j2k/jpeg2000: split stepsize in float & int variables

This is more clear and less prone to mistakes.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/j2k.c

@@ -248,7 +248,6 @@ int ff_j2k_init_component(Jpeg2000Component *comp,
             Jpeg2000Band *band = reslevel->band + bandno;
             int cblkno, precno;
             int nb_precincts;
-            double stepsize;
 
             /* TODO: Implementation of quantization step not finished,
              * see ISO/IEC 15444-1:2002 E.1 and A.6.4. */
@@ -257,13 +256,13 @@ int ff_j2k_init_component(Jpeg2000Component *comp,
                 int numbps;
             case JPEG2000_QSTY_NONE:
                 /* TODO: to verify. No quantization in this case */
-                stepsize = 1;
+                band->f_stepsize = 1;
                 break;
             case JPEG2000_QSTY_SI:
                 /*TODO: Compute formula to implement. */
                 numbps = cbps +
                          lut_gain[codsty->transform][bandno + (reslevelno > 0)];
-                stepsize = SHL(2048 + qntsty->mant[gbandno],
+                band->f_stepsize = SHL(2048 + qntsty->mant[gbandno],
                                             2 + numbps - qntsty->expn[gbandno]);
                 break;
             case JPEG2000_QSTY_SE:
@@ -276,21 +275,20 @@ int ff_j2k_init_component(Jpeg2000Component *comp,
                  * but it works (compared to OpenJPEG). Why?
                  * Further investigation needed. */
                 gain      = cbps;
-                stepsize  = pow(2.0, gain - qntsty->expn[gbandno]);
-                stepsize *= (qntsty->mant[gbandno] / 2048.0 + 1.0);
+                band->f_stepsize  = pow(2.0, gain - qntsty->expn[gbandno]);
+                band->f_stepsize *= (qntsty->mant[gbandno] / 2048.0 + 1.0);
                 break;
             default:
-                stepsize = 0;
+                band->f_stepsize = 0;
                 av_log(avctx, AV_LOG_ERROR, "Unknown quantization format\n");
                 break;
             }
             /* FIXME: In openjepg code stespize = stepsize * 0.5. Why?
              * If not set output of entropic decoder is not correct. */
             if (!av_codec_is_encoder(avctx->codec))
-                stepsize *= 0.5;
-            /* BITEXACT computing case --> convert to int */
-//             if (avctx->flags & CODEC_FLAG_BITEXACT)
-            band->stepsize = stepsize * (1 << 16);
+                band->f_stepsize *= 0.5;
+
+            band->i_stepsize = band->f_stepsize * (1 << 16);
 
             /* computation of tbx_0, tbx_1, tby_0, tby_1
              * see ISO/IEC 15444-1:2002 B.5 eq. B-15 and tbl B.1

libavcodec/j2k.h

@@ -179,7 +179,8 @@ typedef struct Jpeg2000Prec {
 typedef struct Jpeg2000Band {
     uint16_t coord[2][2]; // border coordinates {{x0, x1}, {y0, y1}}
     uint16_t log2_cblk_width, log2_cblk_height;
-    uint32_t stepsize; // quantization stepsize (* 2^13)
+    int i_stepsize; // quantization stepsize
+    float f_stepsize; // quantization stepsize
     Jpeg2000Prec *prec;
 } Jpeg2000Band; // subband
 

libavcodec/j2kdec.c

@@ -827,7 +827,7 @@ static void dequantization_int(int x, int y, Jpeg2000Cblk *cblk,
         for (i = 0; i < (cblk->coord[0][1] - cblk->coord[0][0]); ++i) {
             idx        = (comp->coord[0][1] - comp->coord[0][0]) * j + i;
             datap[idx] =
-                ((int32_t)(t1->data[j][i]) * ((int32_t)band->stepsize) + (1 << 15)) >> 16;
+                ((int32_t)(t1->data[j][i]) * band->i_stepsize + (1 << 15)) >> 16;
         }
 }
 

libavcodec/j2kenc.c

@@ -802,7 +802,7 @@ static void truncpasses(Jpeg2000EncoderContext *s, Jpeg2000Tile *tile)
                         Jpeg2000Cblk *cblk = prec->cblk + cblkno;
 
