Imported Debian version 2.5.2~trusty
[deb_ffmpeg.git] / ffmpeg / libavformat / rtpdec_vp8.c
... / ...
CommitLineData
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
34struct 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
55static 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
65static 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
74static 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
270static 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
279static void vp8_free_context(PayloadContext *vp8)
280{
281 vp8_free_buffer(vp8);
282 av_free(vp8);
283}
284
285static int vp8_need_keyframe(PayloadContext *vp8)
286{
287 return vp8->sequence_dirty || !vp8->sequence_ok;
288}
289
290RTPDynamicProtocolHandler 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};