Final Edit and Output - Animating with Blender: How to Create Short Animations from Start to Finish - page 337

Finally, the MPEG codecs, which are accessible through the FFMPEG option in Blender's animation formats
menu, provide a platform-neutral encoding experience. Figure 16.20 shows the additional Scene buttons
panels that appear upon choosing FFMPEG. Note that one of the panels is labeled Audio. FFMPEG is the
only way to export both audio and video out of Blender in a single fi le. The .AVI and .MOV options in the
main Format panel will not allow you to do this.

Figure 16.20 The FFMPEG Video and Audio panels

However, by choosing FFMPEG in the main Format panel, you can choose either .AVI or .MOV and their
accompanying codecs on the new Video panel, and export them with Audio embedded. The FFMPEG con-
trols offer one other benefi t: simple control of the fi nal fi le size by directly setting the encoding bit rate. On
the Video panel, the rate is listed in “kb/s,” which stands for kilobits per second. The default value is 6000 kb/s,
or about 0.73 MB per second. At this quality level, the entire 4 minute running time of The Beast creates a fi le
that is around 175 MB. Through experimentation and simply trying different encoding rates and watching the
result, you can see how low you have to go to achieve the fi le
size you are aiming for.
At 4 minutes in length, a “medium” download of 50 MB as
designated earlier would require a bit rate of around 1,700 kb/s.
At that rate, the quality will certainly be noticeably worse.
One thing that you can do to produce a nicer looking fi le at
a lower bit rate is to reduce the overall resolution. Fortunately,
this is as simple as either changing the output resolution in the
master Sequence fi le, or clicking one of the 75%, 50%, or 25%
buttons, shown in Figure 16.21. Reducing the output resolu-
tion while maintaining the bit rate (1,700 in this case) gives
a better fi nal result because the bits that are allocated to the
video stream can be used on fewer pixels of a smaller image.

Figure 16.21 Changing fi nal output resolution with
the percentage buttons

NOTE
To calculate a bit rate from a target fi le size, use the following procedure: Divide the target size
in MB by the length of the animation in seconds. This gives you the number of MB per second
of the fi nal fi le. Multiply this by 1024, the number of bytes in 1 MB. Multiply that result by eight,
which is the number of bits in a byte ((size in MB Seconds) 1024 8). The fi nal result is the
number in kb/s that you need to enter into the Video panel.