mirror of https://github.com/opencv/opencv.git
Open Source Computer Vision Library
https://opencv.org/
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
379 lines
12 KiB
379 lines
12 KiB
; YUV-> RGB conversion code Copyright (C) 2008 Robin Watts (robin;wss.co.uk). |
|
; |
|
; Licensed under the GPL. If you need it under another license, contact me |
|
; and ask. |
|
; |
|
; This program is free software ; you can redistribute it and/or modify |
|
; it under the terms of the GNU General Public License as published by |
|
; the Free Software Foundation ; either version 2 of the License, or |
|
; (at your option) any later version. |
|
; |
|
; This program is distributed in the hope that it will be useful, |
|
; but WITHOUT ANY WARRANTY ; without even the implied warranty of |
|
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
; GNU General Public License for more details. |
|
; |
|
; You should have received a copy of the GNU General Public License |
|
; along with this program ; if not, write to the Free Software |
|
; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
|
; |
|
; |
|
; The algorithm used here is based heavily on one created by Sophie Wilson |
|
; of Acorn/e-14/Broadcomm. Many thanks. |
|
; |
|
; Additional tweaks (in the fast fixup code) are from Paul Gardiner. |
|
; |
|
; The old implementation of YUV -> RGB did: |
|
; |
|
; R = CLAMP((Y-16)*1.164 + 1.596*V) |
|
; G = CLAMP((Y-16)*1.164 - 0.391*U - 0.813*V) |
|
; B = CLAMP((Y-16)*1.164 + 2.018*U ) |
|
; |
|
; We're going to bend that here as follows: |
|
; |
|
; R = CLAMP(y + 1.596*V) |
|
; G = CLAMP(y - 0.383*U - 0.813*V) |
|
; B = CLAMP(y + 1.976*U ) |
|
; |
|
; where y = 0 for Y <= 16, |
|
; y = ( Y-16)*1.164, for 16 < Y <= 239, |
|
; y = (239-16)*1.164, for 239 < Y |
|
; |
|
; i.e. We clamp Y to the 16 to 239 range (which it is supposed to be in |
|
; anyway). We then pick the B_U factor so that B never exceeds 511. We then |
|
; shrink the G_U factor in line with that to avoid a colour shift as much as |
|
; possible. |
|
; |
|
; We're going to use tables to do it faster, but rather than doing it using |
|
; 5 tables as as the above suggests, we're going to do it using just 3. |
|
; |
|
; We do this by working in parallel within a 32 bit word, and using one |
|
; table each for Y U and V. |
|
; |
|
; Source Y values are 0 to 255, so 0.. 260 after scaling |
|
; Source U values are -128 to 127, so -49.. 49(G), -253..251(B) after |
|
; Source V values are -128 to 127, so -204..203(R), -104..103(G) after |
|
; |
|
; So total summed values: |
|
; -223 <= R <= 481, -173 <= G <= 431, -253 <= B < 511 |
|
; |
|
; We need to pack R G and B into a 32 bit word, and because of Bs range we |
|
; need 2 bits above the valid range of B to detect overflow, and another one |
|
; to detect the sense of the overflow. We therefore adopt the following |
|
; representation: |
|
; |
|
; osGGGGGgggggosBBBBBbbbosRRRRRrrr |
|
; |
|
; Each such word breaks down into 3 ranges. |
|
; |
|
; osGGGGGggggg osBBBBBbbb osRRRRRrrr |
|
; |
|
; Thus we have 8 bits for each B and R table entry, and 10 bits for G (good |
|
; as G is the most noticable one). The s bit for each represents the sign, |
|
