FFmpeg
intelh263dec.c
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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 "codec_internal.h"
22 #include "mpegutils.h"
23 #include "mpegvideo.h"
24 #include "mpegvideodec.h"
25 #include "h263data.h"
26 #include "h263dec.h"
27 #include "mpegvideodata.h"
28 
29 /* don't understand why they choose a different header ! */
31 {
32  int format;
33 
34  if (get_bits_left(&s->gb) == 64) { /* special dummy frames */
35  return FRAME_SKIPPED;
36  }
37 
38  /* picture header */
39  if (get_bits(&s->gb, 22) != 0x20) {
40  av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
41  return -1;
42  }
43  s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
44 
45  if (check_marker(s->avctx, &s->gb, "after picture_number") != 1) {
46  return -1; /* marker */
47  }
48  if (get_bits1(&s->gb) != 0) {
49  av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
50  return -1; /* H.263 id */
51  }
52  skip_bits1(&s->gb); /* split screen off */
53  skip_bits1(&s->gb); /* camera off */
54  skip_bits1(&s->gb); /* freeze picture release off */
55 
56  format = get_bits(&s->gb, 3);
57  if (format == 0 || format == 6) {
58  av_log(s->avctx, AV_LOG_ERROR, "Intel H.263 free format not supported\n");
59  return -1;
60  }
61  s->h263_plus = 0;
62 
63  s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
64 
65  s->h263_long_vectors = get_bits1(&s->gb);
66 
67  if (get_bits1(&s->gb) != 0) {
68  av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
69  return -1; /* SAC: off */
70  }
71  s->obmc= get_bits1(&s->gb);
72  s->pb_frame = get_bits1(&s->gb);
73 
74  if (format < 6) {
75  s->width = ff_h263_format[format][0];
76  s->height = ff_h263_format[format][1];
77  s->avctx->sample_aspect_ratio.num = 12;
78  s->avctx->sample_aspect_ratio.den = 11;
79  } else {
80  format = get_bits(&s->gb, 3);
81  if(format == 0 || format == 7){
82  av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H.263 format\n");
83  return -1;
84  }
85  if(get_bits(&s->gb, 2))
86  av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
87  s->loop_filter = get_bits1(&s->gb) * !s->avctx->lowres;
88  if(get_bits1(&s->gb))
89  av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
90  if(get_bits1(&s->gb))
91  s->pb_frame = 2;
92  if(get_bits(&s->gb, 5))
93  av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
94  if(get_bits(&s->gb, 5) != 1)
95  av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
96  }
97  if(format == 6){
98  int ar = get_bits(&s->gb, 4);
99  skip_bits(&s->gb, 9); // display width
100  check_marker(s->avctx, &s->gb, "in dimensions");
101  skip_bits(&s->gb, 9); // display height
102  if(ar == 15){
103  s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
104  s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height
105  } else {
106  s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
107  }
108  if (s->avctx->sample_aspect_ratio.num == 0)
109  av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");
110  }
111 
112  s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
113  skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
114 
115  if(s->pb_frame){
116  skip_bits(&s->gb, 3); //temporal reference for B-frame
117  skip_bits(&s->gb, 2); //dbquant
118  }
119 
120  /* PEI */
121  if (skip_1stop_8data_bits(&s->gb) < 0)
122  return AVERROR_INVALIDDATA;
123  s->f_code = 1;
124 
126 
127  return 0;
128 }
129 
131  .p.name = "h263i",
132  CODEC_LONG_NAME("Intel H.263"),
133  .p.type = AVMEDIA_TYPE_VIDEO,
134  .p.id = AV_CODEC_ID_H263I,
135  .priv_data_size = sizeof(MpegEncContext),
137  .close = ff_h263_decode_end,
140  .caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
141  .p.pix_fmts = (const enum AVPixelFormat[]) {
144  },
145 };
h263data.h
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
get_bits_left
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:839
FFCodec
Definition: codec_internal.h:119
mpegvideo.h
mpegutils.h
skip_bits
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:123
ff_h263_pixel_aspect
const AVRational ff_h263_pixel_aspect[16]
Definition: h263data.c:273
mpegvideodec.h
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
h263dec.h
AV_CODEC_ID_H263I
@ AV_CODEC_ID_H263I
Definition: codec_id.h:72
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:298
s
#define s(width, name)
Definition: cbs_vp9.c:256
format
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample format(the sample packing is implied by the sample format) and sample rate. The lists are not just lists
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:363
AV_PIX_FMT_YUV420P
@ AV_PIX_FMT_YUV420P
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:264
FRAME_SKIPPED
#define FRAME_SKIPPED
Return value for header parsers if frame is not coded.
Definition: mpegutils.h:33
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:498
ff_h263_show_pict_info
void ff_h263_show_pict_info(MpegEncContext *s)
Print picture info if FF_DEBUG_PICT_INFO is set.
Definition: ituh263dec.c:80
ff_h263_decode_frame
int ff_h263_decode_frame(AVCodecContext *avctx, AVFrame *pict, int *got_frame, AVPacket *avpkt)
Definition: h263dec.c:416
ff_h263_decode_end
av_cold int ff_h263_decode_end(AVCodecContext *avctx)
Definition: h263dec.c:147
check_marker
static int check_marker(void *logctx, GetBitContext *s, const char *msg)
Definition: mpegvideodec.h:73
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
codec_internal.h
FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM
#define FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM
The decoder extracts and fills its parameters even if the frame is skipped due to the skip_frame sett...
Definition: codec_internal.h:54
mpegvideodata.h
skip_bits1
static void skip_bits1(GetBitContext *s)
Definition: get_bits.h:538
ff_h263_format
const uint16_t ff_h263_format[8][2]
Definition: h263data.c:236
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
ff_h263_decode_init
av_cold int ff_h263_decode_init(AVCodecContext *avctx)
Definition: h263dec.c:74
ff_h263i_decoder
const FFCodec ff_h263i_decoder
Definition: intelh263dec.c:130
skip_1stop_8data_bits
static int skip_1stop_8data_bits(GetBitContext *gb)
Definition: get_bits.h:844
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
ff_intel_h263_decode_picture_header
int ff_intel_h263_decode_picture_header(MpegEncContext *s)
Definition: intelh263dec.c:30
AV_CODEC_CAP_DRAW_HORIZ_BAND
#define AV_CODEC_CAP_DRAW_HORIZ_BAND
Decoder can use draw_horiz_band callback.
Definition: codec.h:44
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
MpegEncContext
MpegEncContext.
Definition: mpegvideo.h:70