Video and Vision Processing Suite Intel® FPGA IP User Guide

ID 683329
Date 10/02/2023
Public

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Document Table of Contents
1. About the Video and Vision Processing Suite 2. Getting Started with the Video and Vision Processing IPs 3. Video and Vision Processing IPs Functional Description 4. Video and Vision Processing IP Interfaces 5. Video and Vision Processing IP Registers 6. Video and Vision Processing IPs Software Programming Model 7. Protocol Converter Intel® FPGA IP 8. 3D LUT Intel® FPGA IP 9. AXI-Stream Broadcaster Intel® FPGA IP 10. Bits per Color Sample Adapter Intel FPGA IP 11. Chroma Key Intel® FPGA IP 12. Chroma Resampler Intel® FPGA IP 13. Clipper Intel® FPGA IP 14. Clocked Video Input Intel® FPGA IP 15. Clocked Video to Full-Raster Converter Intel® FPGA IP 16. Clocked Video Output Intel® FPGA IP 17. Color Space Converter Intel® FPGA IP 18. Deinterlacer Intel® FPGA IP 19. FIR Filter Intel® FPGA IP 20. Frame Cleaner Intel® FPGA IP 21. Full-Raster to Clocked Video Converter Intel® FPGA IP 22. Full-Raster to Streaming Converter Intel® FPGA IP 23. Genlock Controller Intel® FPGA IP 24. Generic Crosspoint Intel® FPGA IP 25. Genlock Signal Router Intel® FPGA IP 26. Guard Bands Intel® FPGA IP 27. Interlacer Intel® FPGA IP 28. Mixer Intel® FPGA IP 29. Pixels in Parallel Converter Intel® FPGA IP 30. Scaler Intel® FPGA IP 31. Stream Cleaner Intel® FPGA IP 32. Switch Intel® FPGA IP 33. Tone Mapping Operator Intel® FPGA IP 34. Test Pattern Generator Intel® FPGA IP 35. Video and Vision Monitor Intel FPGA IP 36. Video Frame Buffer Intel® FPGA IP 37. Video Frame Reader Intel FPGA IP 38. Video Frame Writer Intel FPGA IP 39. Video Streaming FIFO Intel® FPGA IP 40. Video Timing Generator Intel® FPGA IP 41. Warp Intel® FPGA IP 42. Design Security 43. Document Revision History for Video and Vision Processing Suite User Guide
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41.5. Warp IP Software API

The Warp IP software is implemented in C and C++. This topic describes the API functions in the code and provides code examples.
Figure 112. Warp software architecture

The software includes:

  • intel_vvp_warp_driver
  • intel_vvp_warp_data
  • intel_vvp_warp_mesh

The intel_vvp_warp_driver is the warp IP driver. It provides API for initializing, configuring, and controlling the Warp IP, warp video channel management, and using debug features.

The intel_vvp_warp_data is the software component that generates mesh, cache, and filter coefficient data required by the warp IP. Place generated data in a region of RAM accessed by the warp IP. This location and other necessary parameters are passed to the warp driver.

This component requires transformation mesh in a predefined format as the main input data. It also requires some IP parameters e.g. number of available engines, processing block dimensions, block cache size.

The intel_vvp_warp_mesh is the software component that generates warp meshes for common affine transformations such as translation, rotation, zoom; perspective transformations e.g. keystone and radial distortion (fisheye) and arbitrary warps defined by a set of curves. Meshes are generated in the format required by the intel_vvp_warp_data interface.

You can use this reference software in a number of real-world applications. However, in some more complex cases you might want to use external software to generate transformation mesh. For example, when projecting image onto a complex surface.

You can deploy the software on a Nios II based system. However, because of computational intensity of the mesh and data generating components, Intel recommends an SoC with a dedicated CPU such as an Intel Arria 10 SX device.

intel_vvp_warp_driver

Table 878.   intel_vvp_warp_driver API reference

The software driver for Warp IP provides the following set of API functions.

Name Description
intel_vvp_warp_init_instance Initialize driver instance
intel_vvp_warp_create_channel Create single engine video processing channel
intel_vvp_warp_create_double_channel Create dual engine video processing channel
intel_vvp_warp_create_easy_warp_channel Create easy warp video processing channel
intel_vvp_warp_add_engine_to_channel Add a warp engine to existing channel
intel_vvp_warp_free_channel Free video processing channel
intel_vvp_warp_configure_channel Configure video processing channel
intel_vvp_warp_apply_transform Apply video transformation
intel_vvp_warp_bypass Bypass video processing
intel_vvp_warp_reset_skip_ram Reset skip RAM page
intel_vvp_warp_check_easy_warp_capable Check if a warp channel can perform Easy warp
intel_vvp_warp_set_easy_warp Set easy warp transformation
intel_vvp_warp_set_output_latency Set warp output latency
intel_vvp_warp_get_debug_register Get contents of a warp debug register
intel_vvp_warp_get_input_debug_register Get contents of a warp input debug register
intel_vvp_warp_get_output_debug_register Get contents of a warp output debug register
intel_vvp_warp_get_engine_debug_register Get contents of a warp engine debug register
intel_vvp_warp_get_engine_status Get current status flags of the warp engine

