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MPEG-4 encoder settings (main concept) 361
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.
• Variable bit rate: The bit rate varies. For faster movements in the video, the bit
rate increases, and for still images or slow pans, a lower bit rate is sufficient for
creating the video in constant quality.
• Constant quality: Similar to the "Variable bit rate" mode, the bit rate varies
according to the video material. The quality depends on the selected profile and
can be changed.
• 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.
Bit rate (Bits/s)
• In "Constant bit rate" mode: Exactly those values entered are applied to be able
to calculate the size of the video precisely.
• In "Variable bit rate" mode: The values entered here are applied to the video as
an average as a guideline. The size of the video to be exported can only be
approximated.
Max. rate
This is the maximum bit rate that should be present in the video stream, i.e. maximum
number of bits that may be transferred to the decoder.
Note: This option is only available in "Variable bit rate" mode.