image-examples's Introduction

Image Examples

Simple examples of how to convert images from one format to another -- raw rgb565 (rgb16), rgb24 (rgb888), png, jpeg, bmp, etc.

Please fork and contribute!

Usage

See README.md in scripts for mayn rgb, png, and jpeg examples

raw rgb565 to ppm:

# rgb565toppm <infile> <width> <height> <maxval> fb.ppm
# rgb565 has maxval of 255 per pixel because it is converted to rgb888
rgb565toppm fb.rgb565.bin 720 480 255 fb.ppm

raw rgb565 to bmp:

# rgb565toppm <infile> <width> <height> <bitdepth> fb.ppm
# Bug: only reliably works converting from a depth of 16 to 32
rgb565tobmp fb.rgb565.bin 720 480 32 fb.bmp

Dependecies

libbmp

Bugs

bmptorgb565

bmptorgb565 only supports bitmaps with headers that meet the formal spec... so basically it doesn't work

Image size is (7204803) or 1036800 bytes Header is 54 bytes

Header of reference.24.bmp:

0000000 42 4d 36 d2 0f 00 00 00 00 00 36 00 00 00 28 00
0000010 00 00 d0 02 00 00 20 fe ff ff 01 00 18 00 00 00
0000020 00 00 00 00 00 00 13 0b 00 00 13 0b 00 00 00 00
0000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Note that the width is not written correctly by either of OSX Preview or OSX Paintbrush

fe ff ff ff is completely wrong for the height. 00 00 00 00 is obviously not the correct size.

Header read:

type: 4d42
total size: 15
offset: 2621440
width: 4263510016
width: 131071
bitcount(color depth): 0
size image (image size): 185794560
image size in bytes: 181440

 Red16: 0 
 Green16: 0 
 Blue16: 0 
 RGB2Bytes: 0 
Segmentation fault <-- Obvious sign that it doesn't work

References

Interesting examples:

# Multiple Images / RAW Video
ffmpeg -vcodec rawvideo -f rawvideo -pix_fmt rgb565 -s 1024x768 -i movie.raw -f image2 -vcodec png image%d.png

# Stream / RAW Video
command-that-streams-to-stdout | ffmpeg -vcodec rawvideo -f rawvideo -pix_fmt rgb565 -s 1024x768 -i - -f image2 -vcodec png image%d.png

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