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Appendices : MPEG Settings (MainConcept Encoder) Page 251
Note: We strongly recommend that changes in this section are performed only by professional
users.
Profile ID: Five options available: High Profile, Main Profile (standard setting), Simple Profile, 4:2:2
Profile and Multiview Profile
Level ID: Four options available: High Level, High 1440 Level, Main Level (standard setting), and
Low Level.
The MPEG-2 spec (specification) allows for a large number of variations in the settings, e.g. the frame resolution
can theoretically be as large as 2^14 x 2^14. The Profiles and Levels just set limits on what the values of some of
the other settings can be; so if a specification (like the DVD spec) says only Main Profile/Main or Low Level is
allowed, the decoders can safely assume what the bounds of some settings are going to be. A DVD player does not
have to account for the resolution being 2^14 x 2^14 because the DVD spec only allows a maximum of Main Pro-
file/Main Level which only enables for a maximum frame resolution of 720x576.
Noise Sensitivity and Noise Reduction: The NR button toggles between Noise Sensitivity and Noise reduction. The box deter-
mines the value.
Noise Sensitivity specifies how sensitive the video encoder is to noise in the source video; it does not reduce the
noise in the source video at all. It sets a motion search threshold at which point the encoder will stop the search for
matching blocks of pixels from one frame to another. Higher values mean low sensitivity (faster search times, less
quality), while lower values mean higher sensitivity (longer search times, better quality). Typically this option is set
in the
1 ... 14 range as follows:
1 ... 5 - Computer animation, VCD from DV-Source, after a line-filter or noise reducing filter (virtually no noise in the
source video)
3 ... 7 - Digital video, DV-quality, Hi8-quality etc. 5 ... 14 - Analog captured video, Video 8, Hi8, broadcast TV
The setting is based entirely on the condition of the source video; it has nothing to do with the type of output
(DVD, SVCD or VCD).
If you are only concerned with quality (at the expense of speed), you should set the value to 1 all the time, as this
would yield the best results (but for noisy video it would slow the encoder quite a bit without any quality benefit).
Basically, what the setting does, is set a level in the encoder at which point the encoder will give up trying to
match a pixel between two frames.
If the source video is noisy and the setting is set to a low value, the encoder will spend more time trying to match
pixels from frame to frame, and (in the case of noise) it may not find a match at all, so excessive time is spent trying
to find a match when there is none.
If the source video has no noise at all, and the setting is set to a very high value, the encoder may give up to soon
and not match some pixels from frame to frame (wasting bits).