Add GStreamer preview backend

internal/player/frame_player.go

@@ -0,0 +1,18 @@
+package player
+
+import (
+	"image"
+	"time"
+)
+
+type framePlayer interface {
+	Load(path string, offset time.Duration) error
+	Play() error
+	Pause() error
+	SeekToTime(offset time.Duration) error
+	SeekToFrame(frame int64) error
+	GetCurrentTime() time.Duration
+	GetFrameImage() (*image.RGBA, error)
+	SetVolume(level float64) error
+	Close()
+}

internal/player/frame_player_default.go

@@ -0,0 +1,7 @@
+//go:build !gstreamer
+
+package player
+
+func newFramePlayer(config Config) (framePlayer, error) {
+	return NewUnifiedPlayer(config), nil
+}

internal/player/frame_player_gstreamer.go

@@ -0,0 +1,10 @@
+//go:build gstreamer
+
+package player
+
+func newFramePlayer(config Config) (framePlayer, error) {
+	if gstPlayer, err := NewGStreamerPlayer(config); err == nil {
+		return gstPlayer, nil
+	}
+	return NewUnifiedPlayer(config), nil
+}

internal/player/gstreamer_player.go

@@ -0,0 +1,332 @@
+//go:build gstreamer
+
+package player
+
+/*
+#cgo pkg-config: gstreamer-1.0 gstreamer-app-1.0 gstreamer-video-1.0
+#include <gst/gst.h>
+#include <gst/app/gstappsink.h>
+#include <gst/video/video.h>
+#include <stdlib.h>
+
+static void vt_gst_set_str(GstElement* elem, const char* name, const char* value) {
+	g_object_set(G_OBJECT(elem), name, value, NULL);
+}
+static void vt_gst_set_bool(GstElement* elem, const char* name, gboolean value) {
+	g_object_set(G_OBJECT(elem), name, value, NULL);
+}
+static void vt_gst_set_int(GstElement* elem, const char* name, gint value) {
+	g_object_set(G_OBJECT(elem), name, value, NULL);
+}
+static void vt_gst_set_float(GstElement* elem, const char* name, gdouble value) {
+	g_object_set(G_OBJECT(elem), name, value, NULL);
+}
+static void vt_gst_set_obj(GstElement* elem, const char* name, gpointer value) {
+	g_object_set(G_OBJECT(elem), name, value, NULL);
+}
+*/
+import "C"
+
+import (
+	"errors"
+	"image"
+	"net/url"
+	"path/filepath"
+	"runtime"
+	"sync"
+	"time"
+	"unsafe"
+)
+
+var gstInitOnce sync.Once
+
+type GStreamerPlayer struct {
+	mu       sync.Mutex
+	pipeline *C.GstElement
+	appsink  *C.GstElement
+	paused   bool
+	volume   float64
+	preview  bool
+	width    int
+	height   int
+	fps      float64
+}
+
+func NewGStreamerPlayer(config Config) (*GStreamerPlayer, error) {
+	var initErr error
+	gstInitOnce.Do(func() {
+		if C.gst_init_check(nil, nil, nil) == 0 {
+			initErr = errors.New("gstreamer init failed")
+		}
+	})
+	if initErr != nil {
+		return nil, initErr
+	}
+
+	return &GStreamerPlayer{
+		paused:  true,
+		volume:  config.Volume,
+		preview: config.PreviewMode,
+	}, nil
+}
+
+func (p *GStreamerPlayer) Load(path string, offset time.Duration) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	p.closeLocked()
+
+	playbinName := C.CString("playbin")
+	playbin := C.gst_element_factory_make(playbinName, nil)
+	C.free(unsafe.Pointer(playbinName))
+	if playbin == nil {
+		return errors.New("gstreamer playbin unavailable")
+	}
+
+	appsinkName := C.CString("appsink")
+	appsink := C.gst_element_factory_make(appsinkName, nil)
+	C.free(unsafe.Pointer(appsinkName))
+	if appsink == nil {
+		C.gst_object_unref(C.gpointer(playbin))
+		return errors.New("gstreamer appsink unavailable")
+	}
+
+	capsStr := C.CString("video/x-raw,format=RGBA")
