1 /*
2 * Microsoft RTP/ASF support.
3 * Copyright (c) 2008 Ronald S. Bultje
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 Microsoft RTP/ASF support
25 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
26 */
27
28 #include "libavutil/base64.h"
29 #include "libavutil/avstring.h"
30 #include "libavutil/intreadwrite.h"
31 #include "rtpdec_formats.h"
32 #include "rtsp.h"
33 #include "asf.h"
34 #include "avio_internal.h"
35 #include "demux.h"
36 #include "internal.h"
37
38 /**
39 * From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not
40 * contain any padding. Unfortunately, the header min/max_pktsize are not
41 * updated (thus making min_pktsize invalid). Here, we "fix" these faulty
42 * min_pktsize values in the ASF file header.
43 * @return 0 on success, <0 on failure (currently -1).
44 */
rtp_asf_fix_header(uint8_t * buf,int len)45 static int rtp_asf_fix_header(uint8_t *buf, int len)
46 {
47 uint8_t *p = buf, *end = buf + len;
48
49 if (len < sizeof(ff_asf_guid) * 2 + 22 ||
50 memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
51 return -1;
52 }
53 p += sizeof(ff_asf_guid) + 14;
54 do {
55 uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));
56 int skip = 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2;
57 if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
58 if (chunksize > end - p)
59 return -1;
60 p += chunksize;
61 continue;
62 }
63
64 if (end - p < 8 + skip)
65 break;
66 /* skip most of the file header, to min_pktsize */
67 p += skip;
68 if (AV_RL32(p) == AV_RL32(p + 4)) {
69 /* and set that to zero */
70 AV_WL32(p, 0);
71 return 0;
72 }
73 break;
74 } while (end - p >= sizeof(ff_asf_guid) + 8);
75
76 return -1;
77 }
78
79 /**
80 * The following code is basically a buffered AVIOContext,
81 * with the added benefit of returning -EAGAIN (instead of 0)
82 * on packet boundaries, such that the ASF demuxer can return
83 * safely and resume business at the next packet.
84 */
packetizer_read(void * opaque,uint8_t * buf,int buf_size)85 static int packetizer_read(void *opaque, uint8_t *buf, int buf_size)
86 {
87 return AVERROR(EAGAIN);
88 }
89
init_packetizer(FFIOContext * pb,uint8_t * buf,int len)90 static void init_packetizer(FFIOContext *pb, uint8_t *buf, int len)
91 {
92 ffio_init_context(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL);
93
94 /* this "fills" the buffer with its current content */
95 pb->pub.pos = len;
96 pb->pub.buf_end = buf + len;
97 }
98
ff_wms_parse_sdp_a_line(AVFormatContext * s,const char * p)99 int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
100 {
101 int ret = 0;
102 if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
103 FFIOContext pb;
104 RTSPState *rt = s->priv_data;
105 AVDictionary *opts = NULL;
106 int len = strlen(p) * 6 / 8;
107 char *buf = av_mallocz(len);
108 const AVInputFormat *iformat;
109
110 if (!buf)
111 return AVERROR(ENOMEM);
112 av_base64_decode(buf, p, len);
113
114 if (rtp_asf_fix_header(buf, len) < 0)
115 av_log(s, AV_LOG_ERROR,
116 "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
117 init_packetizer(&pb, buf, len);
118 if (rt->asf_ctx) {
119 avformat_close_input(&rt->asf_ctx);
120 }
121
122 if (!(iformat = av_find_input_format("asf"))) {
123 av_free(buf);
124 return AVERROR_DEMUXER_NOT_FOUND;
125 }
126
127 rt->asf_ctx = avformat_alloc_context();
128 if (!rt->asf_ctx) {
129 av_free(buf);
130 return AVERROR(ENOMEM);
131 }
132 rt->asf_ctx->pb = &pb.pub;
133 av_dict_set(&opts, "no_resync_search", "1", 0);
134
135 if ((ret = ff_copy_whiteblacklists(rt->asf_ctx, s)) < 0) {
136 av_dict_free(&opts);
137 return ret;
138 }
139
140 ret = avformat_open_input(&rt->asf_ctx, "", iformat, &opts);
141 av_dict_free(&opts);
142 if (ret < 0) {
143 av_free(pb.pub.buffer);
144 return ret;
145 }
146 av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0);
147 rt->asf_pb_pos = avio_tell(&pb.pub);
148 av_free(pb.pub.buffer);
149 rt->asf_ctx->pb = NULL;
150 }
151 return ret;
152 }
153
asfrtp_parse_sdp_line(AVFormatContext * s,int stream_index,PayloadContext * asf,const char * line)154 static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
155 PayloadContext *asf, const char *line)
156 {
157 if (stream_index < 0)
158 return 0;
159 if (av_strstart(line, "stream:", &line)) {
160 RTSPState *rt = s->priv_data;
161
162 s->streams[stream_index]->id = strtol(line, NULL, 10);
163
164 if (rt->asf_ctx) {
165 int i;
166
167 for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
168 if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
169 avcodec_parameters_copy(s->streams[stream_index]->codecpar,
170 rt->asf_ctx->streams[i]->codecpar);
171 ffstream(s->streams[stream_index])->need_parsing =
172 ffstream(rt->asf_ctx->streams[i])->need_parsing;
173 avpriv_set_pts_info(s->streams[stream_index], 32, 1, 1000);
174 }
175 }
176 }
177 }
178
179 return 0;
180 }
181
182 struct PayloadContext {
183 FFIOContext pb;
184 AVIOContext *pktbuf;
185 uint8_t *buf;
186 };
187
188 /**
189 * @return 0 when a packet was written into /p pkt, and no more data is left;
190 * 1 when a packet was written into /p pkt, and more packets might be left;
191 * <0 when not enough data was provided to return a full packet, or on error.
