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Zynq UltraScale+ MPSoC ZCU106 Video Codec Unit Targeted Reference Design User Guide (UG1250)

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2023.1 English

You can control the Encoder, Record, and Stream Out configuration from the GUI (see This Figure and Table: Encoder Parameter Panel Settings ). Settings options are enabled when the pipeline is in the stop state.

Figure 3-10: Encoder Parameter Panel

X-Ref Target - Figure 3-10

Table 3-3: Encoder Parameter Panel Settings

Encoder Parameter



This can be either H264 or H265.


The standard defines a sets of capabilities, which are referred to as profiles, targeting specific classes of applications. These are declared as a profile code (profile_idc) and a set of constraints applied in the encoder. This allows a decoder to recognize the requirements to decode that specific stream.

H264 supports Baseline, Main, and High profile. In H265, only the Main profile is supported.


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.


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).


Short for bidirectional frame or bidirectional predictive frame, a video compression method used by the MPEG standard. The setting ranges from 0 to 4.


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.


4-22 4K resolution with HEVC codec

4-32 4K 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-Frames+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.