app.py

import gradio as gr
import os
import torch
from shutil import rmtree
from torch import nn
from torch.nn import functional as F
import numpy as np
import subprocess
import cv2
import pickle
import librosa
from decord import VideoReader
from decord import cpu, gpu
from utils.audio_utils import *
from utils.inference_utils import *
from sync_models.gestsync_models import *
from tqdm import tqdm
from glob import glob
import mediapipe as mp
from protobuf_to_dict import protobuf_to_dict
import warnings

mp_holistic = mp.solutions.holistic
warnings.filterwarnings("ignore", category=DeprecationWarning)
warnings.filterwarnings("ignore", category=UserWarning)

# Initialize global variables
CHECKPOINT_PATH = "model_rgb.pth" 
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
use_cuda = torch.cuda.is_available()
batch_size = 12
fps = 25
n_negative_samples = 100

# Initialize the mediapipe holistic keypoint detection model
holistic = mp_holistic.Holistic(min_detection_confidence=0.5, min_tracking_confidence=0.5)


def preprocess_video(path, result_folder, apply_preprocess, padding=20):

	'''
	This function preprocesses the input video to extract the audio and crop the frames using YOLO model

	Args:
		- path (string) : Path of the input video file
		- result_folder (string) : Path of the folder to save the extracted audio and cropped video
		- padding (int) : Padding to add to the bounding box
	Returns:
		- wav_file (string) : Path of the extracted audio file
		- fps (int) : FPS of the input video
		- video_output (string) : Path of the cropped video file
		- msg (string) : Message to be returned
	'''
	
	# Load all video frames
	try:
		vr = VideoReader(path, ctx=cpu(0))
		fps = vr.get_avg_fps()
		frame_count = len(vr)
	except:
		msg = "Oops! Could not load the video. Please check the input video and try again."
		return None, None, None, msg

	if frame_count < 25:
		msg = "Not enough frames to process! Please give a longer video as input"
		return None, None, None, msg

	# Extract the audio from the input video file using ffmpeg
	wav_file  = os.path.join(result_folder, "audio.wav")

	status = subprocess.call('ffmpeg -hide_banner -loglevel panic -y -i %s -async 1 -ac 1 -vn \
					-acodec pcm_s16le -ar 16000 %s -y' % (path, wav_file), shell=True)

	if status != 0:
		msg = "Oops! Could not load the audio file. Please check the input video and try again."
		return None, None, None, msg
	print("Extracted the audio from the video")

	if apply_preprocess=="True":
		all_frames = []
		for k in range(len(vr)):
				all_frames.append(vr[k].asnumpy())
		all_frames = np.asarray(all_frames)
		print("Extracted the frames for pre-processing")

		# Load YOLOv9 model (pre-trained on COCO dataset)
		yolo_model = YOLO("yolov9s.pt")
		print("Loaded the YOLO model")

		

		person_videos = {}
		person_tracks = {}

		print("Processing the frames...")
		for frame_idx in tqdm(range(frame_count)):
		
			frame = all_frames[frame_idx]
		
			# Perform person detection
			results = yolo_model(frame, verbose=False)
			detections = results[0].boxes
		
			for i, det in enumerate(detections):
				x1, y1, x2, y2 = det.xyxy[0]
				cls = det.cls[0]
				if int(cls) == 0:  # Class 0 is 'person' in COCO dataset
				
					x1 = max(0, int(x1) - padding)
					y1 = max(0, int(y1) - padding)
					x2 = min(frame.shape[1], int(x2) + padding)
					y2 = min(frame.shape[0], int(y2) + padding)

					if i not in person_videos:
						person_videos[i] = []
						person_tracks[i] = []

					person_videos[i].append(frame)
					person_tracks[i].append([x1,y1,x2,y2])
			
		
		num_persons = 0
		for i in person_videos.keys():
			if len(person_videos[i]) >= frame_count//2:
				num_persons+=1

		if num_persons==0:
			msg = "No person detected in the video! Please give a video with one person as input"
			return None, None, None, msg
		if num_persons>1:
			msg = "More than one person detected in the video! Please give a video with only one person as input"
			return None, None, None, msg

		

		# For the person detected, crop the frame based on the bounding box
		if len(person_videos[0]) > frame_count-10:
			crop_filename = os.path.join(result_folder, "preprocessed_video.avi")
			fourcc = cv2.VideoWriter_fourcc(*'DIVX')

			# Get bounding box coordinates based on person_tracks[i]
			max_x1 = min([track[0] for track in person_tracks[0]])
			max_y1 = min([track[1] for track in person_tracks[0]])
			max_x2 = max([track[2] for track in person_tracks[0]])
			max_y2 = max([track[3] for track in person_tracks[0]])

			max_width = max_x2 - max_x1
			max_height = max_y2 - max_y1

			out = cv2.VideoWriter(crop_filename, fourcc, fps, (max_width, max_height))
			for frame in person_videos[0]:
				crop = frame[max_y1:max_y2, max_x1:max_x2]
				crop = cv2.cvtColor(crop, cv2.COLOR_BGR2RGB)
				out.write(crop)
			out.release()

			no_sound_video = crop_filename.split('.')[0] + '_nosound.mp4'
			status = subprocess.call('ffmpeg -hide_banner -loglevel panic -y -i %s -c copy -an -strict -2 %s' % (crop_filename, no_sound_video), shell=True)
			if status != 0:
				msg = "Oops! Could not preprocess the video. Please check the input video and try again."
				return None, None, None, msg
			
			video_output = crop_filename.split('.')[0] + '.mp4'
			status = subprocess.call('ffmpeg -hide_banner -loglevel panic -y -i %s -i %s -strict -2 -q:v 1 %s' % 
							(wav_file , no_sound_video, video_output), shell=True)
			if status != 0:
				msg = "Oops! Could not preprocess the video. Please check the input video and try again."
				return None, None, None, msg
			
			os.remove(crop_filename)
			os.remove(no_sound_video)

			print("Successfully saved the pre-processed video: ", video_output)
		else:
			msg = "Could not track the person in the full video! Please give a single-speaker video as input"
			return None, None, None, msg

	else:
		video_output = path

	return wav_file, fps, video_output, "success"

def resample_video(video_file, video_fname, result_folder):

