Merge commit 'f9581f1414ec8e3e7d0868793cda4f2e4fa113ea'

* commit 'f9581f1414ec8e3e7d0868793cda4f2e4fa113ea':
  jpeg2000: Improve reduced resolution decoding
  jpeg2000: Compute quantization for 'scalar derived' in the correct case.
  jpeg2000: Calculate code-block coord in ff_jpeg2000_init_component()

Conflicts:
	libavcodec/jpeg2000.c
	libavcodec/jpeg2000dec.c

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

libavcodec/jpeg2000.c

@@ -316,7 +316,7 @@ int ff_jpeg2000_init_component(Jpeg2000Component *comp,
                 break;
             }
             /* FIXME: In openjepg code stespize = stepsize * 0.5. Why?
-                * If not set output of entropic decoder is not correct. */
+             * If not set output of entropic decoder is not correct. */
             if (!av_codec_is_encoder(avctx->codec))
                 band->f_stepsize *= 0.5;
 
@@ -451,14 +451,18 @@ int ff_jpeg2000_init_component(Jpeg2000Component *comp,
                     /* Compute Cy1 */
                     cblk->coord[1][1] = FFMIN(Cy0 + (1 << band->log2_cblk_height),
                                               prec->coord[1][1]);
-
-                    if((bandno + !!reslevelno) & 1) {
-                        cblk->coord[0][0] += comp->reslevel[reslevelno-1].coord[0][1] - comp->reslevel[reslevelno-1].coord[0][0];
-                        cblk->coord[0][1] += comp->reslevel[reslevelno-1].coord[0][1] - comp->reslevel[reslevelno-1].coord[0][0];
+                    /* Update code-blocks coordinates according sub-band position */
+                    if ((bandno + !!reslevelno) & 1) {
+                        cblk->coord[0][0] += comp->reslevel[reslevelno-1].coord[0][1] -
+                                             comp->reslevel[reslevelno-1].coord[0][0];
+                        cblk->coord[0][1] += comp->reslevel[reslevelno-1].coord[0][1] -
+                                             comp->reslevel[reslevelno-1].coord[0][0];
                     }
-                    if((bandno + !!reslevelno) & 2) {
-                        cblk->coord[1][0] += comp->reslevel[reslevelno-1].coord[1][1] - comp->reslevel[reslevelno-1].coord[1][0];
-                        cblk->coord[1][1] += comp->reslevel[reslevelno-1].coord[1][1] - comp->reslevel[reslevelno-1].coord[1][0];
+                    if ((bandno + !!reslevelno) & 2) {
+                        cblk->coord[1][0] += comp->reslevel[reslevelno-1].coord[1][1] -
+                                             comp->reslevel[reslevelno-1].coord[1][0];
+                        cblk->coord[1][1] += comp->reslevel[reslevelno-1].coord[1][1] -
+                                             comp->reslevel[reslevelno-1].coord[1][0];
                     }
 
                     cblk->zero      = 0;

libavcodec/jpeg2000dec.c

@@ -86,7 +86,6 @@ typedef struct Jpeg2000DecoderContext {
     Jpeg2000Tile    *tile;
 
     /*options parameters*/
-    int             lowres;
     int             reduction_factor;
 } Jpeg2000DecoderContext;
 
@@ -1121,7 +1120,6 @@ static int jpeg2000_decode_tile(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile,
                                     cblk->coord[1][1] - cblk->coord[1][0],
                                     bandpos);
 
-                        /* Manage band offsets */
                         x = cblk->coord[0][0];
                         y = cblk->coord[1][0];
 
@@ -1396,9 +1394,6 @@ static int jpeg2000_decode_frame(AVCodecContext *avctx, void *data,
     bytestream2_init(&s->g, avpkt->data, avpkt->size);
     s->curtileno = -1;
 
-    // reduction factor, i.e number of resolution levels to skip
-    s->reduction_factor = s->lowres;
-
     if (bytestream2_get_bytes_left(&s->g) < 2) {
         ret = AVERROR_INVALIDDATA;
         goto end;
@@ -1463,7 +1458,7 @@ static void jpeg2000_init_static_data(AVCodec *codec)
 
 static const AVOption options[] = {
     { "lowres",  "Lower the decoding resolution by a power of two",
-        OFFSET(lowres), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, JPEG2000_MAX_RESLEVELS - 1, VD },
+        OFFSET(reduction_factor), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, JPEG2000_MAX_RESLEVELS - 1, VD },
     { NULL },
 };