Splitting / Appending

Introduction

The goal of this guide is to show ways to split or append videos without having to re-encode. There are inherent drawbacks which will be explained, as well as solutions to get around most of them.

Tools

• VirtualDubMod - for avi files.
• YAMB - for mp4 files.
• AviSynth
• Codec
• FFDShow

Splitting

The act of taking a video and creating smaller, separate videos.

With VirtualDubMod

• Use the slider and the two arrow buttons next to the frame number to make your selection.
• Video -> Direct Stream Copy.
• File -> Save As.

The drawback: You can only start a cut on an I frame. In VirtualDub(Mod) this is labeled with the letter K which can be seen at the bottom center of the interface. This has to do with how videos are compressed.

Without going too in depth... you start with a full I frame followed by a sequence of P or B frames. Those P and B frames are based off that previous I frame. They ABSOLUTELY NEED that I frame or they won't display correctly, so you wouldn't want to cut out that I frame, would you? What this means is that in VirtualDub(Mod), it doesn't matter where you make your starting selection, it will search backwards until it finds that K frame. So while you may think you're starting a cut on frame 3080, which happens to be a P frame, the cut may actually start on frame 2994, a K frame. The problem is that the spacing between K frames can be very far. The video I'm looking at while writing this guide has them spaced out every 10 seconds. This does not allow me to make a precise cut. The good thing is that this drawback doesn't apply to the end of your selection.

Summary: The start of your cut will not be precise (unless you knowlingly start off a K frame), but the end of your cut will be.

Tip: You can navigate through keyframe placements by pressing the button with an arrow and a yellow key under it.