像素处理加速器 (PPA)

简介

ESP32-P4 含有像素处理加速器 (PPA) 模块，用于实现图像旋转、缩放、镜像和叠加等图像算法的硬件加速。

术语表

与 PPA 驱动程序相关的术语可参见下表及下图。

术语	定义
图片 (pic)	存储在系统内存中的完整图像。
块	从图片中裁剪出的一部分，其最大尺寸等于整个图片。
像素	在 PPA 环境中使用的单位。
PPA 操作	图像算法加速的类型，包括缩放-旋转-镜像 (SRM)、叠加和填充。
PPA 客户端	执行 PPA 操作的主体。通常，每个 PPA 客户端由特定任务持有。
PPA 事务	来自 PPA 客户端的一次 PPA 操作请求即为一次 PPA 事务。

功能概述

以下部分详细介绍了 PPA 驱动程序的设计：

注册 PPA 客户端 - 涵盖如何注册 PPA 客户端来执行一切 PPA 操作。
注册 PPA 事件回调函数 - 涵盖如何将用户特定代码挂接到 PPA 驱动程序事件回调函数。
执行 PPA 操作 - 涵盖如何执行 PPA 操作。
线程安全- 涵盖在线程安全方面使用 PPA 操作 API 的情况。
性能概述 - 涵盖 PPA 操作的性能。

注册 PPA 客户端

执行 PPA 操作的请求由 PPA 客户端发出。因此，在进行 PPA 操作之前应先注册 PPA 客户端。调用 ppa_register_client() 函数注册一个新客户端。使用 ppa_client_config_t 结构体来指定客户端的属性。

ppa_client_config_t::oper_type - 每种 PPA 操作类型对应一个 PPA 客户端类型，已注册的 PPA 客户端只能请求一种特定类型的 PPA 操作。
ppa_client_config_t::max_pending_trans_num - 决定客户端可以持有的最大 PPA 事务挂起数量。

建议为每个任务注册一个独立的 PPA 客户端。例如，一个应用程序包含两个任务：任务 A 需要使用 PPA SRM 和 PPA 填充功能，则应在该任务中注册一个 PPA SRM 客户端和一个 PPA 填充客户端；而任务 B 也需要使用 PPA SRM 功能，那么在任务 B 中应再注册一个 PPA SRM 客户端。

如果任务不再需要执行 PPA 操作，可以调用 ppa_unregister_client() 函数注销相应的 PPA 客户端。

注册 PPA 事件回调函数

当某个事件发生时（例如，完成一个 PPA 事务时），CPU 会通过中断接收到该事件的通知。如果需要在特定事件发生时调用某些特定函数，可以通过调用 ppa_client_register_event_callbacks() 为该事件注册回调函数。这在选择 PPA_TRANS_MODE_NON_BLOCKING 模式来执行 PPA 操作时特别有用。需要注意的是，虽然事件回调函数与 PPA 客户端绑定，但用户上下文是在调用 PPA 操作 API 时按事务提供的，这使事件回调函数能被更灵活得运用。

已注册的回调函数在中断上下文中被调用，因此，要遵循中断服务程序 (ISR) 的一般规则。

执行 PPA 操作

注册好 PPA 客户端，就可以用返回的 ppa_client_handle_t 来请求执行 PPA 操作。

PPA 操作包括：

缩放、旋转、镜像 (SRM)

调用 ppa_do_scale_rotate_mirror() 对图片内部的目标块执行缩放、旋转、镜像中的一个或多个操作。

注意以下几点事项，避免在配置 ppa_srm_oper_config_t 时产生混淆：

执行 SRM 操作时，ppa_in_pic_blk_config_t::buffer 和 ppa_out_pic_blk_config_t::buffer 必须是指向不同图片 buffer 的指针。
ppa_srm_oper_config_t::scale_x 和 ppa_srm_oper_config_t::scale_y 的精度将被截断为 1/16 的步长。
输出块的宽度/高度完全由输入块的宽度/高度、缩放因子和旋转角度决定，因此无需配置输出块的宽度/高度。但请确保输出块可以适应输出图片中的偏移位置。
如果输入或输出图片的色彩模式为 PPA_SRM_COLOR_MODE_YUV420，那么其 pic_w、pic_h、block_w、block_h、block_offset_x 以及 block_offset_y 字段必须为偶数。