	'''
	This function resamples the video to 25 fps

	Args:
		- video_file (string) : Path of the input video file
		- video_fname (string) : Name of the input video file
		- result_folder (string) : Path of the folder to save the resampled video
	Returns:
		- video_file_25fps (string) : Path of the resampled video file
	'''
	video_file_25fps = os.path.join(result_folder, '{}.mp4'.format(video_fname))
	
	# Resample the video to 25 fps
	command = ("ffmpeg -hide_banner -loglevel panic -y -i {} -q:v 1 -filter:v fps=25 {}".format(video_file, video_file_25fps))
	from subprocess import call
	cmd = command.split(' ')
	print('Resampled the video to 25 fps: {}'.format(video_file_25fps))
	call(cmd)

	return video_file_25fps

def load_checkpoint(path, model):
	'''
	This function loads the trained model from the checkpoint

	Args:
		- path (string) : Path of the checkpoint file
		- model (object) : Model object
	Returns:
		- model (object) : Model object with the weights loaded from the checkpoint
	'''	

	# Load the checkpoint
	if use_cuda:
		checkpoint = torch.load(path)
	else:
		checkpoint = torch.load(path, map_location="cpu")
	
	s = checkpoint["state_dict"]
	new_s = {}
	
	for k, v in s.items():
		new_s[k.replace('module.', '')] = v
	model.load_state_dict(new_s)

	if use_cuda:
		model.cuda()

	print("Loaded checkpoint from: {}".format(path))

	return model.eval()


def load_video_frames(video_file):
	'''
	This function extracts the frames from the video

	Args:
		- video_file (string) : Path of the video file
	Returns:
		- frames (list) : List of frames extracted from the video
		- msg (string) : Message to be returned
	'''

	# Read the video
	try:
		vr = VideoReader(video_file, ctx=cpu(0))
	except:
		msg = "Oops! Could not load the input video file"
		return None, msg


	# Extract the frames
	frames = []
	for k in range(len(vr)):
		frames.append(vr[k].asnumpy())

	frames = np.asarray(frames)

	return frames, "success"



def get_keypoints(frames):

	'''
	This function extracts the keypoints from the frames using MediaPipe Holistic pipeline

	Args:
		- frames (list) : List of frames extracted from the video
	Returns:
		- kp_dict (dict) : Dictionary containing the keypoints and the resolution of the frames
		- msg (string) : Message to be returned
	'''

	try:
		holistic = mp_holistic.Holistic(min_detection_confidence=0.5, min_tracking_confidence=0.5) 

		resolution = frames[0].shape
		all_frame_kps = []

		for frame in frames:

			results = holistic.process(frame)

			pose, left_hand, right_hand, face = None, None, None, None
			if results.pose_landmarks is not None:
				pose = protobuf_to_dict(results.pose_landmarks)['landmark']
			if results.left_hand_landmarks is not None:
				left_hand = protobuf_to_dict(results.left_hand_landmarks)['landmark']
			if results.right_hand_landmarks is not None:
				right_hand = protobuf_to_dict(results.right_hand_landmarks)['landmark']
			if results.face_landmarks is not None:
				face = protobuf_to_dict(results.face_landmarks)['landmark']

			frame_dict = {"pose":pose, "left_hand":left_hand, "right_hand":right_hand, "face":face}

			all_frame_kps.append(frame_dict)

		kp_dict = {"kps":all_frame_kps, "resolution":resolution}
	except Exception as e:
		print("Error: ", e)
		return None, "Error: Could not extract keypoints from the frames"

	return kp_dict, "success"


def check_visible_gestures(kp_dict):

	'''
	This function checks if the gestures in the video are visible

	Args:
		- kp_dict (dict) : Dictionary containing the keypoints and the resolution of the frames
	Returns:
		- msg (string) : Message to be returned
	'''

	keypoints = kp_dict['kps']
	keypoints = np.array(keypoints)

	if len(keypoints)<25:
		msg = "Not enough keypoints to process! Please give a longer video as input"
		return msg
	
	pose_count, hand_count = 0, 0
	for frame_kp_dict in keypoints:

		pose = frame_kp_dict["pose"]
		left_hand = frame_kp_dict["left_hand"]
		right_hand = frame_kp_dict["right_hand"]

		if pose is None:
			pose_count += 1
		
		if left_hand is None and right_hand is None:
			hand_count += 1


	if hand_count/len(keypoints) > 0.7 or pose_count/len(keypoints) > 0.7:
		msg = "The gestures in the input video are not visible! Please give a video with visible gestures as input."
		return msg

	print("Successfully verified the input video - Gestures are visible!")

	return "success"

def load_rgb_masked_frames(input_frames, kp_dict, stride=1, window_frames=25, width=480, height=270):

	'''
	This function masks the faces using the keypoints extracted from the frames

	Args:
		- input_frames (list) : List of frames extracted from the video
		- kp_dict (dict) : Dictionary containing the keypoints and the resolution of the frames
		- stride (int) : Stride to extract the frames
		- window_frames (int) : Number of frames in each window that is given as input to the model
		- width (int) : Width of the frames
		- height (int) : Height of the frames
	Returns:
		- input_frames (array) : Frame window to be given as input to the model
		- num_frames (int) : Number of frames to extract
		- orig_masked_frames (array) : Masked frames extracted from the video
		- msg (string) : Message to be returned
	'''