; and o represents the overflow. |
|
; |
|
; For R and B we pack the table by taking the 11 bit representation of their |
|
; values, and toggling bit 10 in the U and V tables. |
|
; |
|
; For the green case we calculate 4*G (thus effectively using 10 bits for the |
|
; valid range) truncate to 12 bits. We toggle bit 11 in the Y table. |
|
|
|
; Theorarm library |
|
; Copyright (C) 2009 Robin Watts for Pinknoise Productions Ltd |
|
|
|
AREA |.text|, CODE, READONLY |
|
|
|
EXPORT yuv420_2_rgb888 |
|
EXPORT yuv420_2_rgb888_PROFILE |
|
|
|
; void yuv420_2_rgb565 |
|
; uint8_t *dst_ptr |
|
; uint8_t *y_ptr |
|
; uint8_t *u_ptr |
|
; uint8_t *v_ptr |
|
; int width |
|
; int height |
|
; int y_span |
|
; int uv_span |
|
; int dst_span |
|
; int *tables |
|
; int dither |
|
|
|
CONST_flags |
|
DCD 0x40080100 |
|
yuv420_2_rgb888 |
|
; r0 = dst_ptr |
|
; r1 = y_ptr |
|
; r2 = u_ptr |
|
; r3 = v_ptr |
|
; <> = width |
|
; <> = height |
|
; <> = y_span |
|
; <> = uv_span |
|
; <> = dst_span |
|
; <> = y_table |
|
; <> = dither |
|
STMFD r13!,{r4-r11,r14} |
|
|
|
LDR r8, [r13,#10*4] ; r8 = height |
|
LDR r10,[r13,#11*4] ; r10= y_span |
|
LDR r9, [r13,#13*4] ; r9 = dst_span |
|
LDR r14,[r13,#14*4] ; r14= y_table |
|
LDR r5, CONST_flags |
|
LDR r11,[r13,#9*4] ; r11= width |
|
ADD r4, r14, #256*4 |
|
SUBS r8, r8, #1 |
|
BLT end |
|
BEQ trail_row1 |
|
yloop1 |
|
SUB r8, r8, r11,LSL #16 ; r8 = height-(width<<16) |
|
ADDS r8, r8, #1<<16 ; if (width == 1) |
|
BGE trail_pair1 ; just do 1 column |
|
xloop1 |
|
LDRB r11,[r2], #1 ; r11 = u = *u_ptr++ |
|
LDRB r12,[r3], #1 ; r12 = v = *v_ptr++ |
|
LDRB r7, [r1, r10] ; r7 = y2 = y_ptr[stride] |
|
LDRB r6, [r1], #1 ; r6 = y0 = *y_ptr++ |
|
ADD r12,r12,#512 |
|
LDR r11,[r4, r11,LSL #2] ; r11 = u = u_table[u] |
|
LDR r12,[r14,r12,LSL #2] ; r12 = v = v_table[v] |
|
LDR r7, [r14,r7, LSL #2] ; r7 = y2 = y_table[y2] |
|
LDR r6, [r14,r6, LSL #2] ; r6 = y0 = y_table[y0] |
|
ADD r11,r11,r12 ; r11 = uv = u+v |
|
|
|
ADD r7, r7, r11 ; r7 = y2 + uv |
|
ADD r6, r6, r11 ; r6 = y0 + uv |
|
ANDS r12,r7, r5 |
|
TSTEQ r6, r5 |
|
BNE fix101 |
|
return101 |
|
; Store the bottom one first |
|
ADD r12,r0, r9 |
|
STRB r7,[r12],#1 ; Store R |
|
MOV r7, r7, ROR #22 |
|
STRB r7,[r12],#1 ; Store G |
|
MOV r7, r7, ROR #21 |
|
STRB r7,[r12],#1 ; Store B |
|
|
|
; Then store the top one |
|
STRB r6,[r0], #1 ; Store R |
|
MOV r6, r6, ROR #22 |
|
STRB r6,[r0], #1 ; Store G |
|
|
|
LDRB r7, [r1, r10] ; r7 = y3 = y_ptr[stride] |
|
LDRB r12,[r1], #1 ; r12= y1 = *y_ptr++ |
|
MOV r6, r6, ROR #21 |
|
LDR r7, [r14, r7, LSL #2] ; r7 = y3 = y_table[y2] |
|
LDR r12,[r14, r12,LSL #2] ; r12= y1 = y_table[y0] |
|
STRB r6,[r0], #1 ; Store B |
|
|
|
ADD r7, r7, r11 ; r7 = y3 + uv |
|
ADD r6, r12,r11 ; r6 = y1 + uv |
|
ANDS r12,r7, r5 |
|
TSTEQ r6, r5 |
|
BNE fix102 |
|
return102 |
|
; Store the bottom one first |
|
ADD r12,r0, r9 |
|
STRB r7,[r12],#1 ; Store R |
|
MOV r7, r7, ROR #22 |
|
STRB r7,[r12],#1 ; Store G |
|
MOV r7, r7, ROR #21 |
|
STRB r7,[r12],#1 ; Store B |
|
|
|
; Then store the top one |
|
STRB r6,[r0], #1 ; Store R |
|
MOV r6, r6, ROR #22 |
|
STRB r6,[r0], #1 ; Store G |
|
MOV r6, r6, ROR #21 |
|
STRB r6,[r0], #1 ; Store B |
|
|
|
ADDS r8, r8, #2<<16 |
|
