merge gif and wav into mp4 with a ui via python and ffmpeg

merger.py

import tkinter as tk
from tkinter import filedialog, messagebox
import subprocess
import os

def browse_file(entry, file_type):
    if file_type == 'audio':
        filename = filedialog.askopenfilename(filetypes=[("Audio files", "*.wav")])
    elif file_type == 'gif':
        filename = filedialog.askopenfilename(filetypes=[("GIF files", "*.gif")])
    elif file_type == 'output':
        filename = filedialog.asksaveasfilename(filetypes=[("MP4 files", "*.mp4")], defaultextension=[("MP4 files", "*.mp4")])
    entry.delete(0, tk.END)
    entry.insert(0, filename)

def merge_files(audio_path, gif_path, output_path):
    command = [
        "ffmpeg",
        "-i", gif_path,
        "-i", audio_path,
        "-c:v", "libx264",
        "-pix_fmt", "yuv420p",
        "-c:a", "aac",
        "-shortest",
        output_path
    ]
    try:
        subprocess.run(command, check=True)
        messagebox.showinfo("Success", "The video file has been successfully created.")
    except subprocess.CalledProcessError as e:
        messagebox.showerror("Error", f"An error occurred during file merging: {e}")

def main():
    root = tk.Tk()
    root.title("Audio-GIF Merger")

    tk.Label(root, text="Select Audio File:").grid(row=0, column=0)
    audio_entry = tk.Entry(root, width=50)
    audio_entry.grid(row=0, column=1)
    tk.Button(root, text="Browse", command=lambda: browse_file(audio_entry, 'audio')).grid(row=0, column=2)

    tk.Label(root, text="Select GIF File:").grid(row=1, column=0)
    gif_entry = tk.Entry(root, width=50)
    gif_entry.grid(row=1, column=1)
    tk.Button(root, text="Browse", command=lambda: browse_file(gif_entry, 'gif')).grid(row=1, column=2)

    tk.Label(root, text="Select Output File:").grid(row=2, column=0)
    output_entry = tk.Entry(root, width=50)
    output_entry.grid(row=2, column=1)
    tk.Button(root, text="Browse", command=lambda: browse_file(output_entry, 'output')).grid(row=2, column=2)

    tk.Button(root, text="Merge Files", command=lambda: merge_files(audio_entry.get(), gif_entry.get(), output_entry.get())).grid(row=3, column=1)

    root.mainloop()

if __name__ == "__main__":
    main()