path: root/libavcodec/flvdec.c (plain)
blob: f9beb40afa6d67657f892313779040f84ee9f824

1	/*
2	* FLV decoding.
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 "libavutil/imgutils.h"
22
23	#include "flv.h"
24	#include "h263.h"
25	#include "mpegvideo.h"
26	#include "mpegvideodata.h"
27
28	int ff_flv_decode_picture_header(MpegEncContext *s)
29	{
30	int format, width, height;
31
32	/* picture header */
33	if (get_bits_long(&s->gb, 17) != 1) {
34	av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
35	return AVERROR_INVALIDDATA;
36	}
37	format = get_bits(&s->gb, 5);
38	if (format != 0 && format != 1) {
39	av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
40	return AVERROR_INVALIDDATA;
41	}
42	s->h263_flv = format + 1;
43	s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
44	format = get_bits(&s->gb, 3);
45	switch (format) {
46	case 0:
47	width = get_bits(&s->gb, 8);
48	height = get_bits(&s->gb, 8);
49	break;
50	case 1:
51	width = get_bits(&s->gb, 16);
52	height = get_bits(&s->gb, 16);
53	break;
54	case 2:
55	width = 352;
56	height = 288;
57	break;
58	case 3:
59	width = 176;
60	height = 144;
61	break;
62	case 4:
63	width = 128;
64	height = 96;
65	break;
66	case 5:
67	width = 320;
68	height = 240;
69	break;
70	case 6:
71	width = 160;
72	height = 120;
73	break;
74	default:
75	width = height = 0;
76	break;
77	}
78	if (av_image_check_size(width, height, 0, s->avctx))
79	return AVERROR(EINVAL);
80	s->width = width;
81	s->height = height;
82
83	s->pict_type = AV_PICTURE_TYPE_I + get_bits(&s->gb, 2);
84	s->droppable = s->pict_type > AV_PICTURE_TYPE_P;
85	if (s->droppable)
86	s->pict_type = AV_PICTURE_TYPE_P;
87
88	skip_bits1(&s->gb); /* deblocking flag */
89	s->chroma_qscale = s->qscale = get_bits(&s->gb, 5);
90
91	s->h263_plus = 0;
92
93	s->unrestricted_mv = 1;
94	s->h263_long_vectors = 0;
95
96	/* PEI */
97	if (skip_1stop_8data_bits(&s->gb) < 0)
98	return AVERROR_INVALIDDATA;
99
100	s->f_code = 1;
101
102	if (s->ehc_mode)
103	s->avctx->sample_aspect_ratio= (AVRational){1,2};
104
105	if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
106	av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
107	s->droppable ? 'D' : av_get_picture_type_char(s->pict_type),
108	s->h263_flv - 1, s->qscale, s->picture_number);
109	}
110
111	s->y_dc_scale_table = s->c_dc_scale_table = ff_mpeg1_dc_scale_table;
112
113	return 0;
114	}
115
116	AVCodec ff_flv_decoder = {
117	.name = "flv",
118	.long_name = NULL_IF_CONFIG_SMALL("FLV / Sorenson Spark / Sorenson H.263 (Flash Video)"),
119	.type = AVMEDIA_TYPE_VIDEO,
120	.id = AV_CODEC_ID_FLV1,
121	.priv_data_size = sizeof(MpegEncContext),
122	.init = ff_h263_decode_init,
123	.close = ff_h263_decode_end,
124	.decode = ff_h263_decode_frame,
125	.capabilities = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
126	.caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
127	.max_lowres = 3,
128	.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
129	AV_PIX_FMT_NONE },
130	};
131