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RGB to YUV conversions (and vice versa).
Collaboration diagram for RGB to YUV conversions (and vice versa).:
Functions | |
| uint8_t | sstvenc_yuv_calc_y (uint8_t r, uint8_t g, uint8_t b) |
| uint8_t | sstvenc_yuv_calc_u (uint8_t r, uint8_t g, uint8_t b) |
| uint8_t | sstvenc_yuv_calc_v (uint8_t r, uint8_t g, uint8_t b) |
| uint8_t | sstvenc_rgb_calc_r (uint8_t r, uint8_t g, uint8_t b) |
| uint8_t | sstvenc_rgb_calc_g (uint8_t r, uint8_t g, uint8_t b) |
| uint8_t | sstvenc_rgb_calc_b (uint8_t r, uint8_t g, uint8_t b) |
| void | sstvenc_rgb_to_mono (uint8_t *dest, const uint8_t *src, uint16_t width, uint16_t height) |
| void | sstvenc_rgb_to_yuv (uint8_t *dest, const uint8_t *src, uint16_t width, uint16_t height) |
| void | sstvenc_yuv_to_rgb (uint8_t *dest, const uint8_t *src, uint16_t width, uint16_t height) |
| void | sstvenc_yuv_to_mono (uint8_t *dest, const uint8_t *src, uint16_t width, uint16_t height) |
| void | sstvenc_mono_to_rgb (uint8_t *dest, const uint8_t *src, uint16_t width, uint16_t height) |
| void | sstvenc_mono_to_yuv (uint8_t *dest, const uint8_t *src, uint16_t width, uint16_t height) |
Detailed Description
Functions for extracting the Y, U or V components of a RGB colour. The equations in this module came from JL Barber (N7CXI)'s presentation at the Dayton SSSTV forum, 2000-05-20.
http://www.barberdsp.com/downloads/Dayton%20Paper.pdf
Function Documentation
◆ sstvenc_mono_to_rgb()
| void sstvenc_mono_to_rgb | ( | uint8_t * | dest, |
| const uint8_t * | src, | ||
| uint16_t | width, | ||
| uint16_t | height ) |
Convert the given mono framebuffer to RGB.
- Parameters
-
[out] dest Destination framebuffer, which is assumed to be triple the size of src. This can be the same location as src – so long as the buffer is sufficiently large. [in] src Source framebuffer, which is assumed to be mono [in] width Width of the framebuffer in pixels [in] height Height of the framebuffer in pixels
Definition at line 122 of file yuv.c.
123 {
124 size_t sz = (size_t)width * (size_t)height;
125 while (sz) {
126 /* Work backwards so we don't overwrite the source */
127 const uint8_t src_pos = sz - 1;
128 const uint8_t dest_pos = src_pos * 3;
129
130 dest[dest_pos + 0] = src[src_pos]; /* R */
131 dest[dest_pos + 1] = src[src_pos]; /* G */
132 dest[dest_pos + 2] = src[src_pos]; /* B */
133
134 sz--;
135 }
136}
◆ sstvenc_mono_to_yuv()
| void sstvenc_mono_to_yuv | ( | uint8_t * | dest, |
| const uint8_t * | src, | ||
| uint16_t | width, | ||
| uint16_t | height ) |
Convert the given mono framebuffer to YUV.
- Parameters
-
[out] dest Destination framebuffer, which is assumed to be triple the size as src. This can be the same location as src if it is big enough. [in] src Source framebuffer, which is assumed to be RGB [in] width Width of the framebuffer in pixels [in] height Height of the framebuffer in pixels
Definition at line 138 of file yuv.c.
139 {
140 size_t sz = (size_t)width * (size_t)height;
141 while (sz) {
142 /* Work backwards so we don't overwrite the source */
143 const uint8_t src_pos = sz - 1;
144 const uint8_t dest_pos = src_pos * 3;
145
146 dest[dest_pos + 0] = src[src_pos]; /* Y */
147 dest[dest_pos + 1] = 0; /* U */
148 dest[dest_pos + 2] = 0; /* V */
149
150 sz--;
151 }
152}
◆ sstvenc_rgb_calc_b()
| uint8_t sstvenc_rgb_calc_b | ( | uint8_t | r, |
| uint8_t | g, | ||
| uint8_t | b ) |
Return the blue component of a YUV colour.