叠加

调用 ppa_do_blend() 将前景 (FG) 和背景 (BG) 图片的两个目标块进行叠加。

叠加遵循一般的 Alpha Blending 公式：

\(A_{out} = A_b + A_f - A_b \times A_f\)

\(C_{out} = (C_b \times A_b \times (1 - A_f) + C_f \times A_f) / (A_b + A_f - A_b \times A_f)\)

其中 \(A_b\) 是背景层的 Alpha 通道，\(A_f\) 是前景层的 Alpha 通道，\(C_b\) 对应背景层的 R、G、B 分量，\(C_f\) 对应前景层的 R、G、B 分量。

注意，此公式对 FG 和 BG 的处理是不对称的。当 \(A_f = 1\) 时， \(C_{out} = C_f\)，\(A_{out} = 1\)，这意味着如果 FG 图片的色彩模式为 PPA_BLEND_COLOR_MODE_RGB565 或 PPA_BLEND_COLOR_MODE_RGB888，PPA 硬件会填充 Alpha 值为 255（即 \(A_f = 1\)），叠加结果将与 FG 块相同。

如果将 ppa_blend_oper_config_t::bg_ck_en 或 ppa_blend_oper_config_t::fg_ck_en 设置为 true，则色键（color-key，也叫 Chroma-key）范围内的像素不会按照正常 Alpha Blending 流程输出。请查看 ESP32-P4 技术参考手册 > 像素处理加速器 (PPA) > 功能描述 > 图层叠加 (BLEND) [PDF] 了解详细规则。

注意以下几点事项，避免在配置 ppa_blend_oper_config_t 时产生混淆：

执行叠加操作时，ppa_out_pic_blk_config_t::buffer 与输入的 ppa_in_pic_blk_config_t::buffer 之一可以是指向相同图片 buffer 的指针。
FG 和 BG 的块宽度/高度应相同，输出块的宽度/高度值应与之一致。
如果输入图片的色彩模式为 PPA_BLEND_COLOR_MODE_A4，那么其 block_w 和 block_offset_x 字段必须为偶数。

填充

调用 ppa_do_fill() 填充图片内部的目标块。

ppa_trans_mode_t 为可配置字段，适用于所有 PPA 操作 API。可以配置该字段，在调用 PPA 操作 API 时等待操作完成后再返回，或者在事务推送到内部队列后立即返回。

线程安全

在以下情境中调用 PPA 操作 API，PPA 驱动程序可确保线程安全：

同一任务中不同类型的客户端之间
不同任务中同一类型的客户端之间
不同任务中不同类型的客户端之间

性能概述

PPA 操作作用于输入图片的目标块。因此，完成一次 PPA 事务所需的时间与块中的数据量成正比。整个图片的大小对性能没有影响。更重要的是，如果图片位于 PSRAM，则 PPA 的性能高度依赖于 PSRAM 的带宽。若有多个外设同时读写 PSRAM，则 PPA 操作的性能将大大降低。

应用示例

peripherals/ppa/ppa_dsi - 使用 DSI 显示屏的 PPA 示例。首先，该示例所使用的图像会被放大、逆时针旋转后复原、镜像后复原、缩小。其次，该图像将与一个透明度较低的全红图像叠加，ESP32 字样将被色键移除。最后，会在 ESP32 周围填充一个框。

API 参考

Header File

components/esp_driver_ppa/include/driver/ppa.h
This header file can be included with:
#include "driver/ppa.h"
This header file is a part of the API provided by the esp_driver_ppa component. To declare that your component depends on esp_driver_ppa, add the following to your CMakeLists.txt:
REQUIRES esp_driver_ppa
or
PRIV_REQUIRES esp_driver_ppa

Functions

esp_err_t ppa_register_client(const ppa_client_config_t *config, ppa_client_handle_t *ret_client)

Register a PPA client to do a specific PPA operation.

