Karaoke Subtitle Encode Problem

[pyrobooby]

Hi, everyone!
I'm working with a karaoke ASS subtitle file with particle effect code(file size: 100MB+).
What I want to do is to hardsub the MV. So I write the following code:
Loadplugin("D:\Program Files\megui_svn\VSFilter.dll")
Directshowsource("E:\mv.mp4")
textsub("E:\mv.ass")

Then I drag the avs script to MeGUI. It takes a pretty long time before the preview window shows up. So does the queue and the encoding(about 10 fps). Pretty slow for my laptop and the video file:
CPU:i5-2450M RAM:8G DDR3 Windows 7 x64 Ultimate 6.1.7601
media info(sorry I don't have an English version):
文件格式 : AVC
文件格式/信息 : Advanced Video Codec
格式简介 : High@L3.1
格式设置, CABAC : yes
格式设置, ReFrames : 1 frame
编码设置ID : avc1
编码设置ID/信息 : Advanced Video Coding
长度 : 3分 32秒
码率 : 2 243 Kbps
最大码率 : 3 749 Kbps
画面宽度 : 1 280像素
画面高度 : 720像素
画面比例 : 16:9
帧率模式 : 恒定
帧率 : 24.000 fps
色彩空间 : YUV
色度抽样 : 4:2:0
位深度 : 8位
扫描方式 : 逐行扫描
bits/(pixel*frame)(数据密度) : 0.101
大小 : 56.7 MiB (92%)

What slows down the speed?
directshowsource, textsub, or both?

I tried to google and it is suggested that use ffmpeg import plugin and assrender for sub.
Any thoughts, Any help?
Thanks in advance!

[the_weirdo]

First you should use FFMS2. It's frame accurate and more stable than DSS.

The slow down problem you encountered because of karaoke effect. You could try xy-VSFilter (https://code.google.com/p/xy-vsfilter/) or AssRender (http://srsfckn.biz/assrender/) to speed up thing a bit. Note that AssRender is a C plugin so you need to use LoadCPlugin(path\to\assrender.dll) to load it.