Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1172 insertions, 0 deletions

diff --git a/media/ffvpx/libavcodec/jrevdct.c b/media/ffvpx/libavcodec/jrevdct.c
new file mode 100644
index 0000000000..7f1863515f
--- /dev/null
+++ b/media/ffvpx/libavcodec/jrevdct.c
@@ -0,0 +1,1172 @@
+/*
+ * This file is part of the Independent JPEG Group's software.
+ *
+ * The authors make NO WARRANTY or representation, either express or implied,
+ * with respect to this software, its quality, accuracy, merchantability, or
+ * fitness for a particular purpose.  This software is provided "AS IS", and
+ * you, its user, assume the entire risk as to its quality and accuracy.
+ *
+ * This software is copyright (C) 1991, 1992, Thomas G. Lane.
+ * All Rights Reserved except as specified below.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute this
+ * software (or portions thereof) for any purpose, without fee, subject to
+ * these conditions:
+ * (1) If any part of the source code for this software is distributed, then
+ * this README file must be included, with this copyright and no-warranty
+ * notice unaltered; and any additions, deletions, or changes to the original
+ * files must be clearly indicated in accompanying documentation.
+ * (2) If only executable code is distributed, then the accompanying
+ * documentation must state that "this software is based in part on the work
+ * of the Independent JPEG Group".
+ * (3) Permission for use of this software is granted only if the user accepts
+ * full responsibility for any undesirable consequences; the authors accept
+ * NO LIABILITY for damages of any kind.
+ *
+ * These conditions apply to any software derived from or based on the IJG
+ * code, not just to the unmodified library.  If you use our work, you ought
+ * to acknowledge us.
+ *
+ * Permission is NOT granted for the use of any IJG author's name or company
+ * name in advertising or publicity relating to this software or products
+ * derived from it.  This software may be referred to only as "the Independent
+ * JPEG Group's software".
+ *
+ * We specifically permit and encourage the use of this software as the basis
+ * of commercial products, provided that all warranty or liability claims are
+ * assumed by the product vendor.
+ *
+ * This file contains the basic inverse-DCT transformation subroutine.
+ *
+ * This implementation is based on an algorithm described in
+ *   C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
+ *   Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
+ *   Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
+ * The primary algorithm described there uses 11 multiplies and 29 adds.
+ * We use their alternate method with 12 multiplies and 32 adds.
+ * The advantage of this method is that no data path contains more than one
+ * multiplication; this allows a very simple and accurate implementation in
+ * scaled fixed-point arithmetic, with a minimal number of shifts.
+ *
+ * I've made lots of modifications to attempt to take advantage of the
+ * sparse nature of the DCT matrices we're getting.  Although the logic
+ * is cumbersome, it's straightforward and the resulting code is much
+ * faster.
+ *
+ * A better way to do this would be to pass in the DCT block as a sparse
+ * matrix, perhaps with the difference cases encoded.
+ */
+
+/**
+ * @file
+ * Independent JPEG Group's LLM idct.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "libavutil/intreadwrite.h"
+
+#include "dct.h"
+#include "idctdsp.h"
+
+#define EIGHT_BIT_SAMPLES
+
+#define DCTSIZE 8
+#define DCTSIZE2 64
+
+#define GLOBAL
+
+#define RIGHT_SHIFT(x, n) ((x) >> (n))
+
+typedef int16_t DCTBLOCK[DCTSIZE2];
+
+#define CONST_BITS 13
+
+/*
+ * This routine is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+  Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/*
+ * A 2-D IDCT can be done by 1-D IDCT on each row followed by 1-D IDCT
+ * on each column.  Direct algorithms are also available, but they are
+ * much more complex and seem not to be any faster when reduced to code.
+ *
+ * The poop on this scaling stuff is as follows:
+ *
+ * Each 1-D IDCT step produces outputs which are a factor of sqrt(N)
+ * larger than the true IDCT outputs.  The final outputs are therefore
+ * a factor of N larger than desired; since N=8 this can be cured by
+ * a simple right shift at the end of the algorithm.  The advantage of
+ * this arrangement is that we save two multiplications per 1-D IDCT,
+ * because the y0 and y4 inputs need not be divided by sqrt(N).
+ *
+ * We have to do addition and subtraction of the integer inputs, which
+ * is no problem, and multiplication by fractional constants, which is
+ * a problem to do in integer arithmetic.  We multiply all the constants
+ * by CONST_SCALE and convert them to integer constants (thus retaining
+ * CONST_BITS bits of precision in the constants).  After doing a
+ * multiplication we have to divide the product by CONST_SCALE, with proper
+ * rounding, to produce the correct output.  This division can be done
+ * cheaply as a right shift of CONST_BITS bits.  We postpone shifting
+ * as long as possible so that partial sums can be added together with
+ * full fractional precision.