参数

config -- [in] Pointer to a collection of configurations for the client
ret_client -- [out] Returned client handle

返回

ESP_OK: Register the PPA client successfully
ESP_ERR_INVALID_ARG: Register the PPA client failed because of invalid argument
ESP_ERR_NO_MEM: Register the PPA client failed because out of memory
ESP_FAIL: Register the PPA client failed because of other error

esp_err_t ppa_unregister_client(ppa_client_handle_t ppa_client)

Unregister a PPA client.

备注

This will also free the resources occupied by the client

参数

ppa_client -- [in] PPA client handle, allocated by ppa_register_client

返回

ESP_OK: Unregister the PPA client successfully
ESP_ERR_INVALID_ARG: Unregister the PPA client failed because of invalid argument
ESP_ERR_INVALID_STATE: Unregister the PPA client failed because there are unfinished transactions

esp_err_t ppa_client_register_event_callbacks(ppa_client_handle_t ppa_client, const ppa_event_callbacks_t *cbs)

Register event callbacks for a PPA client.

备注

Any user private data that wants to be passed directly to callback's user_data is provided per PPA transaction. Please check the user_data field in ppa_xxx_oper_config_t structure.

参数

ppa_client -- [in] PPA client handle
cbs -- [in] Structure with all PPA callbacks

返回

ESP_OK: Register event callbacks for the PPA client successfully
ESP_ERR_INVALID_ARG: Register event callbacks for the PPA client failed because of invalid argument

esp_err_t ppa_do_scale_rotate_mirror(ppa_client_handle_t ppa_client, const ppa_srm_oper_config_t *config)

Perform a scaling-rotating-mirroring (SRM) operation to a picture.

参数

ppa_client -- [in] PPA client handle that has been registered to do SRM operations
config -- [in] Pointer to a collection of configurations for the SRM operation transaction, ppa_srm_oper_config_t

返回

ESP_OK: Perform a SRM operation successfully
ESP_ERR_INVALID_ARG: Perform a SRM operation failed because of invalid argument
ESP_FAIL: Perform a SRM operation failed because the client's pending transactions has reached its maximum capacity

esp_err_t ppa_do_blend(ppa_client_handle_t ppa_client, const ppa_blend_oper_config_t *config)

Perform a blending operation to a picture.

参数

ppa_client -- [in] PPA client handle that has been registered to do blend operations
config -- [in] Pointer to a collection of configurations for the blend operation transaction, ppa_blend_oper_config_t

返回

ESP_OK: Perform a blend operation successfully
ESP_ERR_INVALID_ARG: Perform a blend operation failed because of invalid argument
ESP_FAIL: Perform a blend operation failed because the client's pending transactions has reached its maximum capacity

esp_err_t ppa_do_fill(ppa_client_handle_t ppa_client, const ppa_fill_oper_config_t *config)

Perform a filling operation to a picture.

参数

ppa_client -- [in] PPA client handle that has been registered to do fill operations
config -- [in] Pointer to a collection of configurations for the fill operation transaction, ppa_fill_oper_config_t

返回

ESP_OK: Perform a fill operation successfully
ESP_ERR_INVALID_ARG: Perform a fill operation failed because of invalid argument
ESP_FAIL: Perform a fill operation failed because the client's pending transactions has reached its maximum capacity

Structures

struct ppa_client_config_t

A collection of configuration items that used for registering a PPA client.

