Video_cutter/modules/text_processing/caption.py

import os
import subprocess

import ffmpeg
from moviepy.editor import VideoFileClip, TextClip, CompositeVideoClip
from moviepy.video.tools.subtitles import SubtitlesClip

def sec_to_srt_time(seconds):
    hours = int(seconds // 3600)
    mins = int((seconds % 3600) // 60)
    secs = seconds % 60
    return f"{hours:02d}:{mins:02d}:{secs:06.3f}".replace('.', ',')

def generate_srt_file(text_sequence, output_path):
    """
    生成SRT字幕文件
    
    参数:
    text_sequence: 字幕列表，格式 [(start_sec, end_sec, text), ...]
    """
    with open(output_path, 'w', encoding='utf-8') as f:
        for i, (start, end, text) in enumerate(text_sequence, 1):
            f.write(f"{i}\n")
            f.write(f"{sec_to_srt_time(start)} --> {sec_to_srt_time(end)}\n")
            f.write(f"{text}\n\n")


def burn_subtitles_bash(input_path, srt_path, output_path):
    cmdLine = f"ffmpeg -i {input_path} -vf subtitles={srt_path} -c:a copy -c:v h264_nvenc -preset fast -cq 23 {output_path}"
    subprocess.call(cmdLine, shell=True)


def burn_subtitles_ffmpeg(input_path, srt_path, output_path, style_config=None):
    """
    通过FFmpeg烧录字幕（硬编码） - 极速优化版
    """
    # 默认字幕样式（精简必要参数）
    default_style = {
        'fontsize': 32,
        'fontcolor': 'FFFFFF',  # 直接使用HEX值，避免转换
        'borderw': 2,
        'bordercolor': '000000',
        'alignment': '10',
        'margin': '40'
    }
    style = style_config or default_style

    # 构建FFmpeg命令（直接使用CLI语法更高效）
    (
        ffmpeg
        .input(input_path)
        .filter(
            'subtitles', 
            filename=srt_path,
            force_style=(
                f"Fontsize={style['fontsize']},"
                f"PrimaryColour={style['fontcolor']},"
                f"BackColour={style['bordercolor']},"
                f"Outline={style['borderw']},"
                f"Alignment={style['alignment']},"
                f"MarginV={style['margin']}"
            )
        )
        .output(
            output_path,
            **{
                # 核心加速参数
                'c:v': 'h264_nvenc',       # NVIDIA GPU编码
                'preset': 'fast',          # NVENC最高速预设
                'tune': 'fastdecode',      # 优化解码速度
                'rc': 'constqp',           # 恒定质量模式
                'cq': 28,                  # 质量值（18-32，越高越快）
                'gpu': '0',                # 指定GPU设备
                'c:a': 'copy',             # 直接复制音频
                'threads': '8',            # 多线程处理
                'y': None                  # 覆盖输出文件
            }
        )
        .global_args('-hwaccel', 'cuda')   # 启用CUDA硬件加速
        .global_args('-hwaccel_output_format', 'cuda')  # 显存直接传递
        .run()
    )

if __name__ == "__main__":
    # 生成测试字幕
    text_sequence = [
        (0.0, 10.0, "第一句字幕测试"),
    ]
    generate_srt_file(text_sequence, 'dynamic_subtitles.srt')


    # 示例用法（硬件加速需配置FFmpeg）
    burn_subtitles_ffmpeg('./output/video_clips/cut_video.mp4', 'dynamic_subtitles.srt', 'output.mp4')



## TODO:
# 1、JSON to SRT
# 2、JSON to CLIPS
# 3、SRT add to CLIPS