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flvdec.c
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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 
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);
85  if (s->droppable)
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)
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",
108  s->h263_flv - 1, s->qscale, s->picture_number);
109  }
110 
112 
113  return 0;
114 }
115 
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),
123  .close = ff_h263_decode_end,
126  .max_lowres = 3,
127  .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
128  AV_PIX_FMT_NONE },
129 };
int picture_number
Definition: mpegvideo.h:124
const char * s
Definition: avisynth_c.h:768
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
const uint8_t * y_dc_scale_table
qscale -> y_dc_scale table
Definition: mpegvideo.h:185
misc image utilities
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:247
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown) That is the width of a pixel divided by the height of the pixel...
Definition: avcodec.h:2087
mpegvideo header.
AVCodec.
Definition: avcodec.h:3601
int qscale
QP.
Definition: mpegvideo.h:201
const uint8_t ff_mpeg1_dc_scale_table[128]
Definition: mpegvideodata.c:34
#define FF_DEBUG_PICT_INFO
Definition: avcodec.h:2918
#define height
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:91
#define av_log(a,...)
int h263_plus
H.263+ headers.
Definition: mpegvideo.h:106
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVCodec ff_flv_decoder
Definition: flvdec.c:116
#define AVERROR(e)
Definition: error.h:43
int unrestricted_mv
mv can point outside of the coded picture
Definition: mpegvideo.h:220
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
const char * name
Name of the codec implementation.
Definition: avcodec.h:3608
GetBitContext gb
Definition: mpegvideo.h:445
int ff_h263_decode_init(AVCodecContext *avctx)
Definition: h263dec.c:62
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:251
int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: h263dec.c:409
#define AV_CODEC_CAP_DRAW_HORIZ_BAND
Decoder can use draw_horiz_band callback.
Definition: avcodec.h:953
#define width
int h263_flv
use flv H.263 header
Definition: mpegvideo.h:107
int debug
debug
Definition: avcodec.h:2917
int height
picture size. must be a multiple of 16
Definition: mpegvideo.h:97
static void skip_bits1(GetBitContext *s)
Definition: get_bits.h:324
static const char * format
Definition: movenc.c:47
Rational number (pair of numerator and denominator).
Definition: rational.h:58
int f_code
forward MV resolution
Definition: mpegvideo.h:235
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:332
int pict_type
AV_PICTURE_TYPE_I, AV_PICTURE_TYPE_P, AV_PICTURE_TYPE_B, ...
Definition: mpegvideo.h:209
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:262
const uint8_t * c_dc_scale_table
qscale -> c_dc_scale table
Definition: mpegvideo.h:186
MpegEncContext.
Definition: mpegvideo.h:78
struct AVCodecContext * avctx
Definition: mpegvideo.h:95
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:62
int ff_h263_decode_end(AVCodecContext *avctx)
Definition: h263dec.c:149
int chroma_qscale
chroma QP
Definition: mpegvideo.h:202
static int decode(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *pkt)
Definition: ffmpeg.c:2045
static int skip_1stop_8data_bits(GetBitContext *gb)
Definition: get_bits.h:577
int ff_flv_decode_picture_header(MpegEncContext *s)
Definition: flvdec.c:28
int h263_long_vectors
use horrible H.263v1 long vector mode
Definition: mpegvideo.h:221
AVPixelFormat
Pixel format.
Definition: pixfmt.h:60
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:959
Predicted.
Definition: avutil.h:269