How to create gaming video/Editing game video using Avidemux

Editing game video using Avidemux

In this section we'll talk about how to do basic editing with Avidemux. There are more versatile video editing programs available, but Avidemux is low cost (free) and easy to learn and use. There is virtually so setup needed after installation, so we can dive right into the editing process. These instructions are specific to Windows, but the process is similar for other operating systems.

Opening a file

First open the video you want to edit, presumably a video fresh from your recording software or device. Just click the open folder icon in the toolbar and select the file. If you haven't given the file a meaningful filename yet then this is a good time to do so. Avidemux will keep track of the last place you opened a file from, so after opening one for the first time, you usually won't have to tell it which folder to look in. It takes a few seconds to process the file into memory. (Keep in mine that video is not text, and you're dealing with gigabytes of data, not megabytes.

Navigating through a video

Most of the screen shows the current frame, so you'll start off with whatever was on the screen at the instant you started recording. On the left are Codec Options, but those should already be set properly out of the box. The real action will be taking place with the controls below the frame display. On the bottom left are navigation controls, including:

• A slider bar:

  Drag this to move to any point in the video. It's not usually accurate enough to find an exact frame, but you can get to the approximate area and use the more detailed controls from there.

Below the slider are navigation buttons. Ignore the square buttons marked A and B for now since they are used for editing. Other than those two, from left to right they are:

• Play/Stop:

  This starts playing the video at normal speed starting with the current frame. This plays the audio as well, so it will be the main way to find a location where a specific audio event occurs. While the video is playing, this turns into a pause button, to stop at the current frame.

• Previous and Next frames

  This step forward or backward a singe frame at a time. These are usually too precise, since at 30 frame per second a 30 min. video has 54,000 frames, but they have their uses. One use is to select a single frame to export as an image file.

• Previous and Next keyframes

  Recall from the section on video compression that video files are organized into short sections, and the boundaries of the sections are called keyframes. These buttons allow you to go between keyframes, or go from an intermediate frame to the next or previous keyframe. It's important to be able to locate these frames if you're only going to make edits at the keyframe boundaries. There are some good reasons for doing this when possible.

• Previous and Next cut point

  When you first open a file and haven't done any edits yet, these take you to the first and last frame of the video. As you start editing, you may notice that a vertical red lines appear in the slider at each edit point. These are useful for navigating to an edit so you can review the transition.

• Previous and Next black frame

  These seek out the previous and next black frames. These occur more often in traditional video sources, so you may not use these for game video editing.

• First and Last frame

  The beginning and end of the video. You will probably trim the beginning and end of almost every video you edit, and it's important to check the start and end to make sure that the cuts are well placed.

• Backward and Forward one minute

  This is slightly finer control than the slider bar.

In addition, there are several hot-key combinations you can use for navigation.

• Space: Same as the Play/Stop button.
• Left/Right: Same as the Previous and Next frame buttons.
• Down/Up: Same as the Previous and Next keyframe buttons.
• Shift + Down/Up: Same as the Previous and Next cut point buttons.
• Home, End: Same as the First and Last frame buttons.
• Ctrl+T: Go to a specific time index.
• Shift + Left/Right: Go backward or forward one second.
• Ctrl + Left/Right: Go backward or forward two seconds.
• Ctrl + Shift + Left/Right: Go backward or forward four seconds.
• Ctrl + Down/Up: Same as Backward and Forward one minute.

These are also available under Go in the main menu.

To the right of the main slider is an variable speed slider. Drag the line in the center to the right to move forward, and move it farther to the right to go faster. Similarly, dragging the line to the left will move backward at a speed you can control.

Below this are buttons with time indexes of the A and B markers which we'll talk about next. Click on either of these to go to that marker. The duration of the current selection is show below these.

Making edits

Editing with Avidemux is a lot like editing a text file in that you can highlight a section, then delete it or cut and paste it somewhere else. The main difference is you can't create new video; that's what your recording device or software is for. Highlighting a section is a bit more cumbersome than in a text file, but that's mainly because it's more difficult to navigate to a precise frame. In text you can just click on the spot where you want to make an edit.

To select a section, find the first frame of section using the navigation tools above, then press the square button marked A to set the start of the selection. Now find the last frame of the section, and press the square button marked B to set the end of the selection. You can also set the end of the section first if that's more convenient. As soon as you mark one end of a section, a box appears around the slider bar showing what is currently selected. The default for A is the start of the video and the default for B is the end. So, for example, if you just set B then everything from the start to that point will be selected. At any time you can reset the A and B markers to their default positions using Ctrl + Home or looking under Edit in the main menu.

For example, to have the edited video start just before you start playing, first locate that that point and set the B marker there. Actually, it's better to you go to the first keyframe before that point. If you're doing narration then it wouldn't be where you start playing but the point where you start talking, so play the video until you hear the first word, the back up a second or two, and then preferably to the previous keyframe, and set the B marker there. That sets the selection from the start of the recording to where you want the video to start.

Once you made a selection, you delete it (Delete), Cut it to move to another location (Ctrl+X) or Copy it to copy it to another locations (Ctrl+C). If you use Cut or Copy, then that section of the video is in the clipboard, and you can insert it into the video again by first navigating to the location, and then Pasting (Ctrl+V).

That's all you need to know for the basic mechanics. You should check each edit to make sure, for example, that no words got cut off and nothing was removed that you wanted to keep in. If necessary, you can Undo edits using Ctrl-Z. All editing commands are available under Edit in the main menu. Once you have the basics it's a matter of practice to make edits cleanly and efficiently.

Whenever you try to make an edit that's not on a keyframe, the program will display a warning message. Pay attention to these since saving the edited file after non-keyframe edits have been made will result in a corrupt video. The saved file will be playable, but there will be sections where colors are distorted. If you need to make edits not on keyframes, we'll discuss how to do that at the end.

Saving the editing video

There are several very important points here:

• AVIDEMUX DOES NOT ASK TO SAVE CHANGES BEFORE CLOSING

  So it's very easy after a hour long editing session, to close without saving and lose all that work. Make it a habit to make sure the edits have been saved before closing the file. Fortunately, Avidemux has a "Restore previous session" menu option (under Recent) so you can get back to where you were, but it's best not to rely on it since you may start on another file before you realize what happened.

• AVIDEMUX SAVES ONLY THE CURRENT SELECTION

  So if you save when there are only three seconds selected of a half-hour video, only the three seconds will be saved, not the half hour video. Again, the "Restore previous session" option can come to the rescue, but it's not a good idea to rely on it. We recommend that after you've saved the edited file, you open it and do a quick review in a different video player before closing Avidemux. It's probably a good idea to do a final review of the edited version in any case. To be fair, there are times when you want to only salve the selected section, say to grab a short clip from a long video.

• NEVER SAVE OVER THE ORIGINAL RECORDING

  With all the things that can go wrong in the editing process, be it human, software or hardware error, it's a good idea to keep your original recording in case you need to go back and start over with editing. Video files are large and disk space is finite, so you probably shouldn't keep these files forever, but at least until you're sure that the video has been uploaded and there are no issues that need to be fixed. By default, Avidemux appends "_edit" to the file name for the saved file, and it's a good way to keep track of which is the edited version. You may also want to keep all your edited files in a different folder from the original recording; this will help avoid confusion when you're selecting which file to upload.

So to save you edited file, first make sure the selection markers have been cleared, and only then click the save icon in the tool bar. Note that "Save" is always "Save as" in Avidemux since you're encouraged to keep the original. As an added precaution, review the edited version before closing Avidemux, and if all else fails, there is the "Restore previous session" option.

Non-keyframe edits

Being able to make edits at any frame instead of just on keyframes gives you much more flexibility. But to do this, you have to change the settings slightly. First, locate the "Video Output" part of Codec Options; these should be shown to the left of current frame. (If not, then select View→Toolbars from the main menu and make sure Codec Options is checked.) Change "Copy" to "Mpeg Encode". You'll notice that the "Configure" and "Filters" options are now activated. You shouldn't need to worry about the "Configure" button, so we won't cover that here, but you may want to press the "Filters" button to peruse the additional editing options that are not available. There are too many to list here in detail, but among other things you can do various fade transitions, add subtitles, and adjust the colors.

At this point you can edit normally, except now you don't have to worry about making changes at keyframes all the time. When you're done, press save as described above, but in this case instead of taking a few seconds to copy, the video has to be reprocessed and this will take much longer, using a great deal of computer power.