192 */
asfrtp_parse_packet(AVFormatContext * s,PayloadContext * asf,AVStream * st,AVPacket * pkt,uint32_t * timestamp,const uint8_t * buf,int len,uint16_t seq,int flags)193 static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
194 AVStream *st, AVPacket *pkt,
195 uint32_t *timestamp,
196 const uint8_t *buf, int len, uint16_t seq,
197 int flags)
198 {
199 FFIOContext *const pb0 = &asf->pb;
200 AVIOContext *const pb = &pb0->pub;
201 int res, mflags, len_off;
202 RTSPState *rt = s->priv_data;
203
204 if (!rt->asf_ctx)
205 return -1;
206
207 if (len > 0) {
208 int off, out_len = 0;
209
210 if (len < 4)
211 return -1;
212
213 av_freep(&asf->buf);
214
215 ffio_init_context(pb0, (uint8_t *)buf, len, 0, NULL, NULL, NULL, NULL);
216
217 while (avio_tell(pb) + 4 < len) {
218 int start_off = avio_tell(pb);
219
220 mflags = avio_r8(pb);
221 len_off = avio_rb24(pb);
222 if (mflags & 0x20) /**< relative timestamp */
223 avio_skip(pb, 4);
224 if (mflags & 0x10) /**< has duration */
225 avio_skip(pb, 4);
226 if (mflags & 0x8) /**< has location ID */
227 avio_skip(pb, 4);
228 off = avio_tell(pb);
229
230 if (!(mflags & 0x40)) {
231 /**
232 * If 0x40 is not set, the len_off field specifies an offset
233 * of this packet's payload data in the complete (reassembled)
234 * ASF packet. This is used to spread one ASF packet over
235 * multiple RTP packets.
236 */
237 if (asf->pktbuf && len_off != avio_tell(asf->pktbuf)) {
238 ffio_free_dyn_buf(&asf->pktbuf);
239 }
240 if (!len_off && !asf->pktbuf &&
241 (res = avio_open_dyn_buf(&asf->pktbuf)) < 0)
242 return res;
243 if (!asf->pktbuf)
244 return AVERROR(EIO);
245
246 avio_write(asf->pktbuf, buf + off, len - off);
247 avio_skip(pb, len - off);
248 if (!(flags & RTP_FLAG_MARKER))
249 return -1;
250 out_len = avio_close_dyn_buf(asf->pktbuf, &asf->buf);
251 asf->pktbuf = NULL;
252 } else {
253 /**
254 * If 0x40 is set, the len_off field specifies the length of
255 * the next ASF packet that can be read from this payload
256 * data alone. This is commonly the same as the payload size,
257 * but could be less in case of packet splitting (i.e.
258 * multiple ASF packets in one RTP packet).
259 */
260
261 int cur_len = start_off + len_off - off;
262 int prev_len = out_len;
263 out_len += cur_len;
264 if (FFMIN(cur_len, len - off) < 0)
265 return -1;
266 if ((res = av_reallocp(&asf->buf, out_len)) < 0)
267 return res;
268 memcpy(asf->buf + prev_len, buf + off,
269 FFMIN(cur_len, len - off));
270 avio_skip(pb, cur_len);
271 }
272 }
273
274 init_packetizer(pb0, asf->buf, out_len);
275 pb->pos += rt->asf_pb_pos;
276 pb->eof_reached = 0;
277 rt->asf_ctx->pb = pb;
278 }
279
280 for (;;) {
281 int i;
282
283 res = ff_read_packet(rt->asf_ctx, pkt);
284 rt->asf_pb_pos = avio_tell(pb);
285 if (res != 0)
286 break;
287 for (i = 0; i < s->nb_streams; i++) {
288 if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
289 pkt->stream_index = i;
290 return 1; // FIXME: return 0 if last packet
291 }
292 }
293 av_packet_unref(pkt);
294 }
295
296 return res == 1 ? -1 : res;
297 }
298
asfrtp_close_context(PayloadContext * asf)299 static void asfrtp_close_context(PayloadContext *asf)
300 {
301 ffio_free_dyn_buf(&asf->pktbuf);
302 av_freep(&asf->buf);
303 }
304
305 #define RTP_ASF_HANDLER(n, s, t) \
306 const RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
307 .enc_name = s, \
308 .codec_type = t, \
309 .codec_id = AV_CODEC_ID_NONE, \
310 .priv_data_size = sizeof(PayloadContext), \
311 .parse_sdp_a_line = asfrtp_parse_sdp_line, \
312 .close = asfrtp_close_context, \
313 .parse_packet = asfrtp_parse_packet, \
314 }
315
316 RTP_ASF_HANDLER(asf_pfv, "x-asf-pf", AVMEDIA_TYPE_VIDEO);
317 RTP_ASF_HANDLER(asf_pfa, "x-asf-pf", AVMEDIA_TYPE_AUDIO);
318