+ *
+ * The outputs of the first pass are scaled up by PASS1_BITS bits so that
+ * they are represented to better-than-integral precision.  These outputs
+ * require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word
+ * with the recommended scaling.  (To scale up 12-bit sample data further, an
+ * intermediate int32 array would be needed.)
+ *
+ * To avoid overflow of the 32-bit intermediate results in pass 2, we must
+ * have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26.  Error analysis
+ * shows that the values given below are the most effective.
+ */
+
+#ifdef EIGHT_BIT_SAMPLES
+#define PASS1_BITS  2
+#else
+#define PASS1_BITS  1   /* lose a little precision to avoid overflow */
+#endif
+
+#define ONE         ((int32_t) 1)
+
+#define CONST_SCALE (ONE << CONST_BITS)
+
+/* Convert a positive real constant to an integer scaled by CONST_SCALE.
+ * IMPORTANT: if your compiler doesn't do this arithmetic at compile time,
+ * you will pay a significant penalty in run time.  In that case, figure
+ * the correct integer constant values and insert them by hand.
+ */
+
+/* Actually FIX is no longer used, we precomputed them all */
+#define FIX(x)  ((int32_t) ((x) * CONST_SCALE + 0.5))
+
+/* Descale and correctly round an int32_t value that's scaled by N bits.
+ * We assume RIGHT_SHIFT rounds towards minus infinity, so adding
+ * the fudge factor is correct for either sign of X.
+ */
+
+#define DESCALE(x,n)  RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
+
+/* Multiply an int32_t variable by an int32_t constant to yield an int32_t result.
+ * For 8-bit samples with the recommended scaling, all the variable
+ * and constant values involved are no more than 16 bits wide, so a
+ * 16x16->32 bit multiply can be used instead of a full 32x32 multiply;
+ * this provides a useful speedup on many machines.
+ * There is no way to specify a 16x16->32 multiply in portable C, but
+ * some C compilers will do the right thing if you provide the correct
+ * combination of casts.
+ * NB: for 12-bit samples, a full 32-bit multiplication will be needed.
+ */
+
+#ifdef EIGHT_BIT_SAMPLES
+#ifdef SHORTxSHORT_32           /* may work if 'int' is 32 bits */
+#define MULTIPLY(var,const)  (((int16_t) (var)) * ((int16_t) (const)))
+#endif
+#ifdef SHORTxLCONST_32          /* known to work with Microsoft C 6.0 */
+#define MULTIPLY(var,const)  (((int16_t) (var)) * ((int32_t) (const)))
+#endif
+#endif
+
+#ifndef MULTIPLY                /* default definition */
+#define MULTIPLY(var,const)  ((var) * (const))
+#endif
+
+
+/*
+  Unlike our decoder where we approximate the FIXes, we need to use exact
+ones here or successive P-frames will drift too much with Reference frame coding
+*/
+#define FIX_0_211164243 1730
+#define FIX_0_275899380 2260
+#define FIX_0_298631336 2446
+#define FIX_0_390180644 3196
+#define FIX_0_509795579 4176
+#define FIX_0_541196100 4433
+#define FIX_0_601344887 4926
+#define FIX_0_765366865 6270
+#define FIX_0_785694958 6436
+#define FIX_0_899976223 7373
+#define FIX_1_061594337 8697
+#define FIX_1_111140466 9102
+#define FIX_1_175875602 9633
+#define FIX_1_306562965 10703
+#define FIX_1_387039845 11363
+#define FIX_1_451774981 11893
+#define FIX_1_501321110 12299
+#define FIX_1_662939225 13623
+#define FIX_1_847759065 15137
+#define FIX_1_961570560 16069
+#define FIX_2_053119869 16819
+#define FIX_2_172734803 17799
+#define FIX_2_562915447 20995
+#define FIX_3_072711026 25172
+
+/*
+ * Perform the inverse DCT on one block of coefficients.
+ */
+
+void ff_j_rev_dct(DCTBLOCK data)
+{
+  int32_t tmp0, tmp1, tmp2, tmp3;
+  int32_t tmp10, tmp11, tmp12, tmp13;
+  int32_t z1, z2, z3, z4, z5;
+  int32_t d0, d1, d2, d3, d4, d5, d6, d7;
+  register int16_t *dataptr;
+  int rowctr;
+
+  /* Pass 1: process rows. */
+  /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
+  /* furthermore, we scale the results by 2**PASS1_BITS. */
+
+  dataptr = data;
+
+  for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
+    /* Due to quantization, we will usually find that many of the input
+     * coefficients are zero, especially the AC terms.  We can exploit this
+     * by short-circuiting the IDCT calculation for any row in which all
+     * the AC terms are zero.  In that case each output is equal to the
+     * DC coefficient (with scale factor as needed).
+     * With typical images and quantization tables, half or more of the
+     * row DCT calculations can be simplified this way.
