize?:number }} opts
+ */
+export async function compressVideoWithFFmpeg(ffmpegInstance, file, opts = {}) {
+  return enqueueOn(ffmpegInstance, () => doCompress(ffmpegInstance, file, opts))
+}
+
+async function doCompress(ffmpegInstance, file, opts) {
+  const onProgress = opts.onProgress || (() => {})
+  const { signal, strictSize = false } = opts
+
+  onProgress({ stage: 'preparing', progress: 10 })
+
+  const targetSize = opts.targetSize ?? UPLOAD_CONFIG?.VIDEO?.TARGET_SIZE ?? 12 * 1024 * 1024
+
+  // 小体积直通
+  const sizeKnown = 'size' in file && typeof file.size === 'number'
+  if (sizeKnown && file.size <= targetSize * 0.9) {
+    onProgress({ stage: 'skipped', progress: 100 })
+    return file
+  }
+
+  const params = calculateParamsByRatio(sizeKnown ? file.size : targetSize * 2, targetSize)
+  const { crf, preset, scaleFilter, audioBitrateK, profile } = params
+
+  const name = 'name' in file && typeof file.name === 'string' ? file.name : 'input.mp4'
+  const dot = name.lastIndexOf('.')
+  const outName = (dot > -1 ? name.slice(0, dot) : name) + '.mp4'
+
+  const ext = dot > -1 ? name.slice(dot + 1).toLowerCase() : 'mp4'
+  const id = nanoid()
+  const inputName = `input-${id}.${ext}`
+  const outputName = `output-${id}.mp4`
+  const passlog = `ffpass-${id}`
+
+  // 监听
+  const ring = makeRingLogger()
+  const onFfmpegProgress = ({ progress: p }) => {
+    const adjusted = 20 + p * 70
+    onProgress({ stage: 'compressing', progress: Math.min(90, adjusted) })
+  }
+  const onFfmpegLog = ({ type, message }) => {
+    if (type === 'fferr' || type === 'info') ring.push(message)
+  }
+  ffmpegInstance.on('progress', onFfmpegProgress)
+  ffmpegInstance.on('log', onFfmpegLog)
+
+  let aborted = false
+  const abortHandler = () => {
+    aborted = true
+  }
+  if (signal) signal.addEventListener('abort', abortHandler, { once: true })
+
+  try {
+    await ffmpegInstance.writeFile(inputName, await fetchFile(file))
+    onProgress({ stage: 'analyzing', progress: 20 })
+
+    let durationSec = null
+    try {
+      await ffmpegInstance.exec(['-hide_banner', '-i', inputName, '-f', 'null', '-'])
+      durationSec = parseDurationFromLogs(ring.dump())
+    } catch {
+      durationSec = durationSec ?? parseDurationFromLogs(ring.dump())
+    }
+
+    let videoBitrate = null
+    if (durationSec && sizeKnown && targetSize < file.size) {
+      const totalTargetBits = targetSize * 8
+      const audioBits = audioBitrateK * 1000 * durationSec
+      const maxVideoBits = Math.max(totalTargetBits - audioBits, totalTargetBits * 0.7)
+      const bps = Math.max(180000, Math.floor(maxVideoBits / durationSec))
+      videoBitrate = String(Math.min(bps, 5000000))
+    }
+
+    const baseArgs = [
+      '-hide_banner',
+      '-i',
+      inputName,
+      '-c:v',
+      'libx264',
+      '-pix_fmt',
+      'yuv420p',
+      '-profile:v',
+      profile,
+      '-movflags',
+      '+faststart',
+      '-preset',
+      preset,
+      '-c:a',
+      'aac',
+      '-b:a',
+      `${audioBitrateK}k`,
+      '-ac',
+      '2',
+    ]
+    if (scaleFilter) baseArgs.push('-vf', scaleFilter)
+
+    const onePassArgs = [...baseArgs, '-crf', String(crf)]
+    if (videoBitrate)
+      onePassArgs.push('-maxrate', videoBitrate, '-bufsize', String(parseInt(videoBitrate, 10) * 2))
+
+    const twoPassFirst = [
+      '-y',
+      '-hide_banner',
+      '-i',
+      inputName,
+      '-c:v',
+      'libx264',
+      '-b:v',
+      `${videoBitrate || '1000000'}`,
+      '-pass',
+      '1',
+      '-passlogfile',
+      passlog,
+      '-an',
+      '-f',
+      'mp4',
+      '/dev/null',
+    ]
+    const twoPassSecond = [
+      ...baseArgs,
+      '-b:v',
+      `${videoBitrate || '1000000'}`,
+      '-pass',
+      '2',
+      '-passlogfile',
+      passlog,
+      outputName,
+    ]
+
+    if (aborted) throw new DOMException('Aborted', 'AbortError')
+
+    if (!strictSize) {
+      await ffmpegInstance.exec([...onePassArgs, outputName])
+    } else {
+      if (!videoBitrate) videoBitrate = '1000000'
+      await ffmpegInstance.exec(twoPassFirst)
+      onProgress({ stage: 'second-pass', progress: 85 })
+      await ffmpegInstance.exec(twoPassSecond)
+    }
+
+    if (aborted) throw new DOMException('Aborted', 'AbortError')
+
+    onProgress({ stage: 'finalizing', progress: 95 })
+    const out = await ffmpegInstance.readFile(outputName)
+
+    const mime = 'video/mp4'
+    const blob = new Blob([out], { type: mime })
+    const hasFileCtor = typeof File === 'function'
+    const result = hasFileCtor ? new File([blob], outName, { type: mime }) : blob
+
+    onProgress({ stage: 'completed', progress: 100 })
+    return result
+  } finally {
+    try {
+      await ffmpegInstance.deleteFile(inputName)
+    } catch {}
+    try {
+      await ffmpegInstance.deleteFile(outputName)
+    } catch {}
+    try {
+      await ffmpegInstance.deleteFile(`${passlog}-0.log`)
+    } catch {}
+    try {
+      await ffmpegInstance.deleteFile(`${passlog}-0.log.mbtree`)
+    } catch {}
+
+    ffmpegInstance.off('progress', onFfmpegProgress)
+    ffmpegInstance.off('log', onFfmpegLog)
+    if (signal) signal.removeEventListener('abort', abortHandler)
+  }
+}