- Parameters
-
[in] y Y (monochrome) component in Q8 fixed-point [in] u U (Y - R) component in Q8 fixed-point [in] v V (Y - B) component in Q8 fixed-point
- Returns
- Blue component in Q8 fixed-point.
Definition at line 53 of file yuv.c.
53 {
54 return (0.003906
55 * ((298.082 * ((double)y - 16.0))
56 + (516.411 * ((double)v - 128.0))))
57 + 0.5;
58}
Referenced by sstvenc_yuv_to_rgb().
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◆ sstvenc_rgb_calc_g()
| uint8_t sstvenc_rgb_calc_g | ( | uint8_t | r, |
| uint8_t | g, | ||
| uint8_t | b ) |
Return the green component of a YUV colour.
- Parameters
-
[in] y Y (monochrome) component in Q8 fixed-point [in] u U (Y - R) component in Q8 fixed-point [in] v V (Y - B) component in Q8 fixed-point
- Returns
- Green component in Q8 fixed-point.
Definition at line 45 of file yuv.c.
45 {
46 return (0.003906
47 * ((298.082 * ((double)y - 16.0))
48 + (-100.291 * ((double)v - 128.0))
49 + (-208.12 * ((double)u - 128.0))))
50 + 0.5;
51}
Referenced by sstvenc_yuv_to_rgb().
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◆ sstvenc_rgb_calc_r()
| uint8_t sstvenc_rgb_calc_r | ( | uint8_t | r, |
| uint8_t | g, | ||
| uint8_t | b ) |
Return the red component of a YUV colour.
- Parameters
-
[in] y Y (monochrome) component in Q8 fixed-point [in] u U (Y - R) component in Q8 fixed-point [in] v V (Y - B) component in Q8 fixed-point
- Returns
- Red component in Q8 fixed-point.
Definition at line 38 of file yuv.c.
38 {
39 return (0.003906
40 * ((298.082 * ((double)y - 16.0))
41 + (408.583 * ((double)u - 128.0))))
42 + 0.5;
43}
Referenced by sstvenc_yuv_to_rgb().
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◆ sstvenc_rgb_to_mono()
| void sstvenc_rgb_to_mono | ( | uint8_t * | dest, |
| const uint8_t * | src, | ||
| uint16_t | width, | ||
| uint16_t | height ) |
Convert the given RGB framebuffer to monochrome (Y component only).
- Parameters
-
[out] dest Destination framebuffer, which is assumed to be at least one third of the size of src. This can be the same location as src – after conversion the occupied size will be one third of the original buffer and may be realloc()'d to that size.[in] src Source framebuffer, which is assumed to be RGB [in] width Width of the framebuffer in pixels [in] height Height of the framebuffer in pixels
Definition at line 60 of file yuv.c.
61 {
62 size_t sz = (size_t)width * (size_t)height;
63 while (sz) {
64 /* Convert and write out YUV */
65 dest[0] = sstvenc_yuv_calc_y(src[0], src[1], src[2]);
66
67 dest += 1;
68 src += 3;
69 sz--;
70 }
71}
References sstvenc_yuv_calc_y().
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◆ sstvenc_rgb_to_yuv()
| void sstvenc_rgb_to_yuv | ( | uint8_t * | dest, |
| const uint8_t * | src, | ||
| uint16_t | width, | ||
| uint16_t | height ) |
Convert the given RGB framebuffer to YUV.
- Parameters
-
[out] dest Destination framebuffer, which is assumed to be the same size as src. This can be the same location as src. [in] src Source framebuffer, which is assumed to be RGB [in] width Width of the framebuffer in pixels [in] height Height of the framebuffer in pixels
Definition at line 73 of file yuv.c.
74 {
75 size_t sz = (size_t)width * (size_t)height;
76 while (sz) {
77 /* Pull out RGB values */
78 const uint8_t r = src[0], g = src[1], b = src[2];
79
80 /* Convert and write out YUV */
84
85 dest += 3;
86 src += 3;
87 sz--;
88 }
89}
References sstvenc_yuv_calc_u(), sstvenc_yuv_calc_v(), and sstvenc_yuv_calc_y().
