Tutorial Builder
266 lines
9.6 KiB
Python
266 lines
9.6 KiB
Python
import argparse
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import os
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import platform
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import re
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import shutil
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import subprocess
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import tempfile
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from pathlib import Path
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SRT_BLOCK_RE = re.compile(
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r"\s*(\d+)\s+([\d:,]+)\s+-->\s+([\d:,]+)\s+(.+?)(?=\n\s*\d+\s+\d\d:|\Z)",
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re.S,
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)
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def resolve_path(value: str) -> Path:
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return Path(value).expanduser().resolve()
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def run(command: list[str]) -> None:
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print("Running:", " ".join(command))
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subprocess.run(command, check=True)
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def remove_temp_dir(path: Path) -> None:
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try:
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shutil.rmtree(path, ignore_errors=True)
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except PermissionError:
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pass
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except OSError:
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pass
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def to_seconds(timestamp: str) -> float:
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h, m, rest = timestamp.split(":")
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s, ms = rest.split(",")
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return int(h) * 3600 + int(m) * 60 + int(s) + int(ms) / 1000
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def read_srt(path: Path) -> list[tuple[float, float, str]]:
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text = path.read_text(encoding="utf-8-sig")
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captions = []
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for _, start, end, body in SRT_BLOCK_RE.findall(text):
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clean_text = " ".join(line.strip() for line in body.strip().splitlines())
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captions.append((to_seconds(start), to_seconds(end), clean_text))
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if not captions:
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raise ValueError(f"No captions found in {path}")
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return captions
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def media_duration(path: Path) -> float:
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result = subprocess.run(
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[
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"ffprobe",
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"-v", "error",
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"-show_entries", "format=duration",
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"-of", "default=noprint_wrappers=1:nokey=1",
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str(path),
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],
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check=True,
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capture_output=True,
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text=True,
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)
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return float(result.stdout.strip())
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def ps_quote(value: str) -> str:
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return "'" + value.replace("'", "''") + "'"
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def speak_macos(text: str, voice: str, rate: int, output: Path) -> None:
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run(["say", "-v", voice, "-r", str(rate), "-o", str(output), text])
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def speak_windows(text: str, voice: str, rate: int, volume: int, output: Path) -> None:
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ps_script = f"""
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Add-Type -AssemblyName System.Speech
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$synth = New-Object System.Speech.Synthesis.SpeechSynthesizer
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$synth.SelectVoice({ps_quote(voice)})
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$synth.Rate = {rate}
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$synth.Volume = {volume}
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$synth.SetOutputToWaveFile({ps_quote(str(output))})
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$synth.Speak({ps_quote(text)})
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$synth.Dispose()
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"""
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run(["powershell", "-NoProfile", "-ExecutionPolicy", "Bypass", "-Command", ps_script])
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def default_voice() -> str:
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if platform.system() == "Darwin":
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return "Daniel"
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if platform.system() == "Windows":
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return "Microsoft David Desktop"
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raise RuntimeError("One-step SRT voiceover generation is supported only on macOS and Windows.")
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def default_rate() -> int:
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if platform.system() == "Darwin":
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return 185
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if platform.system() == "Windows":
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return 0
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raise RuntimeError("One-step SRT voiceover generation is supported only on macOS and Windows.")
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def speak(text: str, voice: str, rate: int, volume: float, output: Path) -> None:
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system = platform.system()
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if system == "Darwin":
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speak_macos(text, voice, rate, output)
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return
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if system == "Windows":
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windows_volume = max(0, min(100, round(volume * 100)))
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speak_windows(text, voice, rate, windows_volume, output)
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return
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raise RuntimeError("One-step SRT voiceover generation is supported only on macOS and Windows.")
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def create_voiceover_from_srt(
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srt_path: Path,
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wav_output: Path,
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voice: str,
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rate: int,
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work_dir: Path,
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volume: float,
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silence_padding: float,
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sample_rate: int,
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channels: int,
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) -> None:
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captions = read_srt(srt_path)
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segment_files = []
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for i, (start, end, text) in enumerate(captions, 1):
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duration = end - start
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raw_audio = work_dir / f"raw_{i:03d}.aiff" if platform.system() == "Darwin" else work_dir / f"raw_{i:03d}.wav"
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segment_wav = work_dir / f"seg_{i:03d}.wav"
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speak(text, voice, rate, volume, raw_audio)
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spoken_duration = media_duration(raw_audio)
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padding = min(silence_padding, max(duration - spoken_duration, 0))
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effective_duration = duration if silence_padding == 0 else min(duration, spoken_duration + padding)
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if spoken_duration > duration:
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print(f"Warning: caption {i} speech is {spoken_duration:.2f}s but slot is {duration:.2f}s; it will be trimmed.")