intel_vvp_warp_init_instance

int intel_vvp_warp_init_instance( intel_vvp_warp_instance_t* instance, intel_vvp_warp_base_t base)
Description
Initialize intel_vvp_warp driver instance
Arguments
instance – pointer to the intel_vvp_warp software driver instance structure
base – hardware access handler. In a bare metal environments such as Nios II it is defined as 32-bit unsigned integer representing physical address of the intel_vvp_warp IP on the CPU bus.
Return value
Zero on success, negative integer otherwise

intel_vvp_warp_create_channel intel_vvp_warp_create_double_channel

intel_vvp_warp_channel_t* intel_vvp_warp_create_channel(intel_vvp_warp_instance_t *instance, uint32_t input_idx, uint32_t engine_idx, uint32_t output_idx) intel_vvp_warp_channel_t* intel_vvp_warp_create_double_channel(intel_vvp_warp_instance_t *instance, uint32_t input_idx, uint32_t engine1_idx, uint32_t engine2_idx, uint32_t output_idx)
Description
Create a video processing channel. The functions allocate hardware resources and initialize driver data structures necessary for processing a video stream up to 3840x2160 pixels.
Arguments

instance – pointer to initialized intel_vvp_warp_instance_t structure;

input_idx, engine_idx, engine2_idx, ouput_idx – indexes of the warp IP input, engines and output to use in this channel.

You can configure a single warp IP to provide multiple input, output, and processing engine blocks. These blocks are grouped into video processing channels arbitrarily by using index of the block.

The indexes must be in the range 0..num_inputs(num_outputs or num_engines respectively), where you can obtain num_inputs, num_outputs and num_engines through the intel_vvp_warp_instance_t structure after you initialize the driver instance.

Return value
Valid pointer to initialized intel_vvp_warp_channel_t structure on success, null pointer otherwise.

intel_vvp_warp_create_easy_warp_channel

intel_vvp_warp_channel_t* intel_vvp_warp_create_easy_warp_channel(intel_vvp_warp_instance_t *instance, uint32_t input_idx, uint32_t output_idx)
Description
Create an easy warp video processing channel. The functions allocate hardware resources and initialize driver data structures necessary for processing a video stream up to 3840x2160 pixels using easy warp configuration.
Arguments

instance – pointer to initialized intel_vvp_warp_instance_t structure;

input_idx, ouput_idx – indexes of the warp IP input and output to use in this channel.

Return value
Valid pointer to initialized intel_vvp_warp_channel_t structure on success, null pointer otherwise.

intel_vvp_warp_add_engine_to_channel

int intel_vvp_warp_add_engine_to_channel(intel_vvp_warp_channel_t* channel, uint32_t engine_idx)
Description

Add a warp engine to existing channel.

Warp IP allows you to split video processing between multiple engines. This function adds additional engines to already allocated channels and updates driver and channel data structures accordingly

Arguments

instance – pointer to the intel_vvp_warp software driver instance structure

engine_idx – indexes of the warp IP engine to add to the channel

Return value
Zero on success, negative integer otherwise

intel_vvp_warp_free_channel

void intel_vvp_warp_free_channel(intel_vvp_warp_channel_t* channel)
Description
Delete video processing channel and release hardware resources and driver data structures allocated for it
Arguments
channel – a valid pointer to initialized intel_vvp_warp_channel_t structure
Return value
None

intel_vvp_warp_configure_channel

int intel_vvp_warp_configure_channel(intel_vvp_warp_channel_t* channel, intel_vvp_warp_channel_config_t* cfg)
Description
Configure video processing channel data structures and allocated hardware by providing necessary parameters such as input/output resolutions, frame buffers location etc.
Arguments

channel – a valid pointer to initialized video processing channel;

cfg – a valid pointer to initialized intel_vvp_warp_channel_config_t structure.

Return value
Zero on success, negative integer otherwise

intel_vvp_warp_apply_transform

int intel_vvp_warp_apply_transform(intel_vvp_warp_channel_t* channel, intel_vvp_warp_data_t* data)
Description
Start warping video by configuring the channel to use provided warp data coefficients
Arguments

channel – a valid pointer to initialized video processing channel

data – a valid pointer to initialized intel_vvp_warp_data_t structure.

Return value
Zero on success, negative integer otherwise

intel_vvp_warp_bypass

int intel_vvp_warp_bypass(intel_vvp_warp_channel_t* channel, uint32_t bypass, uint32_t skip_ram_page, uint32_t width, uint32_t height

)
Description
Enable or disable video bypass where the input video displays as is without any processing
Arguments

channel – a valid pointer to initialized video processing channel

bypass – a nonzero value to enable video bypass, zero to disable

skip_ram_page – number of skip ram page to use after enabling/disabling bypass

width, height – override output resolution if necessary. Both width and height have to be nonzero. Typically, use to match the input resolution when enabling video bypass.

