1/* 2 * RTP Depacketization of MP4A-LATM, RFC 3016 3 * Copyright (c) 2010 Martin Storsjo 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#include "rtpdec_formats.h" 23#include "internal.h" 24#include "libavutil/avstring.h" 25#include "libavcodec/get_bits.h" 26 27struct PayloadContext { 28 AVIOContext *dyn_buf; 29 uint8_t *buf; 30 int pos, len; 31 uint32_t timestamp; 32}; 33 34static PayloadContext *latm_new_context(void) 35{ 36 return av_mallocz(sizeof(PayloadContext)); 37} 38 39static 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 52static 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 106static 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 if (ff_alloc_extradata(st->codec, (get_bits_left(&gb) + 7)/8)) { 134 ret = AVERROR(ENOMEM); 135 goto end; 136 } 137 for (i = 0; i < st->codec->extradata_size; i++) 138 st->codec->extradata[i] = get_bits(&gb, 8); 139 140end: 141 av_free(config); 142 return ret; 143} 144 145static int parse_fmtp(AVFormatContext *s, 146 AVStream *stream, PayloadContext *data, 147 char *attr, char *value) 148{ 149 int res; 150 151 if (!strcmp(attr, "config")) { 152 res = parse_fmtp_config(stream, value); 153 if (res < 0) 154 return res; 155 } else if (!strcmp(attr, "cpresent")) { 156 int cpresent = atoi(value); 157 if (cpresent != 0) 158 avpriv_request_sample(s, 159 "RTP MP4A-LATM with in-band configuration"); 160 } 161 162 return 0; 163} 164 165static int latm_parse_sdp_line(AVFormatContext *s, int st_index, 166 PayloadContext *data, const char *line) 167{ 168 const char *p; 169 170 if (st_index < 0) 171 return 0; 172 173 if (av_strstart(line, "fmtp:", &p)) 174 return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp); 175 176 return 0; 177} 178 179RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = { 180 .enc_name = "MP4A-LATM", 181 .codec_type = AVMEDIA_TYPE_AUDIO, 182 .codec_id = AV_CODEC_ID_AAC, 183 .parse_sdp_a_line = latm_parse_sdp_line, 184 .alloc = latm_new_context, 185 .free = latm_free_context, 186 .parse_packet = latm_parse_packet 187}; 188