Statistics
| Branch: | Revision:

ffmpeg / libavformat / rtpdec_asf.c @ 98ec8287

History | View | Annotate | Download (9.4 KB)

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 "rtp.h"
32
#include "rtpdec_formats.h"
33
#include "rtsp.h"
34
#include "asf.h"
35

    
36
/**
37
 * From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not
38
 * contain any padding. Unfortunately, the header min/max_pktsize are not
39
 * updated (thus making min_pktsize invalid). Here, we "fix" these faulty
40
 * min_pktsize values in the ASF file header.
41
 * @return 0 on success, <0 on failure (currently -1).
42
 */
43
static int rtp_asf_fix_header(uint8_t *buf, int len)
44
{
45
    uint8_t *p = buf, *end = buf + len;
46

    
47
    if (len < sizeof(ff_asf_guid) * 2 + 22 ||
48
        memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
49
        return -1;
50
    }
51
    p += sizeof(ff_asf_guid) + 14;
52
    do {
53
        uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));
54
        if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
55
            if (chunksize > end - p)
56
                return -1;
57
            p += chunksize;
58
            continue;
59
        }
60

    
61
        /* skip most of the file header, to min_pktsize */
62
        p += 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2;
63
        if (p + 8 <= end && AV_RL32(p) == AV_RL32(p + 4)) {
64
            /* and set that to zero */
65
            AV_WL32(p, 0);
66
            return 0;
67
        }
68
        break;
69
    } while (end - p >= sizeof(ff_asf_guid) + 8);
70

    
71
    return -1;
72
}
73

    
74
/**
75
 * The following code is basically a buffered ByteIOContext,
76
 * with the added benefit of returning -EAGAIN (instead of 0)
77
 * on packet boundaries, such that the ASF demuxer can return
78
 * safely and resume business at the next packet.
79
 */
80
static int packetizer_read(void *opaque, uint8_t *buf, int buf_size)
81
{
82
    return AVERROR(EAGAIN);
83
}
84

    
85
static void init_packetizer(ByteIOContext *pb, uint8_t *buf, int len)
86
{
87
    init_put_byte(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL);
88

    
89
    /* this "fills" the buffer with its current content */
90
    pb->pos     = len;
91
    pb->buf_end = buf + len;
92
}
93

    
94
int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
95
{
96
    int ret = 0;
97
    if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
98
        ByteIOContext pb;
99
        RTSPState *rt = s->priv_data;
100
        int len = strlen(p) * 6 / 8;
101
        char *buf = av_mallocz(len);
102
        av_base64_decode(buf, p, len);
103

    
104
        if (rtp_asf_fix_header(buf, len) < 0)
105
            av_log(s, AV_LOG_ERROR,
106
                   "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
107
        init_packetizer(&pb, buf, len);
108
        if (rt->asf_ctx) {
109
            av_close_input_stream(rt->asf_ctx);
110
            rt->asf_ctx = NULL;
111
        }
112
        ret = av_open_input_stream(&rt->asf_ctx, &pb, "", &ff_asf_demuxer, NULL);
113
        if (ret < 0)
114
            return ret;
115
        av_metadata_copy(&s->metadata, rt->asf_ctx->metadata, 0);
116
        rt->asf_pb_pos = url_ftell(&pb);
117
        av_free(buf);
118
        rt->asf_ctx->pb = NULL;
119
    }
120
    return ret;
121
}
122

    
123
static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
124
                                 PayloadContext *asf, const char *line)
125
{
126
    if (av_strstart(line, "stream:", &line)) {
127
        RTSPState *rt = s->priv_data;
128

    
129
        s->streams[stream_index]->id = strtol(line, NULL, 10);
130

    
131
        if (rt->asf_ctx) {
132
            int i;
133

    
134
            for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
135
                if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
136
                    *s->streams[stream_index]->codec =
137
                        *rt->asf_ctx->streams[i]->codec;
138
                    rt->asf_ctx->streams[i]->codec->extradata_size = 0;
139
                    rt->asf_ctx->streams[i]->codec->extradata = NULL;
140
                    av_set_pts_info(s->streams[stream_index], 32, 1, 1000);
141
                }
142
           }
143
        }
144
    }
145

    
146
    return 0;
147
}
148

    
149
struct PayloadContext {
150
    ByteIOContext *pktbuf, pb;
151
    uint8_t *buf;
152
};
153

    
154
/**
155
 * @return 0 when a packet was written into /p pkt, and no more data is left;
156
 *         1 when a packet was written into /p pkt, and more packets might be left;
157
 *        <0 when not enough data was provided to return a full packet, or on error.
158
 */
159
static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
160
                               AVStream *st, AVPacket *pkt,
161
                               uint32_t *timestamp,
162
                               const uint8_t *buf, int len, int flags)
163
{
164
    ByteIOContext *pb = &asf->pb;
165
    int res, mflags, len_off;
166
    RTSPState *rt = s->priv_data;
167