+	caps := C.gst_caps_from_string(capsStr)
+	C.free(unsafe.Pointer(capsStr))
+	if caps != nil {
+	capsName := C.CString("caps")
+	C.vt_gst_set_obj(appsink, capsName, C.gpointer(caps))
+	C.free(unsafe.Pointer(capsName))
+		C.gst_caps_unref(caps)
+	}
+	emitSignals := C.CString("emit-signals")
+	C.vt_gst_set_bool(appsink, emitSignals, C.gboolean(0))
+	C.free(unsafe.Pointer(emitSignals))
+	syncName := C.CString("sync")
+	C.vt_gst_set_bool(appsink, syncName, C.gboolean(0))
+	C.free(unsafe.Pointer(syncName))
+	maxBuffers := C.CString("max-buffers")
+	C.vt_gst_set_int(appsink, maxBuffers, C.gint(2))
+	C.free(unsafe.Pointer(maxBuffers))
+	dropName := C.CString("drop")
+	C.vt_gst_set_bool(appsink, dropName, C.gboolean(1))
+	C.free(unsafe.Pointer(dropName))
+
+	var audioSink *C.GstElement
+	if p.preview {
+		fakeName := C.CString("fakesink")
+		audioSink = C.gst_element_factory_make(fakeName, nil)
+		C.free(unsafe.Pointer(fakeName))
+	} else {
+		autoName := C.CString("autoaudiosink")
+		audioSink = C.gst_element_factory_make(autoName, nil)
+		C.free(unsafe.Pointer(autoName))
+	}
+	if audioSink == nil {
+		C.gst_object_unref(C.gpointer(playbin))
+		C.gst_object_unref(C.gpointer(appsink))
+		return errors.New("gstreamer audio sink unavailable")
+	}
+
+	uri := fileURI(path)
+	uriC := C.CString(uri)
+	uriName := C.CString("uri")
+	C.vt_gst_set_str(playbin, uriName, uriC)
+	C.free(unsafe.Pointer(uriName))
+	C.free(unsafe.Pointer(uriC))
+	videoSinkName := C.CString("video-sink")
+	C.vt_gst_set_obj(playbin, videoSinkName, C.gpointer(appsink))
+	C.free(unsafe.Pointer(videoSinkName))
+	audioSinkName := C.CString("audio-sink")
+	C.vt_gst_set_obj(playbin, audioSinkName, C.gpointer(audioSink))
+	C.free(unsafe.Pointer(audioSinkName))
+
+	if p.volume <= 0 {
+		p.volume = 1.0
+	}
+	volumeName := C.CString("volume")
+	C.vt_gst_set_float(playbin, volumeName, C.gdouble(p.volume))
+	C.free(unsafe.Pointer(volumeName))
+
+	p.pipeline = playbin
+	p.appsink = appsink
+	p.paused = true
+
+	C.gst_element_set_state(playbin, C.GST_STATE_PAUSED)
+	if offset > 0 {
+		_ = p.seekLocked(offset)
+	}
+
+	return nil
+}
+
+func (p *GStreamerPlayer) Play() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if p.pipeline == nil {
+		return errors.New("no pipeline loaded")
+	}
+	C.gst_element_set_state(p.pipeline, C.GST_STATE_PLAYING)
+	p.paused = false
+	return nil
+}
+
+func (p *GStreamerPlayer) Pause() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if p.pipeline == nil {
+		return errors.New("no pipeline loaded")
+	}
+	C.gst_element_set_state(p.pipeline, C.GST_STATE_PAUSED)
+	p.paused = true
+	return nil
+}
+
+func (p *GStreamerPlayer) SeekToTime(offset time.Duration) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	return p.seekLocked(offset)
+}
+
+func (p *GStreamerPlayer) seekLocked(offset time.Duration) error {
+	if p.pipeline == nil {
+		return errors.New("no pipeline loaded")
+	}
+	nanos := C.gint64(offset.Nanoseconds())
+	flags := C.GST_SEEK_FLAG_FLUSH | C.GST_SEEK_FLAG_KEY_UNIT
+	if C.gst_element_seek_simple(p.pipeline, C.GST_FORMAT_TIME, flags, nanos) == 0 {
+		return errors.New("gstreamer seek failed")
+	}
+	return nil
+}
+
+func (p *GStreamerPlayer) SeekToFrame(frame int64) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.fps <= 0 {
