Img conv fun (#21)

Adds more functionality and improves the performance in image conversion.
Fix #18

.github/workflows/ESP32.yml

@@ -7,7 +7,7 @@ on:
       - 'src/**'
       - '.github/workflows/*.yml'
     tags-ignore:
-      - '**'
+      - 'v*'
   pull_request:
     branches:
       - master

README.md

@@ -99,14 +99,31 @@ cam.init()
 ### Capture image
 
 ```python
-img = cam.capture() #capture image as configured
-img_rgb888 = cam.capture(PixelFormat.RGB888) #capture image and convert it to RGB888
+img = cam.capture()
 ```
 
 Arguments for capture
 
 - out_format: Output format as PixelFormat (optional)
 
+### Convert image to another format
+
+You can either convert the image with the `capture` method directly passing the desired output format:
+```python
+img_rgb888 = cam.capture(PixelFormat.RGB888) #capture image as configured (e.g. JPEG), convert it to RGB888 and return the converted image
+```
+Or you can first capture the image and then convert it to the desired PixelFormat with the `convert` method.
+Doing so you can have both, the captured and the converted image. Note that more memory will be used.
+```python
+img = cam.capture()
+img_rgb888 = cam.convert(PixelFormat.RGB888) #converts the last captured image to RGB888 and returns the converted image
+```
+
+Convertion supported 
+- from JPEG to RGB565
+- to RGB888 in general
+- to JPEG in gerenal (use the `set_quality` method to set the desired JPEG quality)
+
 ### Camera reconfiguration
 
 ```python
@@ -217,12 +234,12 @@ Example for Xiao sense:
 #define MICROPY_CAMERA_PIN_XCLK     (10)
 #define MICROPY_CAMERA_PIN_PWDN     (-1)
 #define MICROPY_CAMERA_PIN_RESET    (-1)
-#define MICROPY_CAMERA_PIN_SIOD     (40)  // SDA
-#define MICROPY_CAMERA_PIN_SIOC     (39)  // SCL
+#define MICROPY_CAMERA_PIN_SIOD     (40)        // SDA
+#define MICROPY_CAMERA_PIN_SIOC     (39)        // SCL
 #define MICROPY_CAMERA_XCLK_FREQ    (20000000)  // Frequencies are normally either 10 MHz or 20 MHz
-#define MICROPY_CAMERA_FB_COUNT     (2)   // The value is between 1 (slow) and 2 (fast, but more load on CPU and more ram usage)
-#define MICROPY_CAMERA_JPEG_QUALITY (85)  // Quality of JPEG output in percent. Higher means higher quality.
-#define MICROPY_CAMERA_GRAB_MODE    (1)   // 0=WHEN_EMPTY (might have old data, but less resources), 1=LATEST (best, but more resources)
+#define MICROPY_CAMERA_FB_COUNT     (2)         // The value is between 1 (slow) and 2 (fast, but more load on CPU and more ram usage)
+#define MICROPY_CAMERA_JPEG_QUALITY (85)        // Quality of JPEG output in percent. Higher means higher quality.
+#define MICROPY_CAMERA_GRAB_MODE    (1)         // 0=WHEN_EMPTY (might have old data, but less resources), 1=LATEST (best, but more resources)
 
 ```
 #### Customize additional camera settings
@@ -253,7 +270,7 @@ If you experience problems, visit [MicroPython external C modules](https://docs.
 
 ## FPS benchmark
 
-I didn't use a calibrated osziloscope, but here is a benchmark with my ESP32S3 (GrabMode=LATEST, fb_count = 1, jpeg_quality=85%).
+I didn't use a calibrated osziloscope, but here is a benchmark with my ESP32S3 (GrabMode=LATEST, fb_count = 1, jpeg_quality=85%) and OV2640.
 Using fb_count=2 theoretically can double the FPS (see JPEG with fb_count=2). This might also aplly for other PixelFormats.
 
 | Frame Size | GRAYSCALE | RGB565 | YUV422 | JPEG   | JPEG -> RGB565 | JPEG -> RGB888 | JPEG (fb=2) |
@@ -263,8 +280,8 @@ Using fb_count=2 theoretically can double the FPS (see JPEG with fb_count=2). Th
 | QCIF       | 11        | 11     | 11.5   | 25     | 25             | 25             | 50          |
 | HQVGA      | 12.5      | 12.5   | 12.5   | 25     | 16.7           | 16.7           | 50          |
 | R240X240   | 12.5      | 12.5   | 11.5   | 25     | 16.7           | 12.5           | 50          |
-| QVGA       | 12        | 11     | 12     | 25     | 12.5           | 12.5           | 50          |
-| CIF        | 12.5      | No img | No img | 6.3    | 1.6            | 1.6            | 12.5        |
+| QVGA       | 12        | 11     | 12     | 25     | 25             | 25             | 50          |
+| CIF        | 12.5      | No img | No img | 6.3    | 8.3            | 8.3            | 12.5        |
 | HVGA       | 3         | 3      | 2.5    | 12.5   | 6.3            | 6.3            | 25          |
 | VGA        | 3         | 3      | 3      | 12.5   | 3.6            | 3.6            | 25          |
 | SVGA       | 3         | 3      | 3      | 12.5   | 2.8            | 2.5            | 25          |

src/modcamera.c

@@ -148,11 +148,15 @@ void mp_camera_hal_construct(
 
         // defaul parameters
         self->camera_config.fb_location = CAMERA_FB_IN_PSRAM;
-        self->camera_config.ledc_timer = LEDC_TIMER_0;
+        self->camera_config.ledc_timer = LEDC_TIMER_3;
         self->camera_config.ledc_channel = LEDC_CHANNEL_0;
 
         self->initialized = false;
         self->captured_buffer = NULL;
+        self->converted_buffer.len = 0;
+        self->converted_buffer.buf = NULL;
+        self->converted_buffer.typecode = 'B';
+        self->bmp_out = false;
     }
 
 void mp_camera_hal_init(mp_camera_obj_t *self) {
@@ -171,6 +175,11 @@ void mp_camera_hal_init(mp_camera_obj_t *self) {
 
 void mp_camera_hal_deinit(mp_camera_obj_t *self) {
     if (self->initialized) {
+        if (self->converted_buffer.buf) {
+            free(self->converted_buffer.buf);
+            self->converted_buffer.buf = NULL;
+            self->converted_buffer.len = 0;
+        }
         if (self->captured_buffer) {
             esp_camera_return_all();
             self->captured_buffer = NULL;
@@ -205,21 +214,68 @@ void mp_camera_hal_reconfigure(mp_camera_obj_t *self, mp_camera_framesize_t fram
     ESP_LOGI(TAG, "Camera reconfigured successfully");
 }
 
+static bool ensure_buffer(mp_camera_obj_t *self, size_t req_len) {
+    if (self->converted_buffer.len == req_len) {
+        return true;
+    }
+    if (self->converted_buffer.len > 0 || self->converted_buffer.buf) {
+        free(self->converted_buffer.buf);
+    }
+    self->converted_buffer.buf = (uint8_t *)malloc(req_len);
+    if (!self->converted_buffer.buf) {
+        self->converted_buffer.len = 0;
+        ESP_LOGE(TAG, "converted_buffer malloc failed");
+        return false;
+    }
+    self->converted_buffer.len = req_len;
+    return true;
+}
+
+static bool mp_camera_convert(mp_camera_obj_t *self, mp_camera_pixformat_t out_format) {
+    ESP_LOGI(TAG, "Converting image to pixel format: %d", out_format);
+
+    switch (out_format) {
+        case PIXFORMAT_JPEG:
+            return frame2jpg(self->captured_buffer, self->camera_config.jpeg_quality, self->converted_buffer.buf, &self->converted_buffer.len);
+
+        case PIXFORMAT_RGB888:
+            if (ensure_buffer(self, self->captured_buffer->width * self->captured_buffer->height * 3)) {
+                return fmt2rgb888(self->captured_buffer->buf, self->captured_buffer->len, self->captured_buffer->format, self->converted_buffer.buf);
+            } else {
+                return false;
+            }
+
+        case PIXFORMAT_RGB565:
+            if (self->camera_config.pixel_format == PIXFORMAT_JPEG) {
+                if (ensure_buffer(self, self->captured_buffer->width * self->captured_buffer->height * 2)) {
+                    return jpg2rgb565(self->captured_buffer->buf, self->captured_buffer->len, self->converted_buffer.buf, JPG_SCALE_NONE);
+                } else {
+                    return false;
+                }
+            } else {
+                mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("Can only convert JPEG to RGB565"));
+            }
+
+        default:
+            mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("Unsupported pixel format for conversion"));
+    }
+}
+mp_obj_t mp_camera_hal_convert(mp_camera_obj_t *self, int8_t out_format) {
+    check_init(self);
+    if (mp_camera_convert(self, (mp_camera_pixformat_t)out_format)) {
+        return mp_obj_new_memoryview('b', self->converted_buffer.len, self->converted_buffer.buf);    
+    } else {
+        return mp_const_none;
+    }
+}
+
 mp_obj_t mp_camera_hal_capture(mp_camera_obj_t *self, int8_t out_format) {
     check_init(self);
     if (self->captured_buffer) {
         esp_camera_fb_return(self->captured_buffer);
         self->captured_buffer = NULL;
     }
 
