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 "mpegutils.h"
22 #include "mpegvideo.h"
23 #include "h263.h"
24 #include "mpegvideodata.h"
25 
26 /* don't understand why they choose a different header ! */
28 {
29  int format;
30 
31  if (get_bits_left(&s->gb) == 64) { /* special dummy frames */
32  return FRAME_SKIPPED;
33  }
34 
35  /* picture header */
36  if (get_bits(&s->gb, 22) != 0x20) {
37  av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
38  return -1;
39  }
40  s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
41 
42  if (check_marker(s->avctx, &s->gb, "after picture_number") != 1) {
43  return -1; /* marker */
44  }
45  if (get_bits1(&s->gb) != 0) {
46  av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
47  return -1; /* H.263 id */
48  }
49  skip_bits1(&s->gb); /* split screen off */
50  skip_bits1(&s->gb); /* camera off */
51  skip_bits1(&s->gb); /* freeze picture release off */
52 
53  format = get_bits(&s->gb, 3);
54  if (format == 0 || format == 6) {
55  av_log(s->avctx, AV_LOG_ERROR, "Intel H.263 free format not supported\n");
56  return -1;
57  }
58  s->h263_plus = 0;
59 
60  s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
61 
62  s->h263_long_vectors = get_bits1(&s->gb);
63 
64  if (get_bits1(&s->gb) != 0) {
65  av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
66  return -1; /* SAC: off */
67  }
68  s->obmc= get_bits1(&s->gb);
69  s->unrestricted_mv = s->obmc || s->h263_long_vectors;
70  s->pb_frame = get_bits1(&s->gb);
71 
72  if (format < 6) {
73  s->width = ff_h263_format[format][0];
74  s->height = ff_h263_format[format][1];
75  s->avctx->sample_aspect_ratio.num = 12;
76  s->avctx->sample_aspect_ratio.den = 11;
77  } else {
78  format = get_bits(&s->gb, 3);
79  if(format == 0 || format == 7){
80  av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H.263 format\n");
81  return -1;
82  }
83  if(get_bits(&s->gb, 2))
84  av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
85  s->loop_filter = get_bits1(&s->gb) * !s->avctx->lowres;
86  if(get_bits1(&s->gb))
87  av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
88  if(get_bits1(&s->gb))
89  s->pb_frame = 2;
90  if(get_bits(&s->gb, 5))
91  av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
92  if(get_bits(&s->gb, 5) != 1)
93  av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
94  }
95  if(format == 6){
96  int ar = get_bits(&s->gb, 4);
97  skip_bits(&s->gb, 9); // display width
98  check_marker(s->avctx, &s->gb, "in dimensions");
99  skip_bits(&s->gb, 9); // display height
100  if(ar == 15){
101  s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
102  s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height
103  } else {
104  s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
105  }
106  if (s->avctx->sample_aspect_ratio.num == 0)
107  av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");
108  }
109 
110  s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
111  skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
112 
113  if(s->pb_frame){
114  skip_bits(&s->gb, 3); //temporal reference for B-frame
115  skip_bits(&s->gb, 2); //dbquant
116  }
117 
118  /* PEI */
119  if (skip_1stop_8data_bits(&s->gb) < 0)
120  return AVERROR_INVALIDDATA;
121  s->f_code = 1;
122 
123  s->y_dc_scale_table=
124  s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
125 
127 
128  return 0;
129 }
130 
132  .name = "h263i",
133  .long_name = NULL_IF_CONFIG_SMALL("Intel H.263"),
134  .type = AVMEDIA_TYPE_VIDEO,
135  .id = AV_CODEC_ID_H263I,
136  .priv_data_size = sizeof(MpegEncContext),
138  .close = ff_h263_decode_end,
141  .caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
142  .pix_fmts = (const enum AVPixelFormat[]) {
145  },
146 };
AVCodec
AVCodec.
Definition: codec.h:190
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
get_bits_left
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:849
ff_mpeg1_dc_scale_table
const uint8_t ff_mpeg1_dc_scale_table[128]
Definition: mpegvideodata.c:33
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
ff_h263_pixel_aspect
const AVRational ff_h263_pixel_aspect[16]
Definition: h263data.c:275
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: internal.h:60
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AV_CODEC_ID_H263I
@ AV_CODEC_ID_H263I
Definition: codec_id.h:69
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
s
#define s(width, name)
Definition: cbs_vp9.c:257
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
pix_fmts
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:275
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
FRAME_SKIPPED
#define FRAME_SKIPPED
Return value for header parsers if frame is not coded.
Definition: mpegutils.h:34
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:76
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:50
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:188
mpegvideodata.h
skip_bits1
static void skip_bits1(GetBitContext *s)
Definition: get_bits.h:538
ff_h263_decode_init
int ff_h263_decode_init(AVCodecContext *avctx)
Definition: h263dec.c:68
ff_h263_decode_end
int ff_h263_decode_end(AVCodecContext *avctx)
Definition: h263dec.c:155
ff_h263_format
const uint16_t ff_h263_format[8][2]
Definition: h263data.c:238
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:197
skip_1stop_8data_bits
static int skip_1stop_8data_bits(GetBitContext *gb)
Definition: get_bits.h:854
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
ff_h263_decode_frame
int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: h263dec.c:421
check_marker
static int check_marker(void *logctx, GetBitContext *s, const char *msg)
Definition: get_bits.h:612
ff_intel_h263_decode_picture_header
int ff_intel_h263_decode_picture_header(MpegEncContext *s)
Definition: intelh263dec.c:27
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:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
ff_h263i_decoder
AVCodec ff_h263i_decoder
Definition: intelh263dec.c:131
MpegEncContext
MpegEncContext.
Definition: mpegvideo.h:81
h263.h