+		return nil
+	}
+	seconds := float64(frame) / p.fps
+	return p.seekLocked(time.Duration(seconds * float64(time.Second)))
+}
+
+func (p *GStreamerPlayer) GetCurrentTime() time.Duration {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.pipeline == nil {
+		return 0
+	}
+	var pos C.gint64
+	if C.gst_element_query_position(p.pipeline, C.GST_FORMAT_TIME, &pos) == 0 {
+		return 0
+	}
+	return time.Duration(pos)
+}
+
+func (p *GStreamerPlayer) GetFrameImage() (*image.RGBA, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if p.appsink == nil {
+		return nil, errors.New("gstreamer appsink unavailable")
+	}
+	sample := C.gst_app_sink_try_pull_sample((*C.GstAppSink)(unsafe.Pointer(p.appsink)), 0)
+	if sample == nil {
+		return nil, nil
+	}
+	defer C.gst_sample_unref(sample)
+
+	caps := C.gst_sample_get_caps(sample)
+	if caps == nil {
+		return nil, errors.New("gstreamer caps unavailable")
+	}
+	str := C.gst_caps_get_structure(caps, 0)
+	var width C.gint
+	var height C.gint
+	widthName := C.CString("width")
+	C.gst_structure_get_int(str, widthName, &width)
+	C.free(unsafe.Pointer(widthName))
+	heightName := C.CString("height")
+	C.gst_structure_get_int(str, heightName, &height)
+	C.free(unsafe.Pointer(heightName))
+	if width > 0 && height > 0 {
+		p.width = int(width)
+		p.height = int(height)
+	}
+	var fpsNum C.gint
+	var fpsDen C.gint
+	fpsName := C.CString("framerate")
+	if C.gst_structure_get_fraction(str, fpsName, &fpsNum, &fpsDen) != 0 && fpsDen != 0 {
+		p.fps = float64(fpsNum) / float64(fpsDen)
+	}
+	C.free(unsafe.Pointer(fpsName))
+
+	buffer := C.gst_sample_get_buffer(sample)
+	if buffer == nil {
+		return nil, errors.New("gstreamer buffer unavailable")
+	}
+	var mapInfo C.GstMapInfo
+	if C.gst_buffer_map(buffer, &mapInfo, C.GST_MAP_READ) == 0 {
+		return nil, errors.New("gstreamer buffer map failed")
+	}
+	defer C.gst_buffer_unmap(buffer, &mapInfo)
+
+	if p.width == 0 || p.height == 0 {
+		return nil, errors.New("invalid frame size")
+	}
+	frameSize := p.width * p.height * 4
+	if int(mapInfo.size) < frameSize {
+		return nil, errors.New("incomplete frame")
+	}
+
+	img := image.NewRGBA(image.Rect(0, 0, p.width, p.height))
+	data := unsafe.Slice((*byte)(unsafe.Pointer(mapInfo.data)), frameSize)
+	copy(img.Pix, data)
+	return img, nil
+}
+
+func (p *GStreamerPlayer) SetVolume(level float64) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.volume = level
+	if p.pipeline != nil {
+		volumeName := C.CString("volume")
+		C.vt_gst_set_float(p.pipeline, volumeName, C.gdouble(level))
+		C.free(unsafe.Pointer(volumeName))
+	}
+	return nil
+}
+
+func (p *GStreamerPlayer) Close() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.closeLocked()
+}
+
+func (p *GStreamerPlayer) closeLocked() {
+	if p.pipeline != nil {
+		C.gst_element_set_state(p.pipeline, C.GST_STATE_NULL)
+		C.gst_object_unref(C.gpointer(p.pipeline))
+		p.pipeline = nil
+	}
+	if p.appsink != nil {
+		C.gst_object_unref(C.gpointer(p.appsink))
+		p.appsink = nil
+	}
+}
+
+func fileURI(path string) string {
+	abs, err := filepath.Abs(path)
+	if err != nil {
+		abs = path
+	}
+	abs = filepath.ToSlash(abs)
+	if runtime.GOOS == "windows" && len(abs) >= 2 && abs[1] == ':' {
+		abs = "/" + abs
+	}
+	u := url.URL{Scheme: "file", Path: abs}
+	return u.String()
+}