+     */
+
+    register uint8_t *idataptr = (uint8_t*)dataptr;
+
+    /* WARNING: we do the same permutation as MMX idct to simplify the
+       video core */
+    d0 = dataptr[0];
+    d2 = dataptr[1];
+    d4 = dataptr[2];
+    d6 = dataptr[3];
+    d1 = dataptr[4];
+    d3 = dataptr[5];
+    d5 = dataptr[6];
+    d7 = dataptr[7];
+
+    if ((d1 | d2 | d3 | d4 | d5 | d6 | d7) == 0) {
+      /* AC terms all zero */
+      if (d0) {
+          /* Compute a 32 bit value to assign. */
+          int16_t dcval = (int16_t) (d0 * (1 << PASS1_BITS));
+          register unsigned v = (dcval & 0xffff) | ((uint32_t)dcval << 16);
+
+          AV_WN32A(&idataptr[ 0], v);
+          AV_WN32A(&idataptr[ 4], v);
+          AV_WN32A(&idataptr[ 8], v);
+          AV_WN32A(&idataptr[12], v);
+      }
+
+      dataptr += DCTSIZE;       /* advance pointer to next row */
+      continue;
+    }
+
+    /* Even part: reverse the even part of the forward DCT. */
+    /* The rotator is sqrt(2)*c(-6). */
+{
+    if (d6) {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
+                    z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
+                    tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
+                    tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
+
+                    tmp0 = (d0 + d4) * CONST_SCALE;
+                    tmp1 = (d0 - d4) * CONST_SCALE;
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
+                    tmp2 = MULTIPLY(-d6, FIX_1_306562965);
+                    tmp3 = MULTIPLY(d6, FIX_0_541196100);
+
+                    tmp0 = (d0 + d4) * CONST_SCALE;
+                    tmp1 = (d0 - d4) * CONST_SCALE;
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            }
+    } else {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
+                    tmp2 = MULTIPLY(d2, FIX_0_541196100);
+                    tmp3 = MULTIPLY(d2, FIX_1_306562965);
+
+                    tmp0 = (d0 + d4) * CONST_SCALE;
+                    tmp1 = (d0 - d4) * CONST_SCALE;
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
+                    tmp10 = tmp13 = (d0 + d4) * CONST_SCALE;
+                    tmp11 = tmp12 = (d0 - d4) * CONST_SCALE;
+            }
+      }
+
+    /* Odd part per figure 8; the matrix is unitary and hence its
+     * transpose is its inverse.  i0..i3 are y7,y5,y3,y1 respectively.
+     */
+
+    if (d7) {
+        if (d5) {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z2 = d5 + d3;
+                    z3 = d7 + d3;
+                    z4 = d5 + d1;
+                    z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-z1, FIX_0_899976223);
+                    z2 = MULTIPLY(-z2, FIX_2_562915447);
+                    z3 = MULTIPLY(-z3, FIX_1_961570560);
+                    z4 = MULTIPLY(-z4, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
+                    z2 = d5 + d3;
+                    z3 = d7 + d3;
+                    z5 = MULTIPLY(z3 + d5, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    z1 = MULTIPLY(-d7, FIX_0_899976223);
+                    z2 = MULTIPLY(-z2, FIX_2_562915447);
+                    z3 = MULTIPLY(-z3, FIX_1_961570560);
+                    z4 = MULTIPLY(-d5, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 = z1 + z4;
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z4 = d5 + d1;
+                    z5 = MULTIPLY(d7 + z4, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-z1, FIX_0_899976223);
+                    z2 = MULTIPLY(-d5, FIX_2_562915447);
+                    z3 = MULTIPLY(-d7, FIX_1_961570560);
+                    z4 = MULTIPLY(-z4, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 = z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
+                    tmp0 = MULTIPLY(-d7, FIX_0_601344887);
+                    z1 = MULTIPLY(-d7, FIX_0_899976223);
+                    z3 = MULTIPLY(-d7, FIX_1_961570560);
+                    tmp1 = MULTIPLY(-d5, FIX_0_509795579);
+                    z2 = MULTIPLY(-d5, FIX_2_562915447);
+                    z4 = MULTIPLY(-d5, FIX_0_390180644);
+                    z5 = MULTIPLY(d5 + d7, FIX_1_175875602);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z3;
+                    tmp1 += z4;
+                    tmp2 = z2 + z3;
+                    tmp3 = z1 + z4;
+                }
+            }
+        } else {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z3 = d7 + d3;
+                    z5 = MULTIPLY(z3 + d1, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-z1, FIX_0_899976223);
+                    z2 = MULTIPLY(-d3, FIX_2_562915447);
+                    z3 = MULTIPLY(-z3, FIX_1_961570560);
+                    z4 = MULTIPLY(-d1, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 = z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
+                    z3 = d7 + d3;
+
+                    tmp0 = MULTIPLY(-d7, FIX_0_601344887);
+                    z1 = MULTIPLY(-d7, FIX_0_899976223);
+                    tmp2 = MULTIPLY(d3, FIX_0_509795579);
+                    z2 = MULTIPLY(-d3, FIX_2_562915447);
+                    z5 = MULTIPLY(z3, FIX_1_175875602);
+                    z3 = MULTIPLY(-z3, FIX_0_785694958);
+
+                    tmp0 += z3;
+                    tmp1 = z2 + z5;
+                    tmp2 += z3;
+                    tmp3 = z1 + z5;
