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_long(&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 
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);
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 {
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=
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 };
int picture_number
Definition: mpegvideo.h:127
#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:188
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
static int check_marker(void *logctx, GetBitContext *s, const char *msg)
Definition: get_bits.h:612
int num
Numerator.
Definition: rational.h:59
AVCodec ff_h263i_decoder
Definition: intelh263dec.c:131
int obmc
overlapped block motion compensation
Definition: mpegvideo.h:366
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:1947
mpegvideo header.
const uint16_t ff_h263_format[8][2]
Definition: h263data.c:238
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
AVCodec.
Definition: avcodec.h:3492
int qscale
QP.
Definition: mpegvideo.h:204
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
const uint8_t ff_mpeg1_dc_scale_table[128]
Definition: mpegvideodata.c:34
int lowres
low resolution decoding, 1-> 1/2 size, 2->1/4 size
Definition: avcodec.h:2807
#define av_log(a,...)
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:849
int h263_plus
H.263+ headers.
Definition: mpegvideo.h:109
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int unrestricted_mv
mv can point outside of the coded picture
Definition: mpegvideo.h:223
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
const char * name
Name of the codec implementation.
Definition: avcodec.h:3499
GetBitContext gb
Definition: mpegvideo.h:448
int ff_h263_decode_init(AVCodecContext *avctx)
Definition: h263dec.c:68
int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: h263dec.c:421
#define AV_CODEC_CAP_DRAW_HORIZ_BAND
Decoder can use draw_horiz_band callback.
Definition: avcodec.h:978
#define s(width, name)
Definition: cbs_vp9.c:257
int pb_frame
PB-frame mode (0 = none, 1 = base, 2 = improved)
Definition: mpegvideo.h:106
#define FRAME_SKIPPED
Return value for header parsers if frame is not coded.
Definition: mpegutils.h:34
int ff_intel_h263_decode_picture_header(MpegEncContext *s)
Definition: intelh263dec.c:27
int height
picture size. must be a multiple of 16
Definition: mpegvideo.h:100
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:498
static void skip_bits1(GetBitContext *s)
Definition: get_bits.h:538
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:467
int f_code
forward MV resolution
Definition: mpegvideo.h:238
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:546
int pict_type
AV_PICTURE_TYPE_I, AV_PICTURE_TYPE_P, AV_PICTURE_TYPE_B, ...
Definition: mpegvideo.h:212
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:275
const AVRational ff_h263_pixel_aspect[16]
Definition: h263data.c:275
const uint8_t * c_dc_scale_table
qscale -> c_dc_scale table
Definition: mpegvideo.h:189
MpegEncContext.
Definition: mpegvideo.h:81
struct AVCodecContext * avctx
Definition: mpegvideo.h:98
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
#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
int den
Denominator.
Definition: rational.h:60
int ff_h263_decode_end(AVCodecContext *avctx)
Definition: h263dec.c:155
int chroma_qscale
chroma QP
Definition: mpegvideo.h:205
void ff_h263_show_pict_info(MpegEncContext *s)
Print picture info if FF_DEBUG_PICT_INFO is set.
Definition: ituh263dec.c:76
static int skip_1stop_8data_bits(GetBitContext *gb)
Definition: get_bits.h:854
int h263_long_vectors
use horrible H.263v1 long vector mode
Definition: mpegvideo.h:224
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:984