1/* 2 * RTP AMR Depacketizer, RFC 3267 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 "avformat.h" 23#include "rtpdec_formats.h" 24#include "libavutil/avstring.h" 25 26static const uint8_t frame_sizes_nb[16] = { 27 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0 28}; 29static const uint8_t frame_sizes_wb[16] = { 30 17, 23, 32, 36, 40, 46, 50, 58, 60, 5, 5, 0, 0, 0, 0, 0 31}; 32 33struct PayloadContext { 34 int octet_align; 35 int crc; 36 int interleaving; 37 int channels; 38}; 39 40static PayloadContext *amr_new_context(void) 41{ 42 PayloadContext *data = av_mallocz(sizeof(PayloadContext)); 43 if(!data) return data; 44 data->channels = 1; 45 return data; 46} 47 48static void amr_free_context(PayloadContext *data) 49{ 50 av_free(data); 51} 52 53static int amr_handle_packet(AVFormatContext *ctx, 54 PayloadContext *data, 55 AVStream *st, 56 AVPacket * pkt, 57 uint32_t * timestamp, 58 const uint8_t * buf, 59 int len, int flags) 60{ 61 const uint8_t *frame_sizes = NULL; 62 int frames; 63 int i; 64 const uint8_t *speech_data; 65 uint8_t *ptr; 66 67 if (st->codec->codec_id == CODEC_ID_AMR_NB) { 68 frame_sizes = frame_sizes_nb; 69 } else if (st->codec->codec_id == CODEC_ID_AMR_WB) { 70 frame_sizes = frame_sizes_wb; 71 } else { 72 av_log(ctx, AV_LOG_ERROR, "Bad codec ID\n"); 73 return AVERROR_INVALIDDATA; 74 } 75 76 if (st->codec->channels != 1) { 77 av_log(ctx, AV_LOG_ERROR, "Only mono AMR is supported\n"); 78 return AVERROR_INVALIDDATA; 79 } 80 81 /* The AMR RTP packet consists of one header byte, followed 82 * by one TOC byte for each AMR frame in the packet, followed 83 * by the speech data for all the AMR frames. 84 * 85 * The header byte contains only a codec mode request, for 86 * requesting what kind of AMR data the sender wants to 87 * receive. Not used at the moment. 88 */ 89 90 /* Count the number of frames in the packet. The highest bit 91 * is set in a TOC byte if there are more frames following. 92 */ 93 for (frames = 1; frames < len && (buf[frames] & 0x80); frames++) ; 94 95 if (1 + frames >= len) { 96 /* We hit the end of the packet while counting frames. */ 97 av_log(ctx, AV_LOG_ERROR, "No speech data found\n"); 98 return AVERROR_INVALIDDATA; 99 } 100 101 speech_data = buf + 1 + frames; 102 103 /* Everything except the codec mode request byte should be output. */ 104 if (av_new_packet(pkt, len - 1)) { 105 av_log(ctx, AV_LOG_ERROR, "Out of memory\n"); 106 return AVERROR(ENOMEM); 107 } 108 pkt->stream_index = st->index; 109 ptr = pkt->data; 110 111 for (i = 0; i < frames; i++) { 112 uint8_t toc = buf[1 + i]; 113 int frame_size = frame_sizes[(toc >> 3) & 0x0f]; 114 115 if (speech_data + frame_size > buf + len) { 116 /* Too little speech data */ 117 av_log(ctx, AV_LOG_WARNING, "Too little speech data in the RTP packet\n"); 118 /* Set the unwritten part of the packet to zero. */ 119 memset(ptr, 0, pkt->data + pkt->size - ptr); 120 pkt->size = ptr - pkt->data; 121 return 0; 122 } 123 124 /* Extract the AMR frame mode from the TOC byte */ 125 *ptr++ = toc & 0x7C; 126 127 /* Copy the speech data */ 128 memcpy(ptr, speech_data, frame_size); 129 speech_data += frame_size; 130 ptr += frame_size; 131 } 132 133 if (speech_data < buf + len) { 134 av_log(ctx, AV_LOG_WARNING, "Too much speech data in the RTP packet?\n"); 135 /* Set the unwritten part of the packet to zero. */ 136 memset(ptr, 0, pkt->data + pkt->size - ptr); 137 pkt->size = ptr - pkt->data; 138 } 139 140 return 0; 141} 142 143static int amr_parse_fmtp(AVStream *stream, PayloadContext *data, 144 char *attr, char *value) 145{ 146 /* Some AMR SDP configurations contain "octet-align", without 147 * the trailing =1. Therefore, if the value is empty, 148 * interpret it as "1". 149 */ 150 if (!strcmp(value, "")) { 151 av_log(NULL, AV_LOG_WARNING, "AMR fmtp attribute %s had " 152 "nonstandard empty value\n", attr); 153 strcpy(value, "1"); 154 } 155 if (!strcmp(attr, "octet-align")) 156 data->octet_align = atoi(value); 157 else if (!strcmp(attr, "crc")) 158 data->crc = atoi(value); 159 else if (!strcmp(attr, "interleaving")) 160 data->interleaving = atoi(value); 161 else if (!strcmp(attr, "channels")) 162 data->channels = atoi(value); 163 return 0; 164} 165 166static int amr_parse_sdp_line(AVFormatContext *s, int st_index, 167 PayloadContext *data, const char *line) 168{ 169 const char *p; 170 int ret; 171 172 /* Parse an fmtp line this one: 173 * a=fmtp:97 octet-align=1; interleaving=0 174 * That is, a normal fmtp: line followed by semicolon & space 175 * separated key/value pairs. 176 */ 177 if (av_strstart(line, "fmtp:", &p)) { 178 ret = ff_parse_fmtp(s->streams[st_index], data, p, amr_parse_fmtp); 179 if (!data->octet_align || data->crc || 180 data->interleaving || data->channels != 1) { 181 av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n"); 182 return -1; 183 } 184 return ret; 185 } 186 return 0; 187} 188 189RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler = { 190 .enc_name = "AMR", 191 .codec_type = AVMEDIA_TYPE_AUDIO, 192 .codec_id = CODEC_ID_AMR_NB, 193 .parse_sdp_a_line = amr_parse_sdp_line, 194 .alloc = amr_new_context, 195 .free = amr_free_context, 196 .parse_packet = amr_handle_packet, 197}; 198 199RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler = { 200 .enc_name = "AMR-WB", 201 .codec_type = AVMEDIA_TYPE_AUDIO, 202 .codec_id = CODEC_ID_AMR_WB, 203 .parse_sdp_a_line = amr_parse_sdp_line, 204 .alloc = amr_new_context, 205 .free = amr_free_context, 206 .parse_packet = amr_handle_packet, 207}; 208 209