Commit | Line | Data |
---|---|---|
2ba45a60 DM |
1 | /* |
2 | * RTP VP8 Depacketizer | |
3 | * Copyright (c) 2010 Josh Allmann | |
4 | * Copyright (c) 2012 Martin Storsjo | |
5 | * | |
6 | * This file is part of FFmpeg. | |
7 | * | |
8 | * FFmpeg is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * FFmpeg is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with FFmpeg; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
23 | /** | |
24 | * @file | |
25 | * @brief RTP support for the VP8 payload | |
26 | * @author Josh Allmann <joshua.allmann@gmail.com> | |
27 | * @see http://tools.ietf.org/html/draft-ietf-payload-vp8-05 | |
28 | */ | |
29 | ||
30 | #include "libavcodec/bytestream.h" | |
31 | ||
32 | #include "rtpdec_formats.h" | |
33 | ||
34 | struct PayloadContext { | |
35 | AVIOContext *data; | |
36 | uint32_t timestamp; | |
37 | int is_keyframe; | |
38 | /* If sequence_ok is set, we keep returning data (even if we might have | |
39 | * lost some data, but we haven't lost any too critical data that would | |
40 | * cause the decoder to desynchronize and output random garbage). | |
41 | */ | |
42 | int sequence_ok; | |
43 | int first_part_size; | |
44 | uint16_t prev_seq; | |
45 | int prev_pictureid; | |
46 | int broken_frame; | |
47 | /* If sequence_dirty is set, we have lost some data (critical or | |
48 | * non-critical) and decoding will have some sort of artefacts, and | |
49 | * we thus should request a new keyframe. | |
50 | */ | |
51 | int sequence_dirty; | |
52 | int got_keyframe; | |
53 | }; | |
54 | ||
55 | static void vp8_free_buffer(PayloadContext *vp8) | |
56 | { | |
57 | uint8_t *tmp; | |
58 | if (!vp8->data) | |
59 | return; | |
60 | avio_close_dyn_buf(vp8->data, &tmp); | |
61 | av_free(tmp); | |
62 | vp8->data = NULL; | |
63 | } | |
64 | ||
65 | static int vp8_broken_sequence(AVFormatContext *ctx, PayloadContext *vp8, | |
66 | const char *msg) | |
67 | { | |
68 | vp8->sequence_ok = 0; | |
69 | av_log(ctx, AV_LOG_WARNING, "%s", msg); | |
70 | vp8_free_buffer(vp8); | |
71 | return AVERROR(EAGAIN); | |
72 | } | |
73 | ||
74 | static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8, | |
75 | AVStream *st, AVPacket *pkt, uint32_t *timestamp, | |
76 | const uint8_t *buf, int len, uint16_t seq, | |
77 | int flags) | |
78 | { | |
79 | int start_partition, end_packet; | |
80 | int extended_bits, part_id; | |
81 | int pictureid_present = 0, tl0picidx_present = 0, tid_present = 0, | |
82 | keyidx_present = 0; | |
83 | int pictureid = -1, pictureid_mask = 0; | |
84 | int returned_old_frame = 0; | |
85 | uint32_t old_timestamp = 0; | |
86 | ||
87 | if (!buf) { | |
88 | if (vp8->data) { | |
89 | int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); | |
90 | if (ret < 0) | |
91 | return ret; | |
92 | *timestamp = vp8->timestamp; | |
93 | if (vp8->sequence_dirty) | |
94 | pkt->flags |= AV_PKT_FLAG_CORRUPT; | |
95 | return 0; | |
96 | } | |
97 | return AVERROR(EAGAIN); | |
98 | } | |
99 | ||
100 | if (len < 1) | |
101 | return AVERROR_INVALIDDATA; | |
102 | ||
103 | extended_bits = buf[0] & 0x80; | |
104 | start_partition = buf[0] & 0x10; | |
105 | part_id = buf[0] & 0x0f; | |
106 | end_packet = flags & RTP_FLAG_MARKER; | |
107 | buf++; | |
108 | len--; | |
109 | if (extended_bits) { | |
110 | if (len < 1) | |
111 | return AVERROR_INVALIDDATA; | |
112 | pictureid_present = buf[0] & 0x80; | |
113 | tl0picidx_present = buf[0] & 0x40; | |
114 | tid_present = buf[0] & 0x20; | |
115 | keyidx_present = buf[0] & 0x10; | |
116 | buf++; | |
117 | len--; | |
118 | } | |
119 | if (pictureid_present) { | |
120 | if (len < 1) | |
121 | return AVERROR_INVALIDDATA; | |
122 | if (buf[0] & 0x80) { | |
123 | if (len < 2) | |
124 | return AVERROR_INVALIDDATA; | |
125 | pictureid = AV_RB16(buf) & 0x7fff; | |
126 | pictureid_mask = 0x7fff; | |
127 | buf += 2; | |
128 | len -= 2; | |
129 | } else { | |
130 | pictureid = buf[0] & 0x7f; | |
131 | pictureid_mask = 0x7f; | |
132 | buf++; | |
133 | len--; | |
134 | } | |
135 | } | |
136 | if (tl0picidx_present) { | |
137 | // Ignoring temporal level zero index | |
138 | buf++; | |
139 | len--; | |
140 | } | |
141 | if (tid_present || keyidx_present) { | |
142 | // Ignoring temporal layer index, layer sync bit and keyframe index | |
143 | buf++; | |
144 | len--; | |
145 | } | |
146 | if (len < 1) | |
147 | return AVERROR_INVALIDDATA; | |
148 | ||
149 | if (start_partition && part_id == 0 && len >= 3) { | |
150 | int res; | |
151 | int non_key = buf[0] & 0x01; | |
152 | if (!non_key) { | |
153 | vp8_free_buffer(vp8); | |
154 | // Keyframe, decoding ok again | |
155 | vp8->sequence_ok = 1; | |
156 | vp8->sequence_dirty = 0; | |
157 | vp8->got_keyframe = 1; | |
158 | } else { | |
159 | int can_continue = vp8->data && !vp8->is_keyframe && | |
160 | avio_tell(vp8->data) >= vp8->first_part_size; | |
161 | if (!vp8->sequence_ok) | |
162 | return AVERROR(EAGAIN); | |
163 | if (!vp8->got_keyframe) | |
164 | return vp8_broken_sequence(ctx, vp8, "Keyframe missing\n"); | |
165 | if (pictureid >= 0) { | |
166 | if (pictureid != ((vp8->prev_pictureid + 1) & pictureid_mask)) { | |
167 | return vp8_broken_sequence(ctx, vp8, | |
168 | "Missed a picture, sequence broken\n"); | |
169 | } else { | |
170 | if (vp8->data && !can_continue) | |
171 | return vp8_broken_sequence(ctx, vp8, | |
172 | "Missed a picture, sequence broken\n"); | |
173 | } | |
174 | } else { | |
175 | uint16_t expected_seq = vp8->prev_seq + 1; | |
176 | int16_t diff = seq - expected_seq; | |
177 | if (vp8->data) { | |
178 | // No picture id, so we can't know if missed packets | |
179 | // contained any new frames. If diff == 0, we did get | |
180 | // later packets from the same frame (matching timestamp), | |
181 | // so we know we didn't miss any frame. If diff == 1 and | |
182 | // we still have data (not flushed by the end of frame | |
183 | // marker), the single missed packet must have been part | |
184 | // of the same frame. | |
185 | if ((diff == 0 || diff == 1) && can_continue) { | |
186 | // Proceed with what we have | |
187 | } else { | |
188 | return vp8_broken_sequence(ctx, vp8, | |
189 | "Missed too much, sequence broken\n"); | |
190 | } | |
191 | } else { | |
192 | if (diff != 0) | |
193 | return vp8_broken_sequence(ctx, vp8, | |
194 | "Missed unknown data, sequence broken\n"); | |
195 | } | |
196 | } | |
197 | if (vp8->data) { | |
198 | vp8->sequence_dirty = 1; | |
