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rtpdec_h263_rfc2190.c
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1 /*
2  * RTP H.263 Depacketizer, RFC 2190
3  * Copyright (c) 2012 Martin Storsjo
4  * Based on the GStreamer H.263 Depayloder:
5  * Copyright 2005 Wim Taymans
6  * Copyright 2007 Edward Hervey
7  * Copyright 2007 Nokia Corporation
8  * Copyright 2007 Collabora Ltd, Philippe Kalaf
9  * Copyright 2010 Mark Nauwelaerts
10  *
11  * This file is part of FFmpeg.
12  *
13  * FFmpeg is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU Lesser General Public
15  * License as published by the Free Software Foundation; either
16  * version 2.1 of the License, or (at your option) any later version.
17  *
18  * FFmpeg is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21  * Lesser General Public License for more details.
22  *
23  * You should have received a copy of the GNU Lesser General Public
24  * License along with FFmpeg; if not, write to the Free Software
25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26  */
27 
28 #include "avformat.h"
29 #include "avio_internal.h"
30 #include "rtpdec_formats.h"
31 #include "libavutil/attributes.h"
32 #include "libavutil/intreadwrite.h"
33 #include "libavcodec/get_bits.h"
34 
35 struct PayloadContext {
38  int endbyte_bits;
39  uint32_t timestamp;
40  int newformat;
41 };
42 
44 {
45  ffio_free_dyn_buf(&data->buf);
46 }
47 
49  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
50  const uint8_t *buf, int len, uint16_t seq,
51  int flags)
52 {
53  /* Corresponding to header fields in the RFC */
54  int f, p, i, sbit, ebit, src, r;
55  int header_size, ret;
56 
57  if (data->newformat)
58  return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, len,
59  seq, flags);
60 
61  if (data->buf && data->timestamp != *timestamp) {
62  /* Dropping old buffered, unfinished data */
63  ffio_free_dyn_buf(&data->buf);
64  data->endbyte_bits = 0;
65  }
66 
67  if (len < 4) {
68  av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet: %d\n", len);
69  return AVERROR_INVALIDDATA;
70  }
71 
72  f = buf[0] & 0x80;
73  p = buf[0] & 0x40;
74  if (!f) {
75  /* Mode A */
76  header_size = 4;
77  i = buf[1] & 0x10;
78  r = ((buf[1] & 0x01) << 3) | ((buf[2] & 0xe0) >> 5);
79  } else if (!p) {
80  /* Mode B */
81  header_size = 8;
82  if (len < header_size) {
83  av_log(ctx, AV_LOG_ERROR,
84  "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
85  len, header_size);
86  return AVERROR_INVALIDDATA;
87  }
88  r = buf[3] & 0x03;
89  i = buf[4] & 0x80;
90  } else {
91  /* Mode C */
92  header_size = 12;
93  if (len < header_size) {
94  av_log(ctx, AV_LOG_ERROR,
95  "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
96  len, header_size);
97  return AVERROR_INVALIDDATA;
98  }
99  r = buf[3] & 0x03;
100  i = buf[4] & 0x80;
101  }
102  sbit = (buf[0] >> 3) & 0x7;
103  ebit = buf[0] & 0x7;
104  src = (buf[1] & 0xe0) >> 5;
105  if (!(buf[0] & 0xf8)) { /* Reserved bits in RFC 2429/4629 are zero */
106  if ((src == 0 || src >= 6) && r) {
107  /* Invalid src for this format, and bits that should be zero
108  * according to RFC 2190 aren't zero. */
109  av_log(ctx, AV_LOG_WARNING,
110  "Interpreting H.263 RTP data as RFC 2429/4629 even though "
111  "signalled with a static payload type.\n");
112  data->newformat = 1;
113  return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf,
114  len, seq, flags);
115  }
116  }
117 
118  buf += header_size;
119  len -= header_size;
120 
121  if (!data->buf) {
122  /* Check the picture start code, only start buffering a new frame
123  * if this is correct */
124  if (len > 4 && AV_RB32(buf) >> 10 == 0x20) {
125  ret = avio_open_dyn_buf(&data->buf);
126  if (ret < 0)
127  return ret;
128  data->timestamp = *timestamp;
129  } else {
130  /* Frame not started yet, skipping */
131  return AVERROR(EAGAIN);
132  }
133  }
134 
135  if (data->endbyte_bits || sbit) {
136  if (data->endbyte_bits == sbit) {
137  data->endbyte |= buf[0] & (0xff >> sbit);
