Zynq Ult VCU TRD User Guide
37
UG1250 (v2019.1) May 29, 2019
Chapter 3:
APU Software Platform
QP
Quantization in an encoder is controlled by a quantization parameter. It specifies how to
generate the QP per coding unit (CU). Two modes are supported:
• Uniform: All CUs of the slice use the same QP
• Auto: The QP is chosen according to the CU content using a pre-programmed lookup
table.
Rate Control
Selects the way the bit rate is controlled:
CBR: Use
constant bit rate
control.
VBR: Use
variable bit rate
control.
LOW_LATENCY: Use variable bit rate for low latency application.
Bitrate
Encoding bitrate. In digital multimedia, bitrate often refers to the number of bits used per
unit of playback time to represent a continuous medium such as audio or video after source
coding (data compression).
B-frame
Short for bidirectional frame or bidirectional predictive frame, a video compression method
used by the MPEG standard. The setting ranges from 0 to 4.
Slice
Number of slices produced for each frame. Each slice contains one or more complete
macroblock/CTU row(s). Slices are distributed over the frame as regularly as possible. If slice
size is also defined, more slices can be produced to fit the slice size requirement.
Range:
• 4-22 4Kp resolution with HEVC codec
• 4-32 4Kp resolution with AVC codec
• 4-32 1080p resolution with HEVC codec
• 4-32 1080p resolution with AVC codec
GoP Length
In video coding, a group of pictures, or GoP structure, specifies the order in which intra-
and inter-frames are arranged. And GoP Length is a length between two intra-frames. The
GoP is a collection of successive pictures within a coded video stream. Each coded video
stream consists of successive GoPs from which the visible frames are generated. Its range
is from 1– 1000. The GoP length must be a multiple of B-1.
Filler Data
Filler data network abstraction layer (NAL) units for CBR rate control. It can be enabled or
disabled. Applies to CBR mode only.
L2 Cache
Enable or disable L2cache buffer in the encoding process.
Latency Mode
Encoder latency mode. It can be normal or sub_frame mode.
Low Bandwidth
If enabled, decreases the vertical search range used for P-frame motion estimation to
reduce the bandwidth.
GoP Mode
Group of Pictures mode. It can be Basic, low_delay_p, or low_delay_b.
Table 3-3:
Encoder Parameter Panel Settings
(Cont’d)
Encoder Parameter
Setting