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z5 = MULTIPLY(z1, FIX_1_175875602);
+
+                    z1 = MULTIPLY(z1, FIX_0_275899380);
+                    z3 = MULTIPLY(-d7, FIX_1_961570560);
+                    tmp0 = MULTIPLY(-d7, FIX_1_662939225);
+                    z4 = MULTIPLY(-d1, FIX_0_390180644);
+                    tmp3 = MULTIPLY(d1, FIX_1_111140466);
+
+                    tmp0 += z1;
+                    tmp1 = z4 + z5;
+                    tmp2 = z3 + z5;
+                    tmp3 += z1;
+                } else {
+                    /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
+                    tmp0 = MULTIPLY(-d7, FIX_1_387039845);
+                    tmp1 = MULTIPLY(d7, FIX_1_175875602);
+                    tmp2 = MULTIPLY(-d7, FIX_0_785694958);
+                    tmp3 = MULTIPLY(d7, FIX_0_275899380);
+                }
+            }
+        }
+    } else {
+        if (d5) {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
+                    z2 = d5 + d3;
+                    z4 = d5 + d1;
+                    z5 = MULTIPLY(d3 + z4, FIX_1_175875602);
+
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-d1, FIX_0_899976223);
+                    z2 = MULTIPLY(-z2, FIX_2_562915447);
+                    z3 = MULTIPLY(-d3, FIX_1_961570560);
+                    z4 = MULTIPLY(-z4, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 = z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
+                    z2 = d5 + d3;
+
+                    z5 = MULTIPLY(z2, FIX_1_175875602);
+                    tmp1 = MULTIPLY(d5, FIX_1_662939225);
+                    z4 = MULTIPLY(-d5, FIX_0_390180644);
+                    z2 = MULTIPLY(-z2, FIX_1_387039845);
+                    tmp2 = MULTIPLY(d3, FIX_1_111140466);
+                    z3 = MULTIPLY(-d3, FIX_1_961570560);
+
+                    tmp0 = z3 + z5;
+                    tmp1 += z2;
+                    tmp2 += z2;
+                    tmp3 = z4 + z5;
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
+                    z4 = d5 + d1;
+
+                    z5 = MULTIPLY(z4, FIX_1_175875602);
+                    z1 = MULTIPLY(-d1, FIX_0_899976223);
+                    tmp3 = MULTIPLY(d1, FIX_0_601344887);
+                    tmp1 = MULTIPLY(-d5, FIX_0_509795579);
+                    z2 = MULTIPLY(-d5, FIX_2_562915447);
+                    z4 = MULTIPLY(z4, FIX_0_785694958);
+
+                    tmp0 = z1 + z5;
+                    tmp1 += z4;
+                    tmp2 = z2 + z5;
+                    tmp3 += z4;
+                } else {
+                    /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
+                    tmp0 = MULTIPLY(d5, FIX_1_175875602);
+                    tmp1 = MULTIPLY(d5, FIX_0_275899380);
+                    tmp2 = MULTIPLY(-d5, FIX_1_387039845);
+                    tmp3 = MULTIPLY(d5, FIX_0_785694958);
+                }
+            }
+        } else {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
+                    z5 = d1 + d3;
+                    tmp3 = MULTIPLY(d1, FIX_0_211164243);
+                    tmp2 = MULTIPLY(-d3, FIX_1_451774981);
+                    z1 = MULTIPLY(d1, FIX_1_061594337);
+                    z2 = MULTIPLY(-d3, FIX_2_172734803);
+                    z4 = MULTIPLY(z5, FIX_0_785694958);
+                    z5 = MULTIPLY(z5, FIX_1_175875602);
+
+                    tmp0 = z1 - z4;
+                    tmp1 = z2 + z4;
+                    tmp2 += z5;
+                    tmp3 += z5;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
+                    tmp0 = MULTIPLY(-d3, FIX_0_785694958);
+                    tmp1 = MULTIPLY(-d3, FIX_1_387039845);
+                    tmp2 = MULTIPLY(-d3, FIX_0_275899380);
+                    tmp3 = MULTIPLY(d3, FIX_1_175875602);
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
+                    tmp0 = MULTIPLY(d1, FIX_0_275899380);
+                    tmp1 = MULTIPLY(d1, FIX_0_785694958);
+                    tmp2 = MULTIPLY(d1, FIX_1_175875602);
+                    tmp3 = MULTIPLY(d1, FIX_1_387039845);
+                } else {
+                    /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
+                    tmp0 = tmp1 = tmp2 = tmp3 = 0;
+                }
+            }
+        }
+    }
+}
+    /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+    dataptr[0] = (int16_t) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
+    dataptr[7] = (int16_t) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
+    dataptr[1] = (int16_t) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
+    dataptr[6] = (int16_t) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
+    dataptr[2] = (int16_t) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
+    dataptr[5] = (int16_t) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
+    dataptr[3] = (int16_t) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
+    dataptr[4] = (int16_t) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
+
+    dataptr += DCTSIZE;         /* advance pointer to next row */
+  }
+
+  /* Pass 2: process columns. */
+  /* Note that we must descale the results by a factor of 8 == 2**3, */
+  /* and also undo the PASS1_BITS scaling. */
+
+  dataptr = data;
+  for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
+    /* Columns of zeroes can be exploited in the same way as we did with rows.
