Need help with replay renderer

[Dragon0v]

Whenever I try to render a replay, it does it's thing fine, I find the videos in the trackmania folder, but whenever I play them, no matter what codec or what settings I use to render, The video is jumpy, and will play in slowmotion, pause and then glitch to a few seconds foward then freeze, and the sound does the same.

Am I doing anything wrong?

Here are my computer specs:
Operating System: Windows 7 Ultimate 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.110622-1506)
Language: English (Regional Setting: English)
System Manufacturer: Gigabyte Technology Co., Ltd.
System Model: H67MA-D2H
BIOS: Award Modular BIOS v6.00PG
Processor: Intel(R) Core(TM) i5-2500 CPU @ 3.30GHz (4 CPUs), ~3.6GHz
Memory: 4096MB RAM
Available OS Memory: 4080MB RAM
Page File: 2227MB used, 5929MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
User DPI Setting: Using System DPI
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
DxDiag Version: 6.01.7601.17514 32bit Unicode
Graphics card is Nvidia GT220 with 1gb of memory.

[Screek]

What codecs do you try and use?
normally uncompressed is to much for your PC to handle in a media player, so it might go in slowmotion and/or lag a lot!