app.py

import base64
import os
from functools import partial
from multiprocessing import Pool

import gradio as gr
import numpy as np
import requests
from processing_whisper import WhisperPrePostProcessor
from transformers.models.whisper.tokenization_whisper import TO_LANGUAGE_CODE
from transformers.pipelines.audio_utils import ffmpeg_read


title = "Whisper JAX: The Fastest Whisper API ⚡️"

description = "Whisper JAX is an optimised implementation of the [Whisper model](https://huggingface.co/openai/whisper-large-v2) by OpenAI. It runs on JAX with a TPU v4-8 in the backend. Compared to PyTorch on an A100 GPU, it is over **100x** faster, making it the fastest Whisper API available."

API_URL = os.getenv("API_URL")
API_URL_FROM_FEATURES = os.getenv("API_URL_FROM_FEATURES")

article = "Whisper large-v2 model by OpenAI. Backend running JAX on a TPU v4-8 through the generous support of the [TRC](https://sites.research.google/trc/about/) programme. Whisper JAX code and Gradio demo by 🤗 Hugging Face."

language_names = sorted(TO_LANGUAGE_CODE.keys())
CHUNK_LENGTH_S = 30
BATCH_SIZE = 16
NUM_PROC = 16


def query(payload):
    response = requests.post(API_URL, json=payload)
    return response.json(), response.status_code


def inference(inputs, language=None, task=None, return_timestamps=False):
    payload = {"inputs": inputs, "task": task, "return_timestamps": return_timestamps}

    # langauge can come as an empty string from the Gradio `None` default, so we handle it separately
    if language:
        payload["language"] = language

    data, status_code = query(payload)

    if status_code == 200:
        text = data["text"]
    else:
        text = data["detail"]

    if return_timestamps:
        timestamps = data["chunks"]
    else:
        timestamps = None

    return text, timestamps


def chunked_query(payload):
    response = requests.post(API_URL_FROM_FEATURES, json=payload)
    return response.json()


def forward(batch, task=None, return_timestamps=False):
    feature_shape = batch["input_features"].shape
    batch["input_features"] = base64.b64encode(batch["input_features"].tobytes()).decode()
    outputs = chunked_query(
        {"batch": batch, "task": task, "return_timestamps": return_timestamps, "feature_shape": feature_shape}
    )
    outputs["tokens"] = np.asarray(outputs["tokens"])
    return outputs


if __name__ == "__main__":
    processor = WhisperPrePostProcessor.from_pretrained("openai/whisper-large-v2")
    pool = Pool(NUM_PROC)

    def transcribe_chunked_audio(microphone, file_upload, task, return_timestamps):
        warn_output = ""
        if (microphone is not None) and (file_upload is not None):
            warn_output = (
                "WARNING: You've uploaded an audio file and used the microphone. "
                "The recorded file from the microphone will be used and the uploaded audio will be discarded.\n"
            )

        elif (microphone is None) and (file_upload is None):
            return "ERROR: You have to either use the microphone or upload an audio file"

        inputs = microphone if microphone is not None else file_upload

        with open(inputs, "rb") as f:
            inputs = f.read()

        inputs = ffmpeg_read(inputs, processor.feature_extractor.sampling_rate)
        inputs = {"array": inputs, "sampling_rate": processor.feature_extractor.sampling_rate}

        dataloader = processor.preprocess_batch(inputs, chunk_length_s=CHUNK_LENGTH_S, batch_size=BATCH_SIZE)

        try:
            model_outputs = pool.map(partial(forward, task=task, return_timestamps=return_timestamps), dataloader)
        except ValueError as err:
            # pre-processor does all the necessary compatibility checks for our audio inputs
            return err, None

        post_processed = processor.postprocess(model_outputs, return_timestamps=return_timestamps)
        timestamps = post_processed.get("chunks")
        return warn_output + post_processed["text"], timestamps

    def _return_yt_html_embed(yt_url):
        video_id = yt_url.split("?v=")[-1]
        HTML_str = (
            f'<center> <iframe width="500" height="320" src="https://www.youtube.com/embed/{video_id}"> </iframe>'
            " </center>"
        )
        return HTML_str

    def transcribe_youtube(yt_url, task, return_timestamps):
        html_embed_str = _return_yt_html_embed(yt_url)

        text, timestamps = inference(inputs=yt_url, task=task, return_timestamps=return_timestamps)

        return html_embed_str, text, timestamps

    audio_chunked = gr.Interface(
        fn=transcribe_chunked_audio,
        inputs=[
            gr.inputs.Audio(source="microphone", optional=True, type="filepath"),
            gr.inputs.Audio(source="upload", optional=True, type="filepath"),
            gr.inputs.Radio(["transcribe", "translate"], label="Task", default="transcribe"),
            gr.inputs.Checkbox(default=False, label="Return timestamps"),
        ],
        outputs=[
            gr.outputs.Textbox(label="Transcription"),
            gr.outputs.Textbox(label="Timestamps"),
        ],
        allow_flagging="never",
        title=title,
        description=description,
        article=article,
    )

    youtube = gr.Interface(
        fn=transcribe_youtube,
        inputs=[
            gr.inputs.Textbox(lines=1, placeholder="Paste the URL to a YouTube video here", label="YouTube URL"),
            gr.inputs.Radio(["transcribe", "translate"], label="Task", default="transcribe"),
            gr.inputs.Checkbox(default=False, label="Return timestamps"),
        ],
        outputs=[
            gr.outputs.HTML(label="Video"),
            gr.outputs.Textbox(label="Transcription"),
            gr.outputs.Textbox(label="Timestamps"),
        ],
        allow_flagging="never",
        title=title,
        examples=[["https://www.youtube.com/watch?v=m8u-18Q0s7I", "transcribe", False]],
        cache_examples=False,
        description=description,
        article=article,
    )

    demo = gr.Blocks()

    with demo:
        gr.TabbedInterface([audio_chunked, youtube], ["Transcribe Audio", "Transcribe YouTube"])

    demo.queue()
    demo.launch()