libavformat/rtpdec_qt.c

   1 /*
   2  * RTP/Quicktime support.
   3  * Copyright (c) 2009 Ronald S. Bultje
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 Quicktime-style RTP support
  25  * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
  26  */
  27
  28 #include "avformat.h"
  29 #include "internal.h"
  30 #include "avio_internal.h"
  31 #include "rtp.h"
  32 #include "rtpdec.h"
  33 #include "isom.h"
  34 #include "libavcodec/get_bits.h"
  35
  36 struct PayloadContext {
  37     AVPacket pkt;
  38     int bytes_per_frame, remaining;
  39     uint32_t timestamp;
  40 };
  41
  42 static int qt_rtp_parse_packet(AVFormatContext *s, PayloadContext *qt,
  43                                AVStream *st, AVPacket *pkt,
  44                                uint32_t *timestamp, const uint8_t *buf,
  45                                int len, uint16_t seq, int flags)
  46 {
  47     AVIOContext pb;
  48     GetBitContext gb;
  49     int packing_scheme, has_payload_desc, has_packet_info, alen,
  50         has_marker_bit = flags & RTP_FLAG_MARKER;
  51
  52     if (qt->remaining) {
  53         int num = qt->pkt.size / qt->bytes_per_frame;
  54
  55         if (av_new_packet(pkt, qt->bytes_per_frame))
  56             return AVERROR(ENOMEM);
  57         pkt->stream_index = st->index;
  58         pkt->flags        = qt->pkt.flags;
  59         memcpy(pkt->data,
  60                &qt->pkt.data[(num - qt->remaining) * qt->bytes_per_frame],
  61                qt->bytes_per_frame);
  62         if (--qt->remaining == 0) {
  63             av_freep(&qt->pkt.data);
  64             qt->pkt.size = 0;
  65         }
  66         return qt->remaining > 0;
  67     }
  68
  69     /**
  70      * The RTP payload is described in:
  71      * http://developer.apple.com/quicktime/icefloe/dispatch026.html
  72      */
  73     init_get_bits(&gb, buf, len << 3);
  74     ffio_init_context(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
  75
  76     if (len < 4)
  77         return AVERROR_INVALIDDATA;
  78
  79     skip_bits(&gb, 4); // version
  80     if ((packing_scheme = get_bits(&gb, 2)) == 0)
  81         return AVERROR_INVALIDDATA;
  82     if (get_bits1(&gb))
  83         flags          |= RTP_FLAG_KEY;
  84     has_payload_desc    = get_bits1(&gb);
  85     has_packet_info     = get_bits1(&gb);
  86     skip_bits(&gb, 23); // reserved:7, cache payload info:1, payload ID:15
  87
  88     if (has_payload_desc) {
  89         int data_len, pos, is_start, is_finish;
  90         uint32_t tag;
  91
  92         pos = get_bits_count(&gb) >> 3;
  93         if (pos + 12 > len)
  94             return AVERROR_INVALIDDATA;
  95
  96         skip_bits(&gb, 2); // has non-I frames:1, is sparse:1
  97         is_start  = get_bits1(&gb);
  98         is_finish = get_bits1(&gb);
  99         if (!is_start || !is_finish) {
 100             av_log_missing_feature(s, "RTP-X-QT with payload description "
 101                                       "split over several packets", 1);
 102             return AVERROR_PATCHWELCOME;
 103         }
 104         skip_bits(&gb, 12); // reserved
 105         data_len = get_bits(&gb, 16);
 106
 107         avio_seek(&pb, pos + 4, SEEK_SET);
 108         tag = avio_rl32(&pb);
 109         if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
 110                  tag != MKTAG('v','i','d','e')) ||
 111             (st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&
 112                  tag != MKTAG('s','o','u','n')))
 113             return AVERROR_INVALIDDATA;
 114         avpriv_set_pts_info(st, 32, 1, avio_rb32(&pb));
 115
 116         if (pos + data_len > len)
 117             return AVERROR_INVALIDDATA;
 118         /* TLVs */
 119         while (avio_tell(&pb) + 4 < pos + data_len) {
 120             int tlv_len = avio_rb16(&pb);
 121             tag = avio_rl16(&pb);
 122             if (avio_tell(&pb) + tlv_len > pos + data_len)
 123                 return AVERROR_INVALIDDATA;
 124
 125 #define MKTAG16(a,b) MKTAG(a,b,0,0)
 126             switch (tag) {
 127             case MKTAG16('s','d'): {
 128                 MOVStreamContext *msc;
 129                 void *priv_data = st->priv_data;
 130                 int nb_streams = s->nb_streams;
 131                 MOVContext *mc = av_mallocz(sizeof(*mc));
 132                 if (!mc)
 133                     return AVERROR(ENOMEM);
 134                 mc->fc = s;
 135                 st->priv_data = msc = av_mallocz(sizeof(MOVStreamContext));
 136                 if (!msc) {
 137                     av_free(mc);
 138                     st->priv_data = priv_data;
 139                     return AVERROR(ENOMEM);
 140                 }
 141                 /* ff_mov_read_stsd_entries updates stream s->nb_streams-1,