                         cblk->ninclpasses = getcut(cblk, s->lambda,
-                                (int64_t)dwt_norms[codsty->transform][bandpos][lev] * (int64_t)band->stepsize >> 16);
+                                (int64_t)dwt_norms[codsty->transform][bandpos][lev] * (int64_t)band->i_stepsize >> 16);
                     }
                 }
             }
@@ -863,7 +863,7 @@ static int encode_tile(Jpeg2000EncoderContext *s, Jpeg2000Tile *tile, int tileno
                                 int *ptr = t1.data[y-yy0];
                                 for (x = xx0; x < xx1; x++){
                                     *ptr = (comp->data[(comp->coord[0][1] - comp->coord[0][0]) * y + x]);
-                                    *ptr = (int64_t)*ptr * (int64_t)(16384 * 65536 / band->stepsize) >> 14 - NMSEDEC_FRACBITS;
+                                    *ptr = (int64_t)*ptr * (int64_t)(16384 * 65536 / band->i_stepsize) >> 14 - NMSEDEC_FRACBITS;
                                     ptr++;
                                 }
                             }

libavcodec/jpeg2000.c

@@ -267,13 +267,13 @@ int ff_jpeg2000_init_component(Jpeg2000Component *comp,
                 int numbps;
             case JPEG2000_QSTY_NONE:
                 /* TODO: to verify. No quantization in this case */
-                band->stepsize = (float) (1 << 13);
+                band->f_stepsize = (float) (1 << 13);
                 break;
             case JPEG2000_QSTY_SI:
                 /*TODO: Compute formula to implement. */
                 numbps = cbps +
                          lut_gain[codsty->transform][bandno + (reslevelno > 0)];
-                band->stepsize = (float)SHL(2048 + qntsty->mant[gbandno],
+                band->f_stepsize = (float)SHL(2048 + qntsty->mant[gbandno],
                                             2 + numbps - qntsty->expn[gbandno]);
                 break;
             case JPEG2000_QSTY_SE:
@@ -286,20 +286,20 @@ int ff_jpeg2000_init_component(Jpeg2000Component *comp,
                  * but it works (compared to OpenJPEG). Why?
                  * Further investigation needed. */
                 gain            = cbps;
-                band->stepsize  = pow(2.0, gain - qntsty->expn[gbandno]);
-                band->stepsize *= (float)qntsty->mant[gbandno] / 2048.0 + 1.0;
+                band->f_stepsize  = pow(2.0, gain - qntsty->expn[gbandno]);
+                band->f_stepsize *= (float)qntsty->mant[gbandno] / 2048.0 + 1.0;
                 break;
             default:
-                band->stepsize = 0;
+                band->f_stepsize = 0;
                 av_log(avctx, AV_LOG_ERROR, "Unknown quantization format\n");
                 break;
             }
             /* FIXME: In openjepg code stespize = stepsize * 0.5. Why?
                 * If not set output of entropic decoder is not correct. */
-            band->stepsize *= 0.5;
-            /* BITEXACT computing case --> convert to int */
-            if (avctx->flags & CODEC_FLAG_BITEXACT)
-                band->stepsize = (int32_t)(band->stepsize * (1 << 16));
+            if (!av_codec_is_encoder(avctx->codec))
+                band->f_stepsize *= 0.5;
+
+            band->i_stepsize = (int32_t)(band->f_stepsize * (1 << 16));
 
             /* computation of tbx_0, tbx_1, tby_0, tby_1
              * see ISO/IEC 15444-1:2002 B.5 eq. B-15 and tbl B.1

libavcodec/jpeg2000.h

@@ -176,12 +176,11 @@ typedef struct Jpeg2000Prec {
     uint16_t coord[2][2]; // border coordinates {{x0, x1}, {y0, y1}}
 } Jpeg2000Prec; // precinct
 
-/* TODO: stepsize can be float or integer depending on
- * reversible or irreversible transformation. */
 typedef struct Jpeg2000Band {
     uint16_t coord[2][2]; // border coordinates {{x0, x1}, {y0, y1}}
     uint16_t log2_cblk_width, log2_cblk_height;
-    float stepsize; // quantization stepsize
+    int i_stepsize; // quantization stepsize
+    float f_stepsize; // quantization stepsize
     Jpeg2000Prec *prec;
 } Jpeg2000Band; // subband
 

libavcodec/jpeg2000dec.c

@@ -930,7 +930,7 @@ static void dequantization_float(int x, int y, Jpeg2000Cblk *cblk,
     for (j = 0; j < (cblk->coord[1][1] - cblk->coord[1][0]); ++j)
         for (i = 0; i < (cblk->coord[0][1] - cblk->coord[0][0]); ++i) {
             idx        = (comp->coord[0][1] - comp->coord[0][0]) * j + i;
-            datap[idx] = (float)(t1->data[j][i]) * ((float)band->stepsize);
+            datap[idx] = (float)(t1->data[j][i]) * band->f_stepsize;
         }
 }
 
@@ -946,7 +946,7 @@ static void dequantization_int(int x, int y, Jpeg2000Cblk *cblk,
         for (i = 0; i < (cblk->coord[0][1] - cblk->coord[0][0]); ++i) {
             idx        = (comp->coord[0][1] - comp->coord[0][0]) * j + i;
             datap[idx] =
-                ((int32_t)(t1->data[j][i]) * ((int32_t)band->stepsize) + (1 << 15)) >> 16;
+                ((int32_t)(t1->data[j][i]) * band->i_stepsize + (1 << 15)) >> 16;
         }
 }