7f5f0771bcfd7e6c9e10a8c24a49942f39bdb1a1
[libav.git] / libavformat / rtpdec_qdm2.c
1 /*
2 * QDesign Music 2 (QDM2) payload for RTP
3 * Copyright (c) 2010 Ronald S. Bultje
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * @brief RTP support for the QDM2 payload (todo: wiki)
25 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
26 */
27
28 #include <string.h>
29 #include "libavutil/intreadwrite.h"
30 #include "libavcodec/avcodec.h"
31 #include "rtp.h"
32 #include "rtpdec.h"
33 #include "rtpdec_formats.h"
34
35 struct PayloadContext {
36 /** values read from the config header, used as packet headers */
37 //@{
38 int block_type; ///< superblock type, value 2 .. 8
39 int block_size; ///< from extradata, used as pkt length
40 int subpkts_per_block; ///< max. nr. of subpackets to add per output buffer
41 //@}
42
43 /** Temporary storage for superblock restoring, per packet ID (0x80 total) */
44 //@{
45 uint16_t len[0x80]; ///< how much the temporary buffer is filled
46 uint8_t buf[0x80][0x800]; ///< the temporary storage buffer
47
48 unsigned int cache; ///< number of data packets that we have cached right now
49 unsigned int n_pkts; ///< number of RTP packets received since last packet output / config
50 uint32_t timestamp; ///< timestamp of next-to-be-returned packet
51 //@}
52 };
53
54 /**
55 * Parses configuration (basically the codec-specific extradata) from
56 * a RTP config subpacket (starts with 0xff).
57 *
58 * Layout of the config subpacket (in bytes):
59 * 1: 0xFF <- config ID
60 * then an array {
61 * 1: size <- of the current item
62 * 1: item type <- 0 .. 4
63 * size-2: data <- data depends on the item type
64 * }
65 *
66 * Item 0 implies the end of the config subpacket, and has no data.
67 * Item 1 implies a stream configuration without extradata.
68 * Item 2 max. nr. of subpackets per superblock
69 * Item 3 superblock type for the stream
70 * Item 4 implies a stream configuration with extradata (size >= 0x1c).
71 *
72 * @return <0 on error, otherwise the number of bytes parsed from the
73 * input buffer.
74 */
75 static int qdm2_parse_config(PayloadContext *qdm, AVStream *st,
76 const uint8_t *buf, const uint8_t *end)
77 {
78 const uint8_t *p = buf;
79
80 while (end - p >= 2) {
81 unsigned int item_len = p[0], config_item = p[1];
82
83 if (item_len < 2 || end - p < item_len || config_item > 4)
84 return AVERROR_INVALIDDATA;
85
86 switch (config_item) {
87 case 0: /* end of config block */
88 return p - buf + item_len;
89 case 1: /* stream without extradata */
90 /* FIXME: set default qdm->block_size */
91 break;
92 case 2: /**< subpackets per block */
93 if (item_len < 3)
94 return AVERROR_INVALIDDATA;
95 qdm->subpkts_per_block = p[2];
96 break;
97 case 3: /* superblock type */
98 if (item_len < 4)
99 return AVERROR_INVALIDDATA;
100 qdm->block_type = AV_RB16(p + 2);
101 break;
102 case 4: /* stream with extradata */
103 if (item_len < 30)
104 return AVERROR_INVALIDDATA;
105 av_freep(&st->codec->extradata);
106 st->codec->extradata_size = 26 + item_len;
107 if (!(st->codec->extradata = av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE))) {
108 st->codec->extradata_size = 0;
109 return AVERROR(ENOMEM);
110 }
111 AV_WB32(st->codec->extradata, 12);
112 memcpy(st->codec->extradata + 4, "frma", 4);
113 memcpy(st->codec->extradata + 8, "QDM2", 4);
114 AV_WB32(st->codec->extradata + 12, 6 + item_len);
115 memcpy(st->codec->extradata + 16, "QDCA", 4);
116 memcpy(st->codec->extradata + 20, p + 2, item_len - 2);
117 AV_WB32(st->codec->extradata + 18 + item_len, 8);
118 AV_WB32(st->codec->extradata + 22 + item_len, 0);
119
120 qdm->block_size = AV_RB32(p + 26);
121 break;
122 }
123
124 p += item_len;
125 }
126
127 return AVERROR(EAGAIN); /* not enough data */
128 }
129
130 /**
131 * Parses a single subpacket. We store this subpacket in an intermediate
132 * buffer (position depends on the ID (byte[0]). When called, at least
133 * 4 bytes are available for reading (see qdm2_parse_packet()).
134 *
135 * Layout of a single subpacket (RTP packets commonly contain multiple
136 * such subpackets) - length in bytes:
137 * 1: ordering ID <- 0 .. 0x7F
138 * 1: subpacket type <- 0 .. 0x7F; value & 0x80 means subpacket length = 2 bytes, else 1 byte
139 * 1/2: subpacket length <- length of the data following the flags/length fields
140 * if (subpacket type & 0x7F) == 0x7F
141 * 1: subpacket type, higher bits
142 * size: subpacket data
143 *
144 * The subpackets come in randomly, and should be encapsulated into 1
145 * or more superblocks (containing qdm->subpkts_per_block subpackets
146 * each) per RTP packet, in order of ascending "ordering ID", see
147 * qdm2_restore_block().
148 *
149 * @return <0 on error, otherwise the number of bytes parsed from the
150 * input buffer.