+     * However, the row calculation has created many nonzero AC terms, so the
+     * simplification applies less often (typically 5% to 10% of the time).
+     * On machines with very fast multiplication, it's possible that the
+     * test takes more time than it's worth.  In that case this section
+     * may be commented out.
+     */
+
+    d0 = dataptr[DCTSIZE*0];
+    d1 = dataptr[DCTSIZE*1];
+    d2 = dataptr[DCTSIZE*2];
+    d3 = dataptr[DCTSIZE*3];
+    d4 = dataptr[DCTSIZE*4];
+    d5 = dataptr[DCTSIZE*5];
+    d6 = dataptr[DCTSIZE*6];
+    d7 = dataptr[DCTSIZE*7];
+
+    /* Even part: reverse the even part of the forward DCT. */
+    /* The rotator is sqrt(2)*c(-6). */
+    if (d6) {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
+                    z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
+                    tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
+                    tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
+
+                    tmp0 = (d0 + d4) * CONST_SCALE;
+                    tmp1 = (d0 - d4) * CONST_SCALE;
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
+                    tmp2 = MULTIPLY(-d6, FIX_1_306562965);
+                    tmp3 = MULTIPLY(d6, FIX_0_541196100);
+
+                    tmp0 = (d0 + d4) * CONST_SCALE;
+                    tmp1 = (d0 - d4) * CONST_SCALE;
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            }
+    } else {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
+                    tmp2 = MULTIPLY(d2, FIX_0_541196100);
+                    tmp3 = MULTIPLY(d2, FIX_1_306562965);
+
+                    tmp0 = (d0 + d4) * CONST_SCALE;
+                    tmp1 = (d0 - d4) * CONST_SCALE;
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
+                    tmp10 = tmp13 = (d0 + d4) * CONST_SCALE;
+                    tmp11 = tmp12 = (d0 - d4) * CONST_SCALE;
+            }
+    }
+
+    /* Odd part per figure 8; the matrix is unitary and hence its
+     * transpose is its inverse.  i0..i3 are y7,y5,y3,y1 respectively.
+     */
+    if (d7) {
+        if (d5) {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z2 = d5 + d3;
+                    z3 = d7 + d3;
+                    z4 = d5 + d1;
+                    z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-z1, FIX_0_899976223);
+                    z2 = MULTIPLY(-z2, FIX_2_562915447);
+                    z3 = MULTIPLY(-z3, FIX_1_961570560);
+                    z4 = MULTIPLY(-z4, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
+                    z2 = d5 + d3;
+                    z3 = d7 + d3;
+                    z5 = MULTIPLY(z3 + d5, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    z1 = MULTIPLY(-d7, FIX_0_899976223);
+                    z2 = MULTIPLY(-z2, FIX_2_562915447);
+                    z3 = MULTIPLY(-z3, FIX_1_961570560);
+                    z4 = MULTIPLY(-d5, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 = z1 + z4;
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z3 = d7;
+                    z4 = d5 + d1;
+                    z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-z1, FIX_0_899976223);
+                    z2 = MULTIPLY(-d5, FIX_2_562915447);
+                    z3 = MULTIPLY(-d7, FIX_1_961570560);
+                    z4 = MULTIPLY(-z4, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 = z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
+                    tmp0 = MULTIPLY(-d7, FIX_0_601344887);
+                    z1 = MULTIPLY(-d7, FIX_0_899976223);
+                    z3 = MULTIPLY(-d7, FIX_1_961570560);
+                    tmp1 = MULTIPLY(-d5, FIX_0_509795579);
+                    z2 = MULTIPLY(-d5, FIX_2_562915447);
+                    z4 = MULTIPLY(-d5, FIX_0_390180644);
+                    z5 = MULTIPLY(d5 + d7, FIX_1_175875602);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z3;
+                    tmp1 += z4;
+                    tmp2 = z2 + z3;
+                    tmp3 = z1 + z4;
+                }
+            }
+        } else {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z3 = d7 + d3;
+                    z5 = MULTIPLY(z3 + d1, FIX_1_175875602);
+
+                    tmp0 = MULTIPLY(d7, FIX_0_298631336);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-z1, FIX_0_899976223);
+                    z2 = MULTIPLY(-d3, FIX_2_562915447);
+                    z3 = MULTIPLY(-z3, FIX_1_961570560);
+                    z4 = MULTIPLY(-d1, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 += z1 + z3;
+                    tmp1 = z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
+                    z3 = d7 + d3;
+
+                    tmp0 = MULTIPLY(-d7, FIX_0_601344887);
+                    z1 = MULTIPLY(-d7, FIX_0_899976223);
+                    tmp2 = MULTIPLY(d3, FIX_0_509795579);
+                    z2 = MULTIPLY(-d3, FIX_2_562915447);
+                    z5 = MULTIPLY(z3, FIX_1_175875602);
+                    z3 = MULTIPLY(-z3, FIX_0_785694958);
