[JAVA][Beginning Java 8 Games Development]

Chapter 5 ■ An Introduction to Game Design: Concepts, Multimedia, and Using Scene Builder
Once the bits travel through a data pipe, they also need to be processed and displayed on the device screen.
Thus, bit rates for digital video assets must be optimized not only for bandwidth, but also in anticipation of variances
in CPU processing power. Some single-core CPUs may not be able to decode high-resolution, high–bit rate digital
video assets without dropping frames, so do make sure to optimize low–bit rate video assets if you are going to target
older or less expensive consumer electronics devices.
Digital Video Data Footprint Optimization: Using Codecs and Their Settings
As mentioned earlier, your digital video asset will be compressed, using software utilities called codecs. There are two
“sides” to the video codec: one that encodes the video data stream and another that decodes it. The video decoder
will be part of the OS, platform (JavaFX), or browser that uses it. The decoder is primarily optimized for speed, as
smoothness of playback is a key issue, whereas the encoder is optimized to reduce the data footprint for the digital
video asset it is generating. For this reason, the encoding process can take a long time, depending on how many
processing cores a workstation contains. Most digital video content production workstations should support eight
processor cores, like my 64-bit AMD octacore workstation.
Codecs (the encoder side) are like plug-ins, in that they can be installed into different digital video–editing
software packages to enable them to encode different digital video asset file formats. Because Java and JavaFX 8
support the MPEG-4 H.264 AVC format, you need to make sure that you are using one of the digital video software
packages that supports encoding digital video data using (or into) this digital video file format. More than one
software manufacturer makes MPEG-4 encoding software, so there will be different MPEG-4 AVC codecs that will
yield different (better or worse) results, in terms of encoding speed and file size. The professional solution, which I
highly recommend that you secure if you want to produce digital video professionally, is called Sorenson Squeeze Pro.
There is also an open-source solution called EditShare LightWorks 12, which is scheduled to support output
to the MPEG4 codec natively by 2014. When optimizing (setting compression settings) for digital video data file
size, there are many variables that directly affect the digital video data footprint. I will discuss these in their order of
importance, in in terms of effect on video file size, from the most important to the least, so that you will know which
parameters to tweak to obtain the result you are looking for.
Like with digital image compression, the resolution, or number of pixels, in each frame of video is the optimal
place to start the optimization process. If your user is using 800 × 480 or 1,280 × 720 smartphones, e-readers, or
tablets, then you do not need to use true HD 1,920 × 1,080 resolution to get good visual results for your digital video
assets. With superfine density (small dot pitch) displays out there, you can scale a 1,280 video up 33 percent, and it
will look reasonably good. The exception to this may be HD or UHD (popularly termed 4K iTV) games targeted at
iTVs; for these huge, 55- to 75-inch (screen) scenarios, you would want to use the industry standard, true HD
1,920 × 1,080 resolution.
The next level of optimization would come in the number of frames used for each second of video (or FPS),
assuming the actual number of seconds in the digital video itself cannot be shortened. As mentioned earlier, this is
known as the frame rate, and instead of setting the video standard 30FPS frame rate, consider using a film standard
frame rate of 24FPS or even the multimedia standard of 20FPS. You may even be able to use a 15FPS frame rate, half
the video standard, depending on the amount (and speed) of movement within the content. Note that 15FPS is half as
much data as 30FPS (a 100 percent reduction in data encoded). For some video content this will play back (look) the
same as 30FPS content. The only way to test this is to try frame rate settings during the encoding process.
The next most optimal setting for obtaining a smaller data footprint would be the bit rate that you set for a codec
to try to achieve. Bit rate equates to the amount of compression applied and thus sets a quality level for the digital
video data. It is important to note that you could simply use 30FPS, 1,920 resolution HD video and specify a low bitrate
ceiling. If you do this, the results will not be as good-looking as if you had experimented with using a lower frame
rate and resolution, in conjunction with a higher (quality) bit-rate setting. There is no set rule for this, as every digital
video asset contains completely unique data (from the codec’s point of view).
The next most effective setting for obtaining a smaller data footprint is the number of key frames that the codec
uses to sample your digital video. Video codecs apply compression by looking at each frame and then encoding only
the changes, or offsets, over the next several frames so that the codec algorithm does not have to encode every single
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