138  data->endbyte_bits = 0;
139  buf++;
140  len--;
141  avio_w8(data->buf, data->endbyte);
142  } else {
143  /* Start/end skip bits not matching - missed packets? */
144  GetBitContext gb;
145  init_get_bits(&gb, buf, len*8 - ebit);
146  skip_bits(&gb, sbit);
147  if (data->endbyte_bits) {
148  data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits);
149  avio_w8(data->buf, data->endbyte);
150  }
151  while (get_bits_left(&gb) >= 8)
152  avio_w8(data->buf, get_bits(&gb, 8));
153  data->endbyte_bits = get_bits_left(&gb);
154  if (data->endbyte_bits)
155  data->endbyte = get_bits(&gb, data->endbyte_bits) <<
156  (8 - data->endbyte_bits);
157  ebit = 0;
158  len = 0;
159  }
160  }
161  if (ebit) {
162  if (len > 0)
163  avio_write(data->buf, buf, len - 1);
164  data->endbyte_bits = 8 - ebit;
165  data->endbyte = buf[len - 1] & (0xff << ebit);
166  } else {
167  avio_write(data->buf, buf, len);
168  }
169 
170  if (!(flags & RTP_FLAG_MARKER))
171  return AVERROR(EAGAIN);
172 
173  if (data->endbyte_bits)
174  avio_w8(data->buf, data->endbyte);
175  data->endbyte_bits = 0;
176 
177  ret = ff_rtp_finalize_packet(pkt, &data->buf, st->index);
178  if (ret < 0)
179  return ret;
180  if (!i)
181  pkt->flags |= AV_PKT_FLAG_KEY;
182 
183  return 0;
184 }
185 
188  .codec_id = AV_CODEC_ID_H263,
189  .need_parsing = AVSTREAM_PARSE_FULL,
190  .parse_packet = h263_handle_packet,
191  .priv_data_size = sizeof(PayloadContext),
192  .close = h263_close_context,
193  .static_payload_id = 34,
194 };
static int h263_handle_packet(AVFormatContext *ctx, PayloadContext *data, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags)
static void h263_close_context(PayloadContext *data)
Bytestream IO Context.
Definition: avio.h:147
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int ff_h263_handle_packet(AVFormatContext *ctx, PayloadContext *data, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags)
Definition: rtpdec_h263.c:27
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
uint8_t endbyte
Definition: rtpdec_h261.c:31
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:247
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
RTP/JPEG specific private data.
Definition: rdt.c:83
int index
stream index in AVFormatContext
Definition: avformat.h:877
static AVPacket pkt
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1260
enum AVMediaType codec_type
Definition: rtpdec.h:117
Macro definitions for various function/variable attributes.
Format I/O context.
Definition: avformat.h:1325
uint8_t
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:87
bitstream reader API header.
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:204
#define av_log(a,...)
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1612
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:568
uint32_t timestamp
current frame timestamp
Definition: rtpdec_ac3.c:31
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define RTP_FLAG_MARKER
RTP marker bit was set for this packet.
Definition: rtpdec.h:93
#define AVERROR(e)
Definition: error.h:43
const char * r
Definition: vf_curves.c:107
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1586
AVFormatContext * ctx
Definition: movenc.c:48
#define src
Definition: vp9dsp.c:530
void ffio_free_dyn_buf(AVIOContext **s)
Free a dynamic buffer.
Definition: aviobuf.c:1300
Stream structure.
Definition: avformat.h:876
RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:182
void * buf
Definition: avisynth_c.h:553
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:292
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:406
uint8_t * buf
the temporary storage buffer
Definition: rtpdec_asf.c:183
static int flags
Definition: cpu.c:47
full parsing and repack
Definition: avformat.h:806
Main libavformat public API header.
int ff_rtp_finalize_packet(AVPacket *pkt, AVIOContext **dyn_buf, int stream_idx)
Close the dynamic buffer and make a packet from it.
Definition: rtpdec.c:899
int len
This structure stores compressed data.
Definition: avcodec.h:1557