151 */
152 static int qdm2_parse_subpacket(PayloadContext *qdm, AVStream *st,
153 const uint8_t *buf, const uint8_t *end)
154 {
155 const uint8_t *p = buf;
156 unsigned int id, len, type, to_copy;
157
158 /* parse header so we know the size of the header/data */
159 id = *p++;
160 type = *p++;
161 if (type & 0x80) {
162 len = AV_RB16(p);
163 p += 2;
164 type &= 0x7F;
165 } else
166 len = *p++;
167
168 if (end - p < len + (type == 0x7F) || id >= 0x80)
169 return AVERROR_INVALIDDATA;
170 if (type == 0x7F)
171 type |= *p++ << 8;
172
173 /* copy data into a temporary buffer */
174 to_copy = FFMIN(len + (p - &buf[1]), 0x800 - qdm->len[id]);
175 memcpy(&qdm->buf[id][qdm->len[id]], buf + 1, to_copy);
176 qdm->len[id] += to_copy;
177
178 return p + len - buf;
179 }
180
181 /**
182 * Adds a superblock header around a set of subpackets.
183 *
184 * @return <0 on error, else 0.
185 */
186 static int qdm2_restore_block(PayloadContext *qdm, AVStream *st, AVPacket *pkt)
187 {
188 int to_copy, n, res, include_csum;
189 uint8_t *p, *csum_pos = NULL;
190
191 /* create packet to hold subpkts into a superblock */
192 assert(qdm->cache > 0);
193 for (n = 0; n < 0x80; n++)
194 if (qdm->len[n] > 0)
195 break;
196 assert(n < 0x80);
197
198 if ((res = av_new_packet(pkt, qdm->block_size)) < 0)
199 return res;
200 memset(pkt->data, 0, pkt->size);
201 pkt->stream_index = st->index;
202 p = pkt->data;
203
204 /* superblock header */
205 if (qdm->len[n] > 0xff) {
206 *p++ = qdm->block_type | 0x80;
207 AV_WB16(p, qdm->len[n]);
208 p += 2;
209 } else {
210 *p++ = qdm->block_type;
211 *p++ = qdm->len[n];
212 }
213 if ((include_csum = (qdm->block_type == 2 || qdm->block_type == 4))) {
214 csum_pos = p;
215 p += 2;
216 }
217
218 /* subpacket data */
219 to_copy = FFMIN(qdm->len[n], pkt->size - (p - pkt->data));
220 memcpy(p, qdm->buf[n], to_copy);
221 qdm->len[n] = 0;
222
223 /* checksum header */
224 if (include_csum) {
225 unsigned int total = 0;
226 uint8_t *q;
227
228 for (q = pkt->data; q < &pkt->data[qdm->block_size]; q++)
229 total += *q;
230 AV_WB16(csum_pos, (uint16_t) total);
231 }
232
233 return 0;
234 }
235
236 /** return 0 on packet, no more left, 1 on packet, -1 on partial packet... */
237 static int qdm2_parse_packet(AVFormatContext *s, PayloadContext *qdm,
238 AVStream *st, AVPacket *pkt,
239 uint32_t *timestamp,
240 const uint8_t *buf, int len, int flags)
241 {
242 int res = AVERROR_INVALIDDATA, n;
243 const uint8_t *end = buf + len, *p = buf;
244
245 if (len > 0) {
246 if (len < 2)
247 return AVERROR_INVALIDDATA;
248
249 /* configuration block */
250 if (*p == 0xff) {
251 if (qdm->n_pkts > 0) {
252 av_log(s, AV_LOG_WARNING,
253 "Out of sequence config - dropping queue\n");
254 qdm->n_pkts = 0;
255 memset(qdm->len, 0, sizeof(qdm->len));
256 }
257
258 if ((res = qdm2_parse_config(qdm, st, ++p, end)) < 0)
259 return res;
260 p += res;
261
262 /* We set codec_id to CODEC_ID_NONE initially to
263 * delay decoder initialization since extradata is
264 * carried within the RTP stream, not SDP. Here,
265 * by setting codec_id to CODEC_ID_QDM2, we are signalling
266 * to the decoder that it is OK to initialize. */
267 st->codec->codec_id = CODEC_ID_QDM2;
268 }
269
270 /* subpackets */
271 while (end - p >= 4) {
272 if ((res = qdm2_parse_subpacket(qdm, st, p, end)) < 0)
273 return res;
274 p += res;
275 }
276
277 qdm->timestamp = *timestamp;
278 if (++qdm->n_pkts < qdm->subpkts_per_block)
279 return AVERROR(EAGAIN);
280 qdm->cache = 0;
281 for (n = 0; n < 0x80; n++)
282 if (qdm->len[n] > 0)
283 qdm->cache++;
284 }
285
286 /* output the subpackets into freshly created superblock structures */
287 if (!qdm->cache || (res = qdm2_restore_block(qdm, st, pkt)) < 0)
288 return res;
289 if (--qdm->cache == 0)
290 qdm->n_pkts = 0;
291
292 *timestamp = qdm->timestamp;
293 qdm->timestamp = RTP_NOTS_VALUE;
294
295 return (qdm->cache > 0) ? 1 : 0;
296 }
297
298 static PayloadContext *qdm2_extradata_new(void)
299 {
300 return av_mallocz(sizeof(PayloadContext));
301 }
302
303 static void qdm2_extradata_free(PayloadContext *qdm)
304 {
305 av_free(qdm);
306 }
307
308 RTPDynamicProtocolHandler ff_qdm2_dynamic_handler = {
309 .enc_name = "X-QDM",
310 .codec_type = AVMEDIA_TYPE_AUDIO,
311 .codec_id = CODEC_ID_NONE,
312 .alloc = qdm2_extradata_new,
313 .free = qdm2_extradata_free,
314 .parse_packet = qdm2_parse_packet,
315 };