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      1 /*
      2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef VPX_VPX_DSP_INV_TXFM_H_
     12 #define VPX_VPX_DSP_INV_TXFM_H_
     13 
     14 #include <assert.h>
     15 
     16 #include "./vpx_config.h"
     17 #include "vpx_dsp/txfm_common.h"
     18 #include "vpx_ports/mem.h"
     19 
     20 #ifdef __cplusplus
     21 extern "C" {
     22 #endif
     23 
     24 static INLINE tran_high_t check_range(tran_high_t input) {
     25 #if CONFIG_COEFFICIENT_RANGE_CHECKING
     26   // For valid VP9 input streams, intermediate stage coefficients should always
     27   // stay within the range of a signed 16 bit integer. Coefficients can go out
     28   // of this range for invalid/corrupt VP9 streams. However, strictly checking
     29   // this range for every intermediate coefficient can burdensome for a decoder,
     30   // therefore the following assertion is only enabled when configured with
     31   // --enable-coefficient-range-checking.
     32   assert(INT16_MIN <= input);
     33   assert(input <= INT16_MAX);
     34 #endif  // CONFIG_COEFFICIENT_RANGE_CHECKING
     35   return input;
     36 }
     37 
     38 static INLINE tran_high_t dct_const_round_shift(tran_high_t input) {
     39   tran_high_t rv = ROUND_POWER_OF_TWO(input, DCT_CONST_BITS);
     40   return (tran_high_t)rv;
     41 }
     42 
     43 #if CONFIG_VP9_HIGHBITDEPTH
     44 static INLINE tran_high_t highbd_check_range(tran_high_t input, int bd) {
     45 #if CONFIG_COEFFICIENT_RANGE_CHECKING
     46   // For valid highbitdepth VP9 streams, intermediate stage coefficients will
     47   // stay within the ranges:
     48   // - 8 bit: signed 16 bit integer
     49   // - 10 bit: signed 18 bit integer
     50   // - 12 bit: signed 20 bit integer
     51   const int32_t int_max = (1 << (7 + bd)) - 1;
     52   const int32_t int_min = -int_max - 1;
     53   assert(int_min <= input);
     54   assert(input <= int_max);
     55   (void)int_min;
     56 #endif  // CONFIG_COEFFICIENT_RANGE_CHECKING
     57   (void)bd;
     58   return input;
     59 }
     60 #endif  // CONFIG_VP9_HIGHBITDEPTH
     61 
     62 #if CONFIG_EMULATE_HARDWARE
     63 // When CONFIG_EMULATE_HARDWARE is 1 the transform performs a
     64 // non-normative method to handle overflows. A stream that causes
     65 // overflows  in the inverse transform is considered invalid in VP9,
     66 // and a hardware implementer is free to choose any reasonable
     67 // method to handle overflows. However to aid in hardware
     68 // verification they can use a specific implementation of the
     69 // WRAPLOW() macro below that is identical to their intended
     70 // hardware implementation (and also use configure options to trigger
     71 // the C-implementation of the transform).
     72 //
     73 // The particular WRAPLOW implementation below performs strict
     74 // overflow wrapping to match common hardware implementations.
     75 // bd of 8 uses trans_low with 16bits, need to remove 16bits
     76 // bd of 10 uses trans_low with 18bits, need to remove 14bits
     77 // bd of 12 uses trans_low with 20bits, need to remove 12bits
     78 // bd of x uses trans_low with 8+x bits, need to remove 24-x bits
     79 #define WRAPLOW(x) ((((int32_t)check_range(x)) << 16) >> 16)
     80 #if CONFIG_VP9_HIGHBITDEPTH
     81 #define HIGHBD_WRAPLOW(x, bd) \
     82   ((((int32_t)highbd_check_range((x), bd)) << (24 - bd)) >> (24 - bd))
     83 #endif  // CONFIG_VP9_HIGHBITDEPTH
     84 
     85 #else  // CONFIG_EMULATE_HARDWARE
     86 
     87 #define WRAPLOW(x) ((int32_t)check_range(x))
     88 #if CONFIG_VP9_HIGHBITDEPTH
     89 #define HIGHBD_WRAPLOW(x, bd) ((int32_t)highbd_check_range((x), bd))
     90 #endif  // CONFIG_VP9_HIGHBITDEPTH
     91 #endif  // CONFIG_EMULATE_HARDWARE
     92 
     93 void idct4_c(const tran_low_t *input, tran_low_t *output);
     94 void idct8_c(const tran_low_t *input, tran_low_t *output);
     95 void idct16_c(const tran_low_t *input, tran_low_t *output);
     96 void idct32_c(const tran_low_t *input, tran_low_t *output);
     97 void iadst4_c(const tran_low_t *input, tran_low_t *output);
     98 void iadst8_c(const tran_low_t *input, tran_low_t *output);
     99 void iadst16_c(const tran_low_t *input, tran_low_t *output);
    100 
    101 #if CONFIG_VP9_HIGHBITDEPTH
    102 void vpx_highbd_idct4_c(const tran_low_t *input, tran_low_t *output, int bd);
    103 void vpx_highbd_idct8_c(const tran_low_t *input, tran_low_t *output, int bd);
    104 void vpx_highbd_idct16_c(const tran_low_t *input, tran_low_t *output, int bd);
    105 
    106 void vpx_highbd_iadst4_c(const tran_low_t *input, tran_low_t *output, int bd);
    107 void vpx_highbd_iadst8_c(const tran_low_t *input, tran_low_t *output, int bd);
    108 void vpx_highbd_iadst16_c(const tran_low_t *input, tran_low_t *output, int bd);
    109 
    110 static INLINE uint16_t highbd_clip_pixel_add(uint16_t dest, tran_high_t trans,
    111                                              int bd) {
    112   trans = HIGHBD_WRAPLOW(trans, bd);
    113   return clip_pixel_highbd(dest + (int)trans, bd);
    114 }
    115 #endif
    116 
    117 static INLINE uint8_t clip_pixel_add(uint8_t dest, tran_high_t trans) {
    118   trans = WRAPLOW(trans);
    119   return clip_pixel(dest + (int)trans);
    120 }
    121 #ifdef __cplusplus
    122 }  // extern "C"
    123 #endif
    124 
    125 #endif  // VPX_VPX_DSP_INV_TXFM_H_
    126