ESP32-串流显示

让你的ESP32试试串流吧

header-preview
既然有了屏幕,又有了网络,那岂不是可以串流了!

上篇文章已经展示了如何使用ESP32点亮一块屏幕,那么这次我们来整个活。利用ESP32来显示电脑的画面!如果你用的是其他屏幕也没关系,只要是ESP32配合TFT_eSPI就可以实现,只是在帧率上会有所区别。
这个视频为你展示了在M5StickC上的运行效果
现在是除了游戏性以外,一无所有的原神@bilibili

实现方式

电脑作为发送端,负责发送图像数据->EPS32作为接收端,负责接收并绘制图像数据
发送端使用python编写,使用mss模块捕获屏幕画面,再使用python opencv 编码为JPG

接收端使用C++编写,TJpg_Decoder解码,TFT_eSPI绘制

发送的数据以帧为单位,为了减小帧的体积,将会对每一帧原始位图数据使用JPG编码,ESP32接收到数据以后,先对JPG进行解码,再进行绘制。

一次完整通信流程为:
workflow

精简的代码

common_macro.h
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#ifndef COMMON_MACRO_H_
#define COMMON_MACRO_H_
// Debug情况下,暂时不去测试串流,也无需连接wifi
#define DEBUG
/*
======================串流相关======================
*/
// 帧数据接收完毕
#define FRAMEOK 0x01
// 头部接收完毕,接收帧
#define HEADEROK 0x02
// 准备完毕,接收头部 注:0x03无法正常发送
// https://www.cnblogs.com/young525/p/5873795.html
#define PREPAREOK 0x41
/*
======================屏幕相关======================
*/
#define SCREEN_WIDTH 240
#define SCREEN_HEIGHT 135
/*
======================WiFi相关======================
*/
#define ssid "CloseWrt_2.5G"
// WiFi 密码
#define password "have5seeds"
#endif
StreamingComponent.h
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#ifndef STREAMINGCOMPONENT_H_
#define STREAMINGCOMPONENT_H_
#define IDLES 0
#define RUNNING 1
#define EXITING 2
#include <TFT_eSPI.h>
#include <TJpg_Decoder.h>
#include <WiFi.h>
#include "utils.h"
#include "common_macro.h"
class StreamingComponent {
public:
StreamingComponent(WiFiClient &clt, TFT_eSPI &tft);
uint8_t status = IDLES;
void enter();
void exit();
void loop();
bool drawCallBack(int16_t x, int16_t y, uint16_t w, uint16_t h,
uint16_t *bitmap);
// ~StreamingComponent() {
// Serial.printf("~StreamingComponent\n");
// free(wifiBuffer);
// free(headerBuffer);
// free(frameSizeBuffer);
// };
private:
// WiFiClient指针
WiFiClient *client;
// TFT_eSPI指针
TFT_eSPI *Tft;
// 帧率相关
double fps_avg = 0.0;
uint32_t sec{}, psec{};
uint16_t fps = 0, frame_count = 0;
// 帧率相关
// 执行时间相关
// 函数执行时间
uint32_t cost{};
// 一次loop执行时间
uint32_t loopCost{};
// 缓冲部分
// 帧数据大小
uint16_t size{};
// 已经下载帧数据大小
uint16_t bSize{};
// DMA缓冲相关
// 2020.12.04若出现发送端发送超过wifiFrameSize大小(32kb),
// 则会导致出错,而此处无法分配更大内存。
// 暂时未找到正确开启SPIRAM方法
// 2020.12.04将图片压缩方式从LZO改为jpg
const int wifiFrameSize = 1024 * 32;
// 头数据大小
const int headerFrameSize = 10;
// 待下载的jpg图片缓冲
uint8_t *wifiBuffer =
(uint8_t *) heap_caps_malloc(wifiFrameSize, MALLOC_CAP_8BIT);
// 头数据缓冲
uint8_t *headerBuffer =
(uint8_t *) heap_caps_malloc(headerFrameSize, MALLOC_CAP_8BIT);
// 帧数据大小缓冲,用于解析字符串为int
uint8_t *frameSizeBuffer =
(uint8_t *) heap_caps_malloc(headerFrameSize - 1, MALLOC_CAP_8BIT);
// DMA 双缓冲模式
uint16_t dmaBuffer1[16 * 16]{}; // Toggle buffer for 16*16 MCU block, 512bytes
uint16_t dmaBuffer2[16 * 16]{}; // Toggle buffer for 16*16 MCU block, 512bytes
uint16_t *dmaBufferPtr = dmaBuffer1;
// 当前使用的DMA缓冲
bool dmaBufferSel = 0;
/**
* 显示回调,用于Tjpeg
* 2020-12-06
*/
/**
* 接收数据
* 2020-12-01
* size: 5222 bytes
* cost: 16 ms
*/
void onReceiveData();
};