+
+                    tmp0 += z3;
+                    tmp1 = z2 + z5;
+                    tmp2 += z3;
+                    tmp3 = z1 + z5;
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
+                    z1 = d7 + d1;
+                    z5 = MULTIPLY(z1, FIX_1_175875602);
+
+                    z1 = MULTIPLY(z1, FIX_0_275899380);
+                    z3 = MULTIPLY(-d7, FIX_1_961570560);
+                    tmp0 = MULTIPLY(-d7, FIX_1_662939225);
+                    z4 = MULTIPLY(-d1, FIX_0_390180644);
+                    tmp3 = MULTIPLY(d1, FIX_1_111140466);
+
+                    tmp0 += z1;
+                    tmp1 = z4 + z5;
+                    tmp2 = z3 + z5;
+                    tmp3 += z1;
+                } else {
+                    /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
+                    tmp0 = MULTIPLY(-d7, FIX_1_387039845);
+                    tmp1 = MULTIPLY(d7, FIX_1_175875602);
+                    tmp2 = MULTIPLY(-d7, FIX_0_785694958);
+                    tmp3 = MULTIPLY(d7, FIX_0_275899380);
+                }
+            }
+        }
+    } else {
+        if (d5) {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
+                    z2 = d5 + d3;
+                    z4 = d5 + d1;
+                    z5 = MULTIPLY(d3 + z4, FIX_1_175875602);
+
+                    tmp1 = MULTIPLY(d5, FIX_2_053119869);
+                    tmp2 = MULTIPLY(d3, FIX_3_072711026);
+                    tmp3 = MULTIPLY(d1, FIX_1_501321110);
+                    z1 = MULTIPLY(-d1, FIX_0_899976223);
+                    z2 = MULTIPLY(-z2, FIX_2_562915447);
+                    z3 = MULTIPLY(-d3, FIX_1_961570560);
+                    z4 = MULTIPLY(-z4, FIX_0_390180644);
+
+                    z3 += z5;
+                    z4 += z5;
+
+                    tmp0 = z1 + z3;
+                    tmp1 += z2 + z4;
+                    tmp2 += z2 + z3;
+                    tmp3 += z1 + z4;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
+                    z2 = d5 + d3;
+
+                    z5 = MULTIPLY(z2, FIX_1_175875602);
+                    tmp1 = MULTIPLY(d5, FIX_1_662939225);
+                    z4 = MULTIPLY(-d5, FIX_0_390180644);
+                    z2 = MULTIPLY(-z2, FIX_1_387039845);
+                    tmp2 = MULTIPLY(d3, FIX_1_111140466);
+                    z3 = MULTIPLY(-d3, FIX_1_961570560);
+
+                    tmp0 = z3 + z5;
+                    tmp1 += z2;
+                    tmp2 += z2;
+                    tmp3 = z4 + z5;
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
+                    z4 = d5 + d1;
+
+                    z5 = MULTIPLY(z4, FIX_1_175875602);
+                    z1 = MULTIPLY(-d1, FIX_0_899976223);
+                    tmp3 = MULTIPLY(d1, FIX_0_601344887);
+                    tmp1 = MULTIPLY(-d5, FIX_0_509795579);
+                    z2 = MULTIPLY(-d5, FIX_2_562915447);
+                    z4 = MULTIPLY(z4, FIX_0_785694958);
+
+                    tmp0 = z1 + z5;
+                    tmp1 += z4;
+                    tmp2 = z2 + z5;
+                    tmp3 += z4;
+                } else {
+                    /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
+                    tmp0 = MULTIPLY(d5, FIX_1_175875602);
+                    tmp1 = MULTIPLY(d5, FIX_0_275899380);
+                    tmp2 = MULTIPLY(-d5, FIX_1_387039845);
+                    tmp3 = MULTIPLY(d5, FIX_0_785694958);
+                }
+            }
+        } else {
+            if (d3) {
+                if (d1) {
+                    /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
+                    z5 = d1 + d3;
+                    tmp3 = MULTIPLY(d1, FIX_0_211164243);
+                    tmp2 = MULTIPLY(-d3, FIX_1_451774981);
+                    z1 = MULTIPLY(d1, FIX_1_061594337);
+                    z2 = MULTIPLY(-d3, FIX_2_172734803);
+                    z4 = MULTIPLY(z5, FIX_0_785694958);
+                    z5 = MULTIPLY(z5, FIX_1_175875602);
+
+                    tmp0 = z1 - z4;
+                    tmp1 = z2 + z4;
+                    tmp2 += z5;
+                    tmp3 += z5;
+                } else {
+                    /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
+                    tmp0 = MULTIPLY(-d3, FIX_0_785694958);
+                    tmp1 = MULTIPLY(-d3, FIX_1_387039845);
+                    tmp2 = MULTIPLY(-d3, FIX_0_275899380);
+                    tmp3 = MULTIPLY(d3, FIX_1_175875602);
+                }
+            } else {
+                if (d1) {
+                    /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
+                    tmp0 = MULTIPLY(d1, FIX_0_275899380);
+                    tmp1 = MULTIPLY(d1, FIX_0_785694958);
+                    tmp2 = MULTIPLY(d1, FIX_1_175875602);
+                    tmp3 = MULTIPLY(d1, FIX_1_387039845);
+                } else {
+                    /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
+                    tmp0 = tmp1 = tmp2 = tmp3 = 0;
