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LibVideo: Fast-path converting colors by only matrix coefficients

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We don't need to run through the whole floating-point color converter
for videos that use sRGB transfer characteristics and BT.709 color
primaries. This commit adds a new templated inlining function to
ColorConverter to do a very fast fixed-point YCbCr to RGB conversion.

With the fast path, frame conversion times go from ~7.8ms down to
~3.7ms. The fast path can benefit a lot more from extra SIMD vector
width, as well.
This commit is contained in:
Zaggy1024 2023-04-20 05:11:57 -05:00 • committed by Tim Flynn
parent d6b867ba89
commit b10da81c7c
3 changed files with 152 additions and 37 deletions
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66
Userland/Libraries/LibVideo/VideoFrame.cpp
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@ -57,8 +57,8 @@ ALWAYS_INLINE void interpolate_row(u32 const row, u32 const width, u16 const* pl
}
}
template<u32 subsampling_horizontal, u32 subsampling_vertical>
ALWAYS_INLINE DecoderErrorOr<void> convert_to_bitmap(ColorConverter const& converter, u32 const width, u32 const height, FixedArray<u16> const& plane_y, FixedArray<u16> const& plane_u, FixedArray<u16> const& plane_v, Gfx::Bitmap& bitmap)
template<u32 subsampling_horizontal, u32 subsampling_vertical, typename Convert>
ALWAYS_INLINE DecoderErrorOr<void> convert_to_bitmap_subsampled(Convert convert, u32 const width, u32 const height, FixedArray<u16> const& plane_y, FixedArray<u16> const& plane_u, FixedArray<u16> const& plane_v, Gfx::Bitmap& bitmap)
{
VERIFY(bitmap.width() >= 0 && static_cast<u32>(bitmap.width()) == width);
VERIFY(bitmap.height() >= 0 && static_cast<u32>(bitmap.height()) == height);
@ -99,13 +99,13 @@ ALWAYS_INLINE DecoderErrorOr<void> convert_to_bitmap(ColorConverter const& conve
auto* scan_line_a = bitmap.scanline(static_cast<int>(row));
for (size_t column = 0; column < width; column++) {
scan_line_a[column] = converter.convert_yuv_to_full_range_rgb(y_row_a[column], u_row_a[column], v_row_a[column]).value();
scan_line_a[column] = convert(y_row_a[column], u_row_a[column], v_row_a[column]).value();
}
if constexpr (subsampling_vertical != 0) {
auto const* y_row_b = &plane_y[static_cast<size_t>(row + 1) * width];
auto* scan_line_b = bitmap.scanline(static_cast<int>(row + 1));
for (size_t column = 0; column < width; column++) {
scan_line_b[column] = converter.convert_yuv_to_full_range_rgb(y_row_b[column], u_row_b[column], v_row_b[column]).value();
scan_line_b[column] = convert(y_row_b[column], u_row_b[column], v_row_b[column]).value();
}
}
@ -119,7 +119,7 @@ ALWAYS_INLINE DecoderErrorOr<void> convert_to_bitmap(ColorConverter const& conve
auto const* y_row = &plane_y[static_cast<size_t>(height - 1) * width];
auto* scan_line = bitmap.scanline(static_cast<int>(height - 1));
for (size_t column = 0; column < width; column++) {
scan_line[column] = converter.convert_yuv_to_full_range_rgb(y_row[column], u_row_a[column], v_row_a[column]).value();
scan_line[column] = convert(y_row[column], u_row_a[column], v_row_a[column]).value();
}
}
}
@ -127,23 +127,49 @@ ALWAYS_INLINE DecoderErrorOr<void> convert_to_bitmap(ColorConverter const& conve
return {};
}
template<u32 subsampling_horizontal, u32 subsampling_vertical>
static ALWAYS_INLINE DecoderErrorOr<void> convert_to_bitmap_selecting_converter(CodingIndependentCodePoints cicp, u8 bit_depth, u32 const width, u32 const height, FixedArray<u16> const& plane_y, FixedArray<u16> const& plane_u, FixedArray<u16> const& plane_v, Gfx::Bitmap& bitmap)
{
