Support default path of ffmpeg and not needing to specify it in the config

config-example.yaml

@@ -1,6 +1,5 @@
 publicHLSPath: webroot/hls
 privateHLSPath: hls
-ffmpegPath: /usr/bin/ffmpeg
 webServerPort: 8080
 
 instanceDetails:

config/config.go

@@ -2,8 +2,9 @@ package config
 
 import (
 	"errors"
-	"fmt"
 	"io/ioutil"
+	"os/exec"
+	"strings"
 
 	"github.com/gabek/owncast/utils"
 	log "github.com/sirupsen/logrus"
@@ -132,19 +133,26 @@ func (c *config) verifySettings() error {
 		}
 	}
 
-	// if !fileExists(config.PrivateHLSPath) {
-	// 	os.MkdirAll(path.Join(config.PrivateHLSPath, strconv.Itoa(0)), 0777)
-	// }
+	return nil
+}
 
-	// if !fileExists(config.PublicHLSPath) {
-	// 	os.MkdirAll(path.Join(config.PublicHLSPath, strconv.Itoa(0)), 0777)
-	// }
+func (c *config) GetFFMpegPath() string {
+	if c.FFMpegPath != "" {
+		return c.FFMpegPath
+	}
 
-	if !utils.DoesFileExists(c.FFMpegPath) {
-		return fmt.Errorf("ffmpeg does not exist at: %s", c.FFMpegPath)
+	cmd := exec.Command("which", "ffmpeg")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		log.Panicln("Unable to determine path to ffmpeg. Please specify it in the config file.")
 	}
 
-	return nil
+	path := strings.TrimSpace(string(out))
+
+	// Memoize it for future access
+	c.FFMpegPath = path
+
+	return path
 }
 
 //Load tries to load the configuration file

core/ffmpeg/thumbnailGenerator.go

@@ -72,7 +72,7 @@ func fireThumbnailGenerator(chunkPath string, variantIndex int) error {
 	mostRecentFile := path.Join(framePath, names[0])
 
 	thumbnailCmdFlags := []string{
-		config.Config.FFMpegPath,
+		config.Config.GetFFMpegPath(),
 		"-y",                 // Overwrite file
 		"-threads 1",         // Low priority processing
 		"-t 1",               // Pull from frame 1

core/ffmpeg/transcoder.go

@@ -104,7 +104,7 @@ func (t *Transcoder) getString() string {
 
 	ffmpegFlags := []string{
 		"cat", t.input, "|",
-		config.Config.FFMpegPath,
+		config.Config.GetFFMpegPath(),
 		"-hide_banner",
 		"-i pipe:",
 		t.getVariantsString(),