I'm working with someone else's code on a device which can put an image to /dev/fb/0
and show up on video out or send it over the network to a client application.
I don't have access to the old source for the client app, but I know the following about the data:
cat
-able to /dev/fb/0
How can I give this a header or convert it to JPEG, BMP, or a RAW type that I could then view in a desktop application?
Ultimately, I want it to be jpeg and viewable in a browser, but anything I can see with my eyes will work for now.
(see the comments below)
ffmpeg \
-vcodec rawvideo \
-f rawvideo \
-pix_fmt rgb565 \
-s 720x480 \
-i in-buffer.raw \
\
-f image2 \
-vcodec mjpeg \
out-buffer.jpg
Shows the image three times widthwise with almost no color, and squashed vertically:
rawtoppm -rgb -interpixel 720 480 fb.raw > fb.ppm
Shows the image, but with streaks and squashed vertically and bad color:
rawtoppm -rgb -interrow 720 480 fb.raw > fb.ppm
Similar to the above
convert -depth 16 -size 720x480 frame_buffer.rgb fb.jpeg
rgb to ppm: Just season to taste!
maintained at https://github.com/coolaj86/image-examples
#include <stdio.h>
int main(int argc, char* argv[]) {
FILE* infile; // fb.raw
FILE* outfile; // fb.ppm
unsigned char red, green, blue; // 8-bits each
unsigned short pixel; // 16-bits per pixel
unsigned int maxval; // max color val
unsigned short width, height;
size_t i;
infile = fopen("./fb.raw", "r");
outfile = fopen("./fb.ppm", "wb");
width = 720;
height = 480;
maxval = 255;
// P3 - PPM "plain" header
fprintf(outfile, "P3\n#created with rgb2ppm\n%d %d\n%d\n", width, height, maxval);
for (i = 0; i < width * height; i += 1) {
fread(&pixel, sizeof(unsigned short), 1, infile);
red = (unsigned short)((pixel & 0xF800) >> 11); // 5
green = (unsigned short)((pixel & 0x07E0) >> 5); // 6
blue = (unsigned short)(pixel & 0x001F); // 5
// Increase intensity
red = red << 3;
green = green << 2;
blue = blue << 3;
// P6 binary
//fwrite(&(red | green | blue), 1, sizeof(unsigned short), outfile);
// P3 "plain"
fprintf(outfile, "%d %d %d\n", red, green, blue);
}
}