199 | if (avio_tell(vp8->data) >= vp8->first_part_size) { | |
200 | int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); | |
201 | if (ret < 0) | |
202 | return ret; | |
203 | pkt->flags |= AV_PKT_FLAG_CORRUPT; | |
204 | returned_old_frame = 1; | |
205 | old_timestamp = vp8->timestamp; | |
206 | } else { | |
207 | // Shouldn't happen | |
208 | vp8_free_buffer(vp8); | |
209 | } | |
210 | } | |
211 | } | |
212 | vp8->first_part_size = (AV_RL16(&buf[1]) << 3 | buf[0] >> 5) + 3; | |
213 | if ((res = avio_open_dyn_buf(&vp8->data)) < 0) | |
214 | return res; | |
215 | vp8->timestamp = *timestamp; | |
216 | vp8->broken_frame = 0; | |
217 | vp8->prev_pictureid = pictureid; | |
218 | vp8->is_keyframe = !non_key; | |
219 | } else { | |
220 | uint16_t expected_seq = vp8->prev_seq + 1; | |
221 | ||
222 | if (!vp8->sequence_ok) | |
223 | return AVERROR(EAGAIN); | |
224 | ||
225 | if (vp8->timestamp != *timestamp) { | |
226 | // Missed the start of the new frame, sequence broken | |
227 | return vp8_broken_sequence(ctx, vp8, | |
228 | "Received no start marker; dropping frame\n"); | |
229 | } | |
230 | ||
231 | if (seq != expected_seq) { | |
232 | if (vp8->is_keyframe) { | |
233 | return vp8_broken_sequence(ctx, vp8, | |
234 | "Missed part of a keyframe, sequence broken\n"); | |
235 | } else if (vp8->data && avio_tell(vp8->data) >= vp8->first_part_size) { | |
236 | vp8->broken_frame = 1; | |
237 | vp8->sequence_dirty = 1; | |
238 | } else { | |
239 | return vp8_broken_sequence(ctx, vp8, | |
240 | "Missed part of the first partition, sequence broken\n"); | |
241 | } | |
242 | } | |
243 | } | |
244 | ||
245 | if (!vp8->data) | |
246 | return vp8_broken_sequence(ctx, vp8, "Received no start marker\n"); | |
247 | ||
248 | vp8->prev_seq = seq; | |
249 | if (!vp8->broken_frame) | |
250 | avio_write(vp8->data, buf, len); | |
251 | ||
252 | if (returned_old_frame) { | |
253 | *timestamp = old_timestamp; | |
254 | return end_packet ? 1 : 0; | |
255 | } | |
256 | ||
257 | if (end_packet) { | |
258 | int ret; | |
259 | ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); | |
260 | if (ret < 0) | |
261 | return ret; | |
262 | if (vp8->sequence_dirty) | |
263 | pkt->flags |= AV_PKT_FLAG_CORRUPT; | |
264 | return 0; | |
265 | } | |
266 | ||
267 | return AVERROR(EAGAIN); | |
268 | } | |
269 | ||
270 | static PayloadContext *vp8_new_context(void) | |
271 | { | |
272 | PayloadContext *vp8 = av_mallocz(sizeof(PayloadContext)); | |
273 | if (!vp8) | |
274 | return NULL; | |
275 | vp8->sequence_ok = 1; | |
276 | return vp8; | |
277 | } | |
278 | ||
279 | static void vp8_free_context(PayloadContext *vp8) | |
280 | { | |
281 | vp8_free_buffer(vp8); | |
282 | av_free(vp8); | |
283 | } | |
284 | ||
285 | static int vp8_need_keyframe(PayloadContext *vp8) | |
286 | { | |
287 | return vp8->sequence_dirty || !vp8->sequence_ok; | |
288 | } | |
289 | ||
290 | RTPDynamicProtocolHandler ff_vp8_dynamic_handler = { | |
291 | .enc_name = "VP8", | |
292 | .codec_type = AVMEDIA_TYPE_VIDEO, | |
293 | .codec_id = AV_CODEC_ID_VP8, | |
294 | .alloc = vp8_new_context, | |
295 | .free = vp8_free_context, | |
296 | .parse_packet = vp8_handle_packet, | |
297 | .need_keyframe = vp8_need_keyframe, | |
298 | }; |