Return value
Zero on success, negative integer otherwise

intel_vvp_warp_reset_skip_ram

void intel_vvp_warp_reset_skip_ram(intel_vvp_warp_channel_t* channel, uint32_t skip_ram_page)
Description

Reset skip RAM page setting all values to zero.

Skip RAM pages are programmed as part of intel_vvp_warp_apply_transform(). Some use scenarios may require skip RAM to reset explicitly. This function allows for that

Arguments

channel – a valid pointer to initialized video processing channel

ram_page – skip RAM page to reset

Return value
None

intel_vvp_warp_check_easy_warp_capable

int intel_vvp_warp_check_easy_warp_capable(intel_vvp_warp_channel_t* channel)
Description
Check if the channel can perform easy warp transforms
Arguments
channel – a valid pointer to initialized video processing channel
Return value
Zero if the channel can perform easy warp transforms, negative integer otherwise

intel_vvp_warp_set_easy_warp

int intel_vvp_warp_set_easy_warp (intel_vvp_warp_channel_t* channel, uint32_t easy_warp)
Description
Apply an easy warp transformation to the input video
Arguments

channel – a valid pointer to initialized, easy warp capable video processing channel

easy_warp – desired easy warp transformation as 32-bit unsigned integer encoded in the following way:

31 3 2 1 0
Reserved Mirror Rotation
  • Bits 1:0 Rotation field can have the following values:
    • 00b – no rotation;
    • 01b – 90 degrees counter-clockwise rotation
    • 10b – 180 degrees rotation
    • 11b – 270 degrees counter-clockwise rotation
  • Bit 2: mirrors input video if set. If combined with a rotation the mirror is applied first.
Return value
Zero on success, negative integer otherwise

intel_vvp_warp_set_output_latency

void intel_vvp_warp_set_output_latency (intel_vvp_warp_channel_t* channel, uint32_t clock_offset)
Description
Offset the warp output start-of-processing with the start-of-output by the specified number of system clock cycles. For more information, refer to Warp Low Latency.
Arguments

channel – a valid pointer to initialized video processing channel

clock_offset – number of system clock cycles by which to offset the output start-of-processing

Return value
None

intel_vvp_warp_get_debug_register

uint32_t intel_vvp_warp_get_debug_register (intel_vvp_warp_instance_t* instance, uint32_t reg_offset)
Description
Read content of a warp debug and measurement register. Refer to Warp Debug and Measurement Registers.
Arguments

instance – pointer to initialized intel_vvp_warp_instance_t structure

reg_offset – zero based register offset. Use the following register offset macros for this argument:

Macro Value
INTEL_VVP_WARP_DEBUG_MEM_WR_QUEUES0 0
INTEL_VVP_WARP_DEBUG_MEM_WR_QUEUES1 1
INTEL_VVP_WARP_DEBUG_MEM_RD_QUEUES0 2
INTEL_VVP_WARP_DEBUG_MEM_RD_QUEUES1 3
Return value
Current content of the warp debug and measurement register specified by the reg_offset argument

intel_vvp_warp_get_input_debug_register

uint32_t intel_vvp_warp_get_input_debug_register (intel_vvp_warp_instance_t* instance, uint32_t input_idx, uint32_t reg_offset)
Description
Read content of a warp input debug and measurement register. Refer to Warp Debug and Measurement Registers.
Arguments

instance – pointer to initialized intel_vvp_warp_instance_t structure

input_idx – index of the warp IP input to access

reg_offset – zero based register offset. Use the following register offset macros for this argument:

Macro Value
INTEL_VVP_WARP_DEBUG_INPUT_FRAME_COUNT 0
INTEL_VVP_WARP_DEBUG_INPUT_FRAME_PERIOD 1
Return value
Current content of the warp input debug and measurement register specified by the reg_offset argument

intel_vvp_warp_get_output_debug_register

uint32_t intel_vvp_warp_get_output_debug_register (intel_vvp_warp_instance_t* instance, uint32_t output_idx, uint32_t reg_offset)
Description
Read content of a warp output debug and measurement register. Refer to Warp Debug and Measurement Registers.
Arguments

instance – pointer to initialized intel_vvp_warp_instance_t structure

output_idx – index of the warp IP output to access

reg_offset – zero based register offset. Use the following register offset macros for this argument:

Macro Value
INTEL_VVP_WARP_DEBUG_OUTPUT_FRAME_COUNT 0
INTEL_VVP_WARP_DEBUG_OUTPUT_FRAME_PERIOD 1
Return value
Current content of the warp output debug and measurement register specified by the reg_offset argument

intel_vvp_warp_get_engine_debug_register

uint32_t intel_vvp_warp_get_engine_debug_register (intel_vvp_warp_instance_t* instance, uint32_t engine_idx, uint32_t reg_offset)
Description
Read content of a warp output debug and measurement register. Refer to Warp Debug and Measurement Registers.
Arguments

instance – pointer to initialized intel_vvp_warp_instance_t structure

engine_idx – index of the warp IP engine to access

reg_offset – zero based register offset. Use the following register offset macros for this argument:

