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 "codec_internal.h"
22 #include "mpegutils.h"
23 #include "mpegvideo.h"
24 #include "mpegvideodec.h"
25 #include "h263data.h"
26 #include "h263dec.h"
27 #include "mpegvideodata.h"
28
29 /* don't understand why they choose a different header ! */
ff_intel_h263_decode_picture_header(MpegEncContext * s)30 int ff_intel_h263_decode_picture_header(MpegEncContext *s)
31 {
32 int format;
33
34 if (get_bits_left(&s->gb) == 64) { /* special dummy frames */
35 return FRAME_SKIPPED;
36 }
37
38 /* picture header */
39 if (get_bits(&s->gb, 22) != 0x20) {
40 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
41 return -1;
42 }
43 s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
44
45 if (check_marker(s->avctx, &s->gb, "after picture_number") != 1) {
46 return -1; /* marker */
47 }
48 if (get_bits1(&s->gb) != 0) {
49 av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
50 return -1; /* H.263 id */
51 }
52 skip_bits1(&s->gb); /* split screen off */
53 skip_bits1(&s->gb); /* camera off */
54 skip_bits1(&s->gb); /* freeze picture release off */
55
56 format = get_bits(&s->gb, 3);
57 if (format == 0 || format == 6) {
58 av_log(s->avctx, AV_LOG_ERROR, "Intel H.263 free format not supported\n");
59 return -1;
60 }
61 s->h263_plus = 0;
62
63 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
64
65 s->h263_long_vectors = get_bits1(&s->gb);
66
67 if (get_bits1(&s->gb) != 0) {
68 av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
69 return -1; /* SAC: off */
70 }
71 s->obmc= get_bits1(&s->gb);
72 s->pb_frame = get_bits1(&s->gb);
73
74 if (format < 6) {
75 s->width = ff_h263_format[format][0];
76 s->height = ff_h263_format[format][1];
77 s->avctx->sample_aspect_ratio.num = 12;
78 s->avctx->sample_aspect_ratio.den = 11;
79 } else {
80 format = get_bits(&s->gb, 3);
81 if(format == 0 || format == 7){
82 av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H.263 format\n");
83 return -1;
84 }
85 if(get_bits(&s->gb, 2))
86 av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
87 s->loop_filter = get_bits1(&s->gb) * !s->avctx->lowres;
88 if(get_bits1(&s->gb))
89 av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
90 if(get_bits1(&s->gb))
91 s->pb_frame = 2;
92 if(get_bits(&s->gb, 5))
93 av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
94 if(get_bits(&s->gb, 5) != 1)
95 av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
96 }
97 if(format == 6){
98 int ar = get_bits(&s->gb, 4);
99 skip_bits(&s->gb, 9); // display width
100 check_marker(s->avctx, &s->gb, "in dimensions");
101 skip_bits(&s->gb, 9); // display height
102 if(ar == 15){
103 s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
104 s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height
105 } else {
106 s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
107 }
108 if (s->avctx->sample_aspect_ratio.num == 0)
109 av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");
110 }
111
112 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
113 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
114
115 if(s->pb_frame){
116 skip_bits(&s->gb, 3); //temporal reference for B-frame
117 skip_bits(&s->gb, 2); //dbquant
118 }
119
120 /* PEI */
121 if (skip_1stop_8data_bits(&s->gb) < 0)
122 return AVERROR_INVALIDDATA;
123 s->f_code = 1;
124
125 s->y_dc_scale_table=
126 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
127
128 ff_h263_show_pict_info(s);
129
130 return 0;
131 }
132
133 const FFCodec ff_h263i_decoder = {
134 .p.name = "h263i",
135 .p.long_name = NULL_IF_CONFIG_SMALL("Intel H.263"),
136 .p.type = AVMEDIA_TYPE_VIDEO,
137 .p.id = AV_CODEC_ID_H263I,
138 .priv_data_size = sizeof(MpegEncContext),
139 .init = ff_h263_decode_init,
140 .close = ff_h263_decode_end,
141 FF_CODEC_DECODE_CB(ff_h263_decode_frame),
142 .p.capabilities = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
143 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
144 FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
145 .p.pix_fmts = (const enum AVPixelFormat[]) {
146 AV_PIX_FMT_YUV420P,
147 AV_PIX_FMT_NONE
148 },
149 };
150