libavcodec/jpeg2000dec.c: fix error in cod marker

This patch fixes an error where the COC marker
overrides all data of the SPcod field of the
COD marker. It must override only one bit of
SPcod field. This now allows p0_08.j2k to be
decoded correctly (mentioned in #4679).
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/jpeg2000dec.c

@@ -566,6 +566,7 @@ static int get_coc(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c,
                    uint8_t *properties)
 {
     int compno, ret;
+    uint8_t has_eph;
 
     if (bytestream2_get_bytes_left(&s->g) < 2) {
         av_log(s->avctx, AV_LOG_ERROR, "Insufficient space for COC\n");
@@ -582,7 +583,9 @@ static int get_coc(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c,
     }
 
     c      += compno;
+    has_eph = c->csty & JPEG2000_CSTY_EPH;
     c->csty = bytestream2_get_byteu(&s->g);
+    c->csty |= has_eph; //do not override eph present bits from COD
 
     if ((ret = get_cox(s, c)) < 0)
         return ret;