Macro Value
INTEL_VVP_WARP_DEBUG_ENGINE_FRAME_COUNT 0
INTEL_VVP_WARP_DEBUG_ENGINE_FRAME_PERIOD 1
INTEL_VVP_WARP_DEBUG_ENGINE_BUSY_CYCLES 2
INTEL_VVP_WARP_DEBUG_ENGINE_FRAME_DELAY 3
INTEL_VVP_WARP_DEBUG_ENGINE_RUN_STATUS 4
INTEL_VVP_WARP_DEBUG_ENGINE_CACHE_LOADS 5
Return value
Current content of the warp engine debug and measurement register specified by the reg_offset argument

intel_vvp_warp_get_engine_status

uint32_t intel_vvp_warp_get_engine_status (intel_vvp_warp_instance_t* instance, uint32_t engine_idx)
Description
Get current status flags of a warp engine. Refer to Warp Debug and Measurement Registers.
Arguments

instance – pointer to initialized intel_vvp_warp_instance_t structure

engine_idx – index of the warp IP engine to access

Return value
Current values of the engine status flags. The flags are in a 32 bit integer.
Bit Flag Description
0 Engine failed to complete frame A sticky flag indicating that the engine fails to complete the processing of a frame. The flag is cleared when read.

Data structures and types

intel_vvp_warp_base_t

Description
Platform specific type to perform register read and write operations on the warp IP. In bare metal environments such as a Nios II processor, it is defined as 32-bit unsigned integer representing physical address of the warp IP on the CPU bus

intel_vvp_warp_instance

typedef struct intel_vvp_warp_instance
{
	intel_vvp_warp_base_t base;
	uint32_t num_inputs;
	uint32_t num_engines;
	uint32_t num_outputs;
} intel_vvp_warp_instance_t;
 
    
Description
Main data structure of the driver
Members

base – warp IP access handler

num_inputs – number of available warp inputs

num_engines – number of available warp engines

num_outputs – number of available warp outputs

intel_vvp_warp_channel

typedef struct intel_vvp_warp_channel
{
 uint32_t in_use;
 uint32_t idx;
 struct intel_vvp_warp_instance* instance;
 uint32_t num_engines;
 uint32_t ram_addr;
} intel_vvp_warp_channel_t
Description
Video processing channel resources and parameters structure
Arguments
Return value

in_use – non-zero value if the channel is allocated and initialized. Zero otherwise.

idx – index number of the channel

instance – pointer to the parent driver instance the channel belongs to

num_engines – number of warp engines for the channel

ram_addr - base address of RAM region allocated for the channel frame buffers

intel_vvp_warp_channel_config

typedef struct intel_vvp_warp_channel_config
{
 uint32_t ram_addr;
 intel_vvp_warp_cs_t cs;
  uint32_t width_input;
 uint32_t height_input;
 uint32_t width_output;
 uint32_t height_output;
 uint8_t lfr;
} intel_vvp_warp_channel_config_t
Description
Video processing channel configuration
Members

ram_addr - base address of RAM region allocated for the channel frame buffers

cs – video color space. Must be initialized to

  • 00b = YUV
  • 01b = RGB reduced range
  • 10b = RFG full range.

width_input, height_input, width_output, height_output – input and output video dimensions

lfr – low frame rate fallback. Must be initialized to 0x0

intel_vvp_warp_data

typedef struct intel_vvp_warp_data
{
 uint32_t num_engines;
 uint8_t* _skip_megablock_data;
 uint32_t _skip_ram_page;
 intel_vvp_warp_engine_data_t engine_data[0];
} intel_vvp_warp_data_t;
Description
Warp data descriptor
Members

num_engines – data for how many engines this set contains. .

_skip_megablock_data – data for the blank skip logic. Generated by the intel_vvp_warp_data library. See WarpData structure.

_skip_ram_page – blank skip page to use for this transform. Warp IP provides 8 blank skip pages. You can keep skip blank data for different transforms and switch between the pages as necessary.

engine_data – array of intel_vvp_warp_engine_data_t structures containing warp coefficients for each individual engine

intel_vvp_warp_engine_data

typedef struct intel_vvp_warp_engine_data
{
 uint32_t mesh_addr;
 uint32_t mesh_size;
 uint32_t filter_addr;
 uint32_t filter_size;
 uint32_t fetch_addr;
 uint32_t fetch_size;
 uint32_t start_h;
 uint32_t start_v;
 uint32_t end_h;
 uint32_t end_v;
 uint32_t mesh_stride;
} intel_vvp_warp_engine_data_t;
Description
Warp coefficient descriptor for an individual warp engine
Members

mesh_addr – address of the mesh coefficients in memory

mesh_size – size of the mesh coefficients

filter_addr – address of the filter coefficients in memory

filter_size – size of the filter coefficients

fetch_addr – address of the fetch coefficients in memory

fetch_size – size of the fetch coefficients

start_h, start_v, end_h, end_v – engine processing region. Internally warp engine processes video in 16x8 pixel blocks with the top-left corner being block [0, 0]. The processing region is defined by the start and end block indexes in horizontal and vertical dimensions.

mesh_stride – number of warp mesh nodes per mesh data row. (in sets of 4 minus 1). Required mesh stride is calculated by the intel_vvp_warp_data library.

intel_vvp_warp_data

This software component uses transformation mesh in a predefined format to generate mesh, cache and filter coefficient data required by the warp IP.