-    static size_t out_len = 0;
-    static uint8_t *out_buf = NULL;
-    if (out_len > 0 || out_buf) {
-        free(out_buf);
-        out_len = 0;
-        out_buf = NULL;
-    }
-
     ESP_LOGI(TAG, "Capturing image");
     self->captured_buffer = esp_camera_fb_get();
     if (!self->captured_buffer) {
@@ -228,56 +284,12 @@ mp_obj_t mp_camera_hal_capture(mp_camera_obj_t *self, int8_t out_format) {
     }
 
     if (out_format >= 0 && (mp_camera_pixformat_t)out_format != self->camera_config.pixel_format) {
-        ESP_LOGI(TAG, "Converting image to pixel format: %d", out_format);
-        switch ((mp_camera_pixformat_t)out_format) {
-            case PIXFORMAT_JPEG:
-                if (frame2jpg(self->captured_buffer, self->camera_config.jpeg_quality, &out_buf, &out_len)) {
-                    esp_camera_fb_return(self->captured_buffer);
-                    mp_obj_t result = mp_obj_new_memoryview('b', out_len, out_buf);
-                    return result;
-                } else {
-                    return mp_const_none;
-                }
-
-            case PIXFORMAT_RGB888:
-                out_len = self->captured_buffer->width * self->captured_buffer->height * 3;
-                out_buf = (uint8_t *)malloc(out_len);
-                if (!out_buf) {
-                    ESP_LOGE(TAG, "out_buf malloc failed");
-                    return mp_const_none;
-                }
-                if (fmt2rgb888(self->captured_buffer->buf, self->captured_buffer->len, self->captured_buffer->format, out_buf)) {
-                    esp_camera_fb_return(self->captured_buffer);
-                    mp_obj_t result = mp_obj_new_memoryview('b', out_len, out_buf);
-                    return result;
-                } else {
-                    return mp_const_none;
-                }
-
-            case PIXFORMAT_RGB565:
-                out_len = self->captured_buffer->width * self->captured_buffer->height * 2;
-                out_buf = (uint8_t *)malloc(out_len);
-                if (!out_buf) {
-                    ESP_LOGE(TAG, "out_buf malloc failed");
-                    return mp_const_none;
-                }
-                if(self->camera_config.pixel_format == PIXFORMAT_JPEG){
-                    if (jpg2rgb565(self->captured_buffer->buf, self->captured_buffer->len, out_buf, JPG_SCALE_NONE)) {
-                        esp_camera_fb_return(self->captured_buffer);
-                        mp_obj_t result = mp_obj_new_memoryview('b', out_len, out_buf);
-                        return result;
-                    } else {
-                        return mp_const_none;
-                    }
-                } else {
-                    mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("Can only convert JPEG to RGB565"));
-                    return mp_const_none;
-                }
-
-            default:
-                mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("Unsupported pixel format for conversion"));
-                return mp_const_none;
-
+        if (mp_camera_convert(self, (mp_camera_pixformat_t)out_format)) {
+            esp_camera_fb_return(self->captured_buffer);
+            mp_obj_t result = mp_obj_new_memoryview('b', self->converted_buffer.len, self->converted_buffer.buf);
+            return result;
+        } else {
+            return mp_const_none;
         }
     }
 