Public Members

ppa_operation_t oper_type: The desired PPA operation for the client

uint32_t max_pending_trans_num: The maximum number of pending transactions for the client. By default, it will be 1, which is sufficient if all transactions are performed with PPA_TRANS_MODE_BLOCKING

ppa_data_burst_length_t data_burst_length: The desired data burst length for all the transactions of the client. Use a small burst length will decrease PPA performance, but can save burst bandwidth for other peripheral usages. By default, it will be at the maximum burst length, PPA_DATA_BURST_LENGTH_128

struct ppa_event_data_t: Type of PPA event data.

struct ppa_event_callbacks_t

Group of supported PPA callbacks.

Public Members

ppa_event_callback_t on_trans_done: Invoked when a PPA transaction finishes

struct ppa_in_pic_blk_config_t

A collection of configuration items for an input picture and the target block inside the picture.

Public Members

const void *buffer: Pointer to the input picture buffer

uint32_t pic_w: Input picture width (unit: pixel)

uint32_t pic_h: Input picture height (unit: pixel)

uint32_t block_w: Target block width (unit: pixel)

uint32_t block_h: Target block height (unit: pixel)

uint32_t block_offset_x: Target block offset in x direction in the picture (unit: pixel)

uint32_t block_offset_y: Target block offset in y direction in the picture (unit: pixel)

ppa_srm_color_mode_t srm_cm: Color mode of the picture in a PPA SRM operation. Supported color mode in ppa_srm_color_mode_t

ppa_blend_color_mode_t blend_cm: Color mode of the picture in a PPA blend operation. Supported color mode in ppa_blend_color_mode_t

ppa_fill_color_mode_t fill_cm: Color mode of the picture in a PPA fill operation. Supported color mode in ppa_fill_color_mode_t

ppa_color_range_t yuv_range: When the color mode is any YUV color space, this field is to describe its color range

ppa_color_conv_std_rgb_yuv_t yuv_std: When the color mode is any YUV color space, this field is to describe its YUV<->RGB conversion standard

struct ppa_out_pic_blk_config_t

A collection of configuration items for an output picture and the target block inside the picture.

Public Members

void *buffer: Pointer to the output picture buffer (requires alignment: internal memory needs align to L1 cache line size, external memory needs align to L1 and L2 cache line size)

uint32_t buffer_size: Size of the output picture buffer (requires alignment: internal memory needs align to L1 cache line size, external memory needs align to L1 and L2 cache line size)

uint32_t pic_w: Output picture width (unit: pixel)

uint32_t pic_h: Output picture height (unit: pixel)

uint32_t block_offset_x: Target block offset in x direction in the picture (unit: pixel)

uint32_t block_offset_y: Target block offset in y direction in the picture (unit: pixel)

ppa_srm_color_mode_t srm_cm: Color mode of the picture in a PPA SRM operation. Supported color mode in ppa_srm_color_mode_t

ppa_blend_color_mode_t blend_cm: Color mode of the picture in a PPA blend operation. Supported color mode in ppa_blend_color_mode_t

ppa_fill_color_mode_t fill_cm: Color mode of the picture in a PPA fill operation. Supported color mode in ppa_fill_color_mode_t

ppa_color_range_t yuv_range: When the color mode is any YUV color space, this field is to describe its color range

ppa_color_conv_std_rgb_yuv_t yuv_std: When the color mode is any YUV color space, this field is to describe its YUV<->RGB conversion standard

struct ppa_srm_oper_config_t

A collection of configuration items to do a PPA SRM operation transaction.