Table 879.   intel_vvp_warp_data API reference
Name Description
WarpDataGenerator Constructor of the intel_vvp_warp_data component
GenerateData Generate warp data
GenerateLatencyParams Generate recommended minimum latency settings for a given warp
AllowExtraCompression Allow data generation for transforms that exceed 2:1 compression limit
GetLastErrorCode Get warning or error code for the most recent call to GenerateData()
GetErrorString Get a string describing the error code passed as argument
Table 880.   intel_vvp_warp_data Helper functions
Name Description
GetHwContext Create object containing warp IP parameters necessary to generate data
GenerateDriverData Create and fill in warp data object required by the warp driver

WarpDataGenerator

WarpDataGenerator
Description
Constructs the main object of the intel_vvp_warp_data software component.
Arguments
None
Return value
None

GenerateData

WarpDataPtr GenerateData(const WarpDataContext& ctx, const WarpMeshSet& mesh_set)
Description
Generate warp data coefficients using provided transformation mesh, video resolution and necessary IP parameters. If two warp engines are available, the workload is split evenly such that each engine processes either left or right half of the image accordingly
Arguments

ctx – reference to an instance of WarpDataContext object containing information about video resolution and IP parameters required to generate data

mesh_set – reference to a set of transformation meshes

Return value
On success the function returns a valid smart pointer to a WarpData object. On error nullptr object is returned. If the IP detects a downscale ratio higher than 2:1 in any region of the frame, nullptr is returned

GenerateLatencyParams

WarpLatencyParamsGenerateLatencyParams(const WarpDataContext& ctx, const WarpDataPtr warp_data, uint32_t system_clock, uint32_t video_clock, uint32_t full_height, uint32_t frame_rate)const
Description
Generate recommended minimum warp latency settings for a given warp. The generated settings should be used to set up the video pipeline for the low latency processing. Refer to Low Latency.
Arguments
ctx– reference to an instance of WarpDataContext object containing information about video resolution and IP parameters required to generate data

warp_data– a smart pointer to a valid WarpData object

system_clock – system clock frequency

video_clock – video clock frequency

full_height – full output video height (including vertical blanking)

frame_rate – output frame rate

Return value

Initialized WarpLatencyParams object containing recommended minimum latency settings for the given warp

AllowExtraCompression

void AllowExtraCompression(bool v)
Description
Allow warps with compression beyond 2:1. By default if the software detects compression higher than 2:1 in any region of the output image the warp data is not generated. This function allows the customer to lift this restriction.
Arguments
v - true to allow extra compression, false to disallow
Return value
None

GetLastErrorCode

uint32_t GetLastErrorCode()const
Description
Return error or warning code for the most recent call to GenerateData(). The software indicates if warp data generation fails or an important condition is detected by setting a numerical error code. Use this function to retrieve the most recent error code.
Arguments
None
Return value

Possible return values are:

Table 881.  Return Values
Macro Value Description
Success 0 Data generated successfully
BlockCacheUsageHigh 1 Block cache usage too high. Output might be unstable
DataAllocError 2 Unable to allocate memory for the warp data
CompressionTooHigh 3 Software detected compression higher than 2:1
BlockCacheFull 4 Requested warp uses up all available block cache
FetchLogicError 5 Error detected in the block cache control logic
OutOfFetchMem 6 Requested warp requires too many block cache fetches
Unknown 7 All other errors

GetErrorString

std::string GetErrorString(const uint32_t error_code)
          const
Description
Return string describing the error code obtained with GetLastErrorCode().
Arguments
error_code - integral error code value as returned by GetLastErrorCode()
Return value
An object of type std::string containing textual description of the error code

Data structures and types

WarpMesh

class WarpMesh
{
public:
 WarpMesh(uint32_t width, uint32_t height, uint32_t step);
 uint32_t GetStep();
 uint32_t GetVNodes();
 uint32_t GetHNodes();
 mesh_node_t* GetRow(uint32_t v);
}
Description

Class containing user-defined transformation mesh.

