Step 1: Exporting Out of Final Cut
There are two ways to compress files using Apple's Compressor. One is as a standalone application that you can drag and drop files into. The other is to export directly from Final Cut. In this tutorial we'll be focusing on the latter. Rather than exporting a Final Cut movie or using the QuickTime conversion, we'll be exporting using Compressor (Figure 1, left).
No matter what format you are trying to export to, you'll find far more options and greater flexibility by going through Compressor. One advantage that's not often mentioned is that your timeline does not need to be rendered to use the Compressor option. In this way, Compressor will build the frame in the timeline and compress it with no generational loss. I have not however, done comparison tests to see if rendering a timeline before exporting with Compressor will add or decrease the compression time—but avoiding generation loss is worth any trade-off in compression time.
 Step 2: Naming Your Output Files
Once you've exported using Compressor, the Compressor application will automatically open up and put your timeline into the Batch window. Apple's Compressor uses a naming convention of the project name and the name of your timeline for the source media name (Figure 2,left).
Although you can't change the name of the source media, you will have the opportunity to name the output file. Just remember that it's good practice to give your project all the proper names before you export to Compressor. It will also name your batch file with the same convention, so if you will be using the batch file more than once, you'll want to make note of it or change it to something meaningful.
Apple's Compressor application is displayed with four windows; Batch, Monitor, Presets, and the Inspector (if the Inspector window is not present, it will open when double-clicking or adjusting a preset).
Apple's Compressor operates with the understanding that the user is going to start off with a preset, and then change the settings from within a preset to suit your individual needs. You can access the presets in one of three ways: drag and drop from the Presets window onto the file you want to encode; highlight the file to encode and select a preset from the Settings toolbar drop down menu; or, use the pop-up menu under the Settings tab of the Batch window. They will all give you the same results, so determine which you find more convenient.
 Step 3: Choosing MPEG-2 Settings
Since the bulk of most editing work ends up on DVDs, this article will address some of the challenges Final Cut editors face when compressing to MPEG-2. Compressor has a lot of great presets to choose from for compressing to DVD. As spelled out in the Presets window, you have the choice of Best Quality, Fastest Encode, and aspect ratios all based on the length of your video and the requirements of the DVD you are delivering (Figure 3, left).
With every choice there is a compromise. If you want Best Quality, then it will take the longest to encode; if you want Fastest Encoding, then the quality will not be as good. (Incidentally, even though bit rate has a dramatic effect on output quality, it doesn't affect encoding speed—besides the length of the video, one-pass vs. two-pass is the biggest factor, along constant bit rate vs. variable bit rate and other aspects of encoding acuity.) As we will discuss a little later, there are also many choices that will yield results that land somewhere on the middle ground. Given the encoding speed that recent Macs support (even at Best Quality), editors that deal mainly with projects that run under one hour will rarely need to make any changes to a preset. They would likely always choose Best Quality and wait for the results.
The quality of your MPEG compression, and the resulting DVD, comes down to data rate vs. disc space. We know that a single-sided DVD can hold up to a total of 4.37GB of space. (Incidentally, that 4.37GB is what is generally called “engineering” gigabytes, figured in factors of 1,024. “Marketing” gigabytes, figured in factors of 1,000, give you the 4.7GB capacity figure generally associated with DVD, and also account for the discrepancy between what your 500GB hard drive promises on the box and what you see when you attach it to your computer. But the actual disc space is the same.) So given that full 4.37GB capacity at your disposal, you might think, “Since my video is only ten minutes long, I'll crank up the data rate to make it look great!” Please be advised that most DVD players will not be able to play a burned DVD that has a video stream with a data rate of higher than 7.9Mbps. You'll get choking, sputtering, and angry clients sending your discs back.
 Step 4: Adjustments in the Inspector Window
Let's take a look at some of the different encoding choices. Select any of the presets by one of the three procedures mentioned previously. (For the purposes of this section, I chose “DVD: Best Quality 90 min - 4:3.”) Then double-click on the preset in the Settings tab of the Batch window to bring up the Inspector window.
