Commit | Line | Data |
---|---|---|
2ba45a60 DM |
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 "rtpdec_formats.h" | |
30 | #include "libavutil/attributes.h" | |
31 | #include "libavutil/intreadwrite.h" | |
32 | #include "libavcodec/get_bits.h" | |
33 | ||
34 | struct PayloadContext { | |
35 | AVIOContext *buf; | |
36 | uint8_t endbyte; | |
37 | int endbyte_bits; | |
38 | uint32_t timestamp; | |
39 | int newformat; | |
40 | }; | |
41 | ||
42 | static PayloadContext *h263_new_context(void) | |
43 | { | |
44 | return av_mallocz(sizeof(PayloadContext)); | |
45 | } | |
46 | ||
47 | static void h263_free_context(PayloadContext *data) | |
48 | { | |
49 | if (!data) | |
50 | return; | |
51 | if (data->buf) { | |
52 | uint8_t *p; | |
53 | avio_close_dyn_buf(data->buf, &p); | |
54 | av_free(p); | |
55 | } | |
56 | av_free(data); | |
57 | } | |
58 | ||
59 | static av_cold int h263_init(AVFormatContext *ctx, int st_index, PayloadContext *data) | |
60 | { | |
61 | if (st_index < 0) | |
62 | return 0; | |
63 | ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL; | |
64 | return 0; | |
65 | } | |
66 | ||
67 | static int h263_handle_packet(AVFormatContext *ctx, PayloadContext *data, | |
68 | AVStream *st, AVPacket *pkt, uint32_t *timestamp, | |
69 | const uint8_t *buf, int len, uint16_t seq, | |
70 | int flags) | |
71 | { | |
72 | /* Corresponding to header fields in the RFC */ | |
73 | int f, p, i, sbit, ebit, src, r; | |
74 | int header_size, ret; | |
75 | ||
76 | if (data->newformat) | |
77 | return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, len, | |
78 | seq, flags); | |
79 | ||
80 | if (data->buf && data->timestamp != *timestamp) { | |
81 | /* Dropping old buffered, unfinished data */ | |
82 | uint8_t *p; | |
83 | avio_close_dyn_buf(data->buf, &p); | |
84 | av_free(p); | |
85 | data->buf = NULL; | |
86 | } | |
87 | ||
88 | if (len < 4) { | |
89 | av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet: %d\n", len); | |
90 | return AVERROR_INVALIDDATA; | |
91 | } | |
92 | ||
93 | f = buf[0] & 0x80; | |
94 | p = buf[0] & 0x40; | |
95 | if (!f) { | |
96 | /* Mode A */ | |
97 | header_size = 4; | |
98 | i = buf[1] & 0x10; | |
99 | r = ((buf[1] & 0x01) << 3) | ((buf[2] & 0xe0) >> 5); | |
100 | } else if (!p) { | |
101 | /* Mode B */ | |
102 | header_size = 8; | |
103 | if (len < header_size) { | |
104 | av_log(ctx, AV_LOG_ERROR, | |
105 | "Too short H.263 RTP packet: %d bytes, %d header bytes\n", | |
106 | len, header_size); | |
107 | return AVERROR_INVALIDDATA; | |
108 | } | |
109 | r = buf[3] & 0x03; | |
110 | i = buf[4] & 0x80; | |
111 | } else { | |
112 | /* Mode C */ | |
113 | header_size = 12; | |
114 | if (len < header_size) { | |
115 | av_log(ctx, AV_LOG_ERROR, | |
116 | "Too short H.263 RTP packet: %d bytes, %d header bytes\n", | |
117 | len, header_size); | |
118 | return AVERROR_INVALIDDATA; | |
119 | } | |
120 | r = buf[3] & 0x03; | |
121 | i = buf[4] & 0x80; | |
122 | } | |
123 | sbit = (buf[0] >> 3) & 0x7; | |
124 | ebit = buf[0] & 0x7; | |
125 | src = (buf[1] & 0xe0) >> 5; | |
