ESP32-CAM stream handler blocks the code

[karas1k]

Hello! I am writing a sketch for the ESP32-CAM board. Code starts a web server, streams the camera image. Web server has 3 handlers, one for HTML page serving (index_handler), one for camera stream (stream_handler) and one for controlling the motors (control_handler). The problem is in a stream_handler. Code in stream_handler has while(true) cycle that blocks other 2 handlers. How is it possible to capture camera images continuously without while(true) cycle in stream_handler? Or is the problem somewhere else?

#define PART_BOUNDARY "123456789000000000000987654321"
static const char* _STREAM_CONTENT_TYPE = "multipart/x-mixed-replace;boundary=" PART_BOUNDARY;
static const char* _STREAM_BOUNDARY = "\r\n--" PART_BOUNDARY "\r\n";
static const char* _STREAM_PART = "Content-Type: image/jpeg\r\nContent-Length: %u\r\n\r\n";

static esp_err_t stream_handler(httpd_req_t *req){
  camera_fb_t * fb = NULL;
  esp_err_t res = ESP_OK;
  size_t _jpg_buf_len = 0;
  uint8_t * _jpg_buf = NULL;
  char * part_buf[64];

  res = httpd_resp_set_type(req, _STREAM_CONTENT_TYPE);
  if(res != ESP_OK){
    return res;
  }

  while(true){
    fb = esp_camera_fb_get();
    if (!fb) {
      Serial.println("Camera capture failed");
      res = ESP_FAIL;
    } else {
      if(fb->width > 400){
        if(fb->format != PIXFORMAT_JPEG){
          bool jpeg_converted = frame2jpg(fb, 80, &_jpg_buf, &_jpg_buf_len);
          esp_camera_fb_return(fb);
          fb = NULL;
          if(!jpeg_converted){
            Serial.println("JPEG compression failed");
            res = ESP_FAIL;
          }
        } else {
          _jpg_buf_len = fb->len;
          _jpg_buf = fb->buf;
        }
      }
    }
    if(res == ESP_OK){
      size_t hlen = snprintf((char *)part_buf, 64, _STREAM_PART, _jpg_buf_len);
      res = httpd_resp_send_chunk(req, (const char *)part_buf, hlen);
    }
    if(res == ESP_OK){
      res = httpd_resp_send_chunk(req, (const char *)_jpg_buf, _jpg_buf_len);
    }
    if(res == ESP_OK){
      res = httpd_resp_send_chunk(req, _STREAM_BOUNDARY, strlen(_STREAM_BOUNDARY));
    }
    if(fb){
      esp_camera_fb_return(fb);
      fb = NULL;
      _jpg_buf = NULL;
    } else if(_jpg_buf){
      free(_jpg_buf);
      _jpg_buf = NULL;
    }
    if(res != ESP_OK){
      break;
    }
    //Serial.printf("MJPG: %uB\n",(uint32_t)(_jpg_buf_len));
  }
  return res;
}

void webserver() {
    httpd_config_t config = HTTPD_DEFAULT_CONFIG();
    httpd_handle_t server = nullptr; 
    if (httpd_start(&server, &config) == ESP_OK) {
        httpd_uri_t stream_uri = {
            .uri       = "/stream",
            .method    = HTTP_GET,
            .handler   = stream_handler,
            .user_ctx  = nullptr            
        };
        httpd_uri_t index_uri = {
            .uri       = "/",
            .method    = HTTP_GET,
            .handler   = index_handler,
            .user_ctx  = nullptr
        };

        httpd_uri_t control_uri = {
            .uri       = "/control",
            .method    = HTTP_GET,
            .handler   = control_handler,
            .user_ctx  = nullptr
        };

        httpd_register_uri_handler(server, &index_uri);
        httpd_register_uri_handler(server, &stream_uri);
        httpd_register_uri_handler(server, &control_uri);
    }
}

[sterretje]

Your topic has been moved to a more suitable location on the forum. The Nano ESP32 - Arduino Forum section of the forum is only for questions related to the Arduino Nano ESP32.

[sonofcy]

You need to look for the tutorial here on the forum about how to do many things at once. Obviously that while true has to go, reading the tutorial will educate you re what to do instead.