	# Face indices to extract the face-coordinates needed for masking
	face_oval_idx = [10, 21, 54, 58, 67, 93, 103, 109, 127, 132, 136, 148, 149, 150, 152, 162, 172, 
					176, 234, 251, 284, 288, 297, 323, 332, 338, 356, 361, 365, 377, 378, 379, 389, 397, 400, 454]

	
	input_keypoints, resolution = kp_dict['kps'], kp_dict['resolution']
	print("Input keypoints: ", len(input_keypoints))

	print("Creating masked input frames...")
	input_frames_masked = []
	for i, frame_kp_dict in tqdm(enumerate(input_keypoints)):

		img = input_frames[i]
		face = frame_kp_dict["face"]

		if face is None:
			img = cv2.resize(img, (width, height))
			masked_img = cv2.rectangle(img, (0,0), (width,110), (0,0,0), -1)
		else:
			face_kps = []
			for idx in range(len(face)):
				if idx in face_oval_idx:
					x, y = int(face[idx]["x"]*resolution[1]), int(face[idx]["y"]*resolution[0])
					face_kps.append((x,y))

			face_kps = np.array(face_kps)
			x1, y1 = min(face_kps[:,0]), min(face_kps[:,1])
			x2, y2 = max(face_kps[:,0]), max(face_kps[:,1])
			masked_img = cv2.rectangle(img, (0,0), (resolution[1],y2+15), (0,0,0), -1)

		if masked_img.shape[0] != width or masked_img.shape[1] != height:
			masked_img = cv2.resize(masked_img, (width, height))

		input_frames_masked.append(masked_img)

	orig_masked_frames = np.array(input_frames_masked)
	input_frames = np.array(input_frames_masked) / 255.
	print("Input images full: ", input_frames.shape)      	# num_framesx270x480x3 

	input_frames = np.array([input_frames[i:i+window_frames, :, :] for i in range(0,input_frames.shape[0], stride) if (i+window_frames <= input_frames.shape[0])])
	print("Input images window: ", input_frames.shape)      	# Tx25x270x480x3
	
	num_frames = input_frames.shape[0]

	if num_frames<10:
		msg = "Not enough frames to process! Please give a longer video as input."
		return None, None, None, msg
	
	return input_frames, num_frames, orig_masked_frames, "success"

def load_spectrograms(wav_file, num_frames, window_frames=25, stride=4):

	'''
	This function extracts the spectrogram from the audio file

	Args:
		- wav_file (string) : Path of the extracted audio file
		- num_frames (int) : Number of frames to extract
		- window_frames (int) : Number of frames in each window that is given as input to the model
		- stride (int) : Stride to extract the audio frames
	Returns:
		- spec (array) : Spectrogram array window to be used as input to the model
		- orig_spec (array) : Spectrogram array extracted from the audio file
		- msg (string) : Message to be returned
	'''

	# Extract the audio from the input video file using ffmpeg
	try:
		wav = librosa.load(wav_file, sr=16000)[0]
	except:
		msg = "Oops! Could extract the spectrograms from the audio file. Please check the input and try again."
		return None, None, msg
	
	# Convert to tensor
	wav = torch.FloatTensor(wav).unsqueeze(0)
	mel, _, _, _ = wav2filterbanks(wav.to(device))
	spec = mel.squeeze(0).cpu().numpy()
	orig_spec = spec
	spec = np.array([spec[i:i+(window_frames*stride), :] for i in range(0, spec.shape[0], stride) if (i+(window_frames*stride) <= spec.shape[0])])

	if len(spec) != num_frames:
		spec = spec[:num_frames]
		frame_diff = np.abs(len(spec) - num_frames)
		if frame_diff > 60:
			print("The input video and audio length do not match - The results can be unreliable! Please check the input video.")

	return spec, orig_spec, "success"


def calc_optimal_av_offset(vid_emb, aud_emb, num_avg_frames, model):
	'''
	This function calculates the audio-visual offset between the video and audio

	Args:
		- vid_emb (array) : Video embedding array
		- aud_emb (array) : Audio embedding array
		- num_avg_frames (int) : Number of frames to average the scores
		- model (object) : Model object
	Returns:
		- offset (int) : Optimal audio-visual offset
		- msg (string) : Message to be returned
	'''

	pos_vid_emb, all_aud_emb, pos_idx, stride, status = create_online_sync_negatives(vid_emb, aud_emb, num_avg_frames)
	if status != "success":
		return None, status
	scores, _ = calc_av_scores(pos_vid_emb, all_aud_emb, model)
	offset = scores.argmax()*stride - pos_idx

	return offset.item(), "success"

def create_online_sync_negatives(vid_emb, aud_emb, num_avg_frames, stride=5):

	'''
	This function creates all possible positive and negative audio embeddings to compare and obtain the sync offset

	Args:
		- vid_emb (array) : Video embedding array
		- aud_emb (array) : Audio embedding array
		- num_avg_frames (int) : Number of frames to average the scores
		- stride (int) : Stride to extract the negative windows
	Returns:
		- vid_emb_pos (array) : Positive video embedding array
		- aud_emb_posneg (array) : All possible combinations of audio embedding array 
		- pos_idx_frame (int) : Positive video embedding array frame
		- stride (int) : Stride used to extract the negative windows
		- msg (string) : Message to be returned
	'''

	slice_size = num_avg_frames
	aud_emb_posneg = aud_emb.squeeze(1).unfold(-1, slice_size, stride)
	aud_emb_posneg = aud_emb_posneg.permute([0, 2, 1, 3])
	aud_emb_posneg = aud_emb_posneg[:, :int(n_negative_samples/stride)+1]

	pos_idx = (aud_emb_posneg.shape[1]//2)
	pos_idx_frame = pos_idx*stride

	min_offset_frames = -(pos_idx)*stride
	max_offset_frames = (aud_emb_posneg.shape[1] - pos_idx - 1)*stride
	print("With the current video length and the number of average frames, the model can predict the offsets in the range: [{}, {}]".format(min_offset_frames, max_offset_frames))

	vid_emb_pos = vid_emb[:, :, pos_idx_frame:pos_idx_frame+slice_size]
	if vid_emb_pos.shape[2] != slice_size:
		msg = "Video is too short to use {} frames to average the scores. Please use a longer input video or reduce the number of average frames".format(slice_size)
		return None, None, None, None, msg
	
	return vid_emb_pos, aud_emb_posneg, pos_idx_frame, stride, "success"

def calc_av_scores(vid_emb, aud_emb, model):

	'''
	This function calls functions to calculate the audio-visual similarity and attention map between the video and audio embeddings

