Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / mqcenc.c
1 /*
2 * MQ-coder encoder
3 * Copyright (c) 2007 Kamil Nowosad
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * MQ-coder encoder
24 * @file
25 * @author Kamil Nowosad
26 */
27
28 #include "mqc.h"
29
30 static void byteout(MqcState *mqc)
31 {
32 retry:
33 if (*mqc->bp == 0xff){
34 mqc->bp++;
35 *mqc->bp = mqc->c >> 20;
36 mqc->c &= 0xfffff;
37 mqc->ct = 7;
38 } else if ((mqc->c & 0x8000000)){
39 (*mqc->bp)++;
40 mqc->c &= 0x7ffffff;
41 goto retry;
42 } else{
43 mqc->bp++;
44 *mqc->bp = mqc->c >> 19;
45 mqc->c &= 0x7ffff;
46 mqc->ct = 8;
47 }
48 }
49
50 static void renorme(MqcState *mqc)
51 {
52 do{
53 mqc->a += mqc->a;
54 mqc->c += mqc->c;
55 if (!--mqc->ct)
56 byteout(mqc);
57 } while (!(mqc->a & 0x8000));
58 }
59
60 static void setbits(MqcState *mqc)
61 {
62 int tmp = mqc->c + mqc->a;
63 mqc->c |= 0xffff;
64 if (mqc->c >= tmp)
65 mqc->c -= 0x8000;
66 }
67
68 void ff_mqc_initenc(MqcState *mqc, uint8_t *bp)
69 {
70 ff_mqc_init_contexts(mqc);
71 mqc->a = 0x8000;
72 mqc->c = 0;
73 mqc->bp = bp-1;
74 mqc->bpstart = bp;
75 mqc->ct = 12 + (*mqc->bp == 0xff);
76 }
77
78 void ff_mqc_encode(MqcState *mqc, uint8_t *cxstate, int d)
79 {
80 int qe;
81
82 qe = ff_mqc_qe[*cxstate];
83 mqc->a -= qe;
84 if ((*cxstate & 1) == d){
85 if (!(mqc->a & 0x8000)){
86 if (mqc->a < qe)
87 mqc->a = qe;
88 else
89 mqc->c += qe;
90 *cxstate = ff_mqc_nmps[*cxstate];
91 renorme(mqc);
92 } else
93 mqc->c += qe;
94 } else{
95 if (mqc->a < qe)
96 mqc->c += qe;
97 else
98 mqc->a = qe;
99 *cxstate = ff_mqc_nlps[*cxstate];
100 renorme(mqc);
101 }
102 }
103
104 int ff_mqc_length(MqcState *mqc)
105 {
106 return mqc->bp - mqc->bpstart;
107 }
108
109 int ff_mqc_flush(MqcState *mqc)
110 {
111 setbits(mqc);
112 mqc->c = mqc->c << mqc->ct;
113 byteout(mqc);
114 mqc->c = mqc->c << mqc->ct;
115 byteout(mqc);
116 if (*mqc->bp != 0xff)
117 mqc->bp++;
118 return mqc->bp - mqc->bpstart;
119 }