2 * Microsoft RTP/ASF support.
3 * Copyright (c) 2008 Ronald S. Bultje
5 * This file is part of FFmpeg.
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.
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.
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
24 * @brief Microsoft RTP/ASF support
25 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
28 #include "libavutil/avassert.h"
29 #include "libavutil/base64.h"
30 #include "libavutil/avstring.h"
31 #include "libavutil/intreadwrite.h"
33 #include "rtpdec_formats.h"
36 #include "avio_internal.h"
40 * From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not
41 * contain any padding. Unfortunately, the header min/max_pktsize are not
42 * updated (thus making min_pktsize invalid). Here, we "fix" these faulty
43 * min_pktsize values in the ASF file header.
44 * @return 0 on success, <0 on failure (currently -1).
46 static int rtp_asf_fix_header(uint8_t *buf, int len)
48 uint8_t *p = buf, *end = buf + len;
50 if (len < sizeof(ff_asf_guid) * 2 + 22 ||
51 memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
54 p += sizeof(ff_asf_guid) + 14;
56 uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));
57 if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
58 if (chunksize > end - p)
64 /* skip most of the file header, to min_pktsize */
65 p += 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2;
66 if (p + 8 <= end && AV_RL32(p) == AV_RL32(p + 4)) {
67 /* and set that to zero */
72 } while (end - p >= sizeof(ff_asf_guid) + 8);
78 * The following code is basically a buffered AVIOContext,
79 * with the added benefit of returning -EAGAIN (instead of 0)
80 * on packet boundaries, such that the ASF demuxer can return
81 * safely and resume business at the next packet.
83 static int packetizer_read(void *opaque, uint8_t *buf, int buf_size)
85 return AVERROR(EAGAIN);
88 static void init_packetizer(AVIOContext *pb, uint8_t *buf, int len)
90 ffio_init_context(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL);
92 /* this "fills" the buffer with its current content */
94 pb->buf_end = buf + len;
97 int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
100 if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
102 RTSPState *rt = s->priv_data;
103 AVDictionary *opts = NULL;
104 int len = strlen(p) * 6 / 8;
105 char *buf = av_mallocz(len);
106 AVInputFormat *iformat;
108 av_base64_decode(buf, p, len);
110 if (rtp_asf_fix_header(buf, len) < 0)
111 av_log(s, AV_LOG_ERROR,
112 "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
113 init_packetizer(&pb, buf, len);
115 avformat_close_input(&rt->asf_ctx);
117 if (!(iformat = av_find_input_format("asf")))
118 return AVERROR_DEMUXER_NOT_FOUND;
119 if (!(rt->asf_ctx = avformat_alloc_context()))
120 return AVERROR(ENOMEM);
121 rt->asf_ctx->pb = &pb;
122 av_dict_set(&opts, "no_resync_search", "1", 0);
124 if ((ret = ff_copy_whitelists(rt->asf_ctx, s)) < 0) {
129 ret = avformat_open_input(&rt->asf_ctx, "", iformat, &opts);
133 av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0);
134 rt->asf_pb_pos = avio_tell(&pb);
136 rt->asf_ctx->pb = NULL;
141 static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
142 PayloadContext *asf, const char *line)
144 if (stream_index < 0)
146 if (av_strstart(line, "stream:", &line)) {
147 RTSPState *rt = s->priv_data;
149 s->streams[stream_index]->id = strtol(line, NULL, 10);
154 for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
155 if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
156 *s->streams[stream_index]->codec =
157 *rt->asf_ctx->streams[i]->codec;
158 s->streams[stream_index]->need_parsing =
159 rt->asf_ctx->streams[i]->need_parsing;
160 rt->asf_ctx->streams[i]->codec->extradata_size = 0;
161 rt->asf_ctx->streams[i]->codec->extradata = NULL;
162 avpriv_set_pts_info(s->streams[stream_index], 32, 1, 1000);
171 struct PayloadContext {
172 AVIOContext *pktbuf, pb;
177 * @return 0 when a packet was written into /p pkt, and no more data is left;
178 * 1 when a packet was written into /p pkt, and more packets might be left;
179 * <0 when not enough data was provided to return a full packet, or on error.
181 static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
182 AVStream *st, AVPacket *pkt,
184 const uint8_t *buf, int len, uint16_t seq,
187 AVIOContext *pb = &asf->pb;
188 int res, mflags, len_off;
189 RTSPState *rt = s->priv_data;
195 int off, out_len = 0;
202 ffio_init_context(pb, (uint8_t *)buf, len, 0, NULL, NULL, NULL, NULL);
204 while (avio_tell(pb) + 4 < len) {
205 int start_off = avio_tell(pb);
207 mflags = avio_r8(pb);
208 len_off = avio_rb24(pb);
209 if (mflags & 0x20) /**< relative timestamp */
211 if (mflags & 0x10) /**< has duration */
213 if (mflags & 0x8) /**< has location ID */
217 if (!(mflags & 0x40)) {
219 * If 0x40 is not set, the len_off field specifies an offset
220 * of this packet's payload data in the complete (reassembled)
221 * ASF packet. This is used to spread one ASF packet over
222 * multiple RTP packets.
224 if (asf->pktbuf && len_off != avio_tell(asf->pktbuf)) {
225 ffio_free_dyn_buf(&asf->pktbuf);
227 if (!len_off && !asf->pktbuf &&
228 (res = avio_open_dyn_buf(&asf->pktbuf)) < 0)
233 avio_write(asf->pktbuf, buf + off, len - off);
234 avio_skip(pb, len - off);
235 if (!(flags & RTP_FLAG_MARKER))
237 out_len = avio_close_dyn_buf(asf->pktbuf, &asf->buf);
241 * If 0x40 is set, the len_off field specifies the length of
242 * the next ASF packet that can be read from this payload
243 * data alone. This is commonly the same as the payload size,
244 * but could be less in case of packet splitting (i.e.
245 * multiple ASF packets in one RTP packet).
248 int cur_len = start_off + len_off - off;
249 int prev_len = out_len;
251 if (FFMIN(cur_len, len - off) < 0)
253 if ((res = av_reallocp(&asf->buf, out_len)) < 0)
255 memcpy(asf->buf + prev_len, buf + off,
256 FFMIN(cur_len, len - off));
257 avio_skip(pb, cur_len);
261 init_packetizer(pb, asf->buf, out_len);
262 pb->pos += rt->asf_pb_pos;
264 rt->asf_ctx->pb = pb;
270 res = ff_read_packet(rt->asf_ctx, pkt);
271 rt->asf_pb_pos = avio_tell(pb);
274 for (i = 0; i < s->nb_streams; i++) {
275 if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
276 pkt->stream_index = i;
277 return 1; // FIXME: return 0 if last packet
283 return res == 1 ? -1 : res;
286 static void asfrtp_close_context(PayloadContext *asf)
288 ffio_free_dyn_buf(&asf->pktbuf);
292 #define RTP_ASF_HANDLER(n, s, t) \
293 RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
296 .codec_id = AV_CODEC_ID_NONE, \
297 .priv_data_size = sizeof(PayloadContext), \
298 .parse_sdp_a_line = asfrtp_parse_sdp_line, \
299 .close = asfrtp_close_context, \
300 .parse_packet = asfrtp_parse_packet, \
303 RTP_ASF_HANDLER(asf_pfv, "x-asf-pf", AVMEDIA_TYPE_VIDEO);
304 RTP_ASF_HANDLER(asf_pfa, "x-asf-pf", AVMEDIA_TYPE_AUDIO);