	Args:
		- vid_emb (array) : Video embedding array
		- aud_emb (array) : Audio embedding array
		- model (object) : Model object
	Returns:
		- scores (array) : Audio-visual similarity scores
		- att_map (array) : Attention map
	'''

	scores = calc_att_map(vid_emb, aud_emb, model)
	att_map = logsoftmax_2d(scores)
	scores = scores.mean(-1)
	
	return scores, att_map

def calc_att_map(vid_emb, aud_emb, model):

	'''
	This function calculates the similarity between the video and audio embeddings

	Args:
		- vid_emb (array) : Video embedding array
		- aud_emb (array) : Audio embedding array
		- model (object) : Model object
	Returns:
		- scores (array) : Audio-visual similarity scores
	'''

	vid_emb = vid_emb[:, :, None]
	aud_emb = aud_emb.transpose(1, 2)

	scores = run_func_in_parts(lambda x, y: (x * y).sum(1),
							   vid_emb,
							   aud_emb,
							   part_len=10,
							   dim=3,
							   device=device)

	scores = model.logits_scale(scores[..., None]).squeeze(-1)

	return scores

def generate_video(frames, audio_file, video_fname):
	
	'''
	This function generates the video from the frames and audio file

	Args:
		- frames (array) : Frames to be used to generate the video
		- audio_file (string) : Path of the audio file
		- video_fname (string) : Path of the video file
	Returns:
		- video_output (string) : Path of the video file
	'''	

	fname = 'inference.avi'
	video = cv2.VideoWriter(fname, cv2.VideoWriter_fourcc(*'DIVX'), 25, (frames[0].shape[1], frames[0].shape[0]))

	for i in range(len(frames)):
		video.write(cv2.cvtColor(frames[i], cv2.COLOR_BGR2RGB))
	video.release()
	
	no_sound_video = video_fname + '_nosound.mp4'
	status = subprocess.call('ffmpeg -hide_banner -loglevel panic -y -i %s -c copy -an -strict -2 %s' % (fname, no_sound_video), shell=True)
	if status != 0:
		msg = "Oops! Could not generate the video. Please check the input video and try again."
		return None, msg

	video_output = video_fname + '.mp4'
	status = subprocess.call('ffmpeg -hide_banner -loglevel panic -y -i %s -i %s -strict -2 -q:v 1 -shortest %s' % 
					(audio_file, no_sound_video, video_output), shell=True)
	if status != 0:
		msg = "Oops! Could not generate the video. Please check the input video and try again."
		return None, msg

	os.remove(fname)
	os.remove(no_sound_video)
	
	return video_output

def sync_correct_video(video_path, frames, wav_file, offset, result_folder, sample_rate=16000, fps=25):

	'''
	This function corrects the video and audio to sync with each other

	Args:
		- video_path (string) : Path of the video file
		- frames (array) : Frames to be used to generate the video
		- wav_file (string) : Path of the audio file
		- offset (int) : Predicted sync-offset to be used to correct the video
		- result_folder (string) : Path of the result folder to save the output sync-corrected video
		- sample_rate (int) : Sample rate of the audio
		- fps (int) : Frames per second of the video
	Returns:
		- video_output (string) : Path of the video file
	'''

	if offset == 0:
		print("The input audio and video are in-sync! No need to perform sync correction.")
		return video_path
	
	print("Performing Sync Correction...")
	corrected_frames = np.zeros_like(frames)
	if offset > 0:
		audio_offset = int(offset*(sample_rate/fps))
		wav = librosa.core.load(wav_file, sr=sample_rate)[0]
		corrected_wav = wav[audio_offset:]
		corrected_wav_file = os.path.join(result_folder, "audio_sync_corrected.wav")
		write(corrected_wav_file, sample_rate, corrected_wav)
		wav_file = corrected_wav_file
		corrected_frames = frames
	elif offset < 0:
		corrected_frames[0:len(frames)+offset] = frames[np.abs(offset):]
		corrected_frames = corrected_frames[:len(frames)-np.abs(offset)]

	corrected_video_path = os.path.join(result_folder, "result_sync_corrected")
	video_output = generate_video(corrected_frames, wav_file, corrected_video_path)

	return video_output


def load_masked_input_frames(test_videos, spec, wav_file, scene_num, result_folder):

	'''
	This function loads the masked input frames from the video

	Args:
		- test_videos (list) : List of videos to be processed (speaker-specific tracks)
		- spec (array) : Spectrogram of the audio
		- wav_file (string) : Path of the audio file
		- scene_num (int) : Scene number to be used to save the input masked video
		- result_folder (string) : Path of the folder to save the input masked video
	Returns:
		- all_frames (list) : List of masked input frames window to be used as input to the model
		- all_orig_frames (list) : List of original masked input frames
	'''

	all_frames, all_orig_frames = [], []
	for video_num, video in enumerate(test_videos):

		# Load the video frames
		frames, status = load_video_frames(video)
		if status != "success":
			return None, None, status

		# Extract the keypoints from the frames
		kp_dict, status = get_keypoints(frames)
		if status != "success":
			return None, None, status

		# Mask the frames using the keypoints extracted from the frames and prepare the input to the model
		masked_frames, num_frames, orig_masked_frames, status = load_rgb_masked_frames(frames, kp_dict)
		if status != "success":
			return None, None, status

		input_masked_vid_path = os.path.join(result_folder, "input_masked_scene_{}_speaker_{}".format(scene_num, video_num))
		generate_video(orig_masked_frames, wav_file, input_masked_vid_path)

		# Check if the length of the input frames is equal to the length of the spectrogram
		if spec.shape[2]!=masked_frames.shape[0]:
			num_frames = spec.shape[2]
			masked_frames = masked_frames[:num_frames]
			orig_masked_frames = orig_masked_frames[:num_frames]
			frame_diff = np.abs(spec.shape[2] - num_frames)
			if frame_diff > 60:
				print("The input video and audio length do not match - The results can be unreliable! Please check the input video.")

