120 lines
3.7 KiB
Go
120 lines
3.7 KiB
Go
package vision
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import (
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"fmt"
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"os"
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"os/exec"
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"path/filepath"
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"strings"
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)
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// GenerateImagePreview 生成图片预览
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// 支持缩放并裁剪以填充指定尺寸 (Fill 模式)
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func GenerateImagePreview(srcPath, outPath string, width, height int) error {
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// 使用统一的 Load() 加载，内部已处理好 HEIC/sips/FFmpeg 的复杂格式兼容
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c, err := Load(srcPath)
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if err != nil {
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return err
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}
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c.Fill(width, height)
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if strings.HasSuffix(strings.ToLower(outPath), ".webp") {
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// 借用 FFmpeg 将生成的画布转为高质量 WebP
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tmpFile := filepath.Join(os.TempDir(), fmt.Sprintf("preview_%d.png", os.Getpid()))
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defer os.Remove(tmpFile)
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if err := Save(c, tmpFile); err != nil {
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return err
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}
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v, err := NewVideo()
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if err == nil {
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cmd := exec.Command(v.FFmpegPath, "-i", tmpFile, "-c:v", "libwebp", "-quality", "80", "-y", outPath)
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if err := cmd.Run(); err == nil {
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return nil
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}
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}
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}
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return Save(c, outPath)
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}
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// GenerateVideoPreview 生成视频预览 (动态 WebP)
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// 支持缩放并裁剪以填充指定尺寸 (Fill 模式)
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func GenerateVideoPreview(videoPath, outPath string, width, height int) error {
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v, err := NewVideo()
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if err != nil {
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return err
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}
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duration, err := getVideoDuration(videoPath)
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if err != nil {
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return err
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}
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// 动态计算帧数: 适合交给大模型 (VLM) 处理
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// 避免过多的帧浪费 Token，每 30 秒 1 帧，最少 3 帧，最多 8 帧
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frameCount := int(duration / 30.0)
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if frameCount < 3 {
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frameCount = 3
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} else if frameCount > 8 {
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frameCount = 8
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}
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// 在 10% 到 90% 之间均匀采样，跳过片头片尾的可能黑屏
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times := make([]float64, frameCount)
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if frameCount == 1 {
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times[0] = duration * 0.5
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} else {
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for i := 0; i < frameCount; i++ {
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times[i] = duration * (0.10 + 0.80*(float64(i)/float64(frameCount-1)))
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}
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}
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tmpDir, _ := os.MkdirTemp("", "frames")
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defer os.RemoveAll(tmpDir)
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// 使用 ffmpeg 的 scale 和 crop 滤镜实现 Fill 效果
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vf := fmt.Sprintf("scale=%d:%d:force_original_aspect_ratio=increase,crop=%d:%d", width, height, width, height)
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for i, t := range times {
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framePath := filepath.Join(tmpDir, fmt.Sprintf("frame_%02d.png", i))
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// 使用 -ss 快速 seek，性能极高
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cmd := exec.Command(v.FFmpegPath, "-ss", fmt.Sprintf("%f", t), "-i", videoPath, "-frames:v", "1", "-vf", vf, "-y", framePath)
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if err := cmd.Run(); err != nil {
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return err
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}
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}
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// 生成 WebP 动画，每秒 1 帧 (1000ms 间隔，让大模型能看清每一帧)
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cmd := exec.Command(v.FFmpegPath, "-framerate", "1", "-i", filepath.Join(tmpDir, "frame_%02d.png"),
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"-c:v", "libwebp", "-lossless", "0", "-quality", "70", "-loop", "0", "-y", outPath)
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return cmd.Run()
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}
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// GenerateAudioPreview 提取 3 分钟内的音频用于预览或语音转写
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// 格式: Ogg Opus, 16kHz, 单声道, 12kbps (极致压缩，保留人声特征)
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func GenerateAudioPreview(mediaPath, outPath string) error {
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v, err := NewVideo()
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if err != nil {
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return err
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}
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// -vn: 禁用视频
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// -c:a libopus: 高效音频压缩
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// -ar 16000: 采样率 16k (转写标准)
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// -ac 1: 单声道
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// -b:a 12k: 极致压缩
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// -t 180: 最长 180 秒 (足以获得内容概要)
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cmd := exec.Command(v.FFmpegPath, "-i", mediaPath, "-vn", "-c:a", "libopus", "-ar", "16000", "-ac", "1", "-b:a", "12k", "-t", "180", "-y", outPath)
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return cmd.Run()
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}
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func getVideoDuration(videoPath string) (float64, error) {
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out, err := exec.Command("ffprobe", "-v", "error", "-show_entries", "format=duration", "-of", "default=noprint_wrappers=1:nokey=1", videoPath).Output()
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if err != nil {
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return 0, err
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}
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var duration float64
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_, err = fmt.Sscanf(strings.TrimSpace(string(out)), "%f", &duration)
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return duration, err
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}
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