FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
flvdec.c
Go to the documentation of this file.
1 /*
2  * FLV decoding.
3  * This file is part of FFmpeg.
4  *
5  * FFmpeg is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * FFmpeg is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with FFmpeg; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19 
20 #include "mpegvideo.h"
21 #include "h263.h"
22 #include "flv.h"
23 #include "libavutil/imgutils.h"
24 
26 {
27  int format, width, height;
28 
29  /* picture header */
30  if (get_bits_long(&s->gb, 17) != 1) {
31  av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
32  return AVERROR_INVALIDDATA;
33  }
34  format = get_bits(&s->gb, 5);
35  if (format != 0 && format != 1) {
36  av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
37  return AVERROR_INVALIDDATA;
38  }
39  s->h263_flv = format + 1;
40  s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
41  format = get_bits(&s->gb, 3);
42  switch (format) {
43  case 0:
44  width = get_bits(&s->gb, 8);
45  height = get_bits(&s->gb, 8);
46  break;
47  case 1:
48  width = get_bits(&s->gb, 16);
49  height = get_bits(&s->gb, 16);
50  break;
51  case 2:
52  width = 352;
53  height = 288;
54  break;
55  case 3:
56  width = 176;
57  height = 144;
58  break;
59  case 4:
60  width = 128;
61  height = 96;
62  break;
63  case 5:
64  width = 320;
65  height = 240;
66  break;
67  case 6:
68  width = 160;
69  height = 120;
70  break;
71  default:
72  width = height = 0;
73  break;
74  }
75  if (av_image_check_size(width, height, 0, s->avctx))
76  return AVERROR(EINVAL);
77  s->width = width;
78  s->height = height;
79 
80  s->pict_type = AV_PICTURE_TYPE_I + get_bits(&s->gb, 2);
82  if (s->droppable)
84 
85  skip_bits1(&s->gb); /* deblocking flag */
86  s->chroma_qscale = s->qscale = get_bits(&s->gb, 5);
87 
88  s->h263_plus = 0;
89 
90  s->unrestricted_mv = 1;
91  s->h263_long_vectors = 0;
92 
93  /* PEI */
94  if (skip_1stop_8data_bits(&s->gb) < 0)
95  return AVERROR_INVALIDDATA;
96 
97  s->f_code = 1;
98 
99  if (s->ehc_mode)
101 
102  if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
103  av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
105  s->h263_flv - 1, s->qscale, s->picture_number);
106  }
107 
109 
110  return 0;
111 }
112 
114  .name = "flv",
115  .long_name = NULL_IF_CONFIG_SMALL("FLV / Sorenson Spark / Sorenson H.263 (Flash Video)"),
116  .type = AVMEDIA_TYPE_VIDEO,
117  .id = AV_CODEC_ID_FLV1,
118  .priv_data_size = sizeof(MpegEncContext),
122  .capabilities = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
123  .max_lowres = 3,
124  .pix_fmts = (const enum AVPixelFormat[]) {
127  },
128 };