Public Members

ppa_in_pic_blk_config_t in: Information of the input picture and the target block

ppa_out_pic_blk_config_t out: Information of the output picture and the target block

ppa_srm_rotation_angle_t rotation_angle: Rotation (counter-clockwise) to the target block, select from ppa_srm_rotation_angle_t

float scale_x: Scaling factor to the target block in the x direction

float scale_y: Scaling factor to the target block in the y direction

bool mirror_x: Whether to mirror the target block in the x direction

bool mirror_y: Whether to mirror the target block in the y direction

bool rgb_swap: Whether to swap the input data in RGB (e.g. ARGB becomes BGRA, RGB becomes BGR)

bool byte_swap: Whether to swap the input data in byte. Only available feature if input picture color mode is ARGB8888 or RGB565

ppa_alpha_update_mode_t alpha_update_mode: Select whether the alpha channel of the input picture needs update

uint32_t alpha_fix_val: Range: [0, 255] When PPA_ALPHA_FIX_VALUE mode is selected, alpha_fix_val is the new alpha value to replace the input alpha value (output_alpha = alpha_fix_val)

float alpha_scale_ratio: Range: (0, 1) When PPA_ALPHA_SCALE mode is selected, alpha_scale_ratio is the multiplier to the input alpha value (output_alpha = alpha_scale_ratio * input_alpha) Ratio resolution is 1/256

ppa_trans_mode_t mode: Determines whether to block inside the operation functions, see ppa_trans_mode_t

void *user_data: User registered data to be passed into done_cb callback function

struct ppa_blend_oper_config_t

A collection of configuration items to do a PPA blend operation transaction.

Public Members

ppa_in_pic_blk_config_t in_bg: Information of the input background picture and the target block

ppa_in_pic_blk_config_t in_fg: Information of the input foreground picture and the target block

ppa_out_pic_blk_config_t out: Information of the output picture and the target block

bool bg_rgb_swap: Whether to swap the background input data in RGB (e.g. ARGB becomes BGRA, RGB becomes BGR)

bool bg_byte_swap: Whether to swap the background input data in byte. Only available feature if input BG picture color mode is ARGB8888 or RGB565

ppa_alpha_update_mode_t bg_alpha_update_mode: Select whether the alpha channel of the input background picture needs update

uint32_t bg_alpha_fix_val: Range: [0, 255] When PPA_ALPHA_FIX_VALUE mode is selected, alpha_fix_val is the new alpha value to replace the input alpha value (output_alpha = alpha_fix_val)

float bg_alpha_scale_ratio: Range: (0, 1) When PPA_ALPHA_SCALE mode is selected, alpha_scale_ratio is the multiplier to the input alpha value (output_alpha = alpha_scale_ratio * input_alpha) Ratio resolution is 1/256

bool fg_rgb_swap: Whether to swap the foreground input data in RGB (e.g. ARGB becomes BGRA, RGB becomes BGR)

bool fg_byte_swap: Whether to swap the foreground input data in byte. Only available feature if input FG picture color mode is ARGB8888 or RGB565

ppa_alpha_update_mode_t fg_alpha_update_mode: Select whether the alpha channel of the input foreground picture needs update

uint32_t fg_alpha_fix_val: Range: [0, 255] When PPA_ALPHA_FIX_VALUE mode is selected, alpha_fix_val is the new alpha value to replace the input alpha value (output_alpha = alpha_fix_val)

float fg_alpha_scale_ratio: Range: (0, 1) When PPA_ALPHA_SCALE mode is selected, alpha_scale_ratio is the multiplier to the input alpha value (output_alpha = alpha_scale_ratio * input_alpha) Ratio resolution is 1/256

color_pixel_rgb888_data_t fg_fix_rgb_val: When in_fg.blend_cm is PPA_BLEND_COLOR_MODE_A8/4, this field can be used to set a fixed color for the foreground, in RGB888 format

bool bg_ck_en: Whether to enable color keying for background If not enabled, all background pixels are considered as out of the color-keying range

color_pixel_rgb888_data_t bg_ck_rgb_low_thres: The lower threshold of the color-keying range for the background, in RGB888 format

color_pixel_rgb888_data_t bg_ck_rgb_high_thres: The higher threshold of the color-keying range for the background, in RGB888 format