#endif
StreamingComponent.cpp
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#include "StreamingComponent.h"
StreamingComponent::StreamingComponent(WiFiClient &clt, TFT_eSPI &tft) {
this->client = &clt;
this->Tft = &tft;
Serial.println("StreamingComponent Constuctor");
};
void StreamingComponent::enter() { status = RUNNING; };
void StreamingComponent::exit() { status = EXITING; };
void StreamingComponent::loop() {
if (status == RUNNING) {
Serial.println("StreamingComponent loop");
loopCost = millis();
onReceiveData();
Serial.printf("fps_avg:%f,loop cost:%d ms\n", fps_avg, millis() - loopCost);
Tft->drawString(String(fps_avg), 0, 0, 2);
} else if (status == EXITING) {
// 啥也不做
}
};
bool StreamingComponent::drawCallBack(int16_t x, int16_t y, uint16_t w,
uint16_t h, uint16_t *bitmap) {
if (status == RUNNING) {
if (y >= SCREEN_HEIGHT) return 0;
if (dmaBufferSel) {
dmaBufferPtr = dmaBuffer2;
} else {
dmaBufferPtr = dmaBuffer1;
}
dmaBufferSel = !dmaBufferSel;
Tft->pushImageDMA(x, y, w, h, bitmap, dmaBufferPtr);
}
return true;
}
// ~StreamingComponent() {
// Serial.printf("~StreamingComponent\n");
// free(wifiBuffer);
// free(headerBuffer);
// free(frameSizeBuffer);
// };
void StreamingComponent::onReceiveData() {
Serial.println("StreamingComponent onReceiveData");
StreamingComponent::client->write(PREPAREOK);
Serial.println("StreamingComponent client.write(PREPAREOK);");
cost = millis();
if (headerBuffer == nullptr) {
Serial.printf("headerBuffer is null.\n");
} else {
client->readBytes(headerBuffer, headerFrameSize);
Serial.printf("receive header cost:%d ms\n", millis() - cost);
}
int sum = checkSum((const char *)headerBuffer, 8);
// Serial.printf("headerBuffer checkSum: %d\n", sum);
if ((sum & 0xf) == c2i(headerBuffer[9]) &&
(sum >> 4) == c2i(headerBuffer[8])) {
// 有效头数据,准备接收帧数据
strncpy((char *)frameSizeBuffer, (char *)headerBuffer, 8);
frameSizeBuffer[9] = '\0';
size = atoi((char *)frameSizeBuffer);
// Serial.printf("valid header frame size: %d bytes\n", size);
} else {
// 无效头数据,丢弃
// Serial.printf("invalid header\n");
return;
}
client->write(HEADEROK);
// // Serial.printf("send HEADEROK\n");
cost = millis();
bSize = 0;
if (wifiBuffer == NULL) {
Serial.printf("wifiBuffer is null.\n");
Serial.printf("MALLOC_CAP_8BIT heap_caps_get_largest_free_block: %d.\n",
heap_caps_get_largest_free_block(MALLOC_CAP_8BIT));
Serial.printf("MALLOC_CAP_32BIT heap_caps_get_largest_free_block: %d.\n",
heap_caps_get_largest_free_block(MALLOC_CAP_32BIT));
Serial.printf("MALLOC_CAP_SPIRAM heap_caps_get_largest_free_block: %d.\n",
heap_caps_get_largest_free_block(MALLOC_CAP_SPIRAM));
Serial.printf("MALLOC_CAP_8BIT: %d.\n",
heap_caps_get_free_size(MALLOC_CAP_8BIT));
Serial.printf("MALLOC_CAP_32BIT: %d.\n",
heap_caps_get_free_size(MALLOC_CAP_32BIT));
Serial.printf("MALLOC_CAP_SPIRAM: %d.\n",
heap_caps_get_free_size(MALLOC_CAP_SPIRAM));
} else {
bSize = client->readBytes(wifiBuffer, size);
Serial.printf("frame size: %d bytes, receive frame cost:%d ms\n", bSize,