frontend_nuxt/utils/vditor.js

@@ -3,6 +3,8 @@ import { getToken, authState } from './auth'
 import { searchUsers, fetchFollowings, fetchAdmins } from './user'
 import { tiebaEmoji } from './tiebaEmoji'
 import vditorPostCitation from './vditorPostCitation.js'
+import { checkFileSize, formatFileSize, compressVideo, VIDEO_CONFIG } from './videoCompressor.js'
+import { UPLOAD_CONFIG } from '../config/uploadConfig.js'
 
 export function getEditorTheme() {
   return document.documentElement.dataset.theme === 'dark' ? 'dark' : 'classic'
@@ -91,10 +93,81 @@ export function createVditor(editorId, options = {}) {
       multiple: false,
       handler: async (files) => {
         const file = files[0]
-        vditor.tip('图片上传中', 0)
+        const ext = file.name.split('.').pop().toLowerCase()
+        const videoExts = ['mp4', 'webm', 'avi', 'mov', 'wmv', 'flv', 'mkv', 'm4v', 'ogv']
+        const isVideo = videoExts.includes(ext)
+
+        // 检查文件大小
+        const sizeCheck = checkFileSize(file)
+        if (!sizeCheck.isValid) {
+          console.log(
+            '文件大小不能超过',
+            formatFileSize(sizeCheck.maxSize),
+            '，当前文件',
+            formatFileSize(sizeCheck.actualSize),
+          )
+          vditor.tip(
+            `文件大小不能超过 ${formatFileSize(sizeCheck.maxSize)}，当前文件 ${formatFileSize(sizeCheck.actualSize)}`,
+            3000,
+          )
+          return '文件过大'
+        }
+
+        let processedFile = file
+
+        // 如果是视频文件且需要压缩
+        if (isVideo && sizeCheck.needsCompression) {
+          try {
+            vditor.tip('视频压缩中...', 0)
+            vditor.disabled()
+
+            // 使用 FFmpeg 压缩视频
+            processedFile = await compressVideo(file, (progress) => {
+              const messages = {
+                initializing: '初始化 FFmpeg',
+                preparing: '准备压缩',
+                analyzing: '分析视频',
+                compressing: '压缩中',
+                finalizing: '完成压缩',
+                completed: '压缩完成',
+              }
+              const message = messages[progress.stage] || progress.stage
+              vditor.tip(`${message} ${progress.progress}%`, 0)
+            })
+
+            const originalSize = formatFileSize(file.size)
+            const compressedSize = formatFileSize(processedFile.size)
+            const savings = Math.round((1 - processedFile.size / file.size) * 100)
+
+            vditor.tip(`压缩完成！${originalSize} → ${compressedSize} (节省 ${savings}%)`, 2000)
+            // 压缩成功但仍然超过最大限制，则阻止上传
+            if (processedFile.size > VIDEO_CONFIG.MAX_SIZE) {
+              vditor.tip(
+                `压缩后仍超过限制 (${formatFileSize(VIDEO_CONFIG.MAX_SIZE)}). 请降低分辨率或码率后再上传。`,
+                4000,
+              )
+              vditor.enable()
+              return '压缩后仍超过大小限制'
+            }
+          } catch (error) {
+            // 压缩失败时，如果原文件超过最大限制，则阻止上传
+            if (file.size > VIDEO_CONFIG.MAX_SIZE) {
+              vditor.tip(
+                `视频压缩失败，且文件超过限制 (${formatFileSize(VIDEO_CONFIG.MAX_SIZE)}). 请先压缩后再上传。`,
+                4000,
+              )
+              vditor.enable()
+              return '视频压缩失败且文件过大'
+            }
+            vditor.tip('视频压缩失败，将尝试上传原文件', 3000)
+            processedFile = file
+          }
+        }
+
+        vditor.tip('文件上传中', 0)
         vditor.disabled()
         const res = await fetch(
-          `${API_BASE_URL}/api/upload/presign?filename=${encodeURIComponent(file.name)}`,
+          `${API_BASE_URL}/api/upload/presign?filename=${encodeURIComponent(processedFile.name)}`,
           { headers: { Authorization: `Bearer ${getToken()}` } },
         )
         if (!res.ok) {
@@ -103,14 +176,13 @@ export function createVditor(editorId, options = {}) {
           return '获取上传地址失败'
         }
         const info = await res.json()
-        const put = await fetch(info.uploadUrl, { method: 'PUT', body: file })
+        const put = await fetch(info.uploadUrl, { method: 'PUT', body: processedFile })
         if (!put.ok) {
           vditor.enable()
           vditor.tip('上传失败')
           return '上传失败'
         }
 