The Inspector window is where you will be making all of the adjustments to your encoding (Figure 4, left). At the top of the Inspector window there are six button choices: Summary, Encoder, Frame Controls, Filters, Geometry, and Actions. For this tutorial, we're going to stick with the first two buttons, Summary and Encoder. Since we're dealing with MPEG-2 encoding for DVDs, we will leave the File Format pop-up menu alone. Under that are the controls that we're going to be looking at. Of the four tabs, we're going to focus on the first two, Video Format and Quality.
 Step 5: Working in the Quality Tab
The Video Format tab is fairly self-explanatory. You must select a file format (NTSC or PAL), and set the frame rate, aspect ratio, and field dominance. The Quality tab (Figure 5, left) is where most of the “magic” happens during the encoding of a video, and where the choices you make when using Compressor will have the greatest effect on the output quality of your video. Here you will find most of the options that will affect the quality and encoding times.
In the Mode pop-up menu you'll find five choices concerning what type of encoding process you want: One-Pass CBR (constant bit-rate encoding), One-Pass VBR (variable bit-rate encoding), One-Pass VBR Best, Two-Pass VBR, and Two-Pass VBR Best.
You can choose single-pass or two-pass encoding with the bit rate settings you prefer. Two-pass means that Compressor's MPEG-2 encoder will examine the video stream twice to determine the most efficient way to compress it, identifying the video data redundancies and such that make compression possible. Obviously, a two-pass VBR encode will take longer than a single pass, but it can yield better results. Some users prefer to use the CBR setting, to know exactly what bit rate the video will be encoded at. The VBR bit rate can fluctuate, as the encoder applies more bits to less easily compressed segments and fewer bits where possible to maintain the average bit rate you chose, but you can set parameters for the fluctuations as described in Step 6.
 Step 6: Setting VBR Parameters
Next up are the Average Bit Rate and Maximum Bit Rate slider controls, which you will use to moderate VBR fluctuations. If you chose the CBR mode, then the Maximum Bit Rate will be grayed out, because the CBR is fixed at one bit rate only. Compressor uses the Average Bit Rate as its “target” rate, but will sometimes fall below that level and sometimes go higher.
This is why Apple's Compressor also gives you the option to set a maximum bit rate. By doing so, you can be sure to keep the maximum rate within your needs. You'll notice once you start adjusting the sliders that the Maximum Bit Rate slider needs about 1Mbps of “headroom” over the Average Bit Rate slider. This range will become a factor if you try to push the Average Bit Rate above 6.9Mbps. By pushing the Average Bit Rate to 7.0, as shown in Figure 6 (left), you are opening up the possibility of having the video stream peak above 7.9Mbps, which may choke a DVD player.
Using high bit rates will also affect the amount of space you'll be taking up with the video stream. Usually, the two main concerns with users that are authoring DVDs are making the video look as good as possible and fitting it all onto one DVD. There are two ways in which you can see how much a video stream will take up at a given bit rate. One is to take out a pencil, paper, and a calculator and do some tricky equations. The other is to look at the bottom of the Quality tab to see feedback as you adjust the Average Bit Rate slider (e.g., “Allows up to 88 minutes of video on a DVD-5”). I've found that the time display usually underestimates that actual time by roughly 10%. But do keep in mind that you probably have other media—pictures, menus, sounds, and so forth that will also need to fit on the DVD, so don't use all the space just for your video.
Not surprisingly, as you increase the bit rate, you will decrease the amount of minutes allowed onto the DVD. For example, if you need to fit two hours of a video onto one DVD, then a bit rate of 6.0Mbps is going to be too high. This a great tool to help you include all of the material that you want to fit on a disc by adjusting your bit rates. You will need to include all of your material to correctly identify your total disc space.
The Motion Estimation pop-up menu option is another control that can greatly affect the quality and encoding time. As expected, “Best” takes the longest time and “Good” a shorter amount of time. The Motion Estimation control looks at the entire frame of video and decides what is moving and where, in relation to the frames to be encoded next. The better the setting, the further ahead (more frames) the Motion Estimation will look to give you a better compression.
