path: root/libavcodec/intelh263dec.c (plain)
blob: d321dd4dba5f0d6a127c87a3ffff7af92d040397

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 "mpegutils.h"
22	#include "mpegvideo.h"
23	#include "h263.h"
24	#include "mpegvideodata.h"
25
26	/* don't understand why they choose a different header ! */
27	int ff_intel_h263_decode_picture_header(MpegEncContext *s)
28	{
29	int format;
30
31	if (get_bits_left(&s->gb) == 64) { /* special dummy frames */
32	return FRAME_SKIPPED;
33	}
34
35	/* picture header */
36	if (get_bits_long(&s->gb, 22) != 0x20) {
37	av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
38	return -1;
39	}
40	s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
41
42	if (check_marker(s->avctx, &s->gb, "after picture_number") != 1) {
43	return -1; /* marker */
44	}
45	if (get_bits1(&s->gb) != 0) {
46	av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
47	return -1; /* H.263 id */
48	}
49	skip_bits1(&s->gb); /* split screen off */
50	skip_bits1(&s->gb); /* camera off */
51	skip_bits1(&s->gb); /* freeze picture release off */
52
53	format = get_bits(&s->gb, 3);
54	if (format == 0 || format == 6) {
55	av_log(s->avctx, AV_LOG_ERROR, "Intel H.263 free format not supported\n");
56	return -1;
57	}
58	s->h263_plus = 0;
59
60	s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
61
62	s->h263_long_vectors = get_bits1(&s->gb);
63
64	if (get_bits1(&s->gb) != 0) {
65	av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
66	return -1; /* SAC: off */
67	}
68	s->obmc= get_bits1(&s->gb);
69	s->unrestricted_mv = s->obmc || s->h263_long_vectors;
70	s->pb_frame = get_bits1(&s->gb);
71
72	if (format < 6) {
73	s->width = ff_h263_format[format][0];
74	s->height = ff_h263_format[format][1];
75	s->avctx->sample_aspect_ratio.num = 12;
76	s->avctx->sample_aspect_ratio.den = 11;
77	} else {
78	format = get_bits(&s->gb, 3);
79	if(format == 0 || format == 7){
80	av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H.263 format\n");
81	return -1;
82	}
83	if(get_bits(&s->gb, 2))
84	av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
85	s->loop_filter = get_bits1(&s->gb) * !s->avctx->lowres;
86	if(get_bits1(&s->gb))
87	av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
88	if(get_bits1(&s->gb))
89	s->pb_frame = 2;
90	if(get_bits(&s->gb, 5))
91	av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
92	if(get_bits(&s->gb, 5) != 1)
93	av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
94	}
95	if(format == 6){
96	int ar = get_bits(&s->gb, 4);
97	skip_bits(&s->gb, 9); // display width
98	check_marker(s->avctx, &s->gb, "in dimensions");
99	skip_bits(&s->gb, 9); // display height
100	if(ar == 15){
101	s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
102	s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height
103	} else {
104	s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
105	}
106	if (s->avctx->sample_aspect_ratio.num == 0)
107	av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");
108	}
109
110	s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
111	skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
112
113	if(s->pb_frame){
114	skip_bits(&s->gb, 3); //temporal reference for B-frame
115	skip_bits(&s->gb, 2); //dbquant
116	}
117
118	/* PEI */
119	if (skip_1stop_8data_bits(&s->gb) < 0)
120	return AVERROR_INVALIDDATA;
121	s->f_code = 1;
122
123	s->y_dc_scale_table=
124	s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
125
126	ff_h263_show_pict_info(s);
127
128	return 0;
129	}
130
131	AVCodec ff_h263i_decoder = {
132	.name = "h263i",
133	.long_name = NULL_IF_CONFIG_SMALL("Intel H.263"),
134	.type = AVMEDIA_TYPE_VIDEO,
135	.id = AV_CODEC_ID_H263I,
136	.priv_data_size = sizeof(MpegEncContext),
137	.init = ff_h263_decode_init,
138	.close = ff_h263_decode_end,
139	.decode = ff_h263_decode_frame,
140	.capabilities = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
141	.caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
142	.pix_fmts = (const enum AVPixelFormat[]) {
143	AV_PIX_FMT_YUV420P,
144	AV_PIX_FMT_NONE
145	},
146	};
147