flvdec.c
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1 /*
2  * FLV decoding.
3  * This file is part of Libav.
4  *
5  * Libav 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  * Libav 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 Libav; 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 
25 void ff_flv2_decode_ac_esc(GetBitContext *gb, int *level, int *run, int *last){
26  int is11 = get_bits1(gb);
27  *last = get_bits1(gb);
28  *run = get_bits(gb, 6);
29  if(is11){
30  *level = get_sbits(gb, 11);
31  } else {
32  *level = get_sbits(gb, 7);
33  }
34 }
35 
37 {
38  int format, width, height;
39 
40  /* picture header */
41  if (get_bits_long(&s->gb, 17) != 1) {
42  av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
43  return -1;
44  }
45  format = get_bits(&s->gb, 5);
46  if (format != 0 && format != 1) {
47  av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
48  return -1;
49  }
50  s->h263_flv = format+1;
51  s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
52  format = get_bits(&s->gb, 3);
53  switch (format) {
54  case 0:
55  width = get_bits(&s->gb, 8);
56  height = get_bits(&s->gb, 8);
57  break;
58  case 1:
59  width = get_bits(&s->gb, 16);
60  height = get_bits(&s->gb, 16);
61  break;
62  case 2:
63  width = 352;
64  height = 288;
65  break;
66  case 3:
67  width = 176;
68  height = 144;
69  break;
70  case 4:
71  width = 128;
72  height = 96;
73  break;
74  case 5:
75  width = 320;
76  height = 240;
77  break;
78  case 6:
79  width = 160;
80  height = 120;
81  break;
82  default:
83  width = height = 0;
84  break;
85  }
86  if(av_image_check_size(width, height, 0, s->avctx))
87  return -1;
88  s->width = width;
89  s->height = height;
90 
91  s->pict_type = AV_PICTURE_TYPE_I + get_bits(&s->gb, 2);
93  if (s->dropable)
95 
96  skip_bits1(&s->gb); /* deblocking flag */
97  s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
98 
99  s->h263_plus = 0;
100 
101  s->unrestricted_mv = 1;
102  s->h263_long_vectors = 0;
103 
104  /* PEI */
105  while (get_bits1(&s->gb) != 0) {
106  skip_bits(&s->gb, 8);
107  }
108  s->f_code = 1;
109 
110  if(s->avctx->debug & FF_DEBUG_PICT_INFO){
111  av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
113  }
114 
115  s->y_dc_scale_table=
117 
118  return 0;
119 }
120 
122  .name = "flv",
123  .type = AVMEDIA_TYPE_VIDEO,
124  .id = CODEC_ID_FLV1,
125  .priv_data_size = sizeof(MpegEncContext),
129  .capabilities = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
130  .max_lowres= 3,
131  .long_name= NULL_IF_CONFIG_SMALL("Flash Video (FLV) / Sorenson Spark / Sorenson H.263"),
132  .pix_fmts= ff_pixfmt_list_420,
133 };
int picture_number
Definition: mpegvideo.h:235
struct MpegEncContext MpegEncContext
MpegEncContext.
const uint8_t * y_dc_scale_table
qscale -> y_dc_scale table
Definition: mpegvideo.h:306
misc image utilities
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:237
int width
Definition: rotozoom.c:164
mpegvideo header.
uint8_t run
Definition: svq3.c:123
AVCodec.
Definition: avcodec.h:3189
int qscale
QP.
Definition: mpegvideo.h:324
static int get_sbits(GetBitContext *s, int n)
Definition: get_bits.h:223
int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
Definition: h263dec.c:338
static int decode(MimicContext *ctx, int quality, int num_coeffs, int is_iframe)
Definition: mimic.c:228
#define FF_DEBUG_PICT_INFO
Definition: avcodec.h:2008
char av_get_picture_type_char(enum AVPictureType pict_type)
Return a single letter to describe the given picture type pict_type.
Definition: utils.c:43
enum PixelFormat ff_pixfmt_list_420[]
Definition: mpegvideo.c:130
static int init(AVCodecParserContext *s)
Definition: h264_parser.c:336
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:719
int h263_plus
h263 plus headers
Definition: mpegvideo.h:214
AVCodec ff_flv_decoder
Definition: flvdec.c:121
int unrestricted_mv
mv can point outside of the coded picture
Definition: mpegvideo.h:340
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:191
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:140
const char * name
Name of the codec implementation.
Definition: avcodec.h:3196
GetBitContext gb
Definition: mpegvideo.h:603
int ff_h263_decode_init(AVCodecContext *avctx)
Definition: h263dec.c:45
int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of the image can be address...
Definition: imgutils.c:213
int h263_flv
use flv h263 header
Definition: mpegvideo.h:215
int debug
debug
Definition: avcodec.h:2007
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:327
int height
picture size. must be a multiple of 16
Definition: mpegvideo.h:205
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:111
const uint8_t ff_mpeg1_dc_scale_table[128]
Definition: mpegvideo.c:75
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:268
static void skip_bits1(GetBitContext *s)
Definition: get_bits.h:293
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:260
#define CODEC_CAP_DRAW_HORIZ_BAND
Definition: avcodec.h:713
int f_code
forward MV resolution
Definition: mpegvideo.h:344
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:301
int pict_type
AV_PICTURE_TYPE_I, AV_PICTURE_TYPE_P, AV_PICTURE_TYPE_B, ...
Definition: mpegvideo.h:331
const uint8_t * c_dc_scale_table
qscale -> c_dc_scale table
Definition: mpegvideo.h:307
uint8_t level
Definition: svq3.c:123
void ff_flv2_decode_ac_esc(GetBitContext *gb, int *level, int *run, int *last)
Definition: flvdec.c:25
int height
Definition: gxfenc.c:73
MpegEncContext.
Definition: mpegvideo.h:201
struct AVCodecContext * avctx
Definition: mpegvideo.h:203
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:125
int ff_h263_decode_end(AVCodecContext *avctx)
Definition: h263dec.c:121
int chroma_qscale
chroma QP
Definition: mpegvideo.h:325
int ff_flv_decode_picture_header(MpegEncContext *s)
Definition: flvdec.c:36
int h263_long_vectors
use horrible h263v1 long vector mode
Definition: mpegvideo.h:341
Predicted.
Definition: avutil.h:297