|
Tips for creating video for mobile devices
Use these tips when shooting content for
mobile devices:
Tight shots are better. Try to keep
the subject separated from the background; the colors and values
between background and subject should not be too similar.
Be aware of lighting. Poor lighting is a greater problem
with mobile devices and can reduce visibility on small screens.
Shoot and adjust with this limitation in mind.
Avoid excessive panning or rolling.
Use the
following tips when editing video with Adobe Premiere Pro and After Effects:
Set the frame rate for the output movie according to output
device or output type. For example, a commercial in After Effects
might be rendered at 15 frames per second (fps) for distribution
on mobile devices, but at 29.97 fps for broadcast television in
the USA. In general, use a lower frame rate. A frame rate of 22
fps is a good compromise for reducing file size without losing quality
Make the movie as small as possible and remove any extraneous
content, especially empty frames. Many actions can be done pre-encoding
to limit file size. Some of them apply to shooting techniques, while
others (for instance, using motion-stabilization tools in After
Effects or applying a noise-reduction or blur effect) are post-production
tasks that facilitate the compression portion of the encoder.
Note: For
tips on making movies smaller, see the online Help for After Effects
and Adobe Premiere Pro.
Match the color palette to the correct mobile devices. Mobile
devices, in general, have a limited color range. Previewing in Device
Central can help determine if the colors used are optimal for an
individual device or range of devices.
Adjust clips. Grayscale view is helpful to compare values.
Use the presets available in Adobe Media Encoder. Several
presets are designed for export to 3GPP mobile devices in Adobe
Media Encoder. 3GPP presets come in standard sizes: 176 x 144
(QCIF), 320 x 240, and 352 x 288.
Crop wisely. A common practice is to work at standard DV
project settings and output to a combination of DV, DVD, Flash,
WMV and mobile 3GPP. Use the usual presets, but at encoding time
manage the difference between 4:3 or 16:9 video and the 11:9 aspect
ratio of mobile 3GPP. The AME crop tool allows constraint to arbitrary
proportions in the same manner as Photoshop’s Crop tool and adds
an 11:9 constraint preset to the existing 4:3 and 16:9.
Work at an aspect ratio consistent with mobile output. New
project presets (available only on Windows) make this easy. The
frame dimensions are larger than the ultimate output size (working
at 176 x 144 can be difficult, for example, for
titling), but they match the output-frame aspect ratio to facilitate easy
encoding. Each Windows project preset renders to uncompressed video, but
most computers can manage the data rate at these reduced frame sizes and
halved frame rates. (This process is for projects where the only
output is for mobile devices.) Two frame aspect ratios account for
the majority of support in mobile devices: 4:3 (QVGA, VGA etc.)
and 11:9 (CIF, QCIF, Sub‑QCIF). These two common project settings
are included in the Adobe Media Encoder “Mobile & Presets” folder.
Note: Do
not use the device data in Device Central to determine how to configure a
custom preset. Device Central does not have information about video
or audio support (frame sizes, codecs, bit rates, and so on). The
frame size data in Device Central refers to screen size and wallpaper
and screen saver sizes, which are different from video sizes.
For
more tips and techniques for creating content for mobile phones
and devices, see www.adobe.com/go/learn_cs_mobilewiki_en.
|