Create subtitle_utils.py

backend/subtitle_utils.py

@@ -0,0 +1,84 @@
+from moviepy.editor import VideoFileClip, AudioFileClip, TextClip, CompositeVideoClip
+from moviepy.video.tools.subtitles import SubtitlesClip
+import srt
+from datetime import timedelta
+import os
+
+
+def export_srt(text, duration=10, words_per_caption=6, output_path="output.srt"):
+    """
+    Converts text into SRT subtitles and saves to output_path.
+    """
+    lines = []
+    words = text.split()
+    start = 0
+    index = 1
+    while start < len(words):
+        end = start + words_per_caption
+        chunk = words[start:end]
+        content = " ".join(chunk)
+        start_time = timedelta(seconds=(index - 1) * duration)
+        end_time = timedelta(seconds=index * duration)
+        sub = srt.Subtitle(index=index, start=start_time, end=end_time, content=content)
+        lines.append(sub)
+        start += words_per_caption
+        index += 1
+
+    srt_data = srt.compose(lines)
+    with open(output_path, "w", encoding="utf-8") as f:
+        f.write(srt_data)
+    return output_path
+
+
+def add_subtitles_and_bgm(
+    video_path,
+    srt_path,
+    bgm_path,
+    output_path="enhanced_output.mp4",
+    font="Arial-Bold",
+    font_size=36,
+    font_color="white",
+    subtitle_position=("center", "bottom")
+):
+    """
+    Adds subtitles from .srt and background music to the given video.
+    """
+    # Load video
+    video = VideoFileClip(video_path)
+
+    # Parse .srt file
+    with open(srt_path, "r", encoding="utf-8") as f:
+        subtitles = list(srt.parse(f.read()))
+
+    # Create subtitle clips
+    def make_textclip(txt):
+        return TextClip(txt, font=font, fontsize=font_size, color=font_color, stroke_color='black', stroke_width=2)
+
+    subtitle_clips = []
+    for sub in subtitles:
+        txt_clip = (make_textclip(sub.content)
+                    .set_position(subtitle_position)
+                    .set_start(sub.start.total_seconds())
+                    .set_duration((sub.end - sub.start).total_seconds()))
+        subtitle_clips.append(txt_clip)
+
+    # Background music
+    if os.path.exists(bgm_path):
+        bgm = AudioFileClip(bgm_path).volumex(0.2)  # reduce volume
+        bgm = bgm.set_duration(video.duration)
+        final_audio = video.audio.volumex(0.8).audio_fadein(1).audio_fadeout(1).set_duration(video.duration)
+        final_audio = final_audio.set_audio(bgm)
+    else:
+        final_audio = video.audio
+
+    final = CompositeVideoClip([video, *subtitle_clips])
+    final = final.set_audio(final_audio)
+
+    # Export final video
+    final.write_videofile(output_path, codec="libx264", audio_codec="aac", fps=video.fps)
+    return output_path
+
+
+# Aliases for compatibility with streamlit_ui.py
+generate_srt_from_text = export_srt
+enhance_video_with_subtitles_and_bgm = add_subtitles_and_bgm