The mesh is essentially a look-up table that defines a mapping between the output and input images. Each entry of the mesh (node) represents a position in the output image and contains the relevant x and y coordinates of the input image. The step between mesh nodes is defined by the IP. The class automatically manages internal storage for the mesh data

Members

WarpMesh(uint32_t width, uint32_t height, uint32_t step) - Constructor

Arguments: width, height – output image dimensions

step – distance in pixels between mesh nodes. The IP uses the same distance horizontally and vertically. The IP only supports the step of 8 pixels and ignores all other values.

uint32_t GetStep() - Returns distance between mesh nodes

uint32_t GetVNodes()

uint32_t GetHNodes() - Returns number of vertical/horizontal nodes in the mesh respectively

mesh_node_t* GetRow(uint32_t v) - Returns pointer to the mesh row. AccessiIndividual nodes in the row using pointer arithmetic or indexing

Arguments: v – index number of the mesh row

mesh_node_t

typedef struct mesh_node
{
 int32_t _x;
 int32_t _y;
} mesh_node_t
Description
Structure representing individual entry in the mesh
Members
_x, _y – coordinates of the input image this node maps to. the IP represents each value by a 32-bit signed integer with the four least significant bits containing fractional part for subpixel precision.

WarpMeshPtr

using WarpMeshPtr = std::shared_ptr<WarpMesh>
Description
Type alias for a smart pointer wrapper around the mesh class

WarpMeshSet

using WarpMeshSet = std::vector<WarpMeshPtr>
Description
Type alias for a container allowing to group multiple meshes together

WarpDataContext

struct WarpDataContext
{
	WarpDataContext(const WarpHwContextPtr hw, uint32_t wi, uint32_t hi, uint32_t wo, uint32_t ho);
}

Description
Structure containing image dimensions and IP parameters required to generate data. If two warp engines are available, the IP splits the workload evenly such that each engine processes either left or right half of the image accordingly.
Members

WarpDataContext(const WarpHwContextPtr hw, uint32_t wi, uint32_t hi, uint32_t wo, uint32_t ho) - Constructor . . The constructor initializes remaining data members using provided arguments that you should not modify.

Arguments: hw – smart pointer to an instance of WarpHwContext object containing relevant IP parameters

wi, hi – input image width and height

wo, ho – output image width and height

_engine_hblocks – number 16x8 pixel blocks each engine processes horizontally

_engine_mesh_stride – number of mesh nodes per mesh data row each engine processes

_h_blocks_out – total horizontal number of 16x8 blocks in the frame for the given output width

_v_blocks_out – total vertical number of 16x8 blocks in the frame for the given output height

WarpData

class WarpData
{
 virtual uint32_t _GetEngines() const;
 virtual const uint8_t* GetSkipMegablockData() const;
 virtual const_WarpEngineData* GetEngineData(const uint32_t engine) const;
};

Description

Interface class for accessing generated warp coefficients and data

Members

GetEngines() – returns the number of warp engine data objects. The value is always less or equal to MAX_ENGINES

GetSkipMegablockData() – returns pointer to the skip blank logic data

GetEngineData() -returns pointers to individual WarpEngineData objects

WarpEngineData

class WarpEngineData
{
virtual uint32_t GetMeshEntries() const;
virtual uint32_t GetFilterEntries() const;
virtual uint32_t GetFetchEntries() const;

virtual const mesh_entry_t* GetMeshData() const;
 virtual const filter_entry_t* GetFilterData() const;
 virtual const fetch_entry_t* GetFetchData() const;
};
Description
Interface class for accessing data coefficients of individual warp engine
Members

GetMeshEntries() – returns number of mesh entries in the data block

GetFilterEntries() – returns number of filter entries in the data block

GetFetchEntries() – returns number of fetch entries in the data block

GetMeshData() – returns pointer to the mesh data

GetFilterData() – returns pointer to the filter data

GetFetchData() – returns pointer to the fetch data

mesh_entry_t, filter_entry_t, fetch_entry_t

Description

Type aliases to use when accessing individual data blocks and calculating block data size in bytes.

.

WarpLatencyParams

struct WarpLatencyParams
{
 uint32_t _output_latency;
 uint32_t _total_latency;
};
Description

Structure contains recommended pipeline latency settings for the low latency processing. Refer to Warp IP Latency.

Members

_output_latency - the recommended warp output clock offset to be used in intel_vvp_warp_set_output_latency() driver call. The value is in core_clock clock cycles

_total_latency – the recommended minimum offset between the input and output frames. The value is in axi4s_vid_out_0_clock clock cycles

Helper functions

GetHwContext

WarpHwContextPtr GetHwContext(intel_vvp_warp_channel_t* ch)
Description
Create object containing warp IP parameters necessary to generate data. Function uses warp channel driver structure to extract all necessary IP parameters and create object of the type WarpHwContext, required by the GenerateData() call
Arguments
ch - valid pointer to initialized intel_vvp_warp_channel_t structure object mesh_set - reference to a set of transformation meshes
Return value
On success the function returns a valid smart pointer to a WarpHwContext object. On failure a nullptr object is returned

GenerateDriverData

WarpDriverDataPtr GenerateDriverData(const WarpDataContext& ctx, const WarpDataPtr user_data, const uint32_t coef_base_address, const uint32_t skip_ram_page)
Description

Create and fill in an object of type intel_vvp_warp_data_t required by the warp driver’s method intel_vvp_warp_apply_transform() to apply warp.

