From 556aa7a1022c31566f64c9cb8fe8de0d4d5b44b2 Mon Sep 17 00:00:00 2001 From: "Ronald S. Bultje" Date: Wed, 10 Feb 2010 17:20:50 +0000 Subject: RTP/AMR depacketizer, by Martin Storsjö <$firstname at $firstname dot st>. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Originally committed as revision 21740 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavformat/rtpdec_amr.c | 177 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+) create mode 100644 libavformat/rtpdec_amr.c (limited to 'libavformat/rtpdec_amr.c') diff --git a/libavformat/rtpdec_amr.c b/libavformat/rtpdec_amr.c new file mode 100644 index 0000000000..3bb7913609 --- /dev/null +++ b/libavformat/rtpdec_amr.c @@ -0,0 +1,177 @@ +/* + * RTP AMR Depacketizer, RFC 3267 + * Copyright (c) 2010 Martin Storsjo + * + * This file is part of FFmpeg. + * + * FFmpeg 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. + * + * FFmpeg 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 FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "avformat.h" +#include "rtpdec_amr.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 +}; + +static int amr_handle_packet(AVFormatContext *ctx, + PayloadContext *data, + AVStream *st, + AVPacket * pkt, + uint32_t * timestamp, + const uint8_t * buf, + int len, int flags) +{ + const uint8_t *frame_sizes = NULL; + int frames; + int i; + const uint8_t *speech_data; + uint8_t *ptr; + + if (st->codec->codec_id == CODEC_ID_AMR_NB) { + frame_sizes = frame_sizes_nb; + } else if (st->codec->codec_id == 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->codec->channels != 1) { + av_log(ctx, AV_LOG_ERROR, "Only mono AMR is supported\n"); + return AVERROR_INVALIDDATA; + } + + /* 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_NOMEM; + } + 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_sdp_line(AVFormatContext *s, int st_index, + PayloadContext *data, const char *line) +{ + const char *p; + char attr[25], value[25]; + + /* 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)) { + int octet_align = 0; + int crc = 0; + int interleaving = 0; + int channels = 1; + + while (*p && *p == ' ') p++; /* strip spaces */ + while (*p && *p != ' ') p++; /* eat protