[camera] Fix preview freeze issue

packages/camera/CHANGELOG.md

@@ -4,4 +4,8 @@
 
 ## 0.2.0
 
-* Apply new external texture APIs
+* Apply new external texture APIs
+
+## 0.2.1
+
+* Fix a freezing preview issue

packages/camera/README.md

@@ -26,7 +26,7 @@ This package is not an _endorsed_ implementation of `camera`. Therefore, you hav
 ```yaml
 dependencies:
   camera: ^0.8.1
-  camera_tizen: ^0.2.0
+  camera_tizen: ^0.2.1
 ```
 
 Then you can import `camera` in your Dart code:

packages/camera/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_tizen
 description: Tizen implementation of the camera plugin
 homepage: https://github.com/flutter-tizen/plugins
 repository: https://github.com/flutter-tizen/plugins/tree/master/packages/camera
-version: 0.2.0
+version: 0.2.1
 
 dependencies:
   flutter:

packages/camera/tizen/src/camera_device.cc

@@ -16,14 +16,16 @@
 #define VIDEO_ENCODE_BITRATE 40000000 /* bps */
 #define AUDIO_SOURCE_SAMPLERATE_AAC 44100
 
-static uint64_t Timestamp() {
+namespace {
+
+uint64_t Timestamp() {
   struct timeval tv;
   gettimeofday(&tv, nullptr);
   return (uint64_t)tv.tv_sec * 1000UL + tv.tv_usec / 1000UL;
 }
 
-static std::string CreateTempFileName(const std::string &prefix,
-                                      const std::string &extension) {
+std::string CreateTempFileName(const std::string &prefix,
+                               const std::string &extension) {
   std::string file_name;
   char *cache_dir_path = app_get_cache_path();
   if (!cache_dir_path) {
@@ -38,8 +40,17 @@ static std::string CreateTempFileName(const std::string &prefix,
   return file_name;
 }
 
-static ExifTagOrientation ChooseExifTagOrientatoin(
-    OrientationType device_orientation, bool is_front_lens_facing) {
+bool IsValidMediaPacket(media_packet_h media_packet) {
+  tbm_surface_h surface = nullptr;
+  int ret = media_packet_get_tbm_surface(media_packet, &surface);
+  if (ret != MEDIA_PACKET_ERROR_NONE) {
+    return false;
+  }
+  return true;
+}
+
+ExifTagOrientation ChooseExifTagOrientatoin(OrientationType device_orientation,
+                                            bool is_front_lens_facing) {
   ExifTagOrientation orientation = ExifTagOrientation::kTopLeft;
 
   switch (device_orientation) {
@@ -79,7 +90,7 @@ static ExifTagOrientation ChooseExifTagOrientatoin(
   return orientation;
 }
 
-static RecorderOrientationTag ChooseRecorderOrientationTag(
+RecorderOrientationTag ChooseRecorderOrientationTag(
     OrientationType device_orientation) {
   RecorderOrientationTag tag = RecorderOrientationTag::kNone;
   switch (device_orientation) {
@@ -102,6 +113,8 @@ static RecorderOrientationTag ChooseRecorderOrientationTag(
   return tag;
 }
 
