Adobe Flash Professional CC 2014 v.13.0 - Manual (Page 287)

Tips for creating Adobe FLV and F4V video
Follow these guidelines to deliver the best possible FLV or F4V video:
Work with video in the native format of your project until your final output
If you convert a precompressed digital video format into another format such as FLV or F4V, the previous encoder can introduce video noise. The
first compressor already applied its encoding algorithm to the video, reducing its quality, frame size, and rate. That compression may have also
introduced digital artifacts or noise. This additional noise affects the final encoding process, and a higher data rate may be required to encode a
good-quality file.
Strive for simplicity
Avoid elaborate transitions—they don’t compress well and can make your final compressed video look “chunky” during the change. Hard cuts (as
opposed to dissolves) are usually best. Eye-catching video sequences—for instance showing an object zooming from behind the first track, doing
a “page peel,” or wrapping around a ball and then flying off the screen—don’t compress well and should be used sparingly.
Know your audience data rate
When you deliver video over the Internet, produce files at lower data rates. Users with fast Internet connections can view the files with little or no
delay for loading, but dial-up users must wait for files to download. Make the clips short to keep the download times within acceptable limits for
dial-up users.
Select the proper frame rate
Frame rate indicates frames per second (fps). If you have a higher data rate clip, a lower frame rate can improve playback through limited
bandwidth. For example, if you are compressing a clip with little motion, cutting the frame rate in half probably saves you only 20% of the data rate.
However, if you are compressing high-motion video, reducing the frame rate has a much greater effect on the data rate.
Because video looks much better at native frame rates, leave the frame rate high if your delivery channels and playback platforms allow. For web
delivery, get this detail from your hosting service. For mobile devices, use the device-specific encoding presets, and the device emulator available
through Adobe Media Encoder in Adobe Premiere Pro. If you need to reduce the frame rate, the best results come from dividing the frame rate by
whole numbers.
Select a frame size that fits your data rate and frame aspect ratio
At a given data rate (connection speed), increasing the frame size decreases video quality. When you select the frame size for your encoding
settings, consider frame rate, source material, and personal preferences. To prevent pillarboxing, it’s important to choose a frame size of the same
aspect ratio as that of your source footage. For example, you get pillarboxing if you encode NTSC footage to a PAL frame size.
Adobe Media Encoder makes several Adobe FLV or F4V video presets available. These include preset frame sizes and frame rates for the
different television standards at different data rates. Use the following list of common frame sizes (in pixels) as a guide, or experiment with the
various Adobe Media Encoder presets to find the best setting for your project.
Dial-up Modem NTSC 4 x 3 162 x 120
Dial-up Modem PAL 4 x 3 160 x 120
T1/DSL/cable NTSC 4 x 3 648 x 480
T1/DSL/cable PAL 4 x 3 768 x 576
Stream for best performance
To eliminate download time, provide deep interactivity and navigation capabilities, or monitor quality of service, stream Adobe FLV or F4V video
files with the Flash Media Server or use the hosted service from one of Adobe’s Flash Video Streaming Service partners available through the
Adobe website. For more details on the difference between Progressive Download and Streaming with Flash Media Server, see “Delivering Flash
Video: Understanding the Difference Between Progressive Download and Streaming Video” on the Flash Developer Center website.
Know progressive download times
Know how long it will take to download enough of your video so that it can play to the end without pausing to finish downloading. While the first
part of your video clip downloads, you may want to display other content that disguises the download. For short clips, use the following formula:
Pause = download time – play time + 10% of play time. For example, if your clip is 30 seconds long and it takes one minute to download, give
your clip a 33-second buffer (60 seconds – 30 seconds + 3 seconds = 33 seconds).
Remove noise and interlacing
For the best encoding, you might need to remove noise and interlacing.
The higher the quality of the original, the better the final result. Although frame rates and sizes of Internet video are usually smaller than those of
television, computer monitors have much better color fidelity, saturation, sharpness, and resolution than conventional televisions. Even with a small
window, image quality can be more important for digital video than for standard analog television. Artifacts and noise that are barely noticeable on
TV can be obvious on a computer screen.
Adobe Flash is intended for progressive display on computer screens and other devices, rather than on interlaced displays such as TVs. Interlaced
footage viewed on a progressive display can exhibit alternating vertical lines in high-motion areas. Thus, Adobe Media Encoder removes
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