bool fg_ck_en: Whether to enable color keying for foreground If not enabled, all foreground pixels are considered as out of the color-keying range

color_pixel_rgb888_data_t fg_ck_rgb_low_thres: The lower threshold of the color-keying range for the foreground, in RGB888 format

color_pixel_rgb888_data_t fg_ck_rgb_high_thres: The higher threshold of the color-keying range for the foreground, in RGB888 format

color_pixel_rgb888_data_t ck_rgb_default_val: The color to overwrite when a pixel, where its background element and foreground element are both within their color-keying ranges, in RGB888 format

bool ck_reverse_bg2fg: If this bit is set, in color-keying, for the pixel, where its background element is in the color range, but its foreground element is not in the color range, it will output the foreground element instead of the background element

ppa_trans_mode_t mode: Determines whether to block inside the operation functions, see ppa_trans_mode_t

void *user_data: User registered data to be passed into done_cb callback function

struct ppa_fill_oper_config_t

A collection of configuration items to do a PPA fill operation transaction.

Public Members

ppa_out_pic_blk_config_t out: Information of the output picture and the target block

uint32_t fill_block_w: The width of the block to be filled (unit: pixel)

uint32_t fill_block_h: The height of the block to be filled (unit: pixel)

color_pixel_argb8888_data_t fill_argb_color: The color to be filled, in ARGB8888 format

ppa_trans_mode_t mode: Determines whether to block inside the operation functions, see ppa_trans_mode_t

void *user_data: User registered data to be passed into done_cb callback function

Type Definitions

typedef struct ppa_client_t *ppa_client_handle_t: Type of PPA client handle.

typedef bool (*ppa_event_callback_t)(ppa_client_handle_t ppa_client, ppa_event_data_t *event_data, void *user_data)

Type of PPA event callback.

Param ppa_client: [in] PPA client handle
Param event_data: [in] PPA event data
Param user_data: [in] User registered data from calling ppa_do_xxx to perform an operation
Return: Whether a task switch is needed after the callback function returns, this is usually due to the callback wakes up some high priority task.

Enumerations

enum ppa_operation_t

Enumeration of all PPA available operations.

Values:

enumerator PPA_OPERATION_SRM: Do scale-rotate-mirror operation

enumerator PPA_OPERATION_BLEND: Do blend operation

enumerator PPA_OPERATION_FILL: Do fill operation, use one constant pixel to fill a target window

enumerator PPA_OPERATION_INVALID: Invalid PPA operations, indicates the quantity of available PPA operations

enum ppa_trans_mode_t

Modes to perform the PPA operations.

Values:

enumerator PPA_TRANS_MODE_BLOCKING: ppa_do_xxx function will block until the PPA operation is finished

enumerator PPA_TRANS_MODE_NON_BLOCKING: ppa_do_xxx function will return immediately after the PPA operation is pushed to the internal queue

Header File

components/hal/include/hal/ppa_types.h
This header file can be included with:
#include "hal/ppa_types.h"

Enumerations

enum ppa_engine_type_t

Enumeration of engines in PPA modules.

Values:

enumerator PPA_ENGINE_TYPE_SRM: PPA Scaling-Rotating-Mirroring (SRM) engine, used to perform scale, rotate, mirror

enumerator PPA_ENGINE_TYPE_BLEND: PPA Blending engine, used to perform blend or fill

enum ppa_srm_rotation_angle_t

Enumeration of PPA Scaling-Rotating-Mirroring available rotation angle (in the counterclockwise direction)

Values:

enumerator PPA_SRM_ROTATION_ANGLE_0: Picture does no rotation

enumerator PPA_SRM_ROTATION_ANGLE_90: Picture rotates 90 degrees CCW

enumerator PPA_SRM_ROTATION_ANGLE_180: Picture rotates 180 degrees CCW

enumerator PPA_SRM_ROTATION_ANGLE_270: Picture rotates 270 degrees CCW

enum ppa_srm_color_mode_t

Enumeration of PPA Scaling-Rotating-Mirroring available color mode.

