src/streamlit_app.py

import streamlit as st
import os

# Video directory
VIDEO_FOLDER = "./src/synthda_falling_realreal/"

# Set page layout
st.set_page_config(layout="wide")

# Title and description (centered)
st.markdown("""
    <h1 style="text-align: center;">Project SynthDa</h1>
    <h3 style="text-align: center;">SynthDa Interpolation Demo Viewer</h3>
    <p style="text-align: center;">
        AutoSynthDa blends two input motion videos to <strong>generate kinematically coherent, synthetic action videos</strong>.<br>
        Use the slider below to explore how the system interpolates motion from one video to another.<br>
        Source: <a href="https://github.com/nvidia/synthda" target="_blank">github.com/nvidia/synthda</a>
    </p>
""", unsafe_allow_html=True)

# Slider instruction (centered)
st.markdown(
    '<p style="text-align: center;"><strong>Use the slider to control the interpolation between Input Video 1 (left) and Input Video 2 (right).</strong></p>',
    unsafe_allow_html=True
)

# Slider (starts at 0.5)
weight = st.slider("Interpolation Weight", 0.1, 0.9, 0.5, step=0.1)

# Interpolation explanation (centered)
if weight == 0.0:
    interp_text = "Showing Input Video 1 (no interpolation)"
elif weight == 1.0:
    interp_text = "Showing Input Video 2 (no interpolation)"
else:
    w2 = round(1.0 - weight, 1)
    interp_text = f"Generated motion: {weight:.1f} from Input Video 1 + {w2:.1f} from Input Video 2"

st.markdown(f'<p style="text-align: center; color: #444;"><strong>{interp_text}</strong></p>', unsafe_allow_html=True)

# Filepaths
filename_interp = f"videos_generated_{weight:.1f}.mp4"
filename_input1 = "videos_generated_0.0.mp4"
filename_input2 = "videos_generated_1.0.mp4"

video_interp = os.path.join(VIDEO_FOLDER, filename_interp)
video_input1 = os.path.join(VIDEO_FOLDER, filename_input1)
video_input2 = os.path.join(VIDEO_FOLDER, filename_input2)

exists_interp = os.path.exists(video_interp)
exists_1 = os.path.exists(video_input1)
exists_2 = os.path.exists(video_input2)

# Layout: 3 columns for video display
col1, col2, col3 = st.columns(3)

with col1:
    st.markdown("<div style='text-align: center; font-weight: bold;'>Input Video 1</div>", unsafe_allow_html=True)
    if exists_1:
        st.video(video_input1)
    else:
        st.error("Video 1 not found")

with col2:
    st.markdown("<div style='text-align: center; font-weight: bold;'>Interpolated Video</div>", unsafe_allow_html=True)
    if exists_interp:
        st.video(video_interp)
    else:
        st.error("Interpolated video not found")

with col3:
    st.markdown("<div style='text-align: center; font-weight: bold;'>Input Video 2</div>", unsafe_allow_html=True)
    if exists_2:
        st.video(video_input2)
    else:
        st.error("Video 2 not found")