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 compress a clip with little motion, cutting the frame rate in half can save you only 20% of the data rate. However, if you compress 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 Premiere Pro. If reducing 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, choose a frame size of the same aspect ratio as the frame aspect ratio of your source footage. For example, pillarboxing results when you encode NTSC footage to a PAL frame size.
Cover progressive download times
Learn how long it takes 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 can 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 1 minute to download, give your clip a 33‑second buffer. The applied formula is 60 seconds – 30 seconds + 3 seconds = 33 seconds.
Remove noise and interlacing
For the best encoding, remove noise and interlacing.
The higher the quality of the original, the better the final result. Frame rates and sizes of Internet video are smaller than frame rates and sizes of television video. However, computer monitors typically have color fidelity, saturation, sharpness, and resolution at least as good as high-definition televisions. Even with a small window, image quality can be as important for digital video as for HDTV. Artifacts and noise are at least as obvious on a computer screen as on a television screen.
Follow the same guidelines for audio
The same considerations apply to audio production as to video production. To achieve good audio compression, begin with clean audio. If your project contains audio from a CD, transfer the audio files directly from the CD to your hard disk. Do not record the sound through the analog input of your sound card. The sound card introduces an unnecessary digital-to-analog and analog-to-digital conversion that can create noise in your source audio. Direct digital transfer tools are available for Windows and Macintosh® platforms. To record from an analog source, use the highest-quality sound card available.