Values:

enumerator PPA_SRM_COLOR_MODE_ARGB8888: PPA SRM color mode: ARGB8888

enumerator PPA_SRM_COLOR_MODE_RGB888: PPA SRM color mode: RGB888

enumerator PPA_SRM_COLOR_MODE_RGB565: PPA SRM color mode: RGB565

enumerator PPA_SRM_COLOR_MODE_YUV420: PPA SRM color mode: YUV420

enumerator PPA_SRM_COLOR_MODE_YUV444: PPA SRM color mode: YUV444 (limited range only)

enum ppa_blend_color_mode_t

Enumeration of PPA blend available color mode.

Values:

enumerator PPA_BLEND_COLOR_MODE_ARGB8888: PPA blend color mode: ARGB8888

enumerator PPA_BLEND_COLOR_MODE_RGB888: PPA blend color mode: RGB888

enumerator PPA_BLEND_COLOR_MODE_RGB565: PPA blend color mode: RGB565

enumerator PPA_BLEND_COLOR_MODE_A8: PPA blend color mode: A8, only available on blend foreground input

enumerator PPA_BLEND_COLOR_MODE_A4: PPA blend color mode: A4, only available on blend foreground input

enum ppa_fill_color_mode_t

Enumeration of PPA fill available color mode.

Values:

enumerator PPA_FILL_COLOR_MODE_ARGB8888: PPA fill color mode: ARGB8888

enumerator PPA_FILL_COLOR_MODE_RGB888: PPA fill color mode: RGB888

enumerator PPA_FILL_COLOR_MODE_RGB565: PPA fill color mode: RGB565

enum ppa_alpha_update_mode_t

Enumeration of PPA alpha compositing update mode.

Values:

enumerator PPA_ALPHA_NO_CHANGE: Do not replace alpha value (A' = A). If input format does not contain alpha info, alpha value 255 will be used.

enumerator PPA_ALPHA_FIX_VALUE: Replace the alpha value in received pixel with a new, fixed alpha value (A' = val)

enumerator PPA_ALPHA_SCALE: Scale the alpha value in received pixel to be a new alpha value (A' = (A * val) >> 8). If input format does not contain alpha info, A' = (255 * val) >> 8.

enumerator PPA_ALPHA_INVERT: Invert the alpha value in received pixel (A' = 255 - A). If input format does not contain alpha info, A' = 0, i.e. a layer with 0% opacity.

enum ppa_color_conv_std_rgb_yuv_t

Enumeration of PPA supported color conversion standard between RGB and YUV (determines the YUV<->RGB conversion equation)

Values:

enumerator PPA_COLOR_CONV_STD_RGB_YUV_BT601: YUV<->RGB conversion standard: BT.601

enumerator PPA_COLOR_CONV_STD_RGB_YUV_BT709: YUV<->RGB conversion standard: BT.709

enum ppa_color_range_t

Enumeration of PPA supported color range (determines the YUV<->RGB conversion equation)

Values:

enumerator PPA_COLOR_RANGE_LIMIT: Limited color range, 16 is the darkest black and 235 is the brightest white

enumerator PPA_COLOR_RANGE_FULL: Full color range, 0 is the darkest black and 255 is the brightest white

enum ppa_data_burst_length_t

Enumeration of PPA supported data burst length.

Values:

enumerator PPA_DATA_BURST_LENGTH_8: Data burst length: 8 bytes

enumerator PPA_DATA_BURST_LENGTH_16: Data burst length: 16 bytes

enumerator PPA_DATA_BURST_LENGTH_32: Data burst length: 32 bytes

enumerator PPA_DATA_BURST_LENGTH_64: Data burst length: 64 bytes

enumerator PPA_DATA_BURST_LENGTH_128: Data burst length: 128 bytes

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