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◆ sstvenc_yuv_calc_u()
| uint8_t sstvenc_yuv_calc_u | ( | uint8_t | r, |
| uint8_t | g, | ||
| uint8_t | b ) |
Return the U (red - luminance) component of a RGB colour.
- Parameters
-
[in] r Red component in Q8 fixed-point [in] g Green component in Q8 fixed-point [in] b Blue component in Q8 fixed-point
- Returns
- U component in Q8 fixed-point.
Definition at line 22 of file yuv.c.
22 {
23 return (128.0
24 + (.003906
25 * ((112.439 * (double)r) + (-94.154 * (double)g)
26 + (-18.285 * (double)b))))
27 + 0.5;
28}
Referenced by main(), and sstvenc_rgb_to_yuv().
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◆ sstvenc_yuv_calc_v()
| uint8_t sstvenc_yuv_calc_v | ( | uint8_t | r, |
| uint8_t | g, | ||
| uint8_t | b ) |
Return the V (blue - luminance) component of a RGB colour.
- Parameters
-
[in] r Red component in Q8 fixed-point [in] g Green component in Q8 fixed-point [in] b Blue component in Q8 fixed-point
- Returns
- V component in Q8 fixed-point.
Definition at line 30 of file yuv.c.
30 {
31 return (128.0
32 + (.003906
33 * ((-37.945 * (double)r) + (-74.494 * (double)g)
34 + (112.439 * (double)b))))
35 + 0.5;
36}
Referenced by main(), and sstvenc_rgb_to_yuv().
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◆ sstvenc_yuv_calc_y()
| uint8_t sstvenc_yuv_calc_y | ( | uint8_t | r, |
| uint8_t | g, | ||
| uint8_t | b ) |
Return the Y (luminance) component of a RGB colour. This routine is useful for converting colour to monochrome as well as RGB to YUV.
- Parameters
-
[in] r Red component in Q8 fixed-point [in] g Green component in Q8 fixed-point [in] b Blue component in Q8 fixed-point
- Returns
- Y component in Q8 fixed-point.
Definition at line 14 of file yuv.c.
14 {
15 return (16.0
16 + (.003906
17 * ((65.738 * (double)r) + (129.057 * (double)g)
18 + (25.064 * (double)b))))
19 + 0.5;
20}
Referenced by main(), sstvenc_rgb_to_mono(), and sstvenc_rgb_to_yuv().
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◆ sstvenc_yuv_to_mono()
| void sstvenc_yuv_to_mono | ( | uint8_t * | dest, |
| const uint8_t * | src, | ||
| uint16_t | width, | ||
| uint16_t | height ) |
Convert the given YUV framebuffer to monochrome (Y component only).
- Parameters
-
[out] dest Destination framebuffer, which is assumed to be at least one third of the size of src. This can be the same location as src – after conversion the occupied size will be one third of the original buffer and may be realloc()'d to that size.[in] src Source framebuffer, which is assumed to be YUV [in] width Width of the framebuffer in pixels [in] height Height of the framebuffer in pixels
Definition at line 109 of file yuv.c.
110 {
111 size_t sz = (size_t)width * (size_t)height;
112 while (sz) {
113 /* Extract Y out of YUV */
114 dest[0] = src[0];
115
116 dest += 1;
117 src += 3;
118 sz--;
119 }
120}
◆ sstvenc_yuv_to_rgb()
| void sstvenc_yuv_to_rgb | ( | uint8_t * | dest, |
| const uint8_t * | src, | ||
| uint16_t | width, | ||
| uint16_t | height ) |
Convert the given YUV framebuffer to RGB.
- Parameters
-
[out] dest Destination framebuffer, which is assumed to be the same size as src. This can be the same location as src. [in] src Source framebuffer, which is assumed to be YUV [in] width Width of the framebuffer in pixels [in] height Height of the framebuffer in pixels
Definition at line 91 of file yuv.c.
92 {
93 size_t sz = (size_t)width * (size_t)height;
94 while (sz) {
95 /* Pull out YUV values */
96 const uint8_t y = src[0], u = src[1], v = src[2];
97
98 /* Convert and write out RGB */
102
103 dest += 3;
104 src += 3;
105 sz--;
106 }
107}
References sstvenc_rgb_calc_b(), sstvenc_rgb_calc_g(), and sstvenc_rgb_calc_r().
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