Arguments
ctx - reference to the WarpDataContext object containing information about video resolution and parameters the IP uses to generate the warp data
user_data - Warp data as generated by the GenerateData() call
coef_base_address - base address in the FPGA accessible RAM where the warp is placed.
skip_ram_page - number of the blank skip ram page to use for this warp
Return value
On success the function returns a valid smart pointer to an intel_vvp_warp_data_t object. On failure a nullptr object is returned. Before applying the warp the client must still transfer the warp data to the locations specified in the returned intel_vvp_warp_data_t object

intel_vvp_warp_mesh

This reference software component allows you to generate sample warp meshes for common affine transformations, perspective transformations, radial distortion compensation and arbitrary transforms defined by a set of curves.

The main object of the component is WarpConfigurator. The WarpConfigurator provides the following three types of warp configurations that the host application can use independently.:

Figure 113. Fixed warp

In the fixed warp configuration a set of affine transformations such as translation, rotation, scaling, perspective correction as well as radial distortion (fisheye) compensation are configured individually using corresponding API calls.

Figure 114. 4x corner warp

In the 4x corner configuration affine and perspective transformations are defined using four points positioned in or around the screen area; This configuration also allows to apply radial distortion compensation.

Figure 115. Arbitrary warp

Arbitrary transformation is defined by a set of curves controlled by a fixed number of control points (knots).

Warp meshes are tied to a specific input and output video resolution. The user must set these accordingly before generating a mesh.

Offset, sizes and positions are accepted as absolute values in pixels. To allow for sub-pixel precision floating-point type is used. Internally these parameters normalized to the [0..1] range using current output resolution and kept in this form. The warp automatically fits into the new output resolution if it changes.

Table 882.  intel_vvp_warp_mesh API reference
Name Description
WarpConfigurator Constructor of the intel_vvp_warp_mesh component
SetInputResolution, GetInputResolution Set or get input image resolution
SetOutputResolution, GetOutputResolution Set or get output image resolution
GenerateMeshFromFixed Generate mesh using fixed warp configuration
GenerateMeshFromCorners Generate mesh using 4x corner warp configuration
GenerateMeshFromArbitrary Generate mesh using arbitrary warp configuration
SetHSize, GetHSize Set or get horizontal size of the image
SetVSize, GetVSize Set or get vertical size of the image
SetHOffset, GetHOffset Set or get horizontal offset of the image
SetVOffset, GetVOffset Set or get vertical offset of the image
SetRotate, GetRotate Set or get rotation angle
SetHMirror, GetHMirror Set or get horizontal mirroring
SetVMirror, GetVMirror Set or get vertical mirroring
SetZoom, GetZoom Set or get zoom factor
SetHKeystone, GetHKeystone Set or get horizontal keystone angle
SetVKeystone, GetVKeystone Set or get vertical keystone angle
SetFOV, GetFOV Set or get field of view
SetVAxisOffset, GetVAxisOffset Set or get vertical axis offset
SetPreRadial, GetPreRadial Set or get radial distortion compensation parameters
SetCorner, GetCorner Set or get corner position
SetArbitraryKnotsNum, GetArbitraryKnotsNum Set or get size of the arbitrary control grid
SetArbitraryKnot, GetArbitraryKnot Set or get position of arbitrary control knot
SetMaintainRatio, GetMaintainRatio Set or get maintain aspect ratio setting
SetShrinkToFit, GetShrinkToFit Set or get shrink to fit setting

WarpConfigurator

WarpConfigurator(WarpHwContextPtr hw_ctx) 
Description
Constructs the main object of the intel_vvp_warp_mesh software component
Arguments
hw_ctx - smart pointer to an instance of WarpHwContext object containing relevant IP parameters
Return value
None

SetInputResolution, GetInputResolution, SetOutputResolution, GetOutputResolution

void SetInputResolution(const uint32_t width, const uint32_t height) void GetInputResolution(uint32_t& width, uint32_t& height) void SetOutputResolution(const uint32_t width, const uint32_t height) void GetOutputResolution(uint32_t& width, uint32_t& height)
Description
Set or get input and output image resolution
Arguments

width – image width

height – image height

Return value
None

GenerateMeshFromFixed, GenerateMeshFromCorners, GenerateMeshFromArbitrary

WarpMeshPtr GenerateMeshFromFixed() WarpMeshPtr GenerateMeshFromCorners() WarpMeshPtr GenerateMeshFromArbitrary()
Description
Generate transformation mesh using fixed, 4x corners or arbitrary configurations respectively
Arguments
None
Return value
Smart pointer to the object of the type WarpMesh containing generated transformation mesh (please see intel_vvp_data interface section for the description of WarpMesh)

SetHSize, GetHSize, SetVSize, GetVSize

void SetHSize(float pixels) float GetHSize() void SetVSize(float pixels) float GetVSize()
Description
Set or get horizontal and vertical size of the image, which is equivalent to scaling the image along the horizontal/vertical axis
Arguments
pixels – horizontal or vertical size of the image accordingly
Return value
horizontal or vertical size of the image accordingly

