| // 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 |
