diff options
| -rwxr-xr-x | utils/rkisp1/gen-csc-table.py | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/utils/rkisp1/gen-csc-table.py b/utils/rkisp1/gen-csc-table.py index 2fb70274..c47f5042 100755 --- a/utils/rkisp1/gen-csc-table.py +++ b/utils/rkisp1/gen-csc-table.py @@ -7,6 +7,7 @@ import argparse import enum +import numpy as np import sys @@ -63,9 +64,8 @@ class Quantization(enum.Enum): LIMITED = 1 -def scale_coeff(coeff, quantization, luma, precision): - """Scale a coefficient to the output range dictated by the quantization and - the precision. +def scale_coeff(coeff, quantization, luma): + """Scale a coefficient to the output range dictated by the quantization. Parameters ---------- @@ -75,9 +75,6 @@ def scale_coeff(coeff, quantization, luma, precision): The quantization, either FULL or LIMITED luma : bool True if the coefficient corresponds to a luma value, False otherwise - precision : int - The desired precision for the scaled coefficient as a number of - fractional bits """ # Assume the input range is 8 bits. The output range is set by the @@ -91,7 +88,7 @@ def scale_coeff(coeff, quantization, luma, precision): else: out_range = 240 - 16 - return coeff * out_range / in_range * (1 << precision) + return coeff * out_range / in_range def round_array(values): @@ -150,6 +147,8 @@ def main(argv): description='Generate color space conversion table coefficients with ' 'configurable fixed-point precision.' ) + parser.add_argument('--invert', '-i', action='store_true', + help='Invert the color space conversion (YUV -> RGB)') parser.add_argument('--precision', '-p', default='Q1.7', help='The output fixed point precision in Q notation (sign bit excluded)') parser.add_argument('--quantization', '-q', choices=['full', 'limited'], @@ -171,13 +170,25 @@ def main(argv): luma = True scaled_coeffs = [] for line in encoding: - line = [scale_coeff(coeff, quantization, luma, precision.fractional) for coeff in line] + line = [scale_coeff(coeff, quantization, luma) for coeff in line] scaled_coeffs.append(line) luma = False + if args.invert: + scaled_coeffs = np.linalg.inv(scaled_coeffs) + rounded_coeffs = [] for line in scaled_coeffs: - line = round_array(line) + line = [coeff * (1 << precision.fractional) for coeff in line] + # For the RGB to YUV conversion, use a rounding method that preserves + # the rounded sum of each line to avoid biases and overflow, as the sum + # of luma and chroma coefficients should be 1.0 and 0.0 respectively + # (in full range). For the YUV to RGB conversion, there is no such + # constraint, so use simple rounding. + if args.invert: + line = [round(coeff) for coeff in line] + else: + line = round_array(line) # Convert coefficients to the number of bits selected by the precision. # Negative values will be turned into positive integers using 2's @@ -188,7 +199,7 @@ def main(argv): # Print the result as C code. nbits = 1 << (precision.total - 1).bit_length() nbytes = nbits // 4 - print(f'static const u{nbits} rgb2yuv_{args.encoding}_{quantization.name.lower()}_coeffs[] = {{') + print(f'static const u{nbits} {"yuv2rgb" if args.invert else "rgb2yuv"}_{args.encoding}_{quantization.name.lower()}_coeffs[] = {{') for line in rounded_coeffs: line = [f'0x{coeff:0{nbytes}x}' for coeff in line] |