		# Transpose the frames to the correct format
		frames = np.transpose(masked_frames, (4, 0, 1, 2, 3))
		frames = torch.FloatTensor(np.array(frames)).unsqueeze(0)

		all_frames.append(frames)
		all_orig_frames.append(orig_masked_frames)


	return all_frames, all_orig_frames, "success"

def extract_audio(video, result_folder):

	'''
	This function extracts the audio from the video file

	Args:
		- video (string) : Path of the video file
		- result_folder (string) : Path of the folder to save the extracted audio file
	Returns:
		- wav_file (string) : Path of the extracted audio file
	'''

	wav_file  = os.path.join(result_folder, "audio.wav")

	status = subprocess.call('ffmpeg -hide_banner -loglevel panic -threads 1 -y -i %s -async 1 -ac 1 -vn \
					-acodec pcm_s16le -ar 16000 %s' % (video, wav_file), shell=True)

	if status != 0:
		msg = "Oops! Could not load the audio file in the given input video. Please check the input and try again"
		return None, msg
	
	return wav_file, "success"


def get_embeddings(video_sequences, audio_sequences, model, calc_aud_emb=True):

	'''
	This function extracts the video and audio embeddings from the input frames and audio sequences

	Args:
		- video_sequences (array) : Array of video frames to be used as input to the model
		- audio_sequences (array) : Array of audio frames to be used as input to the model
		- model (object) : Model object
		- calc_aud_emb (bool) : Flag to calculate the audio embedding
	Returns:
		- video_emb (array) : Video embedding
		- audio_emb (array) : Audio embedding
	'''

	batch_size = 12
	video_emb = []
	audio_emb = []

	for i in range(0, len(video_sequences), batch_size):
		video_inp = video_sequences[i:i+batch_size, ]  		
		vid_emb = model.forward_vid(video_inp.to(device), return_feats=False)
		vid_emb = torch.mean(vid_emb, axis=-1)

		video_emb.append(vid_emb.detach())

		if calc_aud_emb:
			audio_inp = audio_sequences[i:i+batch_size, ]
			aud_emb = model.forward_aud(audio_inp.to(device))
			audio_emb.append(aud_emb.detach())
		
		torch.cuda.empty_cache()

	video_emb = torch.cat(video_emb, dim=0)

	if calc_aud_emb:
		audio_emb = torch.cat(audio_emb, dim=0)

		return video_emb, audio_emb       

	return video_emb



def predict_active_speaker(all_video_embeddings, audio_embedding, global_score, num_avg_frames, model):
	
	'''
	This function predicts the active speaker in each frame

	Args:
		- all_video_embeddings (array) : Array of video embeddings of all speakers
		- audio_embedding (array) : Audio embedding
		- global_score (bool) : Flag to calculate the global score
	Returns:
		- pred_speaker (list) : List of active speakers in each frame
	'''

	cos = nn.CosineSimilarity(dim=1)

	audio_embedding = audio_embedding.squeeze(2)

	scores = []
	for i in range(len(all_video_embeddings)):
		video_embedding = all_video_embeddings[i]

		# Compute the similarity of each speaker's video embeddings with the audio embedding
		sim = cos(video_embedding, audio_embedding)

		# Apply the logits scale to the similarity scores (scaling the scores)
		output = model.logits_scale(sim.unsqueeze(-1)).squeeze(-1)

		if global_score=="True":
			score = output.mean(0)
		else:
			output_batch = output.unfold(0, num_avg_frames, 1)
			score = torch.mean(output_batch, axis=-1)

		scores.append(score.detach().cpu().numpy())

	if global_score=="True":
		print("Using global predictions")
		pred_speaker = np.argmax(scores)
	else:
		print("Using per-frame predictions")
		pred_speaker = []
		num_negs = list(range(0, len(all_video_embeddings)))
		for frame_idx in range(len(scores[0])):
			score = [scores[i][frame_idx] for i in num_negs] 
			pred_idx = np.argmax(score)
			pred_speaker.append(pred_idx)

	return pred_speaker


def save_video(output_tracks, input_frames, wav_file, result_folder):

	'''
	This function saves the output video with the active speaker detections

	Args:
		- output_tracks (list) : List of active speakers in each frame
		- input_frames (array) : Frames to be used to generate the video
		- wav_file (string) : Path of the audio file
		- result_folder (string) : Path of the result folder to save the output video
	Returns:
		- video_output (string) : Path of the output video
	'''

	output_frames = []
	for i in range(len(input_frames)):

		# If the active speaker is found, draw a bounding box around the active speaker
		if i in output_tracks:
			bbox = output_tracks[i]
			x1, y1, x2, y2 = int(bbox[0]), int(bbox[1]), int(bbox[2]), int(bbox[3])
			out = cv2.rectangle(input_frames[i].copy(), (x1, y1), (x2, y2), color=[0, 255, 0], thickness=3)
		else:
			out = input_frames[i]		

		output_frames.append(out)

	# Generate the output video
	output_video_fname = os.path.join(result_folder, "result_active_speaker_det")
	video_output = generate_video(output_frames, wav_file, output_video_fname)     

	return video_output

def process_video_syncoffset(video_path, num_avg_frames, apply_preprocess):
	
	try:
		# Extract the video filename
		video_fname = os.path.basename(video_path.split(".")[0])
		
		# Create folders to save the inputs and results
		result_folder = os.path.join("results", video_fname)
		result_folder_input = os.path.join(result_folder, "input")
		result_folder_output = os.path.join(result_folder, "output")

		if os.path.exists(result_folder):
			rmtree(result_folder)

		os.makedirs(result_folder)
		os.makedirs(result_folder_input)
		os.makedirs(result_folder_output)

		
		# Preprocess the video
		print("Applying preprocessing: ", apply_preprocess)
		wav_file, fps, vid_path_processed, status = preprocess_video(video_path, result_folder_input, apply_preprocess)
		if status != "success":
			return status, None
		print("Successfully preprocessed the video")

		# Resample the video to 25 fps if it is not already 25 fps
		print("FPS of video: ", fps)
		if fps!=25:
			vid_path = resample_video(vid_path_processed, "preprocessed_video_25fps", result_folder_input)
			orig_vid_path_25fps = resample_video(video_path, "input_video_25fps", result_folder_input)
		else:
			vid_path = vid_path_processed
			orig_vid_path_25fps = video_path

