From 5e8a37110df4f09678afe4cc88e3137a497940ba Mon Sep 17 00:00:00 2001
From: Harisreedhar <46858047+harisreedhar@users.noreply.github.com>
Date: Mon, 27 Jul 2026 18:51:35 +0530
Subject: [PATCH] Restrict the preview frame slider and the reader seek to the
 last frame index (#1207)

* fix index bug

* fix rounding bug
---
 facefusion/ffprobe.py                        | 4 ++--
 facefusion/uis/components/preview_options.py | 5 +++--
 facefusion/video_manager.py                  | 3 ++-
 tests/test_ffprobe.py                        | 2 +-
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/facefusion/ffprobe.py b/facefusion/ffprobe.py
index 9ab75956..c0cf7191 100644
--- a/facefusion/ffprobe.py
+++ b/facefusion/ffprobe.py
@@ -74,7 +74,7 @@ def extract_audio_metadata(audio_path : str) -> AudioMetadata:
 
 	duration = float(format_entries.get('duration'))
 	sample_rate = int(audio_entries.get('sample_rate'))
-	frame_total = int(duration * sample_rate)
+	frame_total = round(duration * sample_rate)
 	channel_total = int(audio_entries.get('channels'))
 	bit_rate = int(format_entries.get('bit_rate'))
 
@@ -101,7 +101,7 @@ def extract_video_metadata(video_path : str) -> VideoMetadata:
 
 	duration = float(format_entries.get('duration'))
 	fps = extract_video_fps(video_entries.get('r_frame_rate'))
-	frame_total = int(duration * fps)
+	frame_total = round(duration * fps)
 	width = int(video_entries.get('width'))
 	height = int(video_entries.get('height'))
 	bit_rate = int(format_entries.get('bit_rate'))
diff --git a/facefusion/uis/components/preview_options.py b/facefusion/uis/components/preview_options.py
index 96942c60..0dcf3c7a 100644
--- a/facefusion/uis/components/preview_options.py
+++ b/facefusion/uis/components/preview_options.py
@@ -26,8 +26,9 @@ def render() -> None:
 		'visible': False
 	}
 	if is_video(state_manager.get_item('target_path')):
+		video_frame_total = count_video_frame_total(state_manager.get_item('target_path'))
 		preview_frame_slider_options['value'] = state_manager.get_item('reference_frame_number')
-		preview_frame_slider_options['maximum'] = count_video_frame_total(state_manager.get_item('target_path'))
+		preview_frame_slider_options['maximum'] = video_frame_total - 1
 		preview_frame_slider_options['visible'] = True
 	PREVIEW_FRAME_SLIDER = gradio.Slider(**preview_frame_slider_options)
 	with gradio.Row():
@@ -57,5 +58,5 @@ def listen() -> None:
 def update_preview_frame_slider() -> gradio.Slider:
 	if is_video(state_manager.get_item('target_path')):
 		video_frame_total = count_video_frame_total(state_manager.get_item('target_path'))
-		return gradio.Slider(maximum = video_frame_total, visible = True)
+		return gradio.Slider(maximum = video_frame_total - 1, visible = True)
 	return gradio.Slider(value = 0, visible = False)
diff --git a/facefusion/video_manager.py b/facefusion/video_manager.py
index 25de398b..543b2fef 100644
--- a/facefusion/video_manager.py
+++ b/facefusion/video_manager.py
@@ -35,7 +35,8 @@ def get_reader(video_path : str, context : str) -> VideoReader:
 
 
 def conditional_seek_video_reader(video_reader : VideoReader, frame_number : int = 0) -> None:
-	frame_number = min(video_reader.get('metadata').get('frame_total'), frame_number)
+	frame_total = video_reader.get('metadata').get('frame_total')
+	frame_number = min(frame_total - 1, frame_number)
 	skip_total = frame_number - video_reader.get('frame_number')
 	skip_margin = 128
 
diff --git a/tests/test_ffprobe.py b/tests/test_ffprobe.py
index ba6d4c7d..41724fdf 100644
--- a/tests/test_ffprobe.py
+++ b/tests/test_ffprobe.py
@@ -41,7 +41,7 @@ def test_extract_audio_metadata() -> None:
 
 	assert audio_metadata.get('sample_rate') == 44100
 	assert audio_metadata.get('channel_total') == 1
-	assert audio_metadata.get('frame_total') == 167039
+	assert audio_metadata.get('frame_total') == 167040
 	assert audio_metadata.get('bit_rate') == 128000
 
 	audio_metadata = extract_audio_metadata(get_test_example_file('source-48000khz-2ch.wav'))