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Diffstat (limited to 'media/libwebp/src/dsp/filters_neon.c')
| -rw-r--r-- | media/libwebp/src/dsp/filters_neon.c | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/media/libwebp/src/dsp/filters_neon.c b/media/libwebp/src/dsp/filters_neon.c new file mode 100644 index 0000000000..3e6a578ea7 --- /dev/null +++ b/media/libwebp/src/dsp/filters_neon.c @@ -0,0 +1,329 @@ +// Copyright 2017 Google Inc. All Rights Reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. +// ----------------------------------------------------------------------------- +// +// NEON variant of alpha filters +// +// Author: Skal (pascal.massimino@gmail.com) + +#include "src/dsp/dsp.h" + +#if defined(WEBP_USE_NEON) + +#include <assert.h> +#include "src/dsp/neon.h" + +//------------------------------------------------------------------------------ +// Helpful macros. + +# define SANITY_CHECK(in, out) \ + assert(in != NULL); \ + assert(out != NULL); \ + assert(width > 0); \ + assert(height > 0); \ + assert(stride >= width); \ + assert(row >= 0 && num_rows > 0 && row + num_rows <= height); \ + (void)height; // Silence unused warning. + +// load eight u8 and widen to s16 +#define U8_TO_S16(A) vreinterpretq_s16_u16(vmovl_u8(A)) +#define LOAD_U8_TO_S16(A) U8_TO_S16(vld1_u8(A)) + +// shift left or right by N byte, inserting zeros +#define SHIFT_RIGHT_N_Q(A, N) vextq_u8((A), zero, (N)) +#define SHIFT_LEFT_N_Q(A, N) vextq_u8(zero, (A), (16 - (N)) % 16) + +// rotate left by N bytes +#define ROTATE_LEFT_N(A, N) vext_u8((A), (A), (N)) +// rotate right by N bytes +#define ROTATE_RIGHT_N(A, N) vext_u8((A), (A), (8 - (N)) % 8) + +static void PredictLine_NEON(const uint8_t* src, const uint8_t* pred, + uint8_t* dst, int length) { + int i; + assert(length >= 0); + for (i = 0; i + 16 <= length; i += 16) { + const uint8x16_t A = vld1q_u8(&src[i]); + const uint8x16_t B = vld1q_u8(&pred[i]); + const uint8x16_t C = vsubq_u8(A, B); + vst1q_u8(&dst[i], C); + } + for (; i < length; ++i) dst[i] = src[i] - pred[i]; +} + +// Special case for left-based prediction (when preds==dst-1 or preds==src-1). +static void PredictLineLeft_NEON(const uint8_t* src, uint8_t* dst, int length) { + PredictLine_NEON(src, src - 1, dst, length); +} + +//------------------------------------------------------------------------------ +// Horizontal filter. + +static WEBP_INLINE void DoHorizontalFilter_NEON(const uint8_t* in, + int width, int height, + int stride, + int row, int num_rows, + uint8_t* out) { + const size_t start_offset = row * stride; + const int last_row = row + num_rows; + SANITY_CHECK(in, out); + in += start_offset; + out += start_offset; + + if (row == 0) { + // Leftmost pixel is the same as input for topmost scanline. + out[0] = in[0]; + PredictLineLeft_NEON(in + 1, out + 1, width - 1); + row = 1; + in += stride; + out += stride; + } + + // Filter line-by-line. + while (row < last_row) { + // Leftmost pixel is predicted from above. + out[0] = in[0] - in[-stride]; + PredictLineLeft_NEON(in + 1, out + 1, width - 1); + ++row; + in += stride; + out += stride; + } +} + +static void HorizontalFilter_NEON(const uint8_t* data, int width, int height, + int stride, uint8_t* filtered_data) { + DoHorizontalFilter_NEON(data, width, height, stride, 0, height, + filtered_data); +} + +//------------------------------------------------------------------------------ +// Vertical filter. + +static WEBP_INLINE void DoVerticalFilter_NEON(const uint8_t* in, + int width, int height, int stride, + int row, int num_rows, + uint8_t* out) { + const size_t start_offset = row * stride; + const int last_row = row + num_rows; + SANITY_CHECK(in, out); + in += start_offset; + out += start_offset; + + if (row == 0) { + // Very first top-left pixel is copied. + out[0] = in[0]; + // Rest of top scan-line is left-predicted. + PredictLineLeft_NEON(in + 1, out + 1, width - 1); + row = 1; + in += stride; + out += stride; + } + + // Filter line-by-line. + while (row < last_row) { + PredictLine_NEON(in, in - stride, out, width); + ++row; + in += stride; + out += stride; + } +} + +static void VerticalFilter_NEON(const uint8_t* data, int width, int height, + int stride, uint8_t* filtered_data) { + DoVerticalFilter_NEON(data, width, height, stride, 0, height, + filtered_data); +} + +//------------------------------------------------------------------------------ +// Gradient filter. + +static WEBP_INLINE int GradientPredictor_C(uint8_t a, uint8_t b, uint8_t c) { + const int g = a + b - c; + return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255; // clip to 8bit +} + +static void GradientPredictDirect_NEON(const uint8_t* const row, + const uint8_t* const top, + uint8_t* const out, int length) { + int i; + for (i = 0; i + 8 <= length; i += 8) { + const uint8x8_t A = vld1_u8(&row[i - 1]); + const uint8x8_t B = vld1_u8(&top[i + 0]); + const int16x8_t C = vreinterpretq_s16_u16(vaddl_u8(A, B)); + const int16x8_t D = LOAD_U8_TO_S16(&top[i - 1]); + const uint8x8_t E = vqmovun_s16(vsubq_s16(C, D)); + const uint8x8_t F = vld1_u8(&row[i + 0]); + vst1_u8(&out[i], vsub_u8(F, E)); + } + for (; i < length; ++i) { + out[i] = row[i] - GradientPredictor_C(row[i - 1], top[i], top[i - 1]); + } +} + +static WEBP_INLINE void DoGradientFilter_NEON(const uint8_t* in, + int width, int height, + int stride, + int row, int num_rows, + uint8_t* out) { + const size_t start_offset = row * stride; + const int last_row = row + num_rows; + SANITY_CHECK(in, out); + in += start_offset; + out += start_offset; + + // left prediction for top scan-line + if (row == 0) { + out[0] = in[0]; + PredictLineLeft_NEON(in + 1, out + 1, width - 1); + row = 1; + in += stride; + out += stride; + } + + // Filter line-by-line. + while (row < last_row) { + out[0] = in[0] - in[-stride]; + GradientPredictDirect_NEON(in + 1, in + 1 - stride, out + 1, width - 1); + ++row; + in += stride; + out += stride; + } +} + +static void GradientFilter_NEON(const uint8_t* data, int width, int height, + int stride, uint8_t* filtered_data) { + DoGradientFilter_NEON(data, width, height, stride, 0, height, + filtered_data); +} + +#undef SANITY_CHECK + +//------------------------------------------------------------------------------ +// Inverse transforms + +static void HorizontalUnfilter_NEON(const uint8_t* prev, const uint8_t* in, + uint8_t* out, int width) { + int i; + const uint8x16_t zero = vdupq_n_u8(0); + uint8x16_t last; + out[0] = in[0] + (prev == NULL ? 