311 lines
11 KiB
TypeScript
311 lines
11 KiB
TypeScript
/**
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* 视频处理工具库
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*
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* 提供视频转码、截图等功能
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* 依赖：需要系统安装 ffmpeg
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*/
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import { exec } from 'child_process'
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import { promisify } from 'util'
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import { readFile, unlink, writeFile, stat } from 'fs/promises'
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import { tmpdir } from 'os'
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import { join, resolve, isAbsolute } from 'path'
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import { uploadToS3, getS3ObjectStream, isS3Url } from './s3'
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import { Readable } from 'stream'
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const execAsync = promisify(exec)
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// 转码参数配置（可通过环境变量覆盖）
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export const TRANSCODE_CONFIG = {
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// 预览视频分辨率（默认 540P）
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previewResolution: parseInt(process.env.VIDEO_PREVIEW_RESOLUTION || '540', 10),
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// 预览片段时长（秒，默认 10 秒）
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clipDuration: parseInt(process.env.VIDEO_CLIP_DURATION || '10', 10),
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// 预览视频质量（CRF，默认 28，范围 0-51，越小质量越高）
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previewCrf: parseInt(process.env.VIDEO_PREVIEW_CRF || '28', 10),
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// 片段视频质量（CRF，默认 32，更低质量但文件更小）
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clipCrf: parseInt(process.env.VIDEO_CLIP_CRF || '32', 10),
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// 转码超时时间（毫秒，默认 1 小时）
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timeout: parseInt(process.env.VIDEO_TRANSCODE_TIMEOUT || '3600000', 10),
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// 临时文件大小限制（字节，默认 10GB）
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maxTempFileSize: parseInt(process.env.VIDEO_MAX_TEMP_FILE_SIZE || '10737418240', 10),
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}
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interface VideoTranscodeOptions {
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inputPath: string // 输入视频路径（S3 URL 或本地路径）
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outputDir: string // 输出目录
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materialId: string // 素材ID，用于生成唯一文件名
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needsCoverImage?: boolean // 是否需要生成封面图（用户未上传时）
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}
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interface TranscodeResult {
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preview540Url: string | null // 540P 预览视频 URL
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clipUrl: string | null // 10秒片段 URL
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coverUrl: string | null // 封面图 URL
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duration: number | null // 视频时长（秒）
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}
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async function deleteLocalSourceIfNeeded(inputPath: string) {
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if (!inputPath || isS3Url(inputPath)) {
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return
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}
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const normalizedPath = inputPath.startsWith('file://') ? inputPath.slice(7) : inputPath.replace(/^\.\/+/, '')
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const absolutePath = isAbsolute(normalizedPath) ? normalizedPath : resolve(process.cwd(), normalizedPath)
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try {
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await stat(absolutePath)
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} catch (error) {
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if ((error as NodeJS.ErrnoException)?.code === 'ENOENT') {
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return
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}
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console.warn('[VideoProcessor] Failed to access local source file:', absolutePath, error)
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return
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}
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try {
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await unlink(absolutePath)
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console.log('[VideoProcessor] Deleted local source file:', absolutePath)
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} catch (error) {
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console.warn('[VideoProcessor] Failed to delete local source file:', absolutePath, error)
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}
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}
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/**
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* 检查 ffmpeg 是否可用
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*/
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export async function checkFFmpegAvailable(): Promise<boolean> {
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try {
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await execAsync('ffmpeg -version')
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return true
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} catch {
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return false
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}
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}
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/**
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* 从 S3 下载视频到临时文件
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*/
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async function downloadVideoToTemp(s3Url: string, tempPath: string): Promise<void> {
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if (!isS3Url(s3Url)) {
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throw new Error('Invalid S3 URL')
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}
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const stream = await getS3ObjectStream(s3Url)
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if (!stream.body) {
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throw new Error('Failed to get video stream from S3')
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}
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const chunks: Buffer[] = []
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const readable = stream.body as Readable
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for await (const chunk of readable) {
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chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk))
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}
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await writeFile(tempPath, Buffer.concat(chunks))
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}
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/**
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* 获取视频时长（秒）