BLT xloop1 |
|
MOVS r8, r8, LSL #16 ; Clear the top 16 bits of r8 |
|
MOV r8, r8, LSR #16 ; If the C bit is clear we still have |
|
BCC trail_pair1 ; 1 more pixel pair to do |
|
end_xloop1 |
|
LDR r11,[r13,#9*4] ; r11= width |
|
LDR r12,[r13,#12*4] ; r12= uv_stride |
|
ADD r0, r0, r9, LSL #1 |
|
SUB r0, r0, r11,LSL #1 |
|
SUB r0, r0, r11 |
|
ADD r1, r1, r10,LSL #1 |
|
SUB r1, r1, r11 |
|
SUB r2, r2, r11,LSR #1 |
|
SUB r3, r3, r11,LSR #1 |
|
ADD r2, r2, r12 |
|
ADD r3, r3, r12 |
|
|
|
SUBS r8, r8, #2 |
|
BGT yloop1 |
|
|
|
LDMLTFD r13!,{r4-r11,pc} |
|
trail_row1 |
|
; We have a row of pixels left to do |
|
SUB r8, r8, r11,LSL #16 ; r8 = height-(width<<16) |
|
ADDS r8, r8, #1<<16 ; if (width == 1) |
|
BGE trail_pix1 ; just do 1 pixel |
|
xloop12 |
|
LDRB r11,[r2], #1 ; r11 = u = *u_ptr++ |
|
LDRB r12,[r3], #1 ; r12 = v = *v_ptr++ |
|
LDRB r6, [r1], #1 ; r6 = y0 = *y_ptr++ |
|
LDRB r7, [r1], #1 ; r7 = y1 = *y_ptr++ |
|
ADD r12,r12,#512 |
|
LDR r11,[r4, r11,LSL #2] ; r11 = u = u_table[u] |
|
LDR r12,[r14,r12,LSL #2] ; r12 = v = v_table[v] |
|
LDR r7, [r14,r7, LSL #2] ; r7 = y1 = y_table[y1] |
|
LDR r6, [r14,r6, LSL #2] ; r6 = y0 = y_table[y0] |
|
ADD r11,r11,r12 ; r11 = uv = u+v |
|
|
|
ADD r6, r6, r11 ; r6 = y0 + uv |
|
ADD r7, r7, r11 ; r7 = y1 + uv |
|
ANDS r12,r7, r5 |
|
TSTEQ r6, r5 |
|
BNE fix104 |
|
return104 |
|
; Store the bottom one first |
|
STRB r6,[r0], #1 ; Store R |
|
MOV r6, r6, ROR #22 |
|
STRB r6,[r0], #1 ; Store G |
|
MOV r6, r6, ROR #21 |
|
STRB r6,[r0], #1 ; Store B |
|
|
|
; Then store the top one |
|
STRB r7,[r0], #1 ; Store R |
|
MOV r7, r7, ROR #22 |
|
STRB r7,[r0], #1 ; Store G |
|
MOV r7, r7, ROR #21 |
|
STRB r7,[r0], #1 ; Store B |
|
|
|
ADDS r8, r8, #2<<16 |
|
BLT xloop12 |
|
MOVS r8, r8, LSL #16 ; Clear the top 16 bits of r8 |
|
MOV r8, r8, LSR #16 ; If the C bit is clear we still have |
|
BCC trail_pix1 ; 1 more pixel pair to do |
|
end |
|
LDMFD r13!,{r4-r11,pc} |
|
trail_pix1 |
|
; We have a single extra pixel to do |
|
LDRB r11,[r2], #1 ; r11 = u = *u_ptr++ |
|
LDRB r12,[r3], #1 ; r12 = v = *v_ptr++ |
|
LDRB r6, [r1], #1 ; r6 = y0 = *y_ptr++ |
|
ADD r12,r12,#512 |
|
LDR r11,[r4, r11,LSL #2] ; r11 = u = u_table[u] |
|
LDR r12,[r14,r12,LSL #2] ; r12 = v = v_table[v] |
|
LDR r6, [r14,r6, LSL #2] ; r6 = y0 = y_table[y0] |
|
ADD r11,r11,r12 ; r11 = uv = u+v |
|
|
|
ADD r6, r6, r11 ; r6 = y0 + uv |
|
ANDS r12,r6, r5 |
|
BNE fix105 |
|
return105 |
|
STRB r6,[r0], #1 ; Store R |
|
MOV r6, r6, ROR #22 |
|
STRB r6,[r0], #1 ; Store G |
|
MOV r6, r6, ROR #21 |
|
STRB r6,[r0], #1 ; Store B |
|
|
|
LDMFD r13!,{r4-r11,pc} |
|
|
|
trail_pair1 |
|
; We have a pair of pixels left to do |
|
LDRB r11,[r2] ; r11 = u = *u_ptr++ |
|
LDRB r12,[r3] ; r12 = v = *v_ptr++ |
|
LDRB r7, [r1, r10] ; r7 = y2 = y_ptr[stride] |
|
LDRB r6, [r1], #1 ; r6 = y0 = *y_ptr++ |
|
ADD r12,r12,#512 |
|
LDR r11,[r4, r11,LSL #2] ; r11 = u = u_table[u] |
|
LDR r12,[r14,r12,LSL #2] ; r12 = v = v_table[v] |
|
LDR r7, [r14,r7, LSL #2] ; r7 = y2 = y_table[y2] |
|
LDR r6, [r14,r6, LSL #2] ; r6 = y0 = y_table[y0] |
|
ADD r11,r11,r12 ; r11 = uv = u+v |
|
|
|
ADD r7, r7, r11 ; r7 = y2 + uv |
|
ADD r6, r6, r11 ; r6 = y0 + uv |
|
ANDS r12,r7, r5 |
|
TSTEQ r6, r5 |
|
BNE fix103 |
|