+                }
+            }
+        }
+    }
+
+    /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+    dataptr[DCTSIZE*0] = (int16_t) DESCALE(tmp10 + tmp3,
+                                           CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSIZE*7] = (int16_t) DESCALE(tmp10 - tmp3,
+                                           CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSIZE*1] = (int16_t) DESCALE(tmp11 + tmp2,
+                                           CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSIZE*6] = (int16_t) DESCALE(tmp11 - tmp2,
+                                           CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSIZE*2] = (int16_t) DESCALE(tmp12 + tmp1,
+                                           CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSIZE*5] = (int16_t) DESCALE(tmp12 - tmp1,
+                                           CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSIZE*3] = (int16_t) DESCALE(tmp13 + tmp0,
+                                           CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSIZE*4] = (int16_t) DESCALE(tmp13 - tmp0,
+                                           CONST_BITS+PASS1_BITS+3);
+
+    dataptr++;                  /* advance pointer to next column */
+  }
+}
+
+#undef DCTSIZE
+#define DCTSIZE 4
+#define DCTSTRIDE 8
+
+void ff_j_rev_dct4(DCTBLOCK data)
+{
+  int32_t tmp0, tmp1, tmp2, tmp3;
+  int32_t tmp10, tmp11, tmp12, tmp13;
+  int32_t z1;
+  int32_t d0, d2, d4, d6;
+  register int16_t *dataptr;
+  int rowctr;
+
+  /* Pass 1: process rows. */
+  /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
+  /* furthermore, we scale the results by 2**PASS1_BITS. */
+
+  data[0] += 4;
+
+  dataptr = data;
+
+  for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
+    /* Due to quantization, we will usually find that many of the input
+     * coefficients are zero, especially the AC terms.  We can exploit this
+     * by short-circuiting the IDCT calculation for any row in which all
+     * the AC terms are zero.  In that case each output is equal to the
+     * DC coefficient (with scale factor as needed).
+     * With typical images and quantization tables, half or more of the
+     * row DCT calculations can be simplified this way.
+     */
+
+    register uint8_t *idataptr = (uint8_t*)dataptr;
+
+    d0 = dataptr[0];
+    d2 = dataptr[1];
+    d4 = dataptr[2];
+    d6 = dataptr[3];
+
+    if ((d2 | d4 | d6) == 0) {
+      /* AC terms all zero */
+      if (d0) {
+          /* Compute a 32 bit value to assign. */
+          int16_t dcval = (int16_t) (d0 * (1 << PASS1_BITS));
+          register unsigned v = (dcval & 0xffff) | ((uint32_t)dcval << 16);
+
+          AV_WN32A(&idataptr[0], v);
+          AV_WN32A(&idataptr[4], v);
+      }
+
+      dataptr += DCTSTRIDE;     /* advance pointer to next row */
+      continue;
+    }
+
+    /* Even part: reverse the even part of the forward DCT. */
+    /* The rotator is sqrt(2)*c(-6). */
+    if (d6) {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
+                    z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
+                    tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
+                    tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
+
+                    tmp0 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp1 = (d0 - d4) * (1 << CONST_BITS);
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
+                    tmp2 = MULTIPLY(-d6, FIX_1_306562965);
+                    tmp3 = MULTIPLY(d6, FIX_0_541196100);
+
+                    tmp0 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp1 = (d0 - d4) * (1 << CONST_BITS);
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            }
+    } else {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
+                    tmp2 = MULTIPLY(d2, FIX_0_541196100);
+                    tmp3 = MULTIPLY(d2, FIX_1_306562965);
+
+                    tmp0 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp1 = (d0 - d4) * (1 << CONST_BITS);
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
+                    tmp10 = tmp13 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp11 = tmp12 = (d0 - d4) * (1 << CONST_BITS);
+            }
+      }
+
+    /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+    dataptr[0] = (int16_t) DESCALE(tmp10, CONST_BITS-PASS1_BITS);
+    dataptr[1] = (int16_t) DESCALE(tmp11, CONST_BITS-PASS1_BITS);
+    dataptr[2] = (int16_t) DESCALE(tmp12, CONST_BITS-PASS1_BITS);
+    dataptr[3] = (int16_t) DESCALE(tmp13, CONST_BITS-PASS1_BITS);
+
+    dataptr += DCTSTRIDE;       /* advance pointer to next row */
+  }
+
+  /* Pass 2: process columns. */
+  /* Note that we must descale the results by a factor of 8 == 2**3, */
+  /* and also undo the PASS1_BITS scaling. */
+
+  dataptr = data;
+  for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
+    /* Columns of zeroes can be exploited in the same way as we did with rows.