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audio_filter = f"volume={volume},apad,atrim=0:{effective_duration}"
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run([
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"ffmpeg", "-y",
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"-i", str(raw_audio),
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"-af", audio_filter,
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"-ar", str(sample_rate),
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"-ac", str(channels),
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str(segment_wav),
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])
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segment_files.append(segment_wav)
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concat_list = work_dir / "list.txt"
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concat_list.write_text("".join(f"file '{os.path.abspath(file)}'\n" for file in segment_files), encoding="utf-8")
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run(["ffmpeg", "-y", "-f", "concat", "-safe", "0", "-i", str(concat_list), "-c:a", "pcm_s16le", str(wav_output)])
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def combine_video_audio(video_file: Path, audio_file: Path, output_file: Path, reencode_video: bool, volume: float) -> None:
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video_codec_args = ["-c:v", "libx264", "-preset", "medium", "-crf", "18"] if reencode_video else ["-c:v", "copy"]
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command = [
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"ffmpeg", "-y",
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"-i", str(video_file),
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"-i", str(audio_file),
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"-map", "0:v:0",
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"-map", "1:a:0",
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*video_codec_args,
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"-af", f"volume={volume}",
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"-c:a", "aac",
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"-b:a", "192k",
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"-movflags", "+faststart",
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str(output_file),
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]
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run(command)
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def main() -> None:
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parser = argparse.ArgumentParser(
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description="Replace a video's original audio with a voiceover audio file, or generate the voiceover from an SRT first."
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)
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parser.add_argument("--video", required=True, help="Input video file, for example input/tutorial.mp4")
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parser.add_argument("--audio", default=None, help="Existing voiceover audio file, for example output/voiceover.wav")
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parser.add_argument("--srt", default=None, help="Input SRT file for one-step voiceover generation")
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parser.add_argument("--output", required=True, help="Output MP4 file, for example output/final_video.mp4")
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parser.add_argument("--voice", default=None, help="Voice name for one-step SRT mode")
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parser.add_argument("--rate", type=int, default=None, help="Speech rate for one-step SRT mode")
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parser.add_argument("--audio-output", default=None, help="Optional copy of the generated voiceover WAV in one-step SRT mode")
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parser.add_argument("--keep-temp", action="store_true", help="Keep temporary voice parts for debugging in one-step SRT mode")
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parser.add_argument("--volume", type=float, default=1.0, help="Voiceover volume multiplier. Default: 1.0")
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parser.add_argument("--silence-padding", type=float, default=0.0, help="Seconds of silence after each caption in one-step SRT mode, if the SRT slot allows it. Default: 0.0")
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parser.add_argument("--sample-rate", type=int, default=44100, help="Generated voiceover sample rate in one-step SRT mode. Default: 44100")
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parser.add_argument("--channels", type=int, default=2, choices=[1, 2], help="Generated voiceover channels in one-step SRT mode. Default: 2")
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parser.add_argument(
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"--reencode-video",
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action="store_true",
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help="Re-encode video with H.264 instead of copying. Use only if the copied output has playback issues.",
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)
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args = parser.parse_args()
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if not args.audio and not args.srt:
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parser.error("Provide either --audio for the current two-step flow or --srt for one-step generation.")
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if args.audio and args.srt:
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parser.error("Use either --audio or --srt, not both.")
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if args.volume <= 0:
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parser.error("--volume must be greater than 0.")
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if args.silence_padding < 0:
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parser.error("--silence-padding must be 0 or greater.")
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video_file = resolve_path(args.video)
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output_file = resolve_path(args.output)
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if not video_file.exists():
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raise FileNotFoundError(f"Video not found: {video_file}")
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output_file.parent.mkdir(parents=True, exist_ok=True)
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if args.audio:
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audio_file = resolve_path(args.audio)
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if not audio_file.exists():
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raise FileNotFoundError(f"Audio not found: {audio_file}")
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combine_video_audio(video_file, audio_file, output_file, args.reencode_video, args.volume)
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else:
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srt_path = resolve_path(args.srt)
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if not srt_path.exists():
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raise FileNotFoundError(f"SRT not found: {srt_path}")
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voice = args.voice or default_voice()
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rate = args.rate if args.rate is not None else default_rate()
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audio_output = resolve_path(args.audio_output) if args.audio_output else None
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if audio_output:
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audio_output.parent.mkdir(parents=True, exist_ok=True)
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temp_dir = Path(tempfile.mkdtemp(prefix="video_generator_"))
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try:
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temp_wav = temp_dir / "voiceover.wav"
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create_voiceover_from_srt(
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srt_path,
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temp_wav,
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voice,
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rate,
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temp_dir,
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args.volume,
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args.silence_padding,
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args.sample_rate,
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args.channels,
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)
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if audio_output:
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run(["ffmpeg", "-y", "-i", str(temp_wav), "-c:a", "pcm_s16le", str(audio_output)])
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print(f"Done: {audio_output}")
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combine_video_audio(video_file, temp_wav, output_file, args.reencode_video, 1.0)
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finally:
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if not args.keep_temp:
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remove_temp_dir(temp_dir)
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else:
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print(f"Kept temporary voice parts: {temp_dir}")
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print(f"Done: {output_file}")
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if __name__ == "__main__":
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main()
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