126 | if (!(buf[0] & 0xf8)) { /* Reserved bits in RFC 2429/4629 are zero */ | |
127 | if ((src == 0 || src >= 6) && r) { | |
128 | /* Invalid src for this format, and bits that should be zero | |
129 | * according to RFC 2190 aren't zero. */ | |
130 | av_log(ctx, AV_LOG_WARNING, | |
131 | "Interpreting H263 RTP data as RFC 2429/4629 even though " | |
132 | "signalled with a static payload type.\n"); | |
133 | data->newformat = 1; | |
134 | return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, | |
135 | len, seq, flags); | |
136 | } | |
137 | } | |
138 | ||
139 | buf += header_size; | |
140 | len -= header_size; | |
141 | ||
142 | if (!data->buf) { | |
143 | /* Check the picture start code, only start buffering a new frame | |
144 | * if this is correct */ | |
145 | if (len > 4 && AV_RB32(buf) >> 10 == 0x20) { | |
146 | ret = avio_open_dyn_buf(&data->buf); | |
147 | if (ret < 0) | |
148 | return ret; | |
149 | data->timestamp = *timestamp; | |
150 | } else { | |
151 | /* Frame not started yet, skipping */ | |
152 | return AVERROR(EAGAIN); | |
153 | } | |
154 | } | |
155 | ||
156 | if (data->endbyte_bits || sbit) { | |
157 | if (data->endbyte_bits == sbit) { | |
158 | data->endbyte |= buf[0] & (0xff >> sbit); | |
159 | data->endbyte_bits = 0; | |
160 | buf++; | |
161 | len--; | |
162 | avio_w8(data->buf, data->endbyte); | |
163 | } else { | |
164 | /* Start/end skip bits not matching - missed packets? */ | |
165 | GetBitContext gb; | |
166 | init_get_bits(&gb, buf, len*8 - ebit); | |
167 | skip_bits(&gb, sbit); | |
168 | if (data->endbyte_bits) { | |
169 | data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits); | |
170 | avio_w8(data->buf, data->endbyte); | |
171 | } | |
172 | while (get_bits_left(&gb) >= 8) | |
173 | avio_w8(data->buf, get_bits(&gb, 8)); | |
174 | data->endbyte_bits = get_bits_left(&gb); | |
175 | if (data->endbyte_bits) | |
176 | data->endbyte = get_bits(&gb, data->endbyte_bits) << | |
177 | (8 - data->endbyte_bits); | |
178 | ebit = 0; | |
179 | len = 0; | |
180 | } | |
181 | } | |
182 | if (ebit) { | |
183 | if (len > 0) | |
184 | avio_write(data->buf, buf, len - 1); | |
185 | data->endbyte_bits = 8 - ebit; | |
186 | data->endbyte = buf[len - 1] & (0xff << ebit); | |
187 | } else { | |
188 | avio_write(data->buf, buf, len); | |
189 | } | |
190 | ||
191 | if (!(flags & RTP_FLAG_MARKER)) | |
192 | return AVERROR(EAGAIN); | |
193 | ||
194 | if (data->endbyte_bits) | |
195 | avio_w8(data->buf, data->endbyte); | |
196 | data->endbyte_bits = 0; | |
197 | ||
198 | ret = ff_rtp_finalize_packet(pkt, &data->buf, st->index); | |
199 | if (ret < 0) | |
200 | return ret; | |
201 | if (!i) | |
202 | pkt->flags |= AV_PKT_FLAG_KEY; | |
203 | ||
204 | return 0; | |
205 | } | |
206 | ||
207 | RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler = { | |
208 | .codec_type = AVMEDIA_TYPE_VIDEO, | |
209 | .codec_id = AV_CODEC_ID_H263, | |
210 | .init = h263_init, | |
211 | .parse_packet = h263_handle_packet, | |
212 | .alloc = h263_new_context, | |
213 | .free = h263_free_context, | |
214 | .static_payload_id = 34, | |
215 | }; |