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*/
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async function getVideoDuration(videoPath: string): Promise<number> {
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try {
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const { stdout } = await execAsync(
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`ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "${videoPath}"`
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)
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const duration = parseFloat(stdout.trim())
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return isNaN(duration) ? 0 : Math.round(duration)
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} catch (error) {
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console.error('[VideoProcessor] Failed to get video duration:', error)
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return 0
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}
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}
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/**
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* 执行带超时的 ffmpeg 命令
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*/
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async function execFFmpegWithTimeout(
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command: string,
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timeout: number = TRANSCODE_CONFIG.timeout
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): Promise<{ stdout: string; stderr: string }> {
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return new Promise((resolve, reject) => {
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const childProcess = exec(command, (error, stdout, stderr) => {
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if (error) {
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reject(error)
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return
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}
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resolve({ stdout, stderr })
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})
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// 设置超时
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const timeoutId = setTimeout(() => {
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childProcess.kill('SIGTERM')
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reject(new Error(`FFmpeg command timeout after ${timeout}ms`))
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}, timeout)
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childProcess.on('exit', () => {
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clearTimeout(timeoutId)
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})
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})
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}
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/**
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* 转码为预览视频（分辨率可配置）
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*/
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async function transcodeToPreview(
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inputPath: string,
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outputPath: string
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): Promise<void> {
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const resolution = TRANSCODE_CONFIG.previewResolution
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const height = resolution
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/**
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* 使用等比缩放，最长边限制在配置分辨率（默认 540P），不再强制填充 16:9。
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* 这样可以保留原始纵横比，避免为竖屏视频生成黑边。
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* scale=-2:${height} 表示高度固定为目标分辨率，宽度自动按比例并保持偶数。
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*/
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const command = `ffmpeg -i "${inputPath}" -vf "scale=-2:${height}:flags=lanczos" -c:v libx264 -preset medium -crf ${TRANSCODE_CONFIG.previewCrf} -c:a aac -b:a 128k -movflags +faststart -y "${outputPath}"`
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const { stdout, stderr } = await execFFmpegWithTimeout(command)
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// ffmpeg 通常将进度信息输出到 stderr，这是正常的
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if (stderr && !stderr.includes('frame=') && !stderr.includes('Duration:')) {
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console.warn('[VideoProcessor] FFmpeg stderr output:', stderr.substring(0, 200))
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}
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}
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/**
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* 生成超小预览片段（时长和分辨率可配置）
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*/
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async function generateClip(
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inputPath: string,
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outputPath: string
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): Promise<void> {
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const duration = TRANSCODE_CONFIG.clipDuration
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const height = 360
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// ffmpeg 命令：截取指定时长，按最长边 360P 等比缩放，超低码率
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// -preset ultrafast: 最快编码速度，适合小片段
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// -crf: 较低质量但文件更小
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// -b:a 64k: 低音频码率
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const command = `ffmpeg -i "${inputPath}" -t ${duration} -vf "scale=-2:${height}:flags=lanczos" -c:v libx264 -preset ultrafast -crf ${TRANSCODE_CONFIG.clipCrf} -c:a aac -b:a 64k -movflags +faststart -y "${outputPath}"`
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const { stdout, stderr } = await execFFmpegWithTimeout(command)
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if (stderr && !stderr.includes('frame=') && !stderr.includes('Duration:')) {
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console.warn('[VideoProcessor] FFmpeg stderr output:', stderr.substring(0, 200))
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}
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}
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/**
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* 从视频中截取封面图（第一帧）
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*
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* 为了避免“封面尺寸”和“预览视频尺寸”不一致导致弹窗在点击播放时突然缩放，
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* 这里使用与预览视频一致的等比缩放策略：按最长边限制在 previewResolution。
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*/
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async function extractCoverImage(
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videoPath: string,
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outputPath: string
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): Promise<void> {
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const height = TRANSCODE_CONFIG.previewResolution
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const command = `ffmpeg -i "${videoPath}" -vf "scale=-2:${height}:flags=lanczos" -frames:v 1 -y "${outputPath}"`
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const { stdout, stderr } = await execFFmpegWithTimeout(command)
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if (stderr && !stderr.includes('frame=') && !stderr.includes('Duration:')) {
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console.warn('[VideoProcessor] FFmpeg stderr output:', stderr.substring(0, 200))
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}
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}
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/**
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* 处理视频转码任务
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*
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* @param options 转码选项
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* @returns 转码结果（包含生成的视频和图片 URL）
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*/
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export async function processVideoTranscode(
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options: VideoTranscodeOptions
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): Promise<TranscodeResult> {
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const { inputPath, outputDir, materialId, needsCoverImage = true } = options
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// 检查 ffmpeg 是否可用
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const ffmpegAvailable = await checkFFmpegAvailable()
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if (!ffmpegAvailable) {
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console.warn('[VideoProcessor] FFmpeg not available, skipping transcode')
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return {
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preview540Url: null,
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clipUrl: null,
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coverUrl: null,
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duration: null,
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}
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}
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const tempDir = tmpdir()
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const tempInputPath = join(tempDir, `video-input-${materialId}-${Date.now()}.mp4`)
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const temp540Path = join(tempDir, `video-540p-${materialId}-${Date.now()}.mp4`)
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const tempClipPath = join(tempDir, `video-clip-${materialId}-${Date.now()}.mp4`)
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const tempCoverPath = join(tempDir, `video-cover-${materialId}-${Date.now()}.jpg`)
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try {
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// 1. 下载视频到临时文件
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console.log('[VideoProcessor] Downloading video from S3...')
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await downloadVideoToTemp(inputPath, tempInputPath)
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// 2. 获取视频时长
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console.log('[VideoProcessor] Getting video duration...')
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const duration = await getVideoDuration(tempInputPath)
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// 3. 转码为预览视频（分辨率可配置）
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console.log(`[VideoProcessor] Transcoding to ${TRANSCODE_CONFIG.previewResolution}P preview...`)
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await transcodeToPreview(tempInputPath, temp540Path)
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const preview540Buffer = await readFile(temp540Path)
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const preview540FileName = `video-preview-${TRANSCODE_CONFIG.previewResolution}p-${materialId}-${Date.now()}.mp4`
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const preview540Url = await uploadToS3(preview540Buffer, preview540FileName, 'video/mp4')
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console.log(`[VideoProcessor] ${TRANSCODE_CONFIG.previewResolution}P preview uploaded:`, preview540Url)
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// 4. 生成预览片段（时长可配置）
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console.log(`[VideoProcessor] Generating ${TRANSCODE_CONFIG.clipDuration}s clip...`)
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await generateClip(tempInputPath, tempClipPath)
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const clipBuffer = await readFile(tempClipPath)
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const clipFileName = `video-clip-${TRANSCODE_CONFIG.clipDuration}s-${materialId}-${Date.now()}.mp4`
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const clipUrl = await uploadToS3(clipBuffer, clipFileName, 'video/mp4')
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console.log(`[VideoProcessor] ${TRANSCODE_CONFIG.clipDuration}s clip uploaded:`, clipUrl)
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// 5. 截取封面图（仅在需要时）
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let coverUrl: string | null = null
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if (needsCoverImage) {
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console.log('[VideoProcessor] Extracting cover image...')
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await extractCoverImage(tempInputPath, tempCoverPath)
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const coverBuffer = await readFile(tempCoverPath)
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const coverFileName = `video-cover-${materialId}-${Date.now()}.jpg`
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coverUrl = await uploadToS3(coverBuffer, coverFileName, 'image/jpeg')
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console.log('[VideoProcessor] Cover image uploaded:', coverUrl)
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} else {
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console.log('[VideoProcessor] Skipping cover image extraction (user already uploaded)')
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}
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await deleteLocalSourceIfNeeded(inputPath)
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return {
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preview540Url,
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clipUrl,
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coverUrl,
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duration,
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}
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} catch (error) {
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console.error('[VideoProcessor] Transcode error:', error)
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throw error
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} finally {
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// 清理临时文件
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const tempFiles = [tempInputPath, temp540Path, tempClipPath, tempCoverPath]
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for (const file of tempFiles) {
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try {
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await unlink(file).catch(() => {
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// 忽略删除失败
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})
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} catch {
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// 忽略错误
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}
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}
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}
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}
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