/* * RTP AMR Depacketizer, RFC 3267 * Copyright (c) 2010 Martin Storsjo * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavutil/channel_layout.h" #include "avformat.h" #include "rtpdec_formats.h" #include "libavutil/avstring.h" static const uint8_t frame_sizes_nb[16] = { 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0 }; static const uint8_t frame_sizes_wb[16] = { 17, 23, 32, 36, 40, 46, 50, 58, 60, 5, 5, 0, 0, 0, 0, 0 }; struct PayloadContext { int octet_align; int crc; int interleaving; int channels; }; static av_cold int amr_init(AVFormatContext *s, int st_index, PayloadContext *data) { data->channels = 1; return 0; } static int amr_handle_packet(AVFormatContext *ctx, PayloadContext *data, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags) { const uint8_t *frame_sizes = NULL; int frames; int i; const uint8_t *speech_data; uint8_t *ptr; if (st->codecpar->codec_id == AV_CODEC_ID_AMR_NB) { frame_sizes = frame_sizes_nb; } else if (st->codecpar->codec_id == AV_CODEC_ID_AMR_WB) { frame_sizes = frame_sizes_wb; } else { av_log(ctx, AV_LOG_ERROR, "Bad codec ID\n"); return AVERROR_INVALIDDATA; } if (st->codecpar->channels != 1) { av_log(ctx, AV_LOG_ERROR, "Only mono AMR is supported\n"); return AVERROR_INVALIDDATA; } st->codecpar->channel_layout = AV_CH_LAYOUT_MONO; /* The AMR RTP packet consists of one header byte, followed * by one TOC byte for each AMR frame in the packet, followed * by the speech data for all the AMR frames. * * The header byte contains only a codec mode request, for * requesting what kind of AMR data the sender wants to * receive. Not used at the moment. */ /* Count the number of frames in the packet. The highest bit * is set in a TOC byte if there are more frames following. */ for (frames = 1; frames < len && (buf[frames] & 0x80); frames++) ; if (1 + frames >= len) { /* We hit the end of the packet while counting frames. */ av_log(ctx, AV_LOG_ERROR, "No speech data found\n"); return AVERROR_INVALIDDATA; } speech_data = buf + 1 + frames; /* Everything except the codec mode request byte should be output. */ if (av_new_packet(pkt, len - 1)) { av_log(ctx, AV_LOG_ERROR, "Out of memory\n"); return AVERROR(ENOMEM); } pkt->stream_index = st->index; ptr = pkt->data; for (i = 0; i < frames; i++) { uint8_t toc = buf[1 + i]; int frame_size = frame_sizes[(toc >> 3) & 0x0f]; if (speech_data + frame_size > buf + len) { /* Too little speech data */ av_log(ctx, AV_LOG_WARNING, "Too little speech data in the RTP packet\n"); /* Set the unwritten part of the packet to zero. */ memset(ptr, 0, pkt->data + pkt->size - ptr); pkt->size = ptr - pkt->data; return 0; } /* Extract the AMR frame mode from the TOC byte */ *ptr++ = toc & 0x7C; /* Copy the speech data */ memcpy(ptr, speech_data, frame_size); speech_data += frame_size; ptr += frame_size; } if (speech_data < buf + len) { av_log(ctx, AV_LOG_WARNING, "Too much speech data in the RTP packet?\n"); /* Set the unwritten part of the packet to zero. */ memset(ptr, 0, pkt->data + pkt->size - ptr); pkt->size = ptr - pkt->data; } return 0; } static int amr_parse_fmtp(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *attr, const char *value) { /* Some AMR SDP configurations contain "octet-align", without * the trailing =1. Therefore, if the value is empty, * interpret it as "1". */ if (!strcmp(value, "")) { av_log(s, AV_LOG_WARNING, "AMR fmtp attribute %s had " "nonstandard empty value\n", attr); value = "1"; } if (!strcmp(attr, "octet-align")) data->octet_align = atoi(value); else if (!strcmp(attr, "crc")) data->crc = atoi(value); else if (!strcmp(attr, "interleaving")) data->interleaving = atoi(value); else if (!strcmp(attr, "channels")) data->channels = atoi(value); return 0; } static int amr_parse_sdp_line(AVFormatContext *s, int st_index, PayloadContext *data, const char *line) { const char *p; int ret; if (st_index < 0) return 0; /* Parse an fmtp line this one: * a=fmtp:97 octet-align=1; interleaving=0 * That is, a normal fmtp: line followed by semicolon & space * separated key/value pairs. */ if (av_strstart(line, "fmtp:", &p)) { ret = ff_parse_fmtp(s, s->streams[st_index], data, p, amr_parse_fmtp); if (!data->octet_align || data->crc || data->interleaving || data->channels != 1) { av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n"); return -1; } return ret; } return 0; } RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler = { .enc_name = "AMR", .codec_type = AVMEDIA_TYPE_AUDIO, .codec_id = AV_CODEC_ID_AMR_NB, .priv_data_size = sizeof(PayloadContext), .init = amr_init, .parse_sdp_a_line = amr_parse_sdp_line, .parse_packet = amr_handle_packet, }; RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler = { .enc_name = "AMR-WB", .codec_type = AVMEDIA_TYPE_AUDIO, .codec_id = AV_CODEC_ID_AMR_WB, .priv_data_size = sizeof(PayloadContext), .init = amr_init, .parse_sdp_a_line = amr_parse_sdp_line, .parse_packet = amr_handle_packet, };