# ESP32 Camera Driver

## General Information

This repository hosts ESP32 compatible driver for OV2640 and OV3660 image sensors. Additionally it provides a few tools, which allow converting the captured frame data to the more common BMP and JPEG formats.

## Important to Remember

- Except when using CIF or lower resolution with JPEG, the driver requires PSRAM to be installed and activated.
- Using YUV or RGB puts a lot of strain on the chip because writing to PSRAM is not particularly fast. The result is that image data might be missing. This is particularly true if WiFi is enabled. If you need RGB data, it is recommended that JPEG is captured and then turned into RGB using `fmt2rgb888` or `fmt2bmp`/`frame2bmp`.
- When 1 frame buffer is used, the driver will wait for the current frame to finish (VSYNC) and start I2S DMA. After the frame is acquired, I2S will be stopped and the frame buffer returned to the application. This approach gives more control over the system, but results in longer time to get the frame.
- When 2 or more frame bufers are used, I2S is running in continuous mode and each frame is pushed to a queue that the application can access. This approach puts more strain on the CPU/Memory, but allows for double the frame rate. Please use only with JPEG.

## Installation Instructions

- Clone or download and extract the repository to the components folder of your ESP-IDF project
- Enable PSRAM in `menuconfig`
- Include `esp_camera.h` in your code

## Examples

### Initialization

```c
#include "esp_camera.h"

//WROVER-KIT PIN Map
#define CAM_PIN_PWDN    -1 //power down is not used
#define CAM_PIN_RESET   -1 //software reset will be performed
#define CAM_PIN_XCLK    21
#define CAM_PIN_SIOD    26
#define CAM_PIN_SIOC    27

#define CAM_PIN_D7      35
#define CAM_PIN_D6      34
#define CAM_PIN_D5      39
#define CAM_PIN_D4      36
#define CAM_PIN_D3      19
#define CAM_PIN_D2      18
#define CAM_PIN_D1       5
#define CAM_PIN_D0       4
#define CAM_PIN_VSYNC   25
#define CAM_PIN_HREF    23
#define CAM_PIN_PCLK    22

static camera_config_t camera_config = {
    .pin_pwdn  = CAM_PIN_PWDN,
    .pin_reset = CAM_PIN_RESET,
    .pin_xclk = CAM_PIN_XCLK,
    .pin_sscb_sda = CAM_PIN_SIOD,
    .pin_sscb_scl = CAM_PIN_SIOC,

    .pin_d7 = CAM_PIN_D7,
    .pin_d6 = CAM_PIN_D6,
    .pin_d5 = CAM_PIN_D5,
    .pin_d4 = CAM_PIN_D4,
    .pin_d3 = CAM_PIN_D3,
    .pin_d2 = CAM_PIN_D2,
    .pin_d1 = CAM_PIN_D1,
    .pin_d0 = CAM_PIN_D0,
    .pin_vsync = CAM_PIN_VSYNC,
    .pin_href = CAM_PIN_HREF,
    .pin_pclk = CAM_PIN_PCLK,

    //XCLK 20MHz or 10MHz for OV2640 double FPS (Experimental)
    .xclk_freq_hz = 20000000,
    .ledc_timer = LEDC_TIMER_0,
    .ledc_channel = LEDC_CHANNEL_0,

    .pixel_format = PIXFORMAT_JPEG,//YUV422,GRAYSCALE,RGB565,JPEG
    .frame_size = FRAMESIZE_UXGA,//QQVGA-QXGA Do not use sizes above QVGA when not JPEG

    .jpeg_quality = 12, //0-63 lower number means higher quality
    .fb_count = 1 //if more than one, i2s runs in continuous mode. Use only with JPEG
};

esp_err_t camera_init(){
    //power up the camera if PWDN pin is defined
    if(CAM_PIN_PWDN != -1){
        pinMode(CAM_PIN_PWDN, OUTPUT);
        digitalWrite(CAM_PIN_PWDN, LOW);
    }

    //initialize the camera
    esp_err_t err = esp_camera_init(&camera_config);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Camera Init Failed");
        return err;
    }

    return ESP_OK;
}

esp_err_t camera_capture(){
    //acquire a frame
    camera_fb_t * fb = esp_camera_fb_get();
    if (!fb) {
        ESP_LOGE(TAG, "Camera Capture Failed");
        return ESP_FAIL;
    }
    //replace this with your own function
    process_image(fb->width, fb->height, fb->format, fb->buf, fb->len);
  
    //return the frame buffer back to the driver for reuse
    esp_camera_fb_return(fb);
    return ESP_OK;
}
```