0 : prev[0]); + if (width <= 1) return; + last = vsetq_lane_u8(out[0], zero, 0); + for (i = 1; i + 16 <= width; i += 16) { + const uint8x16_t A0 = vld1q_u8(&in[i]); + const uint8x16_t A1 = vaddq_u8(A0, last); + const uint8x16_t A2 = SHIFT_LEFT_N_Q(A1, 1); + const uint8x16_t A3 = vaddq_u8(A1, A2); + const uint8x16_t A4 = SHIFT_LEFT_N_Q(A3, 2); + const uint8x16_t A5 = vaddq_u8(A3, A4); + const uint8x16_t A6 = SHIFT_LEFT_N_Q(A5, 4); + const uint8x16_t A7 = vaddq_u8(A5, A6); + const uint8x16_t A8 = SHIFT_LEFT_N_Q(A7, 8); + const uint8x16_t A9 = vaddq_u8(A7, A8); + vst1q_u8(&out[i], A9); + last = SHIFT_RIGHT_N_Q(A9, 15); + } + for (; i < width; ++i) out[i] = in[i] + out[i - 1]; +} + +static void VerticalUnfilter_NEON(const uint8_t* prev, const uint8_t* in, + uint8_t* out, int width) { + if (prev == NULL) { + HorizontalUnfilter_NEON(NULL, in, out, width); + } else { + int i; + assert(width >= 0); + for (i = 0; i + 16 <= width; i += 16) { + const uint8x16_t A = vld1q_u8(&in[i]); + const uint8x16_t B = vld1q_u8(&prev[i]); + const uint8x16_t C = vaddq_u8(A, B); + vst1q_u8(&out[i], C); + } + for (; i < width; ++i) out[i] = in[i] + prev[i]; + } +} + +// GradientUnfilter_NEON is correct but slower than the C-version, +// at least on ARM64. For armv7, it's a wash. +// So best is to disable it for now, but keep the idea around... +#if !defined(USE_GRADIENT_UNFILTER) +#define USE_GRADIENT_UNFILTER 0 // ALTERNATE_CODE +#endif + +#if (USE_GRADIENT_UNFILTER == 1) +#define GRAD_PROCESS_LANE(L) do { \ + const uint8x8_t tmp1 = ROTATE_RIGHT_N(pred, 1); /* rotate predictor in */ \ + const int16x8_t tmp2 = vaddq_s16(BC, U8_TO_S16(tmp1)); \ + const uint8x8_t delta = vqmovun_s16(tmp2); \ + pred = vadd_u8(D, delta); \ + out = vext_u8(out, ROTATE_LEFT_N(pred, (L)), 1); \ +} while (0) + +static void GradientPredictInverse_NEON(const uint8_t* const in, + const uint8_t* const top, + uint8_t* const row, int length) { + if (length > 0) { + int i; + uint8x8_t pred = vdup_n_u8(row[-1]); // left sample + uint8x8_t out = vdup_n_u8(0); + for (i = 0; i + 8 <= length; i += 8) { + const int16x8_t B = LOAD_U8_TO_S16(&top[i + 0]); + const int16x8_t C = LOAD_U8_TO_S16(&top[i - 1]); + const int16x8_t BC = vsubq_s16(B, C); // unclipped gradient basis B - C + const uint8x8_t D = vld1_u8(&in[i]); // base input + GRAD_PROCESS_LANE(0); + GRAD_PROCESS_LANE(1); + GRAD_PROCESS_LANE(2); + GRAD_PROCESS_LANE(3); + GRAD_PROCESS_LANE(4); + GRAD_PROCESS_LANE(5); + GRAD_PROCESS_LANE(6); + GRAD_PROCESS_LANE(7); + vst1_u8(&row[i], out); + } + for (; i < length; ++i) { + row[i] = in[i] + GradientPredictor_C(row[i - 1], top[i], top[i - 1]); + } + } +} +#undef GRAD_PROCESS_LANE + +static void GradientUnfilter_NEON(const uint8_t* prev, const uint8_t* in, + uint8_t* out, int width) { + if (prev == NULL) { + HorizontalUnfilter_NEON(NULL, in, out, width); + } else { + out[0] = in[0] + prev[0]; // predict from above + GradientPredictInverse_NEON(in + 1, prev + 1, out + 1, width - 1); + } +} + +#endif // USE_GRADIENT_UNFILTER + +//------------------------------------------------------------------------------ +// Entry point + +extern void VP8FiltersInitNEON(void); + +WEBP_TSAN_IGNORE_FUNCTION void VP8FiltersInitNEON(void) { + WebPUnfilters[WEBP_FILTER_HORIZONTAL] = HorizontalUnfilter_NEON; + WebPUnfilters[WEBP_FILTER_VERTICAL] = VerticalUnfilter_NEON; +#if (USE_GRADIENT_UNFILTER == 1) + WebPUnfilters[WEBP_FILTER_GRADIENT] = GradientUnfilter_NEON; +#endif + + WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter_NEON; + WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter_NEON; + WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter_NEON; +} + +#else // !WEBP_USE_NEON + +WEBP_DSP_INIT_STUB(VP8FiltersInitNEON) + +#endif // WEBP_USE_NEON |