Merge pull request #71 from djfun/fix-70

Fix #70 - Crash when exporting video in GUI mode

5 files changed, 36 insertions, 25 deletions

diff --git a/src/command.py b/src/command.py
index bf7941a..6d76906 100644
--- a/src/command.py
+++ b/src/command.py
@@ -58,12 +58,16 @@ class Command(QtCore.QObject):
         )
         self.parser.add_argument(
             '--test', action='store_true',
-            help='run tests, generate logfiles, then exit'
+            help='run tests and create a report full of debugging info'
         )
         self.parser.add_argument(
             '--debug', action='store_true',
             help='create bigger logfiles while program is running'
         )
+        self.parser.add_argument(
+            '--no-preview', action='store_true',
+            help='disable live preview during export in GUI mode'
+        )
 
         # optional arguments
         self.parser.add_argument(
@@ -140,6 +144,9 @@ class Command(QtCore.QObject):
             self.createAudioVisualisation(self.args.input, self.args.output)
             return "commandline"
 
+        elif self.args.no_preview:
+            core.Core.previewEnabled = False
+
         elif 'help' not in sys.argv and self.args.projpath is None and '--debug' not in sys.argv:
             self.parser.print_help()
             quit(1)
diff --git a/src/core.py b/src/core.py
index 77b0894..1ad4a67 100644
--- a/src/core.py
+++ b/src/core.py
@@ -487,6 +487,7 @@ class Core:
             ],
             'logDir': os.path.join(dataDir, 'log'),
             'logEnabled': False,
+            'previewEnabled': True,
         }
 
         settings['videoFormats'] = toolkit.appendUppercase([
diff --git a/src/gui/mainwindow.py b/src/gui/mainwindow.py
index f6de763..2bfc4e3 100644
--- a/src/gui/mainwindow.py
+++ b/src/gui/mainwindow.py
@@ -4,7 +4,7 @@
     This shows a preview of the video being created and allows for saving
     projects and exporting the video at a later time.
 '''
-from PyQt5 import QtCore, QtGui, QtWidgets, uic
+from PyQt5 import QtCore, QtWidgets, uic
 import PyQt5.QtWidgets as QtWidgets
 from PIL import Image
 from queue import Queue
@@ -754,7 +754,7 @@ class MainWindow(QtWidgets.QMainWindow):
             self.autosave()
         self.updateWindowTitle()
 
-    @QtCore.pyqtSlot(QtGui.QImage)
+    @QtCore.pyqtSlot('QImage')
     def showPreviewImage(self, image):
         self.previewWindow.changePixmap(image)
 
diff --git a/src/gui/preview_thread.py b/src/gui/preview_thread.py
index 137864b..3943a5c 100644
--- a/src/gui/preview_thread.py
+++ b/src/gui/preview_thread.py
@@ -38,6 +38,7 @@ class Worker(QtCore.QObject):
           "components": components,
         }
         self.queue.put(dic)
+        log.debug('Preview thread id: {}'.format(int(QtCore.QThread.currentThreadId())))
 
     @pyqtSlot()
     def process(self):
@@ -79,6 +80,8 @@ class Worker(QtCore.QObject):
                 except RuntimeError as e:
                     log.error(str(e))
             else:
+                # We must store a reference to this QImage
+                # or else Qt will garbage-collect it on the C++ side
                 self.frame = ImageQt(frame)
                 self.imageCreated.emit(QtGui.QImage(self.frame))
 
diff --git a/src/video_thread.py b/src/video_thread.py
index 5a28beb..dc6db89 100644
--- a/src/video_thread.py
+++ b/src/video_thread.py
@@ -44,6 +44,7 @@ class Worker(QtCore.QObject):
         self.settings = parent.settings
         self.modules = parent.core.modules
         parent.createVideo.connect(self.createVideo)
+        self.previewEnabled = type(parent.core).previewEnabled
 
         #self.parent = parent
         self.components = components
@@ -114,25 +115,23 @@ class Worker(QtCore.QObject):
         for audioI in range(0, self.audioArrayLen, self.sampleSize):
             self.compositeQueue.put(audioI)
 
-    def previewDispatch(self):
+    def showPreview(self, frame):
         '''
-            Grabs frames from the previewQueue, adds them to the checkerboard
-            and emits a final QImage to the MainWindow for the live preview
+            Receives a final frame that will be piped to FFmpeg,
+            adds it to the checkerboard and emits a final QImage
+            to the MainWindow for the live preview
         '''
-        background = Checkerboard(self.width, self.height)
-
-        while not self.stopped:
-            audioI, frame = self.previewQueue.get()
-            if time.time() - self.lastPreview >= 0.06 or audioI == 0:
-                image = Image.alpha_composite(background.copy(), frame)
-                self.imageCreated.emit(QtGui.QImage(ImageQt(image)))
-                self.lastPreview = time.time()
-
-            self.previewQueue.task_done()
+        # We must store a reference to this QImage
+        # or else Qt will garbage-collect it on the C++ side
+        self.latestPreview = ImageQt(frame)
+        self.imageCreated.emit(QtGui.QImage(self.latestPreview))
+        self.lastPreview = time.time()
 
     @pyqtSlot()
     def createVideo(self):
         log.debug("Video worker received signal to createVideo")
+        log.debug(
+            'Video thread id: {}'.format(int(QtCore.QThread.currentThreadId())))
         numpy.seterr(divide='ignore')
         self.encoding.emit(True)
         self.extraAudio = []
@@ -143,7 +142,6 @@ class Worker(QtCore.QObject):
         self.compositeQueue.maxsize = 20
         self.renderQueue = PriorityQueue()
         self.renderQueue.maxsize = 20
-        self.previewQueue = PriorityQueue()
 
         self.reset()
         progressBarValue = 0
@@ -305,15 +303,13 @@ class Worker(QtCore.QObject):
         self.dispatchThread.daemon = True
         self.dispatchThread.start()
 
-        self.lastPreview = 0.0
-        self.previewDispatch = Thread(
-            target=self.previewDispatch, name="Render Dispatch Thread"
-        )
-        self.previewDispatch.daemon = True
-        self.previewDispatch.start()
+        # Last time preview was drawn
+        self.lastPreview = time.time()
 
         # Begin piping into ffmpeg!
-        frameBuffer = {}
+        frameBuffer = {
+            # audioI: bytes ready to be piped
+        }
         progressBarValue = 0
         self.progressBarUpdate.emit(progressBarValue)
         self.progressBarSetText.emit("Exporting video...")
@@ -331,9 +327,12 @@ class Worker(QtCore.QObject):
                 if self.canceled:
                     break
 
+                # Update live preview
+                if self.previewEnabled and time.time() - self.lastPreview > 0.5:
+                    self.showPreview(frameBuffer[audioI])
+
                 try:
                     self.out_pipe.stdin.write(frameBuffer[audioI].tobytes())
-                    self.previewQueue.put([audioI, frameBuffer.pop(audioI)])
                 except Exception:
                     break
 
@@ -346,6 +345,7 @@ class Worker(QtCore.QObject):
                         "Exporting video: %s%%" % str(int(progressBarValue))
                     )
 
+
         numpy.seterr(all='print')
 
         self.closePipe()