return103 |
|
; Store the bottom one first |
|
ADD r12,r0, r9 |
|
STRB r7,[r12],#1 ; Store R |
|
MOV r7, r7, ROR #22 |
|
STRB r7,[r12],#1 ; Store G |
|
MOV r7, r7, ROR #21 |
|
STRB r7,[r12],#1 ; Store B |
|
|
|
; Then store the top one |
|
STRB r6,[r0], #1 ; Store R |
|
MOV r6, r6, ROR #22 |
|
STRB r6,[r0], #1 ; Store G |
|
MOV r6, r6, ROR #21 |
|
STRB r6,[r0], #1 ; Store B |
|
B end_xloop1 |
|
fix101 |
|
; r7 and r6 are the values, at least one of which has overflowed |
|
; r12 = r7 & mask = .s......s......s...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r7, r7, r12 ; r7 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r7, LSR #1 ; r12 = .o......o......o...... |
|
ADD r7, r7, r12,LSR #8 ; r7 = fixed value |
|
|
|
AND r12, r6, r5 ; r12 = .S......S......S...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r6, r6, r12 ; r6 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r6, LSR #1 ; r12 = .o......o......o...... |
|
ADD r6, r6, r12,LSR #8 ; r6 = fixed value |
|
B return101 |
|
fix102 |
|
; r7 and r6 are the values, at least one of which has overflowed |
|
; r12 = r7 & mask = .s......s......s...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r7, r7, r12 ; r7 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r7, LSR #1 ; r12 = .o......o......o...... |
|
ADD r7, r7, r12,LSR #8 ; r7 = fixed value |
|
|
|
AND r12, r6, r5 ; r12 = .S......S......S...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS..SSSSS.SSSSSS |
|
ORR r6, r6, r12 ; r6 |= ..SSSSSS..SSSSS.SSSSSS |
|
BIC r12,r5, r6, LSR #1 ; r12 = .o......o......o...... |
|
ADD r6, r6, r12,LSR #8 ; r6 = fixed value |
|
B return102 |
|
fix103 |
|
; r7 and r6 are the values, at least one of which has overflowed |
|
; r12 = r7 & mask = .s......s......s...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r7, r7, r12 ; r7 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r7, LSR #1 ; r12 = .o......o......o...... |
|
ADD r7, r7, r12,LSR #8 ; r7 = fixed value |
|
|
|
AND r12, r6, r5 ; r12 = .S......S......S...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r6, r6, r12 ; r6 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r6, LSR #1 ; r12 = .o......o......o...... |
|
ADD r6, r6, r12,LSR #8 ; r6 = fixed value |
|
B return103 |
|
fix104 |
|
; r7 and r6 are the values, at least one of which has overflowed |
|
; r12 = r7 & mask = .s......s......s...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r7, r7, r12 ; r7 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r7, LSR #1 ; r12 = .o......o......o...... |
|
ADD r7, r7, r12,LSR #8 ; r7 = fixed value |
|
|
|
AND r12, r6, r5 ; r12 = .S......S......S...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r6, r6, r12 ; r6 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r6, LSR #1 ; r12 = .o......o......o...... |
|
ADD r6, r6, r12,LSR #8 ; r6 = fixed value |
|
B return104 |
|
fix105 |
|
; r6 is the value, which has has overflowed |
|
; r12 = r7 & mask = .s......s......s...... |
|
SUB r12,r12,r12,LSR #8 ; r12 = ..SSSSSS.SSSSSS.SSSSSS |
|
ORR r6, r6, r12 ; r6 |= ..SSSSSS.SSSSSS.SSSSSS |
|
BIC r12,r5, r6, LSR #1 ; r12 = .o......o......o...... |
|
ADD r6, r6, r12,LSR #8 ; r6 = fixed value |
|
B return105 |
|
|
|
END
|
|
|