From b23c3cd61872e29590a617b72695efe3bf63fd4c Mon Sep 17 00:00:00 2001
From: WithoutPants <53250216+WithoutPants@users.noreply.github.com>
Date: Mon, 15 Dec 2025 14:57:00 +1100
Subject: [PATCH] Perform hardware codec checks on separate go routine (#6414)

Warn if tests are taking a long time
Add WaitDelay to try to kill process if hanging
---
 internal/manager/init.go     |  3 ++-
 pkg/ffmpeg/codec_hardware.go | 35 ++++++++++++++++++++++++++++++++---
 pkg/ffmpeg/ffmpeg.go         | 14 +++++++++++---
 3 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/internal/manager/init.go b/internal/manager/init.go
index dd1640ed3..b388bd15c 100644
--- a/internal/manager/init.go
+++ b/internal/manager/init.go
@@ -313,6 +313,7 @@ func (s *Manager) RefreshFFMpeg(ctx context.Context) {
 		s.FFMpeg = ffmpeg.NewEncoder(ffmpegPath)
 		s.FFProbe = ffmpeg.NewFFProbe(ffprobePath)
 
-		s.FFMpeg.InitHWSupport(ctx)
+		// initialise hardware support with background context
+		s.FFMpeg.InitHWSupport(context.Background())
 	}
 }
diff --git a/pkg/ffmpeg/codec_hardware.go b/pkg/ffmpeg/codec_hardware.go
index 530f4dc59..86fe56bde 100644
--- a/pkg/ffmpeg/codec_hardware.go
+++ b/pkg/ffmpeg/codec_hardware.go
@@ -36,6 +36,32 @@ const minHeight int = 480
 
 // Tests all (given) hardware codec's
 func (f *FFMpeg) InitHWSupport(ctx context.Context) {
+	// do the hardware codec tests in a separate goroutine to avoid blocking
+	done := make(chan struct{})
+	go func() {
+		f.initHWSupport(ctx)
+		close(done)
+	}()
+
+	// log if the initialization takes too long
+	const hwInitLogTimeoutSecondsDefault = 5
+	hwInitLogTimeoutSeconds := hwInitLogTimeoutSecondsDefault * time.Second
+	timer := time.NewTimer(hwInitLogTimeoutSeconds)
+
+	go func() {
+		select {
+		case <-timer.C:
+			logger.Warnf("[InitHWSupport] Hardware codec initialization is taking longer than %s...", hwInitLogTimeoutSeconds)
+			logger.Info("[InitHWSupport] Hardware encoding will not be available until initialization is complete.")
+		case <-done:
+			if !timer.Stop() {
+				<-timer.C
+			}
+		}
+	}()
+}
+
+func (f *FFMpeg) initHWSupport(ctx context.Context) {
 	var hwCodecSupport []VideoCodec
 
 	// Note that the first compatible codec is returned, so order is important
@@ -83,6 +109,7 @@ func (f *FFMpeg) InitHWSupport(ctx context.Context) {
 		defer cancel()
 
 		cmd := f.Command(testCtx, args)
+		cmd.WaitDelay = time.Second
 		logger.Tracef("[InitHWSupport] Testing codec %s: %v", codec, cmd.Args)
 
 		var stderr bytes.Buffer
@@ -112,6 +139,8 @@ func (f *FFMpeg) InitHWSupport(ctx context.Context) {
 	}
 	logger.Info(outstr)
 
+	f.hwCodecSupportMutex.Lock()
+	defer f.hwCodecSupportMutex.Unlock()
 	f.hwCodecSupport = hwCodecSupport
 }
 
@@ -411,7 +440,7 @@ func (f *FFMpeg) hwMaxResFilter(toCodec VideoCodec, vf *models.VideoFile, reqHei
 
 // Return if a hardware accelerated for HLS is available
 func (f *FFMpeg) hwCodecHLSCompatible() *VideoCodec {
-	for _, element := range f.hwCodecSupport {
+	for _, element := range f.getHWCodecSupport() {
 		switch element {
 		case VideoCodecN264,
 			VideoCodecN264H,
@@ -429,7 +458,7 @@ func (f *FFMpeg) hwCodecHLSCompatible() *VideoCodec {
 
 // Return if a hardware accelerated codec for MP4 is available
 func (f *FFMpeg) hwCodecMP4Compatible() *VideoCodec {
-	for _, element := range f.hwCodecSupport {
+	for _, element := range f.getHWCodecSupport() {
 		switch element {
 		case VideoCodecN264,
 			VideoCodecN264H,
@@ -445,7 +474,7 @@ func (f *FFMpeg) hwCodecMP4Compatible() *VideoCodec {
 
 // Return if a hardware accelerated codec for WebM is available
 func (f *FFMpeg) hwCodecWEBMCompatible() *VideoCodec {
-	for _, element := range f.hwCodecSupport {
+	for _, element := range f.getHWCodecSupport() {
 		switch element {
 		case VideoCodecIVP9,
 			VideoCodecVVP9:
diff --git a/pkg/ffmpeg/ffmpeg.go b/pkg/ffmpeg/ffmpeg.go
index ce1232e5d..04c58f04b 100644
--- a/pkg/ffmpeg/ffmpeg.go
+++ b/pkg/ffmpeg/ffmpeg.go
@@ -10,6 +10,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"sync"
 
 	stashExec "github.com/stashapp/stash/pkg/exec"
 	"github.com/stashapp/stash/pkg/fsutil"
@@ -216,9 +217,10 @@ func (v Version) String() string {
 
 // FFMpeg provides an interface to ffmpeg.
 type FFMpeg struct {
-	ffmpeg         string
-	version        Version
-	hwCodecSupport []VideoCodec
+	ffmpeg              string
+	version             Version
+	hwCodecSupport      []VideoCodec
+	hwCodecSupportMutex sync.RWMutex
 }
 
 // Creates a new FFMpeg encoder
@@ -241,3 +243,9 @@ func (f *FFMpeg) Command(ctx context.Context, args []string) *exec.Cmd {
 func (f *FFMpeg) Path() string {
 	return f.ffmpeg
 }
+
+func (f *FFMpeg) getHWCodecSupport() []VideoCodec {
+	f.hwCodecSupportMutex.RLock()
+	defer f.hwCodecSupportMutex.RUnlock()
+	return f.hwCodecSupport
+}