app.py

import gradio as gr
import whisper
import subprocess
import os
from pytube import YouTube
from fastapi import FastAPI, Response, Request
import yt_dlp

langs = ["None"] + sorted(list(whisper.tokenizer.LANGUAGES.values()))
model_size = list(whisper._MODELS.keys())


@app.get("/subtitle")
async def get_subtitle(url: str):
    # Download the subtitle with download_subtitle()
    subtitle_url = download_subtitle(url)
    # Stream the subtitle as a response
    return StreamingResponse(requests.get(subtitle_url, stream=True).iter_content(chunk_size=1024))

def get_subtitle(url, lang='en'):
    # Download subtitles if available
    ydl_opts = {
        'writesubtitles': True,
        'outtmpl': '%(id)s.%(ext)s',
        'subtitleslangs': [lang],
        'skip_download': True,
    }
    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        info_dict = ydl.extract_info(url, download=True)
        video_id = info_dict.get("id", None)
        if video_id is None:
            return None
        subtitle_file = f"{video_id}.{lang}.vtt"
        with open(subtitle_file, 'r') as f:
            subtitle_content = f.read()
            subtitle_content = re.sub(r"<[^>]+>", "", subtitle_content)
            return subtitle_content
    return None

def download_audio(video_url, quality: str = '128', speed: float = None):
    ydl_opts = {
        'format': 'bestaudio/best',
        'outtmpl': '%(title)s.%(ext)s',
        'quiet': True,
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3', #'opus',
            'preferredquality': quality,
        }]
    }

    if speed:
        ydl_opts['postprocessors'].append({
            'key': 'FFmpegFilter',
            'filter_complex': f"atempo={speed}"
        })

    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        ydl.download([video_url])
        audio_file = ydl.prepare_filename(ydl.extract_info(video_url, download=False))
        print('audio_file', audio_file)
        return audio_file

    
def get_audio(url):
    yt = YouTube(url)
    return yt.streams.filter(only_audio=True)[0].download(filename="tmp.mp4")

def get_transcript(url, model_size, lang, format):
    subtitle = get_subtitle(url, lang)
    print(subtitle)
    return subtitle

    model = whisper.load_model(model_size)

    if lang == "None":
        lang = None
    
    result = model.transcribe(download_audio(url), fp16=False, language=lang)

    if format == "None":
        return result["text"]
    elif format == ".srt":
        return format_to_srt(result["segments"])

def format_to_srt(segments):
    output = ""
    for i, segment in enumerate(segments):
        output += f"{i + 1}\n"
        output += f"{format_timestamp(segment['start'])} --> {format_timestamp(segment['end'])}\n"
        output += f"{segment['text']}\n\n"
    return output

def format_timestamp(t):
    hh = t//3600
    mm = (t - hh*3600)//60
    ss = t - hh*3600 - mm*60
    mi = (t - int(t))*1000
    return f"{int(hh):02d}:{int(mm):02d}:{int(ss):02d},{int(mi):03d}"


with gr.Blocks() as demo:

    with gr.Row():

        with gr.Column():

            with gr.Row():
                url = gr.Textbox(placeholder='Youtube video URL', label='URL')

            with gr.Row():

                model_size = gr.Dropdown(choices=model_size, value='tiny', label="Model")
                lang = gr.Dropdown(choices=langs, value="None", label="Language (Optional)")
                format = gr.Dropdown(choices=["None", ".srt"], value="None", label="Timestamps? (Optional)")

            with gr.Row():
                gr.Markdown("Larger models are more accurate, but slower. For 1min video, it'll take ~30s (tiny), ~1min (base), ~3min (small), ~5min (medium), etc.")
                transcribe_btn = gr.Button('Transcribe')

        with gr.Column():
            outputs = gr.Textbox(placeholder='Transcription of the video', label='Transcription')

    transcribe_btn.click(get_transcript, inputs=[url, model_size, lang, format], outputs=outputs)

demo.launch(debug=True)