### JPEG HTTP Capture

```c
#include "esp_camera.h"
#include "esp_http_server.h"
#include "esp_timer.h"

typedef struct {
        httpd_req_t *req;
        size_t len;
} jpg_chunking_t;

static size_t jpg_encode_stream(void * arg, size_t index, const void* data, size_t len){
    jpg_chunking_t *j = (jpg_chunking_t *)arg;
    if(!index){
        j->len = 0;
    }
    if(httpd_resp_send_chunk(j->req, (const char *)data, len) != ESP_OK){
        return 0;
    }
    j->len += len;
    return len;
}

esp_err_t jpg_httpd_handler(httpd_req_t *req){
    camera_fb_t * fb = NULL;
    esp_err_t res = ESP_OK;
    size_t fb_len = 0;
    int64_t fr_start = esp_timer_get_time();

    fb = esp_camera_fb_get();
    if (!fb) {
        ESP_LOGE(TAG, "Camera capture failed");
        httpd_resp_send_500(req);
        return ESP_FAIL;
    }
    res = httpd_resp_set_type(req, "image/jpeg");
    if(res == ESP_OK){
        res = httpd_resp_set_hdr(req, "Content-Disposition", "inline; filename=capture.jpg");
    }

    if(res == ESP_OK){
        if(fb->format == PIXFORMAT_JPEG){
            fb_len = fb->len;
            res = httpd_resp_send(req, (const char *)fb->buf, fb->len);
        } else {
            jpg_chunking_t jchunk = {req, 0};
            res = frame2jpg_cb(fb, 80, jpg_encode_stream, &jchunk)?ESP_OK:ESP_FAIL;
            httpd_resp_send_chunk(req, NULL, 0);
            fb_len = jchunk.len;
        }
    }
    esp_camera_fb_return(fb);
    int64_t fr_end = esp_timer_get_time();
    ESP_LOGI(TAG, "JPG: %uKB %ums", (uint32_t)(fb_len/1024), (uint32_t)((fr_end - fr_start)/1000));
    return res;
}
```

### JPEG HTTP Stream

```c
#include "esp_camera.h"
#include "esp_http_server.h"
#include "esp_timer.h"

#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";

esp_err_t jpg_stream_httpd_handler(httpd_req_t *req){
    camera_fb_t * fb = NULL;
    esp_err_t res = ESP_OK;
    size_t _jpg_buf_len;
    uint8_t * _jpg_buf;
    char * part_buf[64];
    static int64_t last_frame = 0;
    if(!last_frame) {
        last_frame = esp_timer_get_time();
    }

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

    while(true){
        fb = esp_camera_fb_get();
        if (!fb) {
            ESP_LOGE(TAG, "Camera capture failed");
            res = ESP_FAIL;
            break;
        }
        if(fb->format != PIXFORMAT_JPEG){
            bool jpeg_converted = frame2jpg(fb, 80, &_jpg_buf, &_jpg_buf_len);
            if(!jpeg_converted){
                ESP_LOGE(TAG, "JPEG compression failed");
                esp_camera_fb_return(fb);
                res = ESP_FAIL;
            }
        } else {
            _jpg_buf_len = fb->len;
            _jpg_buf = fb->buf;
        }

        if(res == ESP_OK){
            res = httpd_resp_send_chunk(req, _STREAM_BOUNDARY, strlen(_STREAM_BOUNDARY));
        }
        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(fb->format != PIXFORMAT_JPEG){
            free(_jpg_buf);
        }
        esp_camera_fb_return(fb);
        if(res != ESP_OK){
            break;
        }
        int64_t fr_end = esp_timer_get_time();
        int64_t frame_time = fr_end - last_frame;
        last_frame = fr_end;
        frame_time /= 1000;
        ESP_LOGI(TAG, "MJPG: %uKB %ums (%.1ffps)",
            (uint32_t)(_jpg_buf_len/1024),
            (uint32_t)frame_time, 1000.0 / (uint32_t)frame_time);
    }

    last_frame = 0;
    return res;
}
```

### BMP HTTP Capture

```c
#include "esp_camera.h"
#include "esp_http_server.h"
#include "esp_timer.h"

esp_err_t bmp_httpd_handler(httpd_req_t *req){
    camera_fb_t * fb = NULL;
    esp_err_t res = ESP_OK;
    int64_t fr_start = esp_timer_get_time();

    fb = esp_camera_fb_get();
    if (!fb) {
        ESP_LOGE(TAG, "Camera capture failed");
        httpd_resp_send_500(req);
        return ESP_FAIL;
    }

    uint8_t * buf = NULL;
    size_t buf_len = 0;
    bool converted = frame2bmp(fb, &buf, &buf_len);
    esp_camera_fb_return(fb);
    if(!converted){
        ESP_LOGE(TAG, "BMP conversion failed");
        httpd_resp_send_500(req);
        return ESP_FAIL;
    }

    res = httpd_resp_set_type(req, "image/x-windows-bmp")
       || httpd_resp_set_hdr(req, "Content-Disposition", "inline; filename=capture.bmp")
       || httpd_resp_send(req, (const char *)buf, buf_len);
    free(buf);
    int64_t fr_end = esp_timer_get_time();
    ESP_LOGI(TAG, "BMP: %uKB %ums", (uint32_t)(buf_len/1024), (uint32_t)((fr_end - fr_start)/1000));
    return res;
}
```
