Adobe Media Encoder CC - Manual (Page 36)

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Encoding quick start and basics
Last updated 12/15/2014
HD video formats include interlaced and noninterlaced varieties. Typically, the highest-resolution formats are
interlaced at the higher frame rates, because noninterlaced video at these pixel dimensions would require a
prohibitively high data rate.
HD video formats are designated by their vertical pixel dimensions, scan mode, and frame or field rate (depending on
the scan mode). For example, 1080i60 denotes interlaced scanning of 60 interlaced 1920x1080 fields per second,
whereas 720p30 denotes progressive scanning of 30 noninterlaced 1280x720 frames per second. In both cases, the
frame rate is approximately 30 frames per second.
Compression tips
Compression tips for video
Work with video in the native format of your project until your final output Use raw footage or the least compressed
footage that is available to you. Each time that you compress video using a lossy encoder, you reduce the quality of the
video. Though one generation of quality loss is often acceptable, re-encoding and recompressing already compressed
video can degrade the quality beyond what is acceptable. Also, video that has already been encoded and compressed
may contain noise and artifacts that make the next encoding and compression step take more time or produce a larger
file.
Make your video as short as possible Trim the beginning and end of your video, and edit your video to remove any
unnecessary content. See Crop and trim source before encoding .
Adjust your compression settings If you compress footage and it looks great, try changing your settings to reduce the
file size. Test your footage, and modify compression settings until you find the best setting possible for the video you
are compressing. All video has varying attributes that affect compression and file size; each video needs its own setting
for the best results. See
Encoding and exporting .
Limit rapid movement Limit movement if you are concerned about file size. Any movement increases file size. Shaky
camera work, rolls, and zooms are particularly bad in this regard. You can use motion stabilization features in After
Effects to remove extraneous movement.
Choose appropriate dimensions See Image aspect ratio and frame size .
Select an appropriate frame rate See Frame rate .
Choose an appropriate number of key frames See Key frames .
Reduce noise and grain Noise and grain in source images increase the size of encoded files. Ideally, use utilities in
Adobe Premiere Pro or After Effects to reduce noise and grain.
Compression tips for audio
The same considerations exist for audio production as for video production. To achieve good audio compression, you
must begin with an audio file that is free of distortion and audible artifacts introduced from the source recording.
If you are encoding material from a CD, try to record the file using direct digital transfer rather than the analog input
of a sound card. The sound card introduces an unnecessary digital-to-analog and analog-to-digital conversion that can
create noise in your transferred audio. Direct digital transfer tools are available for both Windows and Mac OS. If you
must record from an analog source, use the highest quality sound card available.
Note: If your source audio file is monaural (mono), it is recommended that you encode in mono for use with Flash. If you
are encoding with Adobe Media Encoder, and using an encoding preset, be sure to check if the preset encodes in stereo or
mono, and select mono if necessary.