Statistics
| Branch: | Revision:

ffmpeg / libavformat / rtpdec_asf.c @ 965a3ddb

History | View | Annotate | Download (9.29 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, "", &asf_demuxer, NULL);
113
        if (ret < 0)
114
            return ret;
115
        rt->asf_pb_pos = url_ftell(&pb);
116
        av_free(buf);
117
        rt->asf_ctx->pb = NULL;
118
    }
119
    return ret;
120
}
121

    
122
static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
123
                                 PayloadContext *asf, const char *line)
124
{
125
    if (av_strstart(line, "stream:", &line)) {
126
        RTSPState *rt = s->priv_data;
127

    
128
        s->streams[stream_index]->id = strtol(line, NULL, 10);
129

    
130
        if (rt->asf_ctx) {
131
            int i;
132

    
133
            for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
134
                if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
135
                    *s->streams[stream_index]->codec =
136
                        *rt->asf_ctx->streams[i]->codec;
137
                    rt->asf_ctx->streams[i]->codec->extradata_size = 0;
138
                    rt->asf_ctx->streams[i]->codec->extradata = NULL;
139
                    av_set_pts_info(s->streams[stream_index], 32, 1, 1000);
140
                }
141
           }
142
        }
143
    }
144

    
145
    return 0;
146
}
147

    
148
struct PayloadContext {
149
    ByteIOContext *pktbuf, pb;
150
    uint8_t *buf;
151
};
152

    
153
/**
154
 * @return 0 when a packet was written into /p pkt, and no more data is left;
155
 *         1 when a packet was written into /p pkt, and more packets might be left;
156
 *        <0 when not enough data was provided to return a full packet, or on error.
157
 */
158
static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
159
                               AVStream *st, AVPacket *pkt,
160
                               uint32_t *timestamp,
161
                               const uint8_t *buf, int len, int flags)
162
{
163
    ByteIOContext *pb = &asf->pb;
164
    int res, mflags, len_off;
165
    RTSPState *rt = s->priv_data;
166

    
167
    if (!rt->asf_ctx)
168
        return -1;
169

    
170
    if (len > 0) {
171
        int off, out_len = 0;
172

    
173
        if (len < 4)
174
            return -1;
175

    
176
        av_freep(&asf->buf);
177

    
178
        init_put_byte(pb, buf, len, 0, NULL, NULL, NULL, NULL);
179

    
180
        while (url_ftell(pb) + 4 < len) {
181
            int start_off = url_ftell(pb);
182

    
183
            mflags = get_byte(pb);
184
            if (mflags & 0x80)
185
                flags |= RTP_FLAG_KEY;
186
            len_off = get_be24(pb);
187
            if (mflags & 0x20)   /**< relative timestamp */
188
                url_fskip(pb, 4);
189
            if (mflags & 0x10)   /**< has duration */
190
                url_fskip(pb, 4);
191
            if (mflags & 0x8)    /**< has location ID */
192
                url_fskip(pb, 4);
193
            off = url_ftell(pb);
194

    
195
            if (!(mflags & 0x40)) {
196
                /**
197
                 * If 0x40 is not set, the len_off field specifies an offset
198
                 * of this packet's payload data in the complete (reassembled)
199
                 * ASF packet. This is used to spread one ASF packet over
200
                 * multiple RTP packets.
201
                 */
202
                if (asf->pktbuf && len_off != url_ftell(asf->pktbuf)) {
203
                    uint8_t *p;
204
                    url_close_dyn_buf(asf->pktbuf, &p);
205
                    asf->pktbuf = NULL;
206
                    av_free(p);
207
                }
208
                if (!len_off && !asf->pktbuf &&
209
                    (res = url_open_dyn_buf(&asf->pktbuf)) < 0)
210
                    return res;
211
                if (!asf->pktbuf)
212
                    return AVERROR(EIO);
213

    
214
                put_buffer(asf->pktbuf, buf + off, len - off);
215
                url_fskip(pb, len - off);
216
                if (!(flags & RTP_FLAG_MARKER))
217
                    return -1;
218
                out_len     = url_close_dyn_buf(asf->pktbuf, &asf->buf);
219
                asf->pktbuf = NULL;
220
            } else {
221
                /**
222
                 * If 0x40 is set, the len_off field specifies the length of
223
                 * the next ASF packet that can be read from this payload
224
                 * data alone. This is commonly the same as the payload size,
225
                 * but could be less in case of packet splitting (i.e.
226
                 * multiple ASF packets in one RTP packet).
227
                 */
228

    
229
                int cur_len = start_off + len_off - off;
230
                int prev_len = out_len;
231
                out_len += cur_len;
232
                asf->buf = av_realloc(asf->buf, out_len);
233
                memcpy(asf->buf + prev_len, buf + off, cur_len);
234
                url_fskip(pb, cur_len);
235
            }
236
        }
237

    
238
        init_packetizer(pb, asf->buf, out_len);
239
        pb->pos += rt->asf_pb_pos;
240
        pb->eof_reached = 0;
241
        rt->asf_ctx->pb = pb;
242
    }
243

    
244
    for (;;) {
245
        int i;
246

    
247
        res = av_read_packet(rt->asf_ctx, pkt);
248
        rt->asf_pb_pos = url_ftell(pb);
249
        if (res != 0)
250
            break;
251
        for (i = 0; i < s->nb_streams; i++) {
252
            if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
253
                pkt->stream_index = i;
254
                return 1; // FIXME: return 0 if last packet
255
            }
256
        }
257
        av_free_packet(pkt);
258
    }
259

    
260
    return res == 1 ? -1 : res;
261
}
262

    
263
static PayloadContext *asfrtp_new_context(void)
264
{
265
    return av_mallocz(sizeof(PayloadContext));
266
}
267

    
268
static void asfrtp_free_context(PayloadContext *asf)
269
{
270
    if (asf->pktbuf) {
271
        uint8_t *p = NULL;
272
        url_close_dyn_buf(asf->pktbuf, &p);
273
        asf->pktbuf = NULL;
274
        av_free(p);
275
    }
276
    av_freep(&asf->buf);
277
    av_free(asf);
278
}
279

    
280
#define RTP_ASF_HANDLER(n, s, t) \
281
RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
282
    .enc_name         = s, \
283
    .codec_type       = t, \
284
    .codec_id         = CODEC_ID_NONE, \
285
    .parse_sdp_a_line = asfrtp_parse_sdp_line, \
286
    .open             = asfrtp_new_context, \
287
    .close            = asfrtp_free_context, \
288
    .parse_packet     = asfrtp_parse_packet,   \
289
};
290

    
291
RTP_ASF_HANDLER(asf_pfv, "x-asf-pf",  AVMEDIA_TYPE_VIDEO);
292
RTP_ASF_HANDLER(asf_pfa, "x-asf-pf",  AVMEDIA_TYPE_AUDIO);