services/whisper/utils/render.py

import os
import subprocess
import uuid
from utils.logger import logger

OUTPUT_DIR = "jobs"
os.makedirs(OUTPUT_DIR, exist_ok=True)


def render_subtitles(
    video_path: str,
    srt_text: str,
    output_path: str | None = None,
):
    """
    Universal subtitle renderer for V7.

    Supports:
    - API render
    - UI render
    - Batch jobs
    - Worker queue
    """

    if output_path is None:
        output_path = os.path.join(
            OUTPUT_DIR,
            f"{uuid.uuid4()}_render.mp4"
        )

    # --------------------------------------------------
    # Write SRT file
    # --------------------------------------------------

    srt_path = output_path.replace(".mp4", ".srt")

    with open(srt_path, "w", encoding="utf-8") as f:
        f.write(srt_text)

    logger.info(f"[RENDER] SRT saved → {srt_path}")

    # --------------------------------------------------
    # FFmpeg Subtitle Burn
    # --------------------------------------------------

    cmd = [
        "ffmpeg",
        "-y",
        "-i", video_path,
        "-vf", f"subtitles={srt_path}",
        "-c:a", "copy",
        output_path,
    ]

    logger.info("[RENDER] Running ffmpeg render")

    process = subprocess.run(
        cmd,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        text=True
    )

    if process.returncode != 0:
        logger.error(process.stderr)
        raise Exception("FFmpeg render failed")

    if not os.path.exists(output_path):
        raise Exception("Rendered file missing")

    logger.info(f"[RENDER] Output → {output_path}")

    return output_path