Pixels To Frame

Convert pixel stream to frame-based video

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  • Library:

  • Vision HDL Toolbox / I/O Interfaces

  • Pixels To Frame block

Description

The Pixels To Frame block converts a color or grayscale pixel stream and control signals to frame-based video. The control signal bus indicates the validity of each pixel and its location within the frame. The pixel stream format can include padding pixels around the active frame. You can configure the frame and padding dimensions by selecting a common video format or by specifying custom dimensions. The pixel input can support scalar streaming, or multipixel streaming. Multipixel streaming accepts 4 or 8 pixels each clock cycle to support high-rate or high-resolution formats. For details of the pixel stream format, see Streaming Pixel Interface.

This block does not support HDL code generation. However, you can use this block to convert the output of a separate subsystem, targeted for HDL code generation, back to frames.

If your model converts frames to a pixel stream and later converts the stream back to frames, specify the same video format for the Frame To Pixels block and the Pixels To Frame block.

Ports

Input

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For scalar pixel streams, pixel is a single image pixel specified as a scalar or a vector of 1-by-Number of components values. For multipixel streams, pixel is a matrix of Number of pixels-by-Number of components pixel intensity values.

Data Types: single | double | int | uint | Boolean | fixed point

Specify a pixelcontrol bus that contains five signals. The signals describe the validity of the pixel and its location in the frame. For more information, see Pixel Control Bus.

For multipixel streaming, each vector of pixel values has one set of control signals. Because the vector has only one valid signal, the pixels in the vector must be either all valid or all invalid. The hStart and vStart signals apply to the pixel with the lowest index in the vector. The hEnd and vEnd signals apply to the pixel with the highest index in the vector.

Data Types: bus

Output

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Full image frame, returned as an Active pixels per line-by-Active video lines-by-N array. The first two array dimensions are the height and width of the active image specified by the Video format parameter. N is the Number of components used to express a single pixel. The output data type is the same as the data type of the pixel port.

This signal is 1 (true) when the block has successfully recompiled an output frame from the input stream.

Data Types: Boolean

Parameters

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Number of values used to represent each pixel. Each pixel can have 1, 3, or 4 components. Set this parameter to 1 for grayscale video. Set this parameter to 3 for color video, for example, {R,G,B} or {Y,Cb,Cr}. Set this parameter to 4 to use color with an alpha channel for transparency.

To process multicomponent streams for blocks that do not support multicomponent input, replicate the block for each component. The pixelcontrol bus for all components is identical, so you can connect the ctrl output of the Frame To Pixels block to each replicated block.

Number of pixels transferred on the streaming interface for each time step, specified as 1, 4, or 8. To enable multipixel streaming and increase throughput for high-resolution or high-frame-rate video, set this parameter to 4 or 8. Multipixel streaming processes more pixels with the same clock frequency as a single-pixel streaming interface.

Video ResolutionClock Frequency Required for Single-Pixel Streaming at 60 fpsClock Frequency Required for Multipixel Streaming at 60 fps (4 pixels)
1080p150 MHz37.5 MHz
4k UHD600 MHz150 MHz
8k UHD1200 MHz300 MHz

Dimensions of active regions in a video frame. To select a predefined format, use the Video format pull-down menu. The active frame dimensions are set as shown in the table. For a custom format, select Custom, then specify the active frame dimensions as integers.

Video FormatActive Pixels Per LineActive Video Lines
240p320240
480p640480
480pH720480
576p720576
720p1280720
768p1024768
1024p12801024
1080p (default)19201080
1200p16001200
2KCinema20481080
4KUHDTV38402160
8KUHDTV76804320
CustomUser-
defined		User-
defined

Model Examples

Gamma Correction

Gamma Correction

Model pixel-streaming gamma correction for hardware designs. The model compares the results from the Vision HDL Toolbox™ Gamma Corrector block with the results generated by the full-frame Gamma block from Computer Vision System Toolbox™.

Filter Multipixel Video Streams

Filter Multipixel Video Streams

Design filters that operate on a multipixel input video stream. Use multipixel streaming to process high-resolution or high-frame-rate video with the same synthesized clock frequency as a single-pixel streaming interface. Multipixel streaming also improves simulation speed and throughput because fewer iterations are required to process each frame, while maintaining the hardware benefits of a streaming interface.

Extended Capabilities

See Also

Blocks

Objects

Topics

Introduced in R2015a

Vision HDL Toolbox Documentation

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