libavformat/rtp_asf.c

   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 libavformat/rtp_asf.c
  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 "rtp_asf.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 void ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
  95 {
  96     if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
  97         ByteIOContext pb;
  98         RTSPState *rt = s->priv_data;
  99         int len = strlen(p) * 6 / 8;
 100         char *buf = av_mallocz(len);
 101         av_base64_decode(buf, p, len);
 102
 103         if (rtp_asf_fix_header(buf, len) < 0)
 104             av_log(s, AV_LOG_ERROR,
 105                    "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
 106         init_packetizer(&pb, buf, len);
 107         if (rt->asf_ctx) {
 108             av_close_input_stream(rt->asf_ctx);
 109             rt->asf_ctx = NULL;
 110         }
 111         av_open_input_stream(&rt->asf_ctx, &pb, "", &asf_demuxer, NULL);
 112         rt->asf_pb_pos = url_ftell(&pb);
 113         av_free(buf);
 114         rt->asf_ctx->pb = NULL;
 115     }
 116 }
 117
 118 static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
 119                                  PayloadContext *asf, const char *line)
 120 {
 121     if (av_strstart(line, "stream:", &line)) {
 122         RTSPState *rt = s->priv_data;
 123
 124         s->streams[stream_index]->id = strtol(line, NULL, 10);
 125
 126         if (rt->asf_ctx) {
 127             int i;
 128
 129             for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
 130                 if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
 131                     *s->streams[stream_index]->codec =
 132                         *rt->asf_ctx->streams[i]->codec;
 133                     rt->asf_ctx->streams[i]->codec->extradata_size = 0;
 134                     rt->asf_ctx->streams[i]->codec->extradata = NULL;
 135                     av_set_pts_info(s->streams[stream_index], 32, 1, 1000);
 136                 }
 137            }
 138         }
 139     }
 140
 141     return 0;
 142 }
 143
 144 struct PayloadContext {
 145     ByteIOContext *pktbuf, pb;
 146     char *buf;
 147 };
 148
 149 /**
 150  * @return 0 when a packet was written into /p pkt, and no more data is left;
 151  *         1 when a packet was written into /p pkt, and more packets might be left;
 152  *        <0 when not enough data was provided to return a full packet, or on error.
 153  */
 154 static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
 155                                AVStream *st, AVPacket *pkt,
 156                                uint32_t *timestamp,
 157                                const uint8_t *buf, int len, int flags)
 158 {
 159     ByteIOContext *pb = &asf->pb;
 160     int res, mflags, len_off;
 161     RTSPState *rt = s->priv_data;
 162
 163     if (!rt->asf_ctx)
 164         return -1;
 165
 166     if (len > 0) {
 167         int off, out_len;
 168
 169         if (len < 4)
 170             return -1;
 171
 172         init_put_byte(pb, buf, len, 0, NULL, NULL, NULL, NULL);
 173         mflags = get_byte(pb);
 174         if (mflags & 0x80)
 175             flags |= RTP_FLAG_KEY;
 176         len_off = get_be24(pb);
 177         if (mflags & 0x20)   /**< relative timestamp */
 178             url_fskip(pb, 4);
 179         if (mflags & 0x10)   /**< has duration */
 180             url_fskip(pb, 4);
 181         if (mflags & 0x8)    /**< has location ID */
 182             url_fskip(pb, 4);
 183         off = url_ftell(pb);
 184
 185         av_freep(&asf->buf);
 186         if (!(mflags & 0x40)) {
 187             /**
 188              * If 0x40 is not set, the len_off field specifies an offset of this
 189              * packet's payload data in the complete (reassembled) ASF packet.
 190              * This is used to spread one ASF packet over multiple RTP packets.
 191              */
 192             if (asf->pktbuf && len_off != url_ftell(asf->pktbuf)) {
 193                 uint8_t *p;
 194                 url_close_dyn_buf(asf->pktbuf, &p);
 195                 asf->pktbuf = NULL;
 196                 av_free(p);
 197             }
 198             if (!len_off && !asf->pktbuf &&
 199                 !(res = url_open_dyn_packet_buf(&asf->pktbuf, rt->asf_ctx->packet_size)))
 200                 return res;
 201             if (!asf->pktbuf)
 202                 return AVERROR(EIO);
 203
 204             put_buffer(asf->pktbuf, buf + off, len - off);
 205             if (!(flags & RTP_FLAG_MARKER))
 206                 return -1;
 207             out_len     = url_close_dyn_buf(asf->pktbuf, &asf->buf);
 208             asf->pktbuf = NULL;
 209         } else {
 210             /**
 211              * If 0x40 is set, the len_off field specifies the length of the
 212              * next ASF packet that can be read from this payload data alone.
 213              * This is commonly the same as the payload size, but could be
 214              * less in case of packet splitting (i.e. multiple ASF packets in
 215              * one RTP packet).
 216              */
 217             if (len_off != len) {
 218                 av_log_missing_feature(s,
 219                     "RTSP-MS packet splitting", 1);
 220                 return -1;
 221             }
 222             asf->buf = av_malloc(len - off);
 223             out_len  = len - off;
 224             memcpy(asf->buf, buf + off, len - off);
 225         }
 226
 227         init_packetizer(pb, asf->buf, out_len);
 228         pb->pos += rt->asf_pb_pos;
 229         pb->eof_reached = 0;
 230         rt->asf_ctx->pb = pb;
 231     }
 232
 233     for (;;) {
 234         int i;
 235
 236         res = av_read_packet(rt->asf_ctx, pkt);
 237         rt->asf_pb_pos = url_ftell(pb);
 238         if (res != 0)
 239             break;
 240         for (i = 0; i < s->nb_streams; i++) {
 241             if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
 242                 pkt->stream_index = i;
 243                 return 1; // FIXME: return 0 if last packet
 244             }
 245         }
 246         av_free_packet(pkt);
 247     }
 248
 249     return res == 1 ? -1 : res;
 250 }
 251
 252 static PayloadContext *asfrtp_new_context(void)
 253 {
 254     return av_mallocz(sizeof(PayloadContext));
 255 }
 256
 257 static void asfrtp_free_context(PayloadContext *asf)
 258 {
 259     if (asf->pktbuf) {
 260         uint8_t *p = NULL;
 261         url_close_dyn_buf(asf->pktbuf, &p);
 262         asf->pktbuf = NULL;
 263         av_free(p);
 264     }
 265     av_freep(&asf->buf);
 266     av_free(asf);
 267 }
 268
 269 #define RTP_ASF_HANDLER(n, s, t) \
 270 RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
 271     .enc_name         = s, \
 272     .codec_type       = t, \
 273     .codec_id         = CODEC_ID_NONE, \
 274     .parse_sdp_a_line = asfrtp_parse_sdp_line, \
 275     .open             = asfrtp_new_context, \
 276     .close            = asfrtp_free_context, \
 277     .parse_packet     = asfrtp_parse_packet,   \
 278 };
 279
 280 RTP_ASF_HANDLER(asf_pfv, "x-asf-pf",  CODEC_TYPE_VIDEO);
 281 RTP_ASF_HANDLER(asf_pfa, "x-asf-pf",  CODEC_TYPE_AUDIO);