Hi, I'm using an STM32F746bgt6 on a custom board, and I'm using Keil.
I enabled LibJpeg in CubeMX, but I can't get an RGB JPEG.
I have a .jpeg file saved in flash, "frame99.jpg," which I read via littlefs. When I read it, I allocate the buffer to external SDRAM.
int ReadFileSDRAM(lfs_t *lfs, const char *filename)
{
lfs_file_t file;
int res = lfs_file_open(lfs, &file, filename, LFS_O_RDONLY);
if (res < 0)
{
printf("Errore apertura file in lettura\n");
return -1;
}
lfs_soff_t size = lfs_file_size(lfs, &file);
if (size <= 0 || size > SDRAM_SIZE_BYTES)
{
printf("File vuoto, troppo grande o errore lettura dimensione\n");
lfs_file_close(lfs, &file);
return -2;
}
res = lfs_file_read(lfs, &file, image_buffer, size);
if (res < 0)
{
printf("Errore lettura file errore = %d\n", res);
lfs_file_close(lfs, &file);
return -3;
}
uint16_t sample_u = 0;
int16_t sample_s = 0;
image_size1 = size;
while (image_size1 > 0 && image_buffer[image_size1 - 1] == 0xFF)
{
image_size1--;
}
lfs_file_close(lfs, &file);
return (int)size;
}
While the decompression part is
ReadFileSDRAM(&lfs_gd, "frame99.jpg");
int width, height;
int ret = DecodeJPEGtoRGB565_Static(image_buffer, image_size1, image_rgb, &image_size2, &width, &height);
if (ret != 0) {
printf("[JPEG] ERROR JPEG: %d\n", ret);
} else {
printf("[JPEG] OK, width=%d, height=%d, size=%lu\n",
width, height, image_size2);
}
int DecodeJPEGtoRGB565(uint8_t *jpeg_data, size_t jpeg_size, uint8_t *rgb565_buffer, uint32_t *out_size, int *width, int *height)
{
struct jpeg_decompress_struct cinfo;
struct jpeg_error_mgr jerr;
printf("[JPEG] Starting decode, size = %lu bytes\n", (unsigned long)jpeg_size);
cinfo.err = jpeg_std_error(&jerr);
jpeg_create_decompress(&cinfo);
// jpeg_mem_src(&cinfo, jpeg_data, jpeg_size); // Original
jpeg_memory_src(&cinfo, jpeg_data, jpeg_size);
if (jpeg_read_header(&cinfo, TRUE) != JPEG_HEADER_OK)
{
printf("[JPEG] Error: invalid JPEG header!\n");
jpeg_destroy_decompress(&cinfo);
return -1;
}
printf("[JPEG] Header successfully read\n");
jpeg_start_decompress(&cinfo);
*width = cinfo.output_width;
*height = cinfo.output_height;
printf("[JPEG] Image dimensions: %dx%d, components = %d\n", *width, *height, cinfo.output_components);
int row_stride = cinfo.output_width * cinfo.output_components;
uint8_t *row_buffer = (uint8_t *)malloc(row_stride);
if (!row_buffer)
{
printf("[JPEG] Error: malloc failed for row_buffer (%d bytes)\n", row_stride);
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
return -2;
}
printf("[JPEG] Allocated row_buffer of %d bytes\n", row_stride);
uint16_t *pDst = (uint16_t *)rgb565_buffer;
while (cinfo.output_scanline < cinfo.output_height)
{
jpeg_read_scanlines(&cinfo, &row_buffer, 1);
int y = cinfo.output_scanline - 1; // just read row
for (int i = 0; i < cinfo.output_width; i++)
{
uint8_t r = row_buffer[i * 3 + 0];
uint8_t g = row_buffer[i * 3 + 1];
uint8_t b = row_buffer[i * 3 + 2];
*pDst++ = ((r & 0xF8) << 8) |
((g & 0xFC) << 3) |
((b & 0xF8) >> 3);
}
// debug print every 50 rows
if ((y % 50) == 0)
{
printf("[JPEG] Decoded scanline %d/%d\n", y + 1, *height);
}
}
free(row_buffer);
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
*out_size = (*width) * (*height) * 2; // 2 bytes per RGB565 pixel
printf("[JPEG] Decoding completed: final buffer size = %lu bytes\n", (unsigned long)(*out_size));
return 0; // success
}
the code gets stuck in " jpeg_start_decompress(&cinfo); "
I followed it with the print and it gets stuck in - > main = (my_main_ptr)
(*cinfo->mem->alloc_small)((j_common_ptr)cinfo, JPOOL_IMAGE,
SIZEOF(my_main_controller));
how can i solve it?
"