		# Load the original video frames (before pre-processing) - Needed for the final sync-correction 
		orig_frames, status = load_video_frames(orig_vid_path_25fps)
		if status != "success":
			return status, None
			
		# Load the pre-processed video frames
		frames, status = load_video_frames(vid_path)
		if status != "success":
			return status, None
		print("Successfully extracted the video frames")

		if len(frames) < num_avg_frames:
			return "Error: The input video is too short. Please use a longer input video.", None

		# Load keypoints and check if gestures are visible
		kp_dict, status = get_keypoints(frames)
		if status != "success":
			return status, None
		print("Successfully extracted the keypoints: ", len(kp_dict), len(kp_dict["kps"]))

		status = check_visible_gestures(kp_dict)
		if status != "success":
			return status, None

		# Load RGB frames
		rgb_frames, num_frames, orig_masked_frames, status = load_rgb_masked_frames(frames, kp_dict, window_frames=25, width=480, height=270)
		if status != "success":
			return status, None
		print("Successfully loaded the RGB frames")

		# Convert frames to tensor
		rgb_frames = np.transpose(rgb_frames, (4, 0, 1, 2, 3))
		rgb_frames = torch.FloatTensor(rgb_frames).unsqueeze(0)
		B = rgb_frames.size(0)
		print("Successfully converted the frames to tensor")

		# Load spectrograms
		spec, orig_spec, status = load_spectrograms(wav_file, num_frames, window_frames=25)
		if status != "success":
			return status, None
		spec = torch.FloatTensor(spec).unsqueeze(0).unsqueeze(0).permute(0, 1, 2, 4, 3)
		print("Successfully loaded the spectrograms")

		# Create input windows
		video_sequences = torch.cat([rgb_frames[:, :, i] for i in range(rgb_frames.size(2))], dim=0)
		audio_sequences = torch.cat([spec[:, :, i] for i in range(spec.size(2))], dim=0)

		# Load the trained model
		model = Transformer_RGB()
		model = load_checkpoint(CHECKPOINT_PATH, model)
		print("Successfully loaded the model")

		# Process in batches
		batch_size = 12
		video_emb = []
		audio_emb = []

		for i in tqdm(range(0, len(video_sequences), batch_size)):
			video_inp = video_sequences[i:i+batch_size, ]
			audio_inp = audio_sequences[i:i+batch_size, ]
			
			vid_emb = model.forward_vid(video_inp.to(device))
			vid_emb = torch.mean(vid_emb, axis=-1).unsqueeze(-1)
			aud_emb = model.forward_aud(audio_inp.to(device))

			video_emb.append(vid_emb.detach())
			audio_emb.append(aud_emb.detach())
			
			torch.cuda.empty_cache()

		audio_emb = torch.cat(audio_emb, dim=0)
		video_emb = torch.cat(video_emb, dim=0)

		# L2 normalize embeddings
		video_emb = torch.nn.functional.normalize(video_emb, p=2, dim=1)
		audio_emb = torch.nn.functional.normalize(audio_emb, p=2, dim=1)

		audio_emb = torch.split(audio_emb, B, dim=0)
		audio_emb = torch.stack(audio_emb, dim=2)
		audio_emb = audio_emb.squeeze(3)
		audio_emb = audio_emb[:, None]

		video_emb = torch.split(video_emb, B, dim=0)
		video_emb = torch.stack(video_emb, dim=2)
		video_emb = video_emb.squeeze(3)
		print("Successfully extracted GestSync embeddings")

		# Calculate sync offset
		pred_offset, status = calc_optimal_av_offset(video_emb, audio_emb, num_avg_frames, model)
		if status != "success":
			return status, None
		print("Predicted offset: ", pred_offset)

		# Generate sync-corrected video
		video_output = sync_correct_video(video_path, orig_frames, wav_file, pred_offset, result_folder_output, sample_rate=16000, fps=fps)
		print("Successfully generated the video:", video_output)

		return f"Predicted offset: {pred_offset}", video_output

	except Exception as e:
		return f"Error: {str(e)}", None

def process_video_activespeaker(video_path, global_speaker, num_avg_frames):
	try:
		# Extract the video filename
		video_fname = os.path.basename(video_path.split(".")[0])
		
		# Create folders to save the inputs and results
		result_folder = os.path.join("results", video_fname)
		result_folder_input = os.path.join(result_folder, "input")
		result_folder_output = os.path.join(result_folder, "output")

		if os.path.exists(result_folder):
			rmtree(result_folder)

		os.makedirs(result_folder)
		os.makedirs(result_folder_input)
		os.makedirs(result_folder_output)

		if global_speaker=="per-frame-prediction" and num_avg_frames<25:
			msg = "Number of frames to average need to be set to a minimum of 25 frames. Atleast 1-second context is needed for the model. Please change the num_avg_frames and try again..."
			return None, msg

		# Read the video
		try:
			vr = VideoReader(video_path, ctx=cpu(0))
		except:
			msg = "Oops! Could not load the input video file"
			return None, msg

		# Get the FPS of the video
		fps = vr.get_avg_fps()
		print("FPS of video: ", fps)

		# Resample the video to 25 FPS if the original video is of a different frame-rate
		if fps!=25:
			test_video_25fps = resample_video(video_path, video_fname, result_folder_input)
		else:
			test_video_25fps = video_path

		# Load the video frames
		orig_frames, status = load_video_frames(test_video_25fps)
		if status != "success":
			return None, status

		# Extract and save the audio file
		orig_wav_file, status = extract_audio(video_path, result_folder)
		if status != "success":
			return None, status

		# Pre-process and extract per-speaker tracks in each scene 
		print("Pre-processing the input video...")
		status = subprocess.call("python preprocess/inference_preprocess.py --data_dir={}/temp --sd_root={}/crops --work_root={}/metadata --data_root={}".format(result_folder_input, result_folder_input, result_folder_input, video_path), shell=True)
		if status != 0:
			return None, "Error in pre-processing the input video, please check the input video and try again..."
		
