blob: 42be71f1f31a8e6eb9448e978e0a976c0d87af80 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
# Low-Efficiency Video Codec
The codec compresses image sequences by avoiding redundancies by reusing parts
of previous frames. A frame is one block that is then subdivided further as
needed.
## Literal-Block
Stores the pixels' RGB values as is.
## Split-Block
Delegates to two sub-blocks. The block is split orthorgonally on the longest
axis. If needed, the left/top block is rounded down and the right/bottom.
## Reference-Block
Indicates that parts of the last frame are reused. The data reused is at the
position of this block in the last frame with the translation added.
## Advanced-Reference-Block
Like Reference-Block but instead translates by non-integer amount of pixels,
applying a 2x2 matrix from the center of the block and multiplying the color
value of each component, interpolating if necessary.
## Compressed-Literal-Block
_**JPEG? just DCT? idk**_
## File format
- magic bytes: `5e b1 c3 08`
- resolution: _`u16, u16`_
- frame count: _`u64`_
- frames (repeated [frame count]-times)
- block kind: _`u8` (see tags below)_
- block: _one of the following_
- 0 **Literal-Block**
- pixels: _`[[u8; 3]; (inferred)]`_ (stored line-by-line)
- 1 **Compressed-Literal-Block**
- length: _`u32`_
- data: _`[[u8; length]`_
- 2 **Split-Block**
- sub-blocks: _`[block; 2]` (see above)_
- 3 **Reference-Block**
- translation: _`i8, i8`_
- 4 **Advanced-Reference-Block**
- translation: _`s8, s8`_ (translation)
- transform: _`s8, s8, s8, s8`_ (2x2-matrix applied before sampling
relative to the center)
- value_scale: _`i8`_ (multiplication of each color component by $1.05^n$)
### Data Types
- _`u<n>`_: unsigned n-bit integer (little-endian)
- _`i<n>`_: signed n-bit integer using twos-complement (little-endian)
- _`s8`_: 8-bit scalar. When read as _`i8`_ represents a value of
$\frac{x}{|x|} * \sqrt{2}^{|{x}| - 4}$ for $x \neq 0$, otherwise 0
- _`[<T>; <N>]`_: Array of T with length N
|
