TQDM: Adding a Progress Bar to smiler

This week on my twitch live stream, I extended my tool/library smiler to use use a neural network to detect smiling faces:

1:09:00

Using a Convolutional Neural Network (CNN) to Detect Smiling Faces

Matt Hamilton ・ Jul 17 '20 ・ 4 min read

After the show I did some refactoring of the code, and tidied it all for for a release. It is now available to install/download on PyPI:

https://pypi.org/project/choirless-smiler/

You can use it either as a CLI tool, or as a library. We use it as a library in Choirless, and wrap it up as an Apache Openwhisk function for our render pipeline built on IBM Cloud Functions.

This morning I just added an extra feature, a progress bar when you use it as a CLI and specify the --verbose flag.

The progress bar is implemented using a great little Python library called TQDM which makes it really easy to add progress bars into your code.

The changes I made in smiler are to the method that calculates the threshold needed to get just 5% of the "most different" frames.

     def calc_threshold(self, frames, q=0.95):
         prev_frame = next(frames)
         counts = []
+
+        if self.verbose:
+            if self.total_frames is not None:
+                frames = tqdm(frames, total=self.total_frames)
+            else:
+                frames = tqdm(frames)
+            frames.set_description("Calculating threshold")
+
         for frame in frames:
             # Calculate the pixel difference between the current
             # frame and the previous one

and the method that actually analyses each frame:

         best_smile_score = 0
         best_frame = next(frames)

+        if self.verbose:
+            if self.total_frames is not None:
+                frames = tqdm(frames, total=self.total_frames)
+            else:
+                frames = tqdm(frames)
+            frames.set_description("Finding smiliest face")
+
         for frame in frames:
             # Convert the frame to grayscale
             gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

In both cases it was as simple as just wrapping the iterator in a tqdm() call. If I know the total number of frames then I pass that in as a parameter.