58 lines
1.9 KiB
TypeScript
58 lines
1.9 KiB
TypeScript
import { promises as fs } from 'fs';
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import os from 'os';
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import path from 'path';
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import { execFile } from 'child_process';
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import { promisify } from 'util';
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const execFileAsync = promisify(execFile);
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export function pickBestPlayAddr(variants: PlayVariant[] | undefined | null) {
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if (!variants?.length) return null;
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const best = variants.reduce((best, cur) => {
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const b1 = best?.bit_rate ?? -1;
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const b2 = cur?.bit_rate ?? -1;
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return b2 > b1 ? cur : best;
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});
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return best?.play_addr ?? null;
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}
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/**
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* 使用 ffmpeg 从视频二进制中提取第一帧，返回 JPEG buffer
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*/
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export async function extractFirstFrame(videoBuffer: Buffer): Promise<{ buffer: Buffer; contentType: string; ext: string } | null> {
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const ffmpegCmd = process.env.FFMPEG_PATH || 'ffmpeg';
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const tmpDir = os.tmpdir();
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const base = `dy_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`;
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const inPath = path.join(tmpDir, `${base}.mp4`);
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const outPath = path.join(tmpDir, `${base}.jpg`);
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try {
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await fs.writeFile(inPath, videoBuffer);
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const args = [
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'-hide_banner',
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'-loglevel', 'error',
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'-ss', '0',
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'-i', inPath,
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'-frames:v', '1',
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'-q:v', '2',
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'-f', 'image2',
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'-y',
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outPath,
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];
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await execFileAsync(ffmpegCmd, args, { windowsHide: true });
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const img = await fs.readFile(outPath);
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return { buffer: img, contentType: 'image/jpeg', ext: 'jpg' };
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} catch (e: any) {
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if (e && (e.code === 'ENOENT' || /not found|is not recognized/i.test(String(e.message)))) {
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console.warn('系统未检测到 ffmpeg，可安装并配置 PATH 或设置 FFMPEG_PATH 后启用封面提取。');
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return null;
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}
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throw e;
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} finally {
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try { await fs.unlink(inPath); } catch { }
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try { await fs.unlink(outPath); } catch { }
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}
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}
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