SetHOffset, GetHOffset, SetVOffset, GetVOffset

void SetHOffset(float pixels) float GetHOffset() void SetVOffset(float pixels) float GetVOffset()
Description
Set or get horizontal and vertical offsets of the image
Arguments
pixels – horizontal or vertical offset of the image accordingly
Return value
horizontal or vertical offset of the image accordingly

SetRotate, GetRotate

void SetRotate(float angle) float GetRotate()
Description
Set or get rotation angle of the image in degrees. Image is rotated around the center
Arguments
angle – rotation angle in degrees
Return value
rotation angle in degrees

SetHMirror, GetHMirror, SetVMirror, GetVMirror

void SetHMirror(bool v) bool GetHMirror() void SetVMirror(bool v) bool GetVMirror()
Description
Set or get image mirroring along horizontal and vertical axis accordingly
Arguments
v – true to enable mirroring, false to disable
Return value
true if mirroring enabled, false otherwise

SetZoom, GetZoom

void SetZoom(float zoom) float GetZoom()
Description
Set or get image zoom value
Arguments
zoom – value > 1 to zoom in, < 1 to zoom out
Return value
Configured zoom value

SetHKeystone, GetHKeystone, SetVKeystone, GetVKeystone

void SetHKeystone(float angle) float GetHKeystone() void SetVKeystone(float angle) float GetVKeystone()
Description
Set or get horizontal and vertical keystone compensation angle accordingly
Arguments
angle - horizontal or vertical angle in degrees by which the projector is tilting relative to the normal to the projection surface.
Return value
Horizontal or vertical projector tilting angle accordingly

SetFOV, GetFOV

void SetFOV(float angle) float GetFOV()
Description
Set or get field of View. Field of view represents projector’s beam angle. This value is necessary for correct keystone correction. The default value is 30°
Arguments
angle - projector’s beam angle in degrees
Return value
Projector’s beam angle in degrees
Figure 116. Field of View

SetVAxisOffset, GetVAxisOffset

void SetVAxisOffset(float v) float GetVAxisOffset()
Description
Set or get vertical offset of the optical axis from the normal to the projection plane. This value is required for correct keystone correction. Some projectors, particularly short throw models have their beam already at an angle to the wall. Take account of this initial angle when calculating keystone correction. The provided value is the absolute offset divided by the image height. The default value is 0
Arguments
v - value of vertical axis offset
Return value
value of vertical axis offset
Figure 117. Vertical Offset

SetPreRadial, GetPreRadial

void SetPreRadial(float x, float y, float k1, float k2) void GetPreRadial(float& x, float& y, float& k1, float& k2)
Description
Set or get radial distortion compensation parameters. The software uses Brown-Conrady distortion model
Arguments

x, y – distortion center

k1, k2 – 1st and 2nd distortion coefficients

Return value
None

SetCorner, GetCorner

void SetCorner(const ECornerId& corner, float pixel_x, float pixel_y) void GetCorner(const ECornerId& corner, float& pixel_x, float& pixel_y)
Description
Set or get position of an individual corner point of the 4x corner warp configuration
Arguments

corner – corner identifier

pixel_x, pixel_y – horizontal and vertical coordinate of the corner

Return value
None

SetArbitraryKnotsNum, GetArbitraryKnotsNum

void SetArbitraryKnotsNum(uint32_t num) uint32_t GetArbitraryKnotsNum()
Description
Set or get number of control points (knots) for the arbitrary warp. Arbitrary warp is defined by a set of curves and control points arranged into NxN grid. This parameter sets the size of this grid. For simplicity the number of control points in both dimensions is the same
Arguments
num – number of control knots in each dimension
Return value
number of control knots in each dimension

SetArbitraryKnot, GetArbitraryKnot

void SetArbitraryKnot(const uint32_t idx, const float x, const float y) void GetArbitraryKnot(const uint32_t idx, float& x, float& y)
Description
Set or get absolute position of individual control points. Points are numbered left to right, top to bottom
Arguments

idx – zero based point index number

x, y – horizontal and vertical coordinate of the point

Return value
None

SetMaintainRatio, GetMaintainRatio

void SetMaintainRatio(bool val) bool GetMaintainRatio()
Description
Set or get maintain aspect ratio flag. If set the aspect ratio of the input resolution is preserved. As a result the output image may have blank areas along either horizontal or vertical axis
Arguments
val – true to maintain input aspect ratio, false otherwise
Return value
Current maintain aspect ratio setting

SetShrinkToFit, GetShrinkToFit

void SetShrinkToFit(bool val) bool GetShrinkToFit()
Description
Set or get shrink to fit setting. If set the resulting image is scaled down after applying all transforms to make sure it fits into the screen. Otherwise the resulting image is cropped to fit output dimensions. This flag is only relevant for the Fixed warp configuration
Arguments
val – true to shrink resulting image to fit output dimensions, false otherwise
Return value
Current shrink to fit setting

Data structures and types

ECornerId

enum ECornerId { 
ETopLeft = 0, 
ETopRight, 
EBottomLeft, 
EBottomRight, 
ETotalCorners, 
};
Description
Enum identifies individual corners in the 4x corner warp configuration