internal/player/unified_player_adapter.go

@@ -13,8 +13,8 @@ import (
 // UnifiedPlayerAdapter wraps UnifiedPlayer to provide playSession interface compatibility
 // This allows seamless replacement of the dual-process player with UnifiedPlayer
 type UnifiedPlayerAdapter struct {
-	// Core UnifiedPlayer
-	player *UnifiedPlayer
+	// Frame-capable player backend
+	player framePlayer
 
 	// Interface compatibility fields (from playSession)
 	path      string
@@ -64,7 +64,7 @@ func NewUnifiedPlayerAdapter(path string, width, height int, fps, duration float
 		startTime: time.Now(),
 	}
 
-	// Create UnifiedPlayer with proper configuration
+	// Create frame-capable player with proper configuration
 	config := Config{
 		Backend:       BackendAuto, // Use auto for UnifiedPlayer
 		WindowX:       0,
@@ -83,23 +83,10 @@ func NewUnifiedPlayerAdapter(path string, width, height int, fps, duration float
 		LogLevel:      3,                // Debug
 	}
 
-	adapter.player = NewUnifiedPlayer(config)
-
-	// Set up callbacks for progress and frame updates
-	adapter.player.SetTimeCallback(func(d time.Duration) {
-		seconds := d.Seconds()
-		adapter.current = seconds
-		if adapter.prog != nil {
-			adapter.prog(seconds)
-		}
-	})
-
-	adapter.player.SetFrameCallback(func(frame int64) {
-		adapter.frameN = int(frame)
-		if adapter.frameFunc != nil {
-			adapter.frameFunc(int(frame))
-		}
-	})
+	playerBackend, err := newFramePlayer(config)
+	if err == nil {
+		adapter.player = playerBackend
+	}
 
 	return adapter
 }
@@ -328,7 +315,11 @@ func (p *UnifiedPlayerAdapter) startFrameDisplayLoop() {
 
 	go func() {
 		// Display at frame rate
-		frameDuration := time.Second / time.Duration(p.fps)
+		fps := p.fps
+		if fps <= 0 {
+			fps = 24
+		}
+		frameDuration := time.Second / time.Duration(fps)
 		ticker := time.NewTicker(frameDuration)
 		defer ticker.Stop()
 

scripts/build-linux.sh

@@ -58,6 +58,17 @@ mkdir -p "$GOCACHE" "$GOMODCACHE"
 if [ -d "$PROJECT_ROOT/vendor" ] && [ ! -f "$PROJECT_ROOT/vendor/modules.txt" ]; then
     export GOFLAGS="${GOFLAGS:-} -mod=mod"
 fi
+GST_TAG=""
+if [ -n "$VT_GSTREAMER" ]; then
+    GST_TAG="gstreamer"
+elif command -v pkg-config &> /dev/null; then
+    if pkg-config --exists gstreamer-1.0 gstreamer-app-1.0 gstreamer-video-1.0; then
+        GST_TAG="gstreamer"
+    fi
+fi
+if [ -n "$GST_TAG" ]; then
+    export GOFLAGS="${GOFLAGS:-} -tags ${GST_TAG}"
+fi
 if go build -o "$BUILD_OUTPUT" .; then
     echo "Build successful! (VideoTools $APP_VERSION)"
     echo ""

scripts/build.sh

@@ -64,6 +64,9 @@ case "$OS" in
 
         echo "Building VideoTools $APP_VERSION for Windows..."
         export CGO_ENABLED=1
+        if [ -n "$VT_GSTREAMER" ] || command -v gst-launch-1.0 &> /dev/null; then
+            export GOFLAGS="${GOFLAGS:-} -tags gstreamer"
+        fi
         if [ -d "$PROJECT_ROOT/vendor" ] && [ ! -f "$PROJECT_ROOT/vendor/modules.txt" ]; then
             export GOFLAGS="${GOFLAGS:-} -mod=mod"
         fi