#256KB IMAGE SIZE CONVERTER CODE#
Since the OV7670 can generate YUV images, I hope to eliminate the code and execution time needed to do the RGB888 to YUV conversion by having the compressor work directly on the YUV data from the camera. The compression code first converts the RGB888 to YUV, then compresses the YUV data. bmp files under 390KB in size.Ĭompressing and writing a VGA image takes about 180MSec. The original 600KB RGB565 image is too large to upload to the forum which only allows. My compressed test images are about 40KBytes. jpg extension.Īn uncompressed VGA image in RGB565 format is 614KBytes. * The encoder compresses the file and writes it to SD card with. * Call the JPG encoder with a pointer to the RGB888 buffer and a file name. * Use the Pixel Pipeline to convert the captured image from the original format to the RGB888 format the encoder wants. YUV images compress to smaller files due to the reduced spatial color resolution. The image can be either RGB565 or YUV422 encoded. * Capture a VGA-sized image to a buffer in EXTMEM. I changed the code to use a bitmap in EXTMEM as the input data.
In the original code, the bitmap was read from a. The JPEG compressor needs an RGB888 bitmap as input. The fact that DMAMEM doesn't get initialized is not an issue as an initialization function called from setup() fills the tables. The original code used malloc() to allocate 256KB of buffers that hold pre-computed constants used during the compression. So to find the total image size in megabytes, divide the number of kilobytes (43,139.94) by 1024, which gives us 42.1 megabytes (or MB, although for whatever reason, the Image Size dialog box shortens "MB" to just "M").Īnd if we look again at the Image Size dialog box, we see that sure enough, Photoshop is showing me that the size of my image is 42.I've downloaded a JPEG compression program and adapted it to run on the T4.1 to which I've connected my OV7670 camera. So instead, we usually refer to file size in megabytes. Step 4: Convert the image size from kilobytes to megabytesĮven kilobytes is too small of a measurement type to be very practical for most images. So to convert bytes to kilobytes, divide the total number of bytes by 1024. Instead, we usually talk about image size in either kilobytes or, more commonly, in megabytes. But a byte is a very small unit of measurement, so it's not very practical to refer to the size of an image in bytes. Step 3: Convert the image size from bytes to kilobytes So to find the total file size, in bytes, multiply the total number of pixels by 3. Remember that each pixel in the image needs 3 bytes in memory one for the Red channel, one for the Green channel, and one for the Blue channel. Step 2: Multiply the total number of pixels by 3 But as we learned, the pixel count alone isn't the whole story. To find the total number of pixels, multiply the width and height together. The width and height of the image in pixels. I'll re-open it by going back up to the Image menu and choosing Image Size: Step 1: Find the total number of pixels in the imageįirst, we need the total number of pixels, and we find that in the Image Size dialog box.
#256KB IMAGE SIZE CONVERTER HOW TO#
So to figure out the file size of an image, all we need to do is take the total number of pixels, multiply it by 3, and we have our answer! Here's how to do it.
It's always 3 bytes for every pixel one for red, one for green and one for blue. But the amount of memory that each pixel needs doesn't change. Of course, most images contain millions of pixels, not just 10. For example, if your image contained 10 pixels, each pixel would need 1 byte for red, 1 byte for green and 1 byte for blue, for a total of 3 bytes.
Learn more about RGB color and color channels in Photoshop How do color channels affect image size?Įach of the three color channels (Red, Green and Blue) takes up exactly 1 byte in memory for each and every pixel in the image.
All colors in your image are made by mixing red, green and blue.