constexpr auto output_cicp = CodingIndependentCodePoints(ColorPrimaries::BT709, TransferCharacteristics::SRGB, MatrixCoefficients::BT709, VideoFullRangeFlag::Full);
if (bit_depth == 8 && cicp.transfer_characteristics() == output_cicp.transfer_characteristics() && cicp.color_primaries() == output_cicp.color_primaries() && cicp.video_full_range_flag() == VideoFullRangeFlag::Studio) {
switch (cicp.matrix_coefficients()) {
case MatrixCoefficients::BT709:
return convert_to_bitmap_subsampled<subsampling_horizontal, subsampling_vertical>([](u16 y, u16 u, u16 v) { return ColorConverter::convert_simple_yuv_to_rgb<MatrixCoefficients::BT709, VideoFullRangeFlag::Studio>(y, u, v); }, width, height, plane_y, plane_u, plane_v, bitmap);
case MatrixCoefficients::BT601:
return convert_to_bitmap_subsampled<subsampling_horizontal, subsampling_vertical>([](u16 y, u16 u, u16 v) { return ColorConverter::convert_simple_yuv_to_rgb<MatrixCoefficients::BT601, VideoFullRangeFlag::Studio>(y, u, v); }, width, height, plane_y, plane_u, plane_v, bitmap);
case MatrixCoefficients::BT2020ConstantLuminance:
case MatrixCoefficients::BT2020NonConstantLuminance:
return convert_to_bitmap_subsampled<subsampling_horizontal, subsampling_vertical>([](u16 y, u16 u, u16 v) { return ColorConverter::convert_simple_yuv_to_rgb<MatrixCoefficients::BT2020ConstantLuminance, VideoFullRangeFlag::Studio>(y, u, v); }, width, height, plane_y, plane_u, plane_v, bitmap);
default:
VERIFY_NOT_REACHED();
}
}
auto converter = TRY(ColorConverter::create(bit_depth, cicp, output_cicp));
return convert_to_bitmap_subsampled<subsampling_horizontal, subsampling_vertical>([&](u16 y, u16 u, u16 v) { return converter.convert_yuv(y, u, v); }, width, height, plane_y, plane_u, plane_v, bitmap);
}
static DecoderErrorOr<void> convert_to_bitmap_selecting_subsampling(bool subsampling_horizontal, bool subsampling_vertical, CodingIndependentCodePoints cicp, u8 bit_depth, u32 const width, u32 const height, FixedArray<u16> const& plane_y, FixedArray<u16> const& plane_u, FixedArray<u16> const& plane_v, Gfx::Bitmap& bitmap)
{
if (subsampling_horizontal && subsampling_vertical) {
return convert_to_bitmap_selecting_converter<true, true>(cicp, bit_depth, width, height, plane_y, plane_u, plane_v, bitmap);
}
if (subsampling_horizontal && !subsampling_vertical) {
return convert_to_bitmap_selecting_converter<true, false>(cicp, bit_depth, width, height, plane_y, plane_u, plane_v, bitmap);
}
if (!subsampling_horizontal && subsampling_vertical) {
return convert_to_bitmap_selecting_converter<false, true>(cicp, bit_depth, width, height, plane_y, plane_u, plane_v, bitmap);
}
return convert_to_bitmap_selecting_converter<false, false>(cicp, bit_depth, width, height, plane_y, plane_u, plane_v, bitmap);
}
DecoderErrorOr<void> SubsampledYUVFrame::output_to_bitmap(Gfx::Bitmap& bitmap)
{
auto converter = TRY(ColorConverter::create(bit_depth(), cicp()));
if (m_subsampling_horizontal && m_subsampling_vertical) {
return convert_to_bitmap<true, true>(converter, width(), height(), m_plane_y, m_plane_u, m_plane_v, bitmap);
}
if (m_subsampling_horizontal && !m_subsampling_vertical) {
return convert_to_bitmap<true, false>(converter, width(), height(), m_plane_y, m_plane_u, m_plane_v, bitmap);
}
if (!m_subsampling_horizontal && m_subsampling_vertical) {
return convert_to_bitmap<false, true>(converter, width(), height(), m_plane_y, m_plane_u, m_plane_v, bitmap);
}
return convert_to_bitmap<false, false>(converter, width(), height(), m_plane_y, m_plane_u, m_plane_v, bitmap);
return convert_to_bitmap_selecting_subsampling(m_subsampling_horizontal, m_subsampling_vertical, cicp(), bit_depth(), width(), height(), m_plane_y, m_plane_u, m_plane_v, bitmap);
}
}