		# Load the tracks file saved during pre-processing
		with open('{}/metadata/tracks.pckl'.format(result_folder_input), 'rb') as file:
			tracks = pickle.load(file)


		# Create a dictionary of all tracks found along with the bounding-boxes
		track_dict = {}
		for scene_num in range(len(tracks)):
			track_dict[scene_num] = {}
			for i in range(len(tracks[scene_num])):
				track_dict[scene_num][i] = {}
				for frame_num, bbox in zip(tracks[scene_num][i]['track']['frame'], tracks[scene_num][i]['track']['bbox']):
					track_dict[scene_num][i][frame_num] = bbox

		# Get the total number of scenes 
		test_scenes = os.listdir("{}/crops".format(result_folder_input))
		print("Total scenes found in the input video = ", len(test_scenes))

		# Load the trained model
		model = Transformer_RGB()
		model = load_checkpoint(CHECKPOINT_PATH, model) 

		# Compute the active speaker in each scene 
		output_tracks = {}
		for scene_num in tqdm(range(len(test_scenes))):
			test_videos = glob(os.path.join("{}/crops".format(result_folder_input), "scene_{}".format(str(scene_num)), "*.avi"))
			test_videos.sort(key=lambda x: int(os.path.basename(x).split('.')[0]))
			print("Scene {} -> Total video files found (speaker-specific tracks) = {}".format(scene_num, len(test_videos)))

			if len(test_videos)<=1:
				msg = "To detect the active speaker, at least 2 visible speakers are required for each scene! Please check the input video and try again..."
				return None, msg

			# Load the audio file
			audio_file = glob(os.path.join("{}/crops".format(result_folder_input), "scene_{}".format(str(scene_num)), "*.wav"))[0]
			spec, _, status = load_spectrograms(audio_file, window_frames=25)
			if status != "success":
				return None, status
			spec = torch.FloatTensor(spec).unsqueeze(0).unsqueeze(0).permute(0,1,2,4,3)
			
			# Load the masked input frames
			all_masked_frames, all_orig_masked_frames, status = load_masked_input_frames(test_videos, spec, audio_file, scene_num, result_folder_input)
			if status != "success":
				return None, status
			

			# Prepare the audio and video sequences for the model
			audio_sequences = torch.cat([spec[:, :, i] for i in range(spec.size(2))], dim=0)

			print("Obtaining audio and video embeddings...")
			all_video_embs = []
			for idx in tqdm(range(len(all_masked_frames))):
				with torch.no_grad():
					video_sequences = torch.cat([all_masked_frames[idx][:, :, i] for i in range(all_masked_frames[idx].size(2))], dim=0)

					if idx==0:
						video_emb, audio_emb = get_embeddings(video_sequences, audio_sequences, model, calc_aud_emb=True)
					else:
						video_emb = get_embeddings(video_sequences, audio_sequences, model, calc_aud_emb=False)
					all_video_embs.append(video_emb)

			# Predict the active speaker in each scene
			if global_speaker=="per-frame-prediction":
				predictions = predict_active_speaker(all_video_embs, audio_emb, "False", num_avg_frames, model)
			else:
				predictions = predict_active_speaker(all_video_embs, audio_emb, "True", num_avg_frames, model)

			# Get the frames present in the scene
			frames_scene = tracks[scene_num][0]['track']['frame']

			# Prepare the active speakers list to draw the bounding boxes
			if global_speaker=="global-prediction":
				print("Aggregating scores using global predictoins")
				active_speakers = [predictions]*len(frames_scene)
				start, end = 0, len(frames_scene)
			else:
				print("Aggregating scores using per-frame predictions")
				active_speakers = [0]*len(frames_scene)
				mid = num_avg_frames//2

				if num_avg_frames%2==0:	
					frame_pred = len(frames_scene)-(mid*2)+1
					start, end = mid, len(frames_scene)-mid+1
				else:
					frame_pred = len(frames_scene)-(mid*2)
					start, end = mid, len(frames_scene)-mid

				if len(predictions) != frame_pred:
					msg = "Predicted frames {} and input video frames {} do not match!!".format(len(predictions), frame_pred)
					return None, msg

				active_speakers[start:end] = predictions[0:]

				# Depending on the num_avg_frames, interpolate the intial and final frame predictions to get a full video output
				initial_preds = max(set(predictions[:num_avg_frames]), key=predictions[:num_avg_frames].count)
				active_speakers[0:start] = [initial_preds] * start
				
				final_preds = max(set(predictions[-num_avg_frames:]), key=predictions[-num_avg_frames:].count)
				active_speakers[end:] = [final_preds] * (len(frames_scene) - end)
				start, end = 0, len(active_speakers)
		
			# Get the output tracks for each frame
			pred_idx = 0
			for frame in frames_scene[start:end]:
				label = active_speakers[pred_idx]
				pred_idx += 1
				output_tracks[frame] = track_dict[scene_num][label][frame]

		# Save the output video
		video_output, status = save_video(output_tracks, orig_frames.copy(), orig_wav_file, result_folder_output)
		if status != "success":
			return None, status
		print("Successfully saved the output video: ", video_output)

		return video_output, "success"

	except Exception as e:
		return None, f"Error: {str(e)}"


if __name__ == "__main__":

	
	# Custom CSS and HTML
	custom_css = """
	<style>
		body {
			background-color: #ffffff;
			color: #333333;  /* Default text color */
		}
		.container {
			max-width: 100% !important;
			padding-left: 0 !important;
			padding-right: 0 !important;
		}
		.header {
			background-color: #f0f0f0;
			color: #333333;
			padding: 30px;
			margin-bottom: 30px;
			text-align: center;
			font-family: 'Helvetica Neue', Arial, sans-serif;
			box-shadow: 0 2px 4px rgba(0,0,0,0.1);
		}
		.header h1 {
			font-size: 36px;
			margin-bottom: 15px;
			font-weight: bold;
			color: #333333;  /* Explicitly set heading color */
		}
		.header h2 {
			font-size: 24px;
			margin-bottom: 10px;
			color: #333333;  /* Explicitly set subheading color */
		}
		.header p {
			font-size: 18px;
			margin: 5px 0;
			color: #666666;
		}
		.blue-text {
			color: #4a90e2;
		}
		/* Custom styles for slider container */
		.slider-container {
			background-color: white !important;
			padding-top: 0.9em;
			padding-bottom: 0.9em;
		}
		/* Add gap before examples */
		.examples-holder {
			margin-top: 2em;
		}

