libavformat/rtpdec_latm.c

   1 /*
   2  * RTP Depacketization of MP4A-LATM, RFC 3016
   3  * Copyright (c) 2010 Martin Storsjo
   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 #include "rtpdec_formats.h"
  23 #include "internal.h"
  24 #include "libavutil/avstring.h"
  25 #include "libavcodec/get_bits.h"
  26
  27 struct PayloadContext {
  28     AVIOContext *dyn_buf;
  29     uint8_t *buf;
  30     int pos, len;
  31     uint32_t timestamp;
  32 };
  33
  34 static PayloadContext *latm_new_context(void)
  35 {
  36     return av_mallocz(sizeof(PayloadContext));
  37 }
  38
  39 static void latm_free_context(PayloadContext *data)
  40 {
  41     if (!data)
  42         return;
  43     if (data->dyn_buf) {
  44         uint8_t *p;
  45         avio_close_dyn_buf(data->dyn_buf, &p);
  46         av_free(p);
  47     }
  48     av_free(data->buf);
  49     av_free(data);
  50 }
  51
  52 static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data,
  53                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
  54                              const uint8_t *buf, int len, uint16_t seq,
  55                              int flags)
  56 {
  57     int ret, cur_len;
  58
  59     if (buf) {
  60         if (!data->dyn_buf || data->timestamp != *timestamp) {
  61             av_freep(&data->buf);
  62             if (data->dyn_buf)
  63                 avio_close_dyn_buf(data->dyn_buf, &data->buf);
  64             data->dyn_buf = NULL;
  65             av_freep(&data->buf);
  66
  67             data->timestamp = *timestamp;
  68             if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0)
  69                 return ret;
  70         }
  71         avio_write(data->dyn_buf, buf, len);
  72
  73         if (!(flags & RTP_FLAG_MARKER))
  74             return AVERROR(EAGAIN);
  75         av_free(data->buf);
  76         data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf);
  77         data->dyn_buf = NULL;
  78         data->pos = 0;
  79     }
  80
  81     if (!data->buf) {
  82         av_log(ctx, AV_LOG_ERROR, "No data available yet\n");
  83         return AVERROR(EIO);
  84     }
  85
  86     cur_len = 0;
  87     while (data->pos < data->len) {
  88         uint8_t val = data->buf[data->pos++];
  89         cur_len += val;
  90         if (val != 0xff)
  91             break;
  92     }
  93     if (data->pos + cur_len > data->len) {
  94         av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n");
  95         return AVERROR(EIO);
  96     }
  97
  98     if ((ret = av_new_packet(pkt, cur_len)) < 0)
  99         return ret;
 100     memcpy(pkt->data, data->buf + data->pos, cur_len);
 101     data->pos += cur_len;
 102     pkt->stream_index = st->index;
 103     return data->pos < data->len;
 104 }
 105
 106 static int parse_fmtp_config(AVStream *st, char *value)
 107 {
 108     int len = ff_hex_to_data(NULL, value), i, ret = 0;
 109     GetBitContext gb;
 110     uint8_t *config;
 111     int audio_mux_version, same_time_framing, num_programs, num_layers;
 112
 113     /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */
 114     config = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
 115     if (!config)
 116         return AVERROR(ENOMEM);
 117     ff_hex_to_data(config, value);
 118     init_get_bits(&gb, config, len*8);
 119     audio_mux_version = get_bits(&gb, 1);
 120     same_time_framing = get_bits(&gb, 1);
 121     skip_bits(&gb, 6); /* num_sub_frames */
 122     num_programs      = get_bits(&gb, 4);
 123     num_layers        = get_bits(&gb, 3);
 124     if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
 125         num_layers != 0) {
 126         av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n",
 127                                      audio_mux_version, same_time_framing,
 128                                      num_programs, num_layers);
 129         ret = AVERROR_PATCHWELCOME;
 130         goto end;
 131     }
 132     av_freep(&st->codec->extradata);
 133     st->codec->extradata_size = (get_bits_left(&gb) + 7)/8;
 134     st->codec->extradata = av_mallocz(st->codec->extradata_size +
 135                                       FF_INPUT_BUFFER_PADDING_SIZE);
 136     if (!st->codec->extradata) {
 137         ret = AVERROR(ENOMEM);
 138         goto end;
 139     }
 140     for (i = 0; i < st->codec->extradata_size; i++)
 141         st->codec->extradata[i] = get_bits(&gb, 8);
 142
 143 end:
 144     av_free(config);
 145     return ret;
 146 }
 147
 148 static int parse_fmtp(AVStream *stream, PayloadContext *data,
 149                       char *attr, char *value)
 150 {
 151     int res;
 152
 153     if (!strcmp(attr, "config")) {
 154         res = parse_fmtp_config(stream, value);
 155         if (res < 0)
 156             return res;
 157     } else if (!strcmp(attr, "cpresent")) {
 158         int cpresent = atoi(value);
 159         if (cpresent != 0)
 160             av_log_missing_feature(NULL, "RTP MP4A-LATM with in-band "
 161                                          "configuration", 1);
 162     }
 163
 164     return 0;
 165 }
 166
 167 static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
 168                                PayloadContext *data, const char *line)
 169 {
 170     const char *p;
 171
 172     if (st_index < 0)
 173         return 0;
 174
 175     if (av_strstart(line, "fmtp:", &p))
 176         return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);
 177
 178     return 0;
 179 }
 180
 181 RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = {
 182     .enc_name           = "MP4A-LATM",
 183     .codec_type         = AVMEDIA_TYPE_AUDIO,
 184     .codec_id           = AV_CODEC_ID_AAC,
 185     .parse_sdp_a_line   = latm_parse_sdp_line,
 186     .alloc              = latm_new_context,
 187     .free               = latm_free_context,
 188     .parse_packet       = latm_parse_packet
 189 };