As an example of how the presets work in relation to the Quality tab, if we were to apply a Best Quality 90 minute preset and change the mode from Two-Pass VBR to One-Pass VBR Best and the Motion Estimation from Best to Good, we would end up with the Fastest Encode 90 minute Preset. Notice that we didn't change the bit rate.
 Step 7: Creating an MPEG Preset
Once you've tweaked your MPEG encoding settings to your liking, save them as a preset to simplify similar future projects. Or, if you've found an Apple-supplied preset that closely matches how you want to encode your work, then click the Save As button and give it a descriptive name that will distinguish it from the rest of the list. From there you can adjust the settings on an as-needed basis. Now let's create a good “mid-range” setting for an MPEG file. From the pop-up menu in the Settings tab in the Batch window, chose Fastest Encode 90 min. (Figure 7, left).
Next double-click on the setting to bring up the Inspector Window. Before you make any changes to the preset, click Save As, and name it something descriptive like “MPEG Mid.”
 Step 8: Change Encoding Mode
Now we'll go in and modify the setting a little to create a mid-level MPEG encoding. Make sure the Encoder button is selected, then chose the Quality tab. We only need to make two changes to have a real positive impact on the quality of our MPEG encoding and as a result our DVD-Video. First, change the Mode to One-Pass VBR Best (Figure 8, left).
 Step 9: Change Motion Estimation
Leave the bit rate alone. In the Motion Estimation pop-up, change it from Good to Better (Figure 9). So you've created a preset that is better quality than a Fastest Encode, but is still a quicker encoding than the Best Quality setting. In short, a mid-level encoding preset!
 Step 10: Managing Your Presets
Now when you go into the Preset list, either in the Preset window or the pop-up menu, your new MPEG Mid setting will be listed. You can further manage your presets in the Preset window by creating folders to group settings, renaming your setting, and/or further adjusting the setting as your projects require (Figure 10, left). In a future tutorial we'll go into further detail on how to group presets to create “droplets” for an even faster workflow.
 Step 11: Creating a Custom Destination
Now that we've made our choices for bit rates and created a preset, the next step is the destination for the encoded file. In the Destinations tab of the Batch window there are four choices in the pop-up menu: Source, Desktop, User's Movies Folder, and Cluster Storage. We'll create our own custom destination that will be added to the pop-up menu. From the pop-up menu, chose Other (Figure 11, left).
Next we'll create a new folder for our MPEG encodes and we'll name it “MPEG Encodes.” Then click Create > Open, and go to the Preset window using Cmd+2. Choose the Destinations tab, click on the plus (+), and choose Local. If you're continuing on from the previous step, then it should bring up the new folder destination that we just created. If not, navigate to your MPEG Encodes folder. Click on the Open button. Now you'll have a new shortcut in the Destination tab. Double-click on it to open the Inspector window. Rename it “MPEG Encodes” and hit the return key.
Now, when you go to the Destinations pop-up menu in the Batch window, you'll find your new custom destination among the choices.
 Step 12: Ready to Encode
Now that you've chosen the encoding settings and selected a destination, you're ready to encode. You can read my article, “Distributed Network Encoding with Apple Compressor” (November 2006, pp. 30–36) to see how to improve your render times. Compressor will also let you know if there's a problem with the naming or location of your files. If you are encoding a file to a location that already has the same name or if a file has been moved, then you will see an exclamation point next to the file (Figure 12, left).
With all of the vagaries of compression processes, data rates, file sizes, and so on it can be difficult to know what will look good. I highly recommend running a test encode before you're done with the project and then testing again until it looks the way you want it to.
And while we've covered a lot of information, there is still a lot more that we could go though. Be looking for future Compressor tutorials covering audio formats, web streaming/download codecs, and advanced conversion (where we can really unlock the power of Compressor!). I hope that the next time you're ready to export to Compressor through Final Cut you'll have a better understanding of what's available to you and how to make the most of your DVD.
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About DVPA
Bob Donlon