		/* Set fixed size for example videos */
		.gradio-container .gradio-examples .gr-sample {
			width: 240px !important;
			height: 135px !important;
			object-fit: cover;
			display: inline-block;
			margin-right: 10px;
		}

		.gradio-container .gradio-examples {
			display: flex;
			flex-wrap: wrap;
			gap: 10px;
		}

		/* Ensure the parent container does not stretch */
		.gradio-container .gradio-examples {
			max-width: 100%;
			overflow: hidden;
		}

		/* Additional styles to ensure proper sizing in Safari */
		.gradio-container .gradio-examples .gr-sample img {
			width: 240px !important;
			height: 135px !important;
			object-fit: cover;
		}
	</style>
	"""

	custom_html = custom_css + """
	<div class="header">
		<h1><span class="blue-text">GestSync:</span> Determining who is speaking without a talking head</h1>
		<h2>Synchronization and Active Speaker Detection Demo</h2>
		<p>Sindhu Hegde and Andrew Zisserman</p>
		<p>VGG, University of Oxford</p>
	</div>
	"""

	# Define functions
	def toggle_slider(global_speaker):
		if global_speaker == "per-frame-prediction":
			return gr.update(visible=True)
		else:
			return gr.update(visible=False)

	def toggle_demo(demo_choice):
		if demo_choice == "Synchronization-correction":
			return (
				gr.update(value=None, visible=True),  # video_input
				gr.update(value=75, visible=True),  # num_avg_frames
				gr.update(value=None, visible=True),  # apply_preprocess
				gr.update(value="global-prediction", visible=False), # global_speaker
				gr.update(value="", visible=True),  # result_text
				gr.update(value=None, visible=True),  # output_video
				gr.update(visible=True),  # submit_button
				gr.update(visible=True),  # clear_button
				gr.update(visible=True),  # sync_examples
				gr.update(visible=False)  # asd_examples
			)
		else:
			return (
				gr.update(value=None, visible=True),  # video_input
				gr.update(value=75, visible=True), # num_avg_frames
				gr.update(value=None, visible=False), # apply_preprocess
				gr.update(value="global-prediction", visible=True),  # global_speaker
				gr.update(value="", visible=True),  # result_text
				gr.update(value=None, visible=True),  # output_video
				gr.update(visible=True),  # submit_button
				gr.update(visible=True),  # clear_button
				gr.update(visible=False), # sync_examples
				gr.update(visible=True)   # asd_examples
			)

	def clear_inputs():
		return None, None, "global-prediction", 75, None, "", None

	def process_video(video_input, demo_choice, global_speaker, num_avg_frames, apply_preprocess):
		if demo_choice == "Synchronization-correction":
			return process_video_syncoffset(video_input, num_avg_frames, apply_preprocess)
		else:
			return process_video_activespeaker(video_input, global_speaker, num_avg_frames)


	# Define paths to sample videos
	sync_sample_videos = [
		"samples/sync_sample_1.mp4",
		"samples/sync_sample_2.mp4",
		"samples/sync_sample_3.mp4"
	]

	asd_sample_videos = [
		"samples/asd_sample_1.mp4",
		"samples/asd_sample_2.mp4"
	]

	# Define Gradio interface
	with gr.Blocks(css=custom_css, theme=gr.themes.Default(primary_hue=gr.themes.colors.red, secondary_hue=gr.themes.colors.pink)) as demo:
		gr.HTML(custom_html)
		demo_choice = gr.Radio(
			choices=["Synchronization-correction", "Active-speaker-detection"],
			label="Please select the task you want to perform"
		)
		with gr.Row():
			with gr.Column():
				video_input = gr.Video(label="Upload Video", height=400, visible=False)
				num_avg_frames = gr.Slider(
					minimum=50,
					maximum=150,
					step=5,
					value=75,
					label="Number of Average Frames",
					visible=False
				)
				apply_preprocess = gr.Checkbox(label="Apply Preprocessing", value=False, visible=False)
				global_speaker = gr.Radio(
					choices=["global-prediction", "per-frame-prediction"],
					value="global-prediction",
					label="Global Speaker Prediction",
					visible=False
				)
				global_speaker.change(
					fn=toggle_slider,
					inputs=global_speaker,
					outputs=num_avg_frames
				)
			with gr.Column():
				result_text = gr.Textbox(label="Result", visible=False)
				output_video = gr.Video(label="Output Video", height=400, visible=False)
		
		with gr.Row():
			submit_button = gr.Button("Submit", variant="primary", visible=False)
			clear_button = gr.Button("Clear", visible=False)

		# Add a gap before examples
		gr.HTML('<div class="examples-holder"></div>')

		# Add examples that only populate the video input
		sync_examples = gr.Examples(
			examples=sync_sample_videos,
			inputs=video_input,
			outputs=None,
			fn=None,
			cache_examples=False,
			visible=False
		)

		asd_examples = gr.Examples(
			examples=asd_sample_videos,
			inputs=video_input,
			outputs=None,
			fn=None,
			cache_examples=False,
			visible=False
		)


		demo_choice.change(
			fn=toggle_demo,
			inputs=demo_choice,
			outputs=[video_input, num_avg_frames, apply_preprocess, global_speaker, result_text, output_video, submit_button, clear_button, sync_examples.dataset, asd_examples.dataset]
		)


		submit_button.click(
			fn=process_video,
			inputs=[video_input, demo_choice, global_speaker, num_avg_frames, apply_preprocess],
			outputs=[result_text, output_video]
		)
		
		clear_button.click(
			fn=clear_inputs,
			inputs=[],
			outputs=[demo_choice, video_input, global_speaker, num_avg_frames, apply_preprocess, result_text, output_video]
		)
	# Launch the interface
	demo.launch(allowed_paths=["."], server_name="0.0.0.0", server_port=7860, share=True)