+     * However, the row calculation has created many nonzero AC terms, so the
+     * simplification applies less often (typically 5% to 10% of the time).
+     * On machines with very fast multiplication, it's possible that the
+     * test takes more time than it's worth.  In that case this section
+     * may be commented out.
+     */
+
+    d0 = dataptr[DCTSTRIDE*0];
+    d2 = dataptr[DCTSTRIDE*1];
+    d4 = dataptr[DCTSTRIDE*2];
+    d6 = dataptr[DCTSTRIDE*3];
+
+    /* Even part: reverse the even part of the forward DCT. */
+    /* The rotator is sqrt(2)*c(-6). */
+    if (d6) {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
+                    z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
+                    tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
+                    tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
+
+                    tmp0 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp1 = (d0 - d4) * (1 << CONST_BITS);
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
+                    tmp2 = MULTIPLY(-d6, FIX_1_306562965);
+                    tmp3 = MULTIPLY(d6, FIX_0_541196100);
+
+                    tmp0 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp1 = (d0 - d4) * (1 << CONST_BITS);
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            }
+    } else {
+            if (d2) {
+                    /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
+                    tmp2 = MULTIPLY(d2, FIX_0_541196100);
+                    tmp3 = MULTIPLY(d2, FIX_1_306562965);
+
+                    tmp0 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp1 = (d0 - d4) * (1 << CONST_BITS);
+
+                    tmp10 = tmp0 + tmp3;
+                    tmp13 = tmp0 - tmp3;
+                    tmp11 = tmp1 + tmp2;
+                    tmp12 = tmp1 - tmp2;
+            } else {
+                    /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
+                    tmp10 = tmp13 = (d0 + d4) * (1 << CONST_BITS);
+                    tmp11 = tmp12 = (d0 - d4) * (1 << CONST_BITS);
+            }
+    }
+
+    /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+    dataptr[DCTSTRIDE*0] = tmp10 >> (CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSTRIDE*1] = tmp11 >> (CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSTRIDE*2] = tmp12 >> (CONST_BITS+PASS1_BITS+3);
+    dataptr[DCTSTRIDE*3] = tmp13 >> (CONST_BITS+PASS1_BITS+3);
+
+    dataptr++;                  /* advance pointer to next column */
+  }
+}
+
+void ff_j_rev_dct2(DCTBLOCK data){
+  int d00, d01, d10, d11;
+
+  data[0] += 4;
+  d00 = data[0+0*DCTSTRIDE] + data[1+0*DCTSTRIDE];
+  d01 = data[0+0*DCTSTRIDE] - data[1+0*DCTSTRIDE];
+  d10 = data[0+1*DCTSTRIDE] + data[1+1*DCTSTRIDE];
+  d11 = data[0+1*DCTSTRIDE] - data[1+1*DCTSTRIDE];
+
+  data[0+0*DCTSTRIDE]= (d00 + d10)>>3;
+  data[1+0*DCTSTRIDE]= (d01 + d11)>>3;
+  data[0+1*DCTSTRIDE]= (d00 - d10)>>3;
+  data[1+1*DCTSTRIDE]= (d01 - d11)>>3;
+}
+
+void ff_j_rev_dct1(DCTBLOCK data){
+  data[0] = (data[0] + 4)>>3;
+}
+
+#undef FIX
+#undef CONST_BITS
+
+void ff_jref_idct_put(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
+{
+    ff_j_rev_dct(block);
+    ff_put_pixels_clamped_c(block, dest, line_size);
+}
+
+void ff_jref_idct_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
+{
+    ff_j_rev_dct(block);
+    ff_add_pixels_clamped_c(block, dest, line_size);
+}