JPEG 2000 decoder for DCinema

Based on the 2007 GSoC project from Kamil Nowosad <k.nowosad@students.mimuw.edu.pl>
Updated to current programming standards, style and many more small
fixes by Diego Biurrun <diego@biurrun.de>.

Signed-off-by: Diego Biurrun <diego@biurrun.de>

1 files changed, 93 insertions, 0 deletions

diff --git a/libavcodec/mqcdec.c b/libavcodec/mqcdec.c
new file mode 100644
index 0000000000..889763ac66
--- /dev/null
+++ b/libavcodec/mqcdec.c
@@ -0,0 +1,93 @@
+/*
+ * MQ-coder decoder
+ * Copyright (c) 2007 Kamil Nowosad
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * MQ-coder decoder
+ * @file
+ * @author Kamil Nowosad
+ */
+
+#include "mqc.h"
+
+static void bytein(MqcState *mqc)
+{
+    if (*mqc->bp == 0xff) {
+        if (*(mqc->bp + 1) > 0x8f)
+            mqc->c++;
+        else {
+            mqc->bp++;
+            mqc->c += 2 + 0xfe00 - (*mqc->bp << 9);
+        }
+    } else {
+        mqc->bp++;
+        mqc->c += 1 + 0xff00 - (*mqc->bp << 8);
+    }
+}
+
+static int exchange(MqcState *mqc, uint8_t *cxstate, int lps)
+{
+    int d;
+    if ((mqc->a < ff_mqc_qe[*cxstate]) ^ (!lps)) {
+        if (lps)
+            mqc->a = ff_mqc_qe[*cxstate];
+        d = *cxstate & 1;
+        *cxstate = ff_mqc_nmps[*cxstate];
+    } else {
+        if (lps)
+            mqc->a = ff_mqc_qe[*cxstate];
+        d = 1 - (*cxstate & 1);
+        *cxstate = ff_mqc_nlps[*cxstate];
+    }
+    // do RENORMD: see ISO/IEC 15444-1:2002 §C.3.3
+    do {
+        if (!(mqc->c & 0xff)) {
+            mqc->c -= 0x100;
+            bytein(mqc);
+        }
+        mqc->a += mqc->a;
+        mqc->c += mqc->c;
+    } while (!(mqc->a & 0x8000));
+    return d;
+}
+
+void ff_mqc_initdec(MqcState *mqc, uint8_t *bp)
+{
+    ff_mqc_init_contexts(mqc);
+    mqc->bp = bp;
+    mqc->c  = (*mqc->bp ^ 0xff) << 16;
+    bytein(mqc);
+    mqc->c = mqc->c << 7;
+    mqc->a = 0x8000;
+}
+
+int ff_mqc_decode(MqcState *mqc, uint8_t *cxstate)
+{
+    mqc->a -= ff_mqc_qe[*cxstate];
+    if ((mqc->c >> 16) < mqc->a) {
+        if (mqc->a & 0x8000)
+            return *cxstate & 1;
+        else
+            return exchange(mqc, cxstate, 0);
+    } else {
+        mqc->c -= mqc->a << 16;
+        return exchange(mqc, cxstate, 1);
+    }
+}