DivX 10
47
DivX, LLC
User Guide
4K
AAC
4K refers to video resolutions whose horizontal dimensions are at
least 4,000 pixels. Normal high definition video has a horizontal
resolution of 1,920 pixels (for a 1920x1080 resolution, also referred
to as 1080p), so a video with a resolution of 4096x2160, for
example, far exceeds the resolution of current 1080p HD video.
There are a few common 4K resolutions depending on the reasons
they are used, but not a single standard. In theatrical video, the
Digital Cinema Initiatives specification uses 4096x2160. Many
consumer electronics use this as well. A more common trend is to
use resolutions of 3840x2160; although technically less than 4,000
horizontal pixels, it is what the Consumer Electronics Association
considers “Ultra High-Definition” or “Ultra HD”.
4K resolutions are often discussed when talking about HEVC video
compression, which can support resolutions up to 8K Ultra HD,
or 8192x4320, but the two are not necessarily tied. While HEVC
supports these higher resolutions very well, a 4K resolution can
also be used in H.264 video compression, just as a video with a
1080p resolution could be compressed with either H.264 or DivX
(ASP) technologies.
Advanced Audio Coding (AAC) is the preferred audio format for
high definition videos and is a substantial improvement on the
well-known MP3 format. AAC has become the standard for
high-quality digital audio and DivX Plus video supports AAC
audio tracks with 5.1 channel surround sound to deliver a
cinematic experience with your home theater setup.
Given the same file size, AAC audio tracks can achieve better
sound quality than MP3 audio tracks so you can achieve
matching quality while reducing the data rate and audio stream
in your DivX Plus file. This will take up less space than before,
making for smaller files or the option to encode video with
higher quality. Where storage or bandwidth is constrained,
AAC’s High Efficiency modes provide technologies like spectral
band replication that allows you to come close to CD-quality
sound at roughly half the data rate that MP3 would require.
AAC audio is much more efficient to decode than other audio
formats, which means that it leaves more CPU power to make
sure your video plays smooth and stutter-free. The AAC
standard is the perfect complement to the H.264 video
technology that powers DivX Plus Software, providing high
definition audio to match the HD video on your computer, in
your living room or on the go.