+}  // namespace
+
 bool StringToCameraPixelFormat(std::string Image_format,
                                CameraPixelFormat &pixel_format) {
   if (Image_format == "bgra8888") {
@@ -330,28 +343,40 @@ CameraDevice::CameraDevice(flutter::PluginRegistrar *registrar,
           [this](size_t width,
                  size_t height) -> const FlutterDesktopGpuBuffer * {
             std::lock_guard<std::mutex> lock(mutex_);
-            if (packet_ == nullptr) {
+            if (prepared_packet_ && !IsValidMediaPacket(prepared_packet_)) {
+              media_packet_destroy(prepared_packet_);
+              prepared_packet_ = nullptr;
+            }
+            if (current_packet_ && !IsValidMediaPacket(current_packet_)) {
+              media_packet_destroy(current_packet_);
+              current_packet_ = nullptr;
+            }
+            if (!prepared_packet_ && !current_packet_) {
               return nullptr;
             }
-            tbm_surface_h surface;
-            int ret = media_packet_get_tbm_surface(packet_, &surface);
+            if (prepared_packet_ && !current_packet_) {
+              current_packet_ = prepared_packet_;
+              prepared_packet_ = nullptr;
+            }
+
+            tbm_surface_h surface = nullptr;
+            int ret = media_packet_get_tbm_surface(current_packet_, &surface);
             if (ret != MEDIA_PACKET_ERROR_NONE) {
               LOG_ERROR("media_packet_get_tbm_surface failed, error: %d", ret);
-              media_packet_destroy(packet_);
-              packet_ = nullptr;
+              media_packet_destroy(current_packet_);
+              current_packet_ = nullptr;
               return nullptr;
             }
-
             flutter_desktop_gpu_buffer_->buffer = surface;
             flutter_desktop_gpu_buffer_->width = width;
             flutter_desktop_gpu_buffer_->height = height;
             return flutter_desktop_gpu_buffer_.get();
           },
           [this](void *buffer) -> void {
             std::lock_guard<std::mutex> lock(mutex_);
-            if (packet_) {
-              media_packet_destroy(packet_);
-              packet_ = nullptr;
+            if (current_packet_) {
+              media_packet_destroy(current_packet_);
+              current_packet_ = nullptr;
             }
           }));
   texture_id_ =
@@ -431,6 +456,16 @@ void CameraDevice::Dispose() {
   if (texture_id_ != 0) {
     registrar_->texture_registrar()->UnregisterTexture(texture_id_);
   }
+
+  if (current_packet_) {
+    media_packet_destroy(current_packet_);
+    current_packet_ = nullptr;
+  }
+
+  if (prepared_packet_) {
+    media_packet_destroy(prepared_packet_);
+    prepared_packet_ = nullptr;
+  }
 }
 
 bool CameraDevice::ForeachCameraSupportedCaptureResolutions(
@@ -950,17 +985,17 @@ void CameraDevice::Open(
     SetCameraPreviewFormat(pixel_format);
   }
 
-  if (!SetCameraMediaPacketPreviewCb([](media_packet_h pkt, void *data) {
+  if (!SetCameraMediaPacketPreviewCb([](media_packet_h packet, void *data) {
         auto self = static_cast<CameraDevice *>(data);
         std::lock_guard<std::mutex> lock(self->mutex_);
-        media_packet_h unused_packet = self->packet_;
-        self->packet_ = pkt;
-        if (unused_packet != nullptr) {
-          media_packet_destroy(unused_packet);
-        } else {
-          self->registrar_->texture_registrar()->MarkTextureFrameAvailable(
-              self->texture_id_);
+        if (self->prepared_packet_) {
+          media_packet_destroy(self->prepared_packet_);
+          self->prepared_packet_ = packet;
+          return;
         }
+        self->prepared_packet_ = packet;
+        self->registrar_->texture_registrar()->MarkTextureFrameAvailable(
+            self->texture_id_);
       })) {
     result->Error(kCameraDeviceError, "Failed to set media callback");
     return;

packages/camera/tizen/src/camera_device.h

@@ -325,7 +325,9 @@ class CameraDevice {
   flutter::PluginRegistrar *registrar_{nullptr};
   std::unique_ptr<flutter::TextureVariant> texture_variant_;
   std::unique_ptr<FlutterDesktopGpuBuffer> flutter_desktop_gpu_buffer_;
-  media_packet_h packet_{nullptr};
+  media_packet_h current_packet_{nullptr};
+  media_packet_h prepared_packet_{nullptr};
+
   std::mutex mutex_;
 
   std::unique_ptr<CameraMethodChannel> camera_method_channel_;