Improve image scanning performance and thumbnail generation (#1655)

* Improve image scanning performance and thumbnail generation
* Add vips-tools to build image
* Add option to write generated thumbnails to disk
* Fallback to image if thumbnail generation fails

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

pkg/image/thumbnail.go

@@ -2,39 +2,126 @@ package image
 
 import (
 	"bytes"
-	"image"
-	"image/jpeg"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+	"sync"
 
-	"github.com/disintegration/imaging"
+	"github.com/stashapp/stash/pkg/logger"
+	"github.com/stashapp/stash/pkg/models"
 )
 
-func ThumbnailNeeded(srcImage image.Image, maxSize int) bool {
-	dim := srcImage.Bounds().Max
-	w := dim.X
-	h := dim.Y
+var vipsPath string
+var once sync.Once
 
-	return w > maxSize || h > maxSize
+type ThumbnailEncoder struct {
+	FFMPEGPath string
+	VipsPath   string
+}
+
+func GetVipsPath() string {
+	once.Do(func() {
+		vipsPath, _ = exec.LookPath("vips")
+	})
+	return vipsPath
+}
+
+func NewThumbnailEncoder(ffmpegPath string) ThumbnailEncoder {
+	return ThumbnailEncoder{
+		FFMPEGPath: ffmpegPath,
+		VipsPath:   GetVipsPath(),
+	}
 }
 
 // GetThumbnail returns the thumbnail image of the provided image resized to
 // the provided max size. It resizes based on the largest X/Y direction.
 // It returns nil and an error if an error occurs reading, decoding or encoding
 // the image.
-func GetThumbnail(srcImage image.Image, maxSize int) ([]byte, error) {
-	var resizedImage image.Image
-
-	// if height is longer then resize by height instead of width
-	dim := srcImage.Bounds().Max
-	if dim.Y > dim.X {
-		resizedImage = imaging.Resize(srcImage, 0, maxSize, imaging.Box)
-	} else {
-		resizedImage = imaging.Resize(srcImage, maxSize, 0, imaging.Box)
-	}
-
-	buf := new(bytes.Buffer)
-	err := jpeg.Encode(buf, resizedImage, nil)
+func (e *ThumbnailEncoder) GetThumbnail(img *models.Image, maxSize int) ([]byte, error) {
+	reader, err := openSourceImage(img.Path)
 	if err != nil {
 		return nil, err
 	}
-	return buf.Bytes(), nil
+
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(reader)
+
+	_, format, err := DecodeSourceImage(img)
+	if err != nil {
+		return nil, err
+	}
+
+	if format != nil && *format == "gif" {
+		return buf.Bytes(), nil
+	}
+
+	if e.VipsPath != "" {
+		return e.getVipsThumbnail(buf, maxSize)
+	} else {
+		return e.getFFMPEGThumbnail(buf, format, maxSize, img.Path)
+	}
+}
+
+func (e *ThumbnailEncoder) getVipsThumbnail(image *bytes.Buffer, maxSize int) ([]byte, error) {
+	args := []string{
+		"thumbnail_source",
+		"[descriptor=0]",
+		".jpg[Q=70,strip]",
+		fmt.Sprint(maxSize),
+		"--size", "down",
+	}
+	data, err := e.run(e.VipsPath, args, image)
+
+	return []byte(data), err
+}
+
+func (e *ThumbnailEncoder) getFFMPEGThumbnail(image *bytes.Buffer, format *string, maxDimensions int, path string) ([]byte, error) {
+	// ffmpeg spends a long sniffing image format when data is piped through stdio, so we pass the format explicitly instead
+	ffmpegformat := ""
+	if format != nil && *format == "jpeg" {
+		ffmpegformat = "mjpeg"
+	} else if format != nil && *format == "png" {
+		ffmpegformat = "png_pipe"
+	} else if format != nil && *format == "webp" {
+		ffmpegformat = "webp_pipe"
+	} else {
+		return nil, errors.New("unsupported image format")
+	}
+
+	args := []string{
+		"-f", ffmpegformat,
+		"-i", "-",
+		"-vf", fmt.Sprintf("scale=%v:%v:force_original_aspect_ratio=decrease", maxDimensions, maxDimensions),
+		"-c:v", "mjpeg",
+		"-q:v", "5",
+		"-f", "image2pipe",
+		"-",
+	}
+	data, err := e.run(e.FFMPEGPath, args, image)
+
+	return []byte(data), err
+}
+
+func (e *ThumbnailEncoder) run(path string, args []string, stdin *bytes.Buffer) (string, error) {
+	cmd := exec.Command(path, args...)
+
+	var stdout, stderr bytes.Buffer
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	cmd.Stdin = stdin
+
+	if err := cmd.Start(); err != nil {
+		return "", err
+	}
+
+	err := cmd.Wait()
+
+	if err != nil {
+		// error message should be in the stderr stream
+		logger.Errorf("image encoder error when running command <%s>: %s", strings.Join(cmd.Args, " "), stderr.String())
+		return stdout.String(), err
+	}
+
+	return stdout.String(), nil
 }