 142                  * so set it temporarily to indicate which stream to update. */
 143                 s->nb_streams = st->index + 1;
 144                 ff_mov_read_stsd_entries(mc, &pb, 1);
 145                 qt->bytes_per_frame = msc->bytes_per_frame;
 146                 av_free(msc);
 147                 av_free(mc);
 148                 st->priv_data = priv_data;
 149                 s->nb_streams = nb_streams;
 150                 break;
 151             }
 152             default:
 153                 avio_skip(&pb, tlv_len);
 154                 break;
 155             }
 156         }
 157
 158         /* 32-bit alignment */
 159         avio_skip(&pb, ((avio_tell(&pb) + 3) & ~3) - avio_tell(&pb));
 160     } else
 161         avio_seek(&pb, 4, SEEK_SET);
 162
 163     if (has_packet_info) {
 164         av_log_missing_feature(s, "RTP-X-QT with packet specific info", 1);
 165         return AVERROR_PATCHWELCOME;
 166     }
 167
 168     alen = len - avio_tell(&pb);
 169     if (alen <= 0)
 170         return AVERROR_INVALIDDATA;
 171
 172     switch (packing_scheme) {
 173     case 3: /* one data packet spread over 1 or multiple RTP packets */
 174         if (qt->pkt.size > 0 && qt->timestamp == *timestamp) {
 175             qt->pkt.data = av_realloc(qt->pkt.data, qt->pkt.size + alen +
 176                                       FF_INPUT_BUFFER_PADDING_SIZE);
 177         } else {
 178             av_freep(&qt->pkt.data);
 179             av_init_packet(&qt->pkt);
 180             qt->pkt.data = av_malloc(alen + FF_INPUT_BUFFER_PADDING_SIZE);
 181             qt->pkt.size = 0;
 182             qt->timestamp = *timestamp;
 183         }
 184         if (!qt->pkt.data)
 185             return AVERROR(ENOMEM);
 186         memcpy(qt->pkt.data + qt->pkt.size, buf + avio_tell(&pb), alen);
 187         qt->pkt.size += alen;
 188         if (has_marker_bit) {
 189             int ret = av_packet_from_data(pkt, qt->pkt.data, qt->pkt.size);
 190             if (ret < 0)
 191                 return ret;
 192
 193             qt->pkt.size = 0;
 194             qt->pkt.data = NULL;
 195             pkt->flags        = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;
 196             pkt->stream_index = st->index;
 197             memset(pkt->data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
 198             return 0;
 199         }
 200         return AVERROR(EAGAIN);
 201
 202     case 1: /* constant packet size, multiple packets per RTP packet */
 203         if (qt->bytes_per_frame == 0 ||
 204             alen % qt->bytes_per_frame != 0)
 205             return AVERROR_INVALIDDATA; /* wrongly padded */
 206         qt->remaining = (alen / qt->bytes_per_frame) - 1;
 207         if (av_new_packet(pkt, qt->bytes_per_frame))
 208             return AVERROR(ENOMEM);
 209         memcpy(pkt->data, buf + avio_tell(&pb), qt->bytes_per_frame);
 210         pkt->flags = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;
 211         pkt->stream_index = st->index;
 212         if (qt->remaining > 0) {
 213             av_freep(&qt->pkt.data);
 214             qt->pkt.data = av_malloc(qt->remaining * qt->bytes_per_frame);
 215             if (!qt->pkt.data) {
 216                 av_free_packet(pkt);
 217                 return AVERROR(ENOMEM);
 218             }
 219             qt->pkt.size = qt->remaining * qt->bytes_per_frame;
 220             memcpy(qt->pkt.data,
 221                    buf + avio_tell(&pb) + qt->bytes_per_frame,
 222                    qt->remaining * qt->bytes_per_frame);
 223             qt->pkt.flags = pkt->flags;
 224             return 1;
 225         }
 226         return 0;
 227
 228     default:  /* unimplemented */
 229         av_log_missing_feature(NULL, "RTP-X-QT with packing scheme 2", 1);
 230         return AVERROR_PATCHWELCOME;
 231     }
 232 }
 233
 234 static PayloadContext *qt_rtp_new(void)
 235 {
 236     return av_mallocz(sizeof(PayloadContext));
 237 }
 238
 239 static void qt_rtp_free(PayloadContext *qt)
 240 {
 241     av_freep(&qt->pkt.data);
 242     av_free(qt);
 243 }
 244
 245 #define RTP_QT_HANDLER(m, n, s, t) \
 246 RTPDynamicProtocolHandler ff_ ## m ## _rtp_ ## n ## _handler = { \
 247     .enc_name         = s, \
 248     .codec_type       = t, \
 249     .codec_id         = AV_CODEC_ID_NONE, \
 250     .alloc            = qt_rtp_new,    \
 251     .free             = qt_rtp_free,   \
 252     .parse_packet     = qt_rtp_parse_packet, \
 253 }
 254
 255 RTP_QT_HANDLER(qt,        vid, "X-QT",        AVMEDIA_TYPE_VIDEO);
 256 RTP_QT_HANDLER(qt,        aud, "X-QT",        AVMEDIA_TYPE_AUDIO);
 257 RTP_QT_HANDLER(quicktime, vid, "X-QUICKTIME", AVMEDIA_TYPE_VIDEO);
 258 RTP_QT_HANDLER(quicktime, aud, "X-QUICKTIME", AVMEDIA_TYPE_AUDIO);