@@ -286,16 +298,15 @@ mp_obj_t mp_camera_hal_capture(mp_camera_obj_t *self, int8_t out_format) {
         return mp_obj_new_memoryview('b', self->captured_buffer->len, self->captured_buffer->buf);
     } else {
         ESP_LOGI(TAG, "Returning image as bitmap");
-        if (frame2bmp(self->captured_buffer, &out_buf, &out_len)) {
+        if (frame2bmp(self->captured_buffer, self->converted_buffer.buf, &self->converted_buffer.len)) {
             esp_camera_fb_return(self->captured_buffer);
-            mp_obj_t result = mp_obj_new_memoryview('b', out_len, out_buf);
+            mp_obj_t result = mp_obj_new_memoryview('b', self->converted_buffer.len, self->converted_buffer.buf);
             return result;
         } else {
-            free(out_buf);
-            out_buf = NULL;
-            out_len = 0;
+            free(self->converted_buffer.buf);
+            self->converted_buffer.buf = NULL;
+            self->converted_buffer.len = 0;
             mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("Failed to convert image to BMP"));
-            return mp_const_none;
         }
     }
 } // mp_camera_hal_capture

src/modcamera.h

@@ -98,6 +98,7 @@ typedef struct hal_camera_obj {
     bool                initialized;
     camera_fb_t         *captured_buffer;
     bool                bmp_out;
+    mp_buffer_info_t    converted_buffer;
 } hal_camera_obj_t;
 
 #endif // CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2 || CONFIG_IDF_TARGET_ESP32S3
@@ -191,6 +192,15 @@ extern void mp_camera_hal_reconfigure(mp_camera_obj_t *self, mp_camera_framesize
  */
 extern mp_obj_t mp_camera_hal_capture(mp_camera_obj_t *self, int8_t out_format);
 
+/**
+ * @brief Converts an image from one pixelformat to another.
+ * 
+ * @param self Pointer to the camera object.
+ * @param out_format Output pixelformat format.
+ * @return Converted image as micropython object.
+ */
+extern mp_obj_t mp_camera_hal_convert(mp_camera_obj_t *self, int8_t out_format);
+
 /**
  * @brief Table mapping pixel formats API to their corresponding values at HAL.
  * @details Needs to be defined in the port-specific implementation.

src/modcamera_api.c

@@ -154,6 +154,13 @@ static mp_obj_t camera_capture(size_t n_args, const mp_obj_t *args){
 }
 static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(camera_capture_obj, 1, 2, camera_capture);
 
+static mp_obj_t camera_convert(mp_obj_t self_in, mp_obj_t arg) {
+    mp_camera_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    int8_t out_format = mp_obj_get_int(arg);
+    return mp_camera_hal_convert(self, out_format);
+}
+static MP_DEFINE_CONST_FUN_OBJ_2(camera_convert_obj, camera_convert);
+
 static mp_obj_t camera_reconfigure(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args){
     //OPEN: Validate inputs
     mp_camera_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
@@ -291,6 +298,7 @@ CREATE_GETSET_FUNCTIONS(lenc, mp_obj_new_bool, mp_obj_is_true);
 static const mp_rom_map_elem_t camera_camera_locals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_reconfigure), MP_ROM_PTR(&camera_reconfigure_obj) },
     { MP_ROM_QSTR(MP_QSTR_capture), MP_ROM_PTR(&camera_capture_obj) },
+    { MP_ROM_QSTR(MP_QSTR_convert), MP_ROM_PTR(&camera_convert_obj) },
     { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&camera_init_obj) },
     { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&mp_camera_deinit_obj) },
     { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&mp_camera_deinit_obj) },