From c81a70638116eaf4251075475e5cbb600a33c5ec Mon Sep 17 00:00:00 2001 From: Nicolas Bertrand Date: Mon, 22 Apr 2013 11:41:01 +0200 Subject: JPEG 2000 decoder for DCinema Based on the 2007 GSoC project from Kamil Nowosad Updated to current programming standards, style and many more small fixes by Diego Biurrun . Signed-off-by: Diego Biurrun --- libavcodec/mqcdec.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 libavcodec/mqcdec.c (limited to 'libavcodec/mqcdec.c') 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); + } +} -- cgit v1.2.3