Change ffmpeg handling (#4688)

* Make ffmpeg/ffprobe settable and remove auto download
* Detect when ffmpeg not present in setup
* Add download ffmpeg task
* Add download ffmpeg button in system settings
* Download ffmpeg during setup

pkg/ffmpeg/ffmpeg.go

@@ -3,11 +3,96 @@ package ffmpeg
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"os/exec"
+	"strings"
 
 	stashExec "github.com/stashapp/stash/pkg/exec"
+	"github.com/stashapp/stash/pkg/fsutil"
+	"github.com/stashapp/stash/pkg/logger"
 )
 
+func ValidateFFMpeg(ffmpegPath string) error {
+	cmd := stashExec.Command(ffmpegPath, "-h")
+	bytes, err := cmd.CombinedOutput()
+	output := string(bytes)
+	if err != nil {
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			return fmt.Errorf("error running ffmpeg: %v", output)
+		}
+
+		return fmt.Errorf("error running ffmpeg: %v", err)
+	}
+
+	if !strings.Contains(output, "--enable-libopus") {
+		return fmt.Errorf("ffmpeg is missing libopus support")
+	}
+	if !strings.Contains(output, "--enable-libvpx") {
+		return fmt.Errorf("ffmpeg is missing libvpx support")
+	}
+	if !strings.Contains(output, "--enable-libx264") {
+		return fmt.Errorf("ffmpeg is missing libx264 support")
+	}
+	if !strings.Contains(output, "--enable-libx265") {
+		return fmt.Errorf("ffmpeg is missing libx265 support")
+	}
+	if !strings.Contains(output, "--enable-libwebp") {
+		return fmt.Errorf("ffmpeg is missing libwebp support")
+	}
+	return nil
+}
+
+func LookPathFFMpeg() string {
+	ret, _ := exec.LookPath(getFFMpegFilename())
+
+	if ret != "" {
+		// ensure ffmpeg has the correct flags
+		if err := ValidateFFMpeg(ret); err != nil {
+			logger.Warnf("ffmpeg found in PATH (%s), but it is missing required flags: %v", ret, err)
+			ret = ""
+		}
+	}
+
+	return ret
+}
+
+func FindFFMpeg(path string) string {
+	ret := fsutil.FindInPaths([]string{path}, getFFMpegFilename())
+
+	if ret != "" {
+		// ensure ffmpeg has the correct flags
+		if err := ValidateFFMpeg(ret); err != nil {
+			logger.Warnf("ffmpeg found (%s), but it is missing required flags: %v", ret, err)
+			ret = ""
+		}
+	}
+
+	return ret
+}
+
+// ResolveFFMpeg attempts to resolve the path to the ffmpeg executable.
+// It first looks in the provided path, then resolves from the environment, and finally looks in the fallback path.
+// Returns an empty string if a valid ffmpeg cannot be found.
+func ResolveFFMpeg(path string, fallbackPath string) string {
+	// look in the provided path first
+	ret := FindFFMpeg(path)
+	if ret != "" {
+		return ret
+	}
+
+	// then resolve from the environment
+	ret = LookPathFFMpeg()
+	if ret != "" {
+		return ret
+	}
+
+	// finally, look in the fallback path
+	ret = FindFFMpeg(fallbackPath)
+	return ret
+}
+
 // FFMpeg provides an interface to ffmpeg.
 type FFMpeg struct {
 	ffmpeg         string
@@ -27,3 +112,7 @@ func NewEncoder(ffmpegPath string) *FFMpeg {
 func (f *FFMpeg) Command(ctx context.Context, args []string) *exec.Cmd {
 	return stashExec.CommandContext(ctx, string(f.ffmpeg), args...)
 }
+
+func (f *FFMpeg) Path() string {
+	return f.ffmpeg
+}