fix error when no person detected in video

app.py

@@ -155,7 +155,6 @@ def process_video(
             # ------------------------------------------------------------------------
             # Stage 1. Detect humans on the image
             # ------------------------------------------------------------------------
-
             inputs = person_image_processor(images=frame, return_tensors="pt").to(
                 device
             )
@@ -182,6 +181,9 @@ def process_video(
             # Stage 2. Detect keypoints for each person found
             # ------------------------------------------------------------------------
 
+            if len(person_boxes) == 0:
+                sink.write_frame(frame)
+                continue
             inputs = image_processor(
                 frame, boxes=[person_boxes], return_tensors="pt"
             ).to(device)
@@ -231,7 +233,7 @@ with gr.Blocks(theme=gr.themes.Soft(), css=css) as demo:
     gr.Markdown(
         """
 SynthPose is a new approach that enables finetuning of pre-trained 2D human pose models to predict an arbitrarily denser set of keypoints for accurate kinematic analysis through the use of synthetic data.
-More details are available in [OpenCapBench: A Benchmark to Bridge Pose Estimation and Biomechanics](https://arxiv.org/abs/2406.09788).
+More details are available in [OpenCapBench: A Benchmark to Bridge Pose Estimation and Biomechanics](https://arxiv.org/abs/2406.09788).<br />
 This particular variant was finetuned on a set of keypoints usually found on motion capture setups, and include coco keypoints as well.<br />
 The keypoints part of the skeleton are the COCO keypoints, and the pink ones the anatomical markers.
 """