1 files changed, 97 insertions, 0 deletions
diff --git a/main/jpeg_decoder.c b/main/jpeg_decoder.c
new file mode 100644
index 0000000..b34612d
--- /dev/null
+++ b/main/jpeg_decoder.c
@@ -0,0 +1,97 @@
+#include "jpeg_decoder.h"
+
+#include <string.h>
+
+#include "driver/jpeg_decode.h"
+#include "esp_check.h"
+#include "esp_log.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/semphr.h"
+
+static const char *TAG = "jpeg";
+
+static jpeg_decoder_handle_t s_engine;
+static SemaphoreHandle_t     s_mutex;
+static void   *s_in_buf;
+static size_t  s_in_cap;
+static void   *s_out_buf;
+static size_t  s_out_cap;
+
+esp_err_t jpeg_decoder_init(void)
+{
+    s_mutex = xSemaphoreCreateMutex();
+    if (!s_mutex) return ESP_ERR_NO_MEM;
+
+    jpeg_decode_engine_cfg_t cfg = {
+        .intr_priority = 0,
+        .timeout_ms    = 200,
+    };
+    ESP_RETURN_ON_ERROR(jpeg_new_decoder_engine(&cfg, &s_engine),
+                       TAG, "jpeg_new_decoder_engine");
+
+    // DMA-aligned PSRAM scratch buffers. Allocate once, reuse.
+    jpeg_decode_memory_alloc_cfg_t in_cfg  = { .buffer_direction = JPEG_DEC_ALLOC_INPUT_BUFFER };
+    jpeg_decode_memory_alloc_cfg_t out_cfg = { .buffer_direction = JPEG_DEC_ALLOC_OUTPUT_BUFFER };
+
+    s_in_buf = jpeg_alloc_decoder_mem(JPEG_DECODER_MAX_INPUT_BYTES,  &in_cfg,  &s_in_cap);
+    if (!s_in_buf) {
+        ESP_LOGE(TAG, "jpeg input buf alloc failed");
+        return ESP_ERR_NO_MEM;
+    }
+    s_out_buf = jpeg_alloc_decoder_mem(JPEG_DECODER_MAX_OUTPUT_BYTES, &out_cfg, &s_out_cap);
+    if (!s_out_buf) {
+        ESP_LOGE(TAG, "jpeg output buf alloc failed");
+        return ESP_ERR_NO_MEM;
+    }
+
+    ESP_LOGI(TAG, "decoder ready (in=%u bytes, out=%u bytes)",
+             (unsigned)s_in_cap, (unsigned)s_out_cap);
+    return ESP_OK;
+}
+
+bool jpeg_decoder_try_lock(uint32_t timeout_ms)
+{
+    return xSemaphoreTake(s_mutex, pdMS_TO_TICKS(timeout_ms)) == pdTRUE;
+}
+
+void jpeg_decoder_unlock(void)
+{
+    xSemaphoreGive(s_mutex);
+}
+
+void *jpeg_decoder_input_buffer(void) { return s_in_buf; }
+
+esp_err_t jpeg_decoder_decode(size_t   jpeg_len,
+                              void   **out_rgb565,
+                              uint16_t *out_width,
+                              uint16_t *out_height)
+{
+    if (jpeg_len == 0 || jpeg_len > s_in_cap) return ESP_ERR_INVALID_SIZE;
+
+    jpeg_decode_cfg_t dec_cfg = {
+        .output_format = JPEG_DECODE_OUT_FORMAT_RGB565,
+        .rgb_order     = JPEG_DEC_RGB_ELEMENT_ORDER_RGB,
+        .conv_std      = JPEG_YUV_RGB_CONV_STD_BT601,
+    };
+
+    jpeg_decode_picture_info_t info = {0};
+    esp_err_t err = jpeg_decoder_get_info(s_in_buf, jpeg_len, &info);
+    if (err != ESP_OK) {
+        ESP_LOGW(TAG, "jpeg_decoder_get_info: %s", esp_err_to_name(err));
+        return err;
+    }
+
+    uint32_t out_size = 0;
+    err = jpeg_decoder_process(s_engine, &dec_cfg,
+                               s_in_buf,  jpeg_len,
+                               s_out_buf, s_out_cap, &out_size);
+    if (err != ESP_OK) {
+        ESP_LOGW(TAG, "jpeg_decoder_process: %s", esp_err_to_name(err));
+        return err;
+    }
+
+    *out_rgb565 = s_out_buf;
+    *out_width  = info.width;
+    *out_height = info.height;
+    return ESP_OK;
+}