-        const ext = file.name.split('.').pop().toLowerCase()
         const imageExts = [
           'apng',
           'bmp',
@@ -132,6 +204,8 @@ export function createVditor(editorId, options = {}) {
           md = `![${file.name}](${info.fileUrl})`
         } else if (audioExts.includes(ext)) {
           md = `<audio controls="controls" src="${info.fileUrl}"></audio>`
+        } else if (videoExts.includes(ext)) {
+          md = `<video width="600" controls>\n  <source src="${info.fileUrl}" type="video/${ext}">\n  你的浏览器不支持 video 标签。\n</video>`
         } else {
           md = `[${file.name}](${info.fileUrl})`
         }

frontend_nuxt/utils/videoCompressor.js

@@ -0,0 +1,79 @@
+/**
+ * 基于 FFmpeg.wasm 的视频压缩工具
+ * 专为现代浏览器 (Chrome/Safari) 优化
+ */
+
+import { UPLOAD_CONFIG } from '../config/uploadConfig.js'
+import { compressVideoWithFFmpeg, isFFmpegSupported } from './ffmpegVideoCompressor.js'
+import { useNuxtApp } from '#app'
+
+// 导出配置供外部使用
+export const VIDEO_CONFIG = UPLOAD_CONFIG.VIDEO
+
+/**
+ * 检查文件大小是否超出限制
+ */
+export function checkFileSize(file) {
+  return {
+    isValid: file.size <= VIDEO_CONFIG.MAX_SIZE,
+    actualSize: file.size,
+    maxSize: VIDEO_CONFIG.MAX_SIZE,
+    needsCompression: file.size > VIDEO_CONFIG.TARGET_SIZE,
+  }
+}
+
+/**
+ * 格式化文件大小显示
+ */
+export function formatFileSize(bytes) {
+  if (bytes === 0) return '0 B'
+  const k = 1024
+  const sizes = ['B', 'KB', 'MB', 'GB']
+  const i = Math.floor(Math.log(bytes) / Math.log(k))
+  return parseFloat((bytes / Math.pow(k, i)).toFixed(1)) + ' ' + sizes[i]
+}
+
+/**
+ * 压缩视频文件 - 使用 FFmpeg.wasm
+ */
+export async function compressVideo(file, onProgress = () => {}) {
+  // 检查是否需要压缩
+  const sizeCheck = checkFileSize(file)
+  if (!sizeCheck.needsCompression) {
+    onProgress({ stage: 'completed', progress: 100 })
+    return file
+  }
+
+  // 检查 FFmpeg 支持
+  if (!isFFmpegSupported()) {
+    throw new Error('当前浏览器不支持视频压缩功能，请使用 Chrome 或 Safari 浏览器')
+  }
+
+  try {
+    const { $ffmpeg } = useNuxtApp()
+    const ff = await $ffmpeg()
+    return await compressVideoWithFFmpeg(ff, file, { onProgress })
+  } catch (error) {
+    console.error('FFmpeg 压缩失败:', error)
+    throw new Error(`视频压缩失败: ${error.message}`)
+  }
+}
+
+/**
+ * 预加载 FFmpeg（可选的性能优化）
+ */
+export async function preloadVideoCompressor() {
+  try {
+    // FFmpeg 初始化现在通过 Nuxt 插件处理
+    // 这里只需要检查支持性
+    if (!isFFmpegSupported()) {
+      throw new Error('当前浏览器不支持 FFmpeg')
+    }
+    const { $ffmpeg } = useNuxtApp()
+    await $ffmpeg()
+    return { success: true, message: 'FFmpeg 预加载成功' }
+  } catch (error) {
+    console.warn('FFmpeg 预加载失败:', error)
+    return { success: false, error: error.message }
+  }
+}