millis() - cost);
}
if (bSize > 64 && bSize == size) {
cost = millis();
Tft->startWrite();
TJpgDec.drawJpg(0, 0, wifiBuffer, bSize);
Tft->endWrite();
frame_count++;
sec = millis() / 1000;
if (psec != sec) {
psec = sec;
fps = frame_count;
fps_avg = (fps_avg + fps) / 2.0;
frame_count = 0;
}
// 31ms
Serial.printf("draw cost:%d ms\n", millis() - cost);
} else {
// 无效帧,丢弃
// return;
}
client->write(FRAMEOK);
// // Serial.printf("send FRAMEOK\n");
}
utils.h
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#ifndef LIB_UTILS_H_
#define LIB_UTILS_H_
#include <stdint.h>
#include "TFT_eSPI.h"
int checkSum(const char* src, int length);
int c2i(char ch);
int getTextWidth(const char* text, TFT_eSprite &sprite);
int getTextWidth(const char* text, TFT_eSprite *sprite);
#endif
utils.cpp
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#include "utils.h"
/**
* @brief 计算16校验和计算
* @param src 待校验内容
* @param length 待校验内容长度
* @retval 校验和
* */
int checkSum(const char *src, int length) {
int16_t sum = 0;
for (int i = 0; i < length; i++) {
sum += src[i];
}
sum = (sum & 0xff) + (sum >> 16);
return ~sum & 0xff;
}
/**
* @brief 16进制字符转int
* @param ch 待转换内容
* @retval 校验和
* */
// https://www.cnblogs.com/lidabo/p/3995055.html
int c2i(char ch) {
// 如果是数字,则用数字的ASCII码减去48, 如果ch = '2' ,则 '2' - 48 = 2
if (isdigit(ch)) return ch - 48;
// 如果是字母,但不是A~F,a~f则返回
if (ch < 'A' || (ch > 'F' && ch < 'a') || ch > 'z') return -1;
// 如果是大写字母,则用数字的ASCII码减去55, 如果ch = 'A' ,则 'A' - 55 = 10
// 如果是小写字母,则用数字的ASCII码减去87, 如果ch = 'a' ,则 'a' - 87 = 10
if (isalpha(ch)) return isupper(ch) ? ch - 55 : ch - 87;
return -1;
}
int getTextWidth(const char* text, TFT_eSprite &sprite){
return sprite.textWidth(text);
}
int getTextWidth(const char* text, TFT_eSprite *sprite){
return sprite->textWidth(text);
}
tiny_monitor.cpp
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#pragma GCC optimize("O3")
#include <stdint.h>
#include <TFT_eSPI.h>
#include <TJpg_Decoder.h>
#include <WiFi.h>
#include <Wire.h>
#include "StreamingComponent.h"
// 第三方基础组件
// WiFi客户端实例
WiFiClient client;
// 显示屏驱动实例
TFT_eSPI Tft = TFT_eSPI();
// 自定义对象
StreamingComponent *streaming;
bool drawCallback(int16_t x, int16_t y, uint16_t w, uint16_t h,
uint16_t *bitmap) {
streaming->drawCallBack(x, y, w, h, bitmap);
return true;
}
void main_setup() {
// 配置串口
Serial.begin(115200);
// 配置显示
Tft.init();
Tft.setRotation(1);
Tft.fillScreen(TFT_BLACK);
Tft.initDMA();
// 配置TJpeg
TJpgDec.setJpgScale(1);
TJpgDec.setSwapBytes(true);
// 设置TJpg解码器回调函数
TJpgDec.setCallback(drawCallback);
// 配置WiFi
client.setTimeout(1);
WiFi.begin(ssid, password);
delay(1000);
if (WiFi.status() == WL_CONNECTED) {
const int httpPort = 715;
client.connect("192.168.10.207", httpPort);
Serial.println("Socket Connected");
}
// 用户自定义对象初始化区
streaming = new StreamingComponent(client, Tft);
streaming->status = RUNNING;
}
void setup() {
main_setup();
}
void loop() {
streaming->loop();
}
tiny_monitor.py