    
168
    if (!rt->asf_ctx)
169
        return -1;
170

    
171
    if (len > 0) {
172
        int off, out_len = 0;
173

    
174
        if (len < 4)
175
            return -1;
176

    
177
        av_freep(&asf->buf);
178

    
179
        init_put_byte(pb, buf, len, 0, NULL, NULL, NULL, NULL);
180

    
181
        while (url_ftell(pb) + 4 < len) {
182
            int start_off = url_ftell(pb);
183

    
184
            mflags = get_byte(pb);
185
            if (mflags & 0x80)
186
                flags |= RTP_FLAG_KEY;
187
            len_off = get_be24(pb);
188
            if (mflags & 0x20)   /**< relative timestamp */
189
                url_fskip(pb, 4);
190
            if (mflags & 0x10)   /**< has duration */
191
                url_fskip(pb, 4);
192
            if (mflags & 0x8)    /**< has location ID */
193
                url_fskip(pb, 4);
194
            off = url_ftell(pb);
195

    
196
            if (!(mflags & 0x40)) {
197
                /**
198
                 * If 0x40 is not set, the len_off field specifies an offset
199
                 * of this packet's payload data in the complete (reassembled)
200
                 * ASF packet. This is used to spread one ASF packet over
201
                 * multiple RTP packets.
202
                 */
203
                if (asf->pktbuf && len_off != url_ftell(asf->pktbuf)) {
204
                    uint8_t *p;
205
                    url_close_dyn_buf(asf->pktbuf, &p);
206
                    asf->pktbuf = NULL;
207
                    av_free(p);
208
                }
209
                if (!len_off && !asf->pktbuf &&
210
                    (res = url_open_dyn_buf(&asf->pktbuf)) < 0)
211
                    return res;
212
                if (!asf->pktbuf)
213
                    return AVERROR(EIO);
214

    
215
                put_buffer(asf->pktbuf, buf + off, len - off);
216
                url_fskip(pb, len - off);
217
                if (!(flags & RTP_FLAG_MARKER))
218
                    return -1;
219
                out_len     = url_close_dyn_buf(asf->pktbuf, &asf->buf);
220
                asf->pktbuf = NULL;
221
            } else {
222
                /**
223
                 * If 0x40 is set, the len_off field specifies the length of
224
                 * the next ASF packet that can be read from this payload
225
                 * data alone. This is commonly the same as the payload size,
226
                 * but could be less in case of packet splitting (i.e.
227
                 * multiple ASF packets in one RTP packet).
228
                 */
229

    
230
                int cur_len = start_off + len_off - off;
231
                int prev_len = out_len;
232
                out_len += cur_len;
233
                asf->buf = av_realloc(asf->buf, out_len);
234
                memcpy(asf->buf + prev_len, buf + off,
235
                       FFMIN(cur_len, len - off));
236
                url_fskip(pb, cur_len);
237
            }
238
        }
239

    
240
        init_packetizer(pb, asf->buf, out_len);
241
        pb->pos += rt->asf_pb_pos;
242
        pb->eof_reached = 0;
243
        rt->asf_ctx->pb = pb;
244
    }
245

    
246
    for (;;) {
247
        int i;
248

    
249
        res = av_read_packet(rt->asf_ctx, pkt);
250
        rt->asf_pb_pos = url_ftell(pb);
251
        if (res != 0)
252
            break;
253
        for (i = 0; i < s->nb_streams; i++) {
254
            if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
255
                pkt->stream_index = i;
256
                return 1; // FIXME: return 0 if last packet
257
            }
258
        }
259
        av_free_packet(pkt);
260
    }
261

    
262
    return res == 1 ? -1 : res;
263
}
264

    
265
static PayloadContext *asfrtp_new_context(void)
266
{
267
    return av_mallocz(sizeof(PayloadContext));
268
}
269

    
270
static void asfrtp_free_context(PayloadContext *asf)
271
{
272
    if (asf->pktbuf) {
273
        uint8_t *p = NULL;
274
        url_close_dyn_buf(asf->pktbuf, &p);
275
        asf->pktbuf = NULL;
276
        av_free(p);
277
    }
278
    av_freep(&asf->buf);
279
    av_free(asf);
280
}
281

    
282
#define RTP_ASF_HANDLER(n, s, t) \
283
RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
284
    .enc_name         = s, \
285
    .codec_type       = t, \
286
    .codec_id         = CODEC_ID_NONE, \
287
    .parse_sdp_a_line = asfrtp_parse_sdp_line, \
288
    .open             = asfrtp_new_context, \
289
    .close            = asfrtp_free_context, \
290
    .parse_packet     = asfrtp_parse_packet,   \
291
}
292

    
293
RTP_ASF_HANDLER(asf_pfv, "x-asf-pf",  AVMEDIA_TYPE_VIDEO);
294
RTP_ASF_HANDLER(asf_pfa, "x-asf-pf",  AVMEDIA_TYPE_AUDIO);