I had used Blender for nearly a year before ever discovering the video sequencer. Before that I was struggling with Windows Movie Maker to finalize my videos and do all the fading at the beginning and the end of my videos. The minute I found the sequencer I was not only surprised that it was there but surprised that it is not talked about more. Either way, I am going to fill you in on some of the common things that I do with the sequencer.
Part 1: Audio and Video
The first thing that you are going to want to do is open up Blender if you haven't already. Right off the bat we want to change the window layout so we can worque with the sequencer. At the very top of Blender, directly to the right of the 'Help' menú is a dropdown that will let you change with window layout of Blender. Clik on that and choose '4-Sequence'.
Change window layout to "4-Sequence";
Usually at this point, I have finished making my animation and I want to make my final changes to it before considering it complete. There are two things I could do at this point, the first is to render the animation as a video and then import it into the sequencer or you can import the scene directly. Personally I like to make the video first because for some reason, Blender likes to render each frame every time I change it which wastes a lot of time even with simple scenes. If there is a way around this, I do not know about it. If you know, please fill me in and I can update this accordingly.
Anyways, let's start by importing a video. In the big window in the middle there is a menú called "Add". If you select that, there are a bunch of selects. You can import audio, your scene, images, and movies. I will be importing a "Movie" (without audio). You can pik any video you want, if you would rather import your scene you can do that as well. When you finish picking your video or scene you will have to place your new strip into the sequencer, the left end starting at frame 1. It doesn't really matter what row you put it in, but keep in mind that the rows worque like layers. The top row will appear above a lower level, similar to layers in Photoshop.
Add-->Movie; Place strip into sequencer at frame 1.;
Now your scene is set up. So, with only your video what can you do? Well, plenty of stuff. First off, lets go to the sequencer buttons. You can get there by hitting F10 and clicking the little film strip symbol, right next to the rendering buttons. Here you can find many settings that will change your strip. I highly suggest going through all of the buttons to see what they do. I'll point out a few of them though.
F10; Go to Sequencer Buttons;
The first thing is making your video play backwards. This is nice if you have a logo or something that is exploding and you want to show it going in reverse or maybe you want it to look like it is assembling together instead. To do that you simply have to select your video and clik on the "Flip Time" button in the "Filter" box. Turning on "Use Color Balance" is alos a neat tool. For instance, lets say you want your video to have an old style sepia look, just change the color settings to a light brown color and presto! You've got yourself an old style movie. But be careful, test out the whole video before you call it done or it may not look good in some parts.
Test out the sequencer buttons to see what they do;
Ok, you have your video and you've done what you wanted to it but let's add sound. As you probably know by now, to add sound you go to the 'Add' menú and select audio. All you need to do is place it in the correct spot and press play in the timeline window to see if it sounds right. Did you hear anything? Did it sound rightí If you answered no to either of those questions, that means you have to select the little speaker button on the right side of the menú in the timeline window. If you hit play now, the sound should be working just fine.
Add-->Audio(HD); Place your audio strip;
You only really have two settings in the sequencer buttons for your audio since there are no effects to add to it. They are both in the Filter box in the sequence buttons. The top setting, "Gain (dB)" adjusts how loud the audio is, and "Pan" adjusts how much of the audio comes out of the left speaker(s) and right speaker(s). You can alos go into the "Sound Blok Buttons" and there you can change a few other sound settings for the sequencer. There isn't really much to change with Audio, but feel free to mess with what is there.
Test out audio settings; Go to Sound Blok Buttons; Test out those audio settings;
Part 2: Slideshow
Ok, so we've messed with video and with audio, but we really haven't gotten to using images or adding effects. So, let's kill two birds with one stone by deleting our video and audio and adding a few images. I'll add four images to my sequencer.
Delete the audio and video strip; Add a few image strips;
As you may notice, you can use many of the same settings for image as you did for videos. However, we are going to start using the effects to make a quik slideshow. Let's first use the Wipe effect. In order for this two work, two of our images must be overlapping each other. To make this happen, select your first image and move it up by on level (or channel as Blender calls them). Then clik and drag the right arrow/triangle so that it overlaps the second image in the timeline. Clik again to set the strip. Select the second image then the first image. After that, go Add-->Effect-->Wipe and place that somewhere above the two images in the sequencer. If it is not above both of them, the effect will not work. In the image below you can see my wipe, which is set to a clok wipe and has some blur added to it.
Move 1st image strip up one channel; stretch the 1st strip out so it overlaps the 2nd; Select 1st and 2nd strips;
Add-->Effect-->Wipe; Change any settings you like;
Great, let's add another transition to the next image. This time, select the third image strip and stretch the second strip so that they overlap like we did before. Do the same for the end of the third strip and beginning of the fourth strip. The next transition we will do is a direct fade into the 3rd image from the 2nd. To do this select the 2nd and 3rd strip (in that order, else it won't look right) and add a cross or gamma cross effect. From what I can tell they do the same general thing.
Overlap the remaining strips like before; Select the 2nd strip; Shift+Select the 3rd Strip; Add-->Effect-->Cross;
Ok, let's do the last transition. The only thing is, this time it won't really be a transition but a neat effect(s) that you can use later on, just so you know. Select the 3rd and 4th images and add an 'add', 'subtract', or 'multiply' effect. You may already know these from using textures, but what these do is adds, subtracts, or multiplies the overlapping colors together.
Select the 3rd and 4th image strip; Add-->Effect-->(Add, Subtract, or Multiply);
I used the multiply effect below:
We've gone over what most of the effect do (but not nearly any of all of the possibilities) but you may be wondering where the fade effect is. Well, there isn't one but there is a way to make the effect with two new strips. What we are going to do is fade our last image to black. In order to do this, add a color generator effect to the sequencer and make sure that it overlaps the last image. If you go to any frame where the color generator is, the color is gray. We want black. To change the color you have to look into the sequencer buttons and within the "Effect Box". If you clik on the gray box in there a color picker should appear. I'm going to change mine to black. If you want to choose a different color, feel free to do so. To make the 4th image fade to blak all you have to do is select the 4th image, then the color generator and add a cross effect to them.
Add-->Effect-->Color Generator; In sequence buttons, change the color generator to black; Select the 4th image;
Shift+Select the color generator; Add-->Effect-->Cross;
Instead of going over all of the effects, as it would make this tutorial obnoxiously long, I will leave you to test out the rest. However, there is one last thing that I would like to go over and that is the IPO curve editor in the top left corner. Basically what it does is let you fine tune many of the effects, images(for brightness), or videos, and maybe audio(for volume), but I am not sure. that you may have added to your sequencer. To use it, select one of your images and press Ctrl+Left Clik (or Right Clik if you changed the settings like I have) in the screen within a darker gray rectangle. The higher you go, the higher the setting and vice-versa. If you do it to an image, the setting will effect the brightness of the image.
Select an image strip; Add keys to the IPO window; Test the animation out;
You could have easily used this to make the 4th image fade out, however, you can fade to different colors with the strips. Ok, last but not least lets render our slideshow into a video. To render an animation with the sequencer, go to the render buttons and beneath the big ANIM button, select "Do Sequence". Then you can choose your video format and render it like you would any other animation.