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import socket
import time
from multiprocessing import Process, Queue,Value,Manager
from multiprocessing.sharedctypes import Array
import ctypes
from mss.tools import to_png
import cv2
import lzo
import mss
import numpy as np
ip = "0.0.0.0"
port = 715
fps = 0
def main():
global fps
# 1. 创建套接字 socket
if True:
tcp_server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# 2. 绑定本地信息 bind
tcp_server_socket.bind((ip, port))
# 3. 让默认的套接字由主动变为被动 listen
tcp_server_socket.listen(128)
print("启动TCP服务器\r\n" + f'启动在{ip}:{port}上')
# 4. 等待客户端的链接 accept
print("等待客户端的链接\r\n")
new_client_socket, client_addr = tcp_server_socket.accept()
print(f'当前链接:{client_addr}')
frame_buffer = grab_screen_to_buffer(0, 0, 1920, 1080)
start_time = time.time()
while True:
s = time.time()
recv = new_client_socket.recv(1)
if recv == b'\x41':
# 客户端就绪,发送头数据
start_time = time.time()
header = len(frame_buffer.tobytes())
header = package_header(header)
new_client_socket.sendall(header)
end_time = time.time()
cost = end_time - start_time
# print("客户端就绪,发送头数据")
elif recv == b'\x02':
# 客户端准备头部接收完成,发送帧数据
new_client_socket.sendall(frame_buffer.tobytes())
frame_buffer = grab_screen_to_buffer(0, 0, 1920, 1080)
# print("客户端准备头部接收完成,发送帧数据")
elif recv == b'\x01':
# pass
# 客户端准备帧数据接收完成,等待客户端就绪
# print("客户端准备帧数据接收完成,等待客户端就绪")
end_time = time.time()
cost = end_time - start_time
print("Backend FPS:{:.2f}".format(1.0 / cost))
## grab screen by left top width height
def grab_screen_to_buffer(l, t, w, h):
monitor = {"top": t, "left": l, "width": w, "height": h}
with mss.mss() as sct:
sct_frame = sct.grab(monitor)
img = np.array(sct_frame)
img = cv2.resize(img, dsize=(240, 135))
# img = cv2.cvtColor(img, cv2.COLOR_BGR2BGR565)
# print("bmp no comporess size:{}",len(img.tobytes()))
# print("bmp lzo comporess size:{}",len(lzo.compress(img.tobytes(), 9, False)))
quality = 60
encode_params = [cv2.IMWRITE_JPEG_QUALITY,quality,cv2.IMWRITE_JPEG_PROGRESSIVE,0]
retval, img = cv2.imencode(".jpg", img, encode_params)
# with open("write.jpg", "wb") as f:
# f.write(img.tobytes())
# img = img[..., ::-1]
# print("jpg no comporess size:{}",len(img.tobytes()))
# print("jpg lzo comporess size:{}",len(lzo.compress(img.tobytes(), 9, False)))
return img
def package_header(size):
data = num_package(size)
header = ''.join(data).encode() + hex(check_sum(data)).encode()[2:]
return header
# 校验和
def check_sum(value):
s = 0
for d in value:
s += ord(d)
s = (s & 0xff) + (s >> 16)
return ~s & 0xff
# 打包数字
def num_package(num):
if num < 100000000:
li_str = list(str(num))
result = ['0' for _ in range(8)]
for index, item in zip(range(len(li_str)), li_str):
result[-index + len(li_str) - 1] = item
return result[::-1]
else:
return ['9' for _ in range(6)]
if __name__ == '__main__':
time.sleep(1)
main()

预览

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参考资料

以下内容为实际开发中参考过的资料,有些资料中的方案已经舍弃,并未体现在上述代码中,特此列出,但俺仍要向他们表示由衷的感谢。

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