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MPEG-4 encoder settings (main concept) 357
H.264 defines different levels. The level determines which bit rate and resolution are
possible for the video.
With the "Auto level" option, the encoder determines the level automatically on the
basis of the resolution of "AVC preset" video formats, the set bit rate and the profile.
Frame type
"Picture type" specifies which parts of a frame should be used as the basis for the
encoding:
• Progressive Frame: A single image from a video sequence, also called a fullscreen.
• Interlaced Field: This is half an image. Two of these are combined to produce a
frame. Read more about this explanation regarding "Interlace (view page 373)".
• Interlace Frame: Th
e encoder creates a „Frame field“ which is the basis for the
encoding.
Field order
Note: This parameter is only available if the setting "Field" is selected for "Frame
type".
In case of interlaced streams, the half-image sequence is set. Read more about this
explanation regarding "Interlace (view page 373)".
Slice count
A frame can be divided into multiple slices for encoding. Specify the maximum
number of slices are permitted. If set to "0", then the number will be determined
automatically.
Rate control
The bit rate indicates how much data per second is saved in the video (playback
speed). This makes the bit rate the deciding parameter with regard to the file size and
quality of the video to be encoded. A higher bit rate means more quality but also a
larger file size.
Mode
• Constant bit rate: The constant bit rate should only be used if the device used to
play the video supports constant bit rates.
• Constant quantizer: In this mode, a fixed colour quantization is used for the
macro blocks. Under Advanced settings, a value between 1 and 32 can be set
independent of the respective frame (I-Frame (view page 373), P-Frame, or B-
Fram
e (view page 374)). The higher the value, the stronger the quantization:
smal
l values produce qualitatively high-quality images and the data rate
increases, and larger values produce a reduction in data, but the quality suffers.