1/*
2 * H.263i decoder
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include "mpegvideo.h"
22#include "h263.h"
23
24/* don't understand why they choose a different header ! */
25int ff_intel_h263_decode_picture_header(MpegEncContext *s)
26{
27    int format;
28
29    /* picture header */
30    if (get_bits_long(&s->gb, 22) != 0x20) {
31        av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
32        return -1;
33    }
34    s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
35
36    if (get_bits1(&s->gb) != 1) {
37        av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
38        return -1;      /* marker */
39    }
40    if (get_bits1(&s->gb) != 0) {
41        av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
42        return -1;      /* h263 id */
43    }
44    skip_bits1(&s->gb);         /* split screen off */
45    skip_bits1(&s->gb);         /* camera  off */
46    skip_bits1(&s->gb);         /* freeze picture release off */
47
48    format = get_bits(&s->gb, 3);
49    if (format != 7) {
50        av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n");
51        return -1;
52    }
53    s->h263_plus = 0;
54
55    s->pict_type = FF_I_TYPE + get_bits1(&s->gb);
56
57    s->unrestricted_mv = get_bits1(&s->gb);
58    s->h263_long_vectors = s->unrestricted_mv;
59
60    if (get_bits1(&s->gb) != 0) {
61        av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
62        return -1;      /* SAC: off */
63    }
64    s->obmc= get_bits1(&s->gb);
65    s->pb_frame = get_bits1(&s->gb);
66
67    if(format == 7){
68        format = get_bits(&s->gb, 3);
69        if(format == 0 || format == 7){
70            av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H263 format\n");
71            return -1;
72        }
73        if(get_bits(&s->gb, 2))
74            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
75        s->loop_filter = get_bits1(&s->gb);
76        if(get_bits1(&s->gb))
77            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
78        if(get_bits1(&s->gb))
79            s->pb_frame = 2;
80        if(get_bits(&s->gb, 5))
81            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
82        if(get_bits(&s->gb, 5) != 1)
83            av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
84    }
85    if(format == 6){
86        int ar = get_bits(&s->gb, 4);
87        skip_bits(&s->gb, 9); // display width
88        skip_bits1(&s->gb);
89        skip_bits(&s->gb, 9); // display height
90        if(ar == 15){
91            skip_bits(&s->gb, 8); // aspect ratio - width
92            skip_bits(&s->gb, 8); // aspect ratio - height
93        }
94    }
95
96    s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
97    skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
98
99    if(s->pb_frame){
100        skip_bits(&s->gb, 3); //temporal reference for B-frame
101        skip_bits(&s->gb, 2); //dbquant
102    }
103
104    /* PEI */
105    while (get_bits1(&s->gb) != 0) {
106        skip_bits(&s->gb, 8);
107    }
108    s->f_code = 1;
109
110    s->y_dc_scale_table=
111    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
112
113    ff_h263_show_pict_info(s);
114
115    return 0;
116}
117
118AVCodec h263i_decoder = {
119    "h263i",
120    AVMEDIA_TYPE_VIDEO,
121    CODEC_ID_H263I,
122    sizeof(MpegEncContext),
123    ff_h263_decode_init,
124    NULL,
125    ff_h263_decode_end,
126    ff_h263_decode_frame,
127    CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
128    .long_name = NULL_IF_CONFIG_SMALL("Intel H.263"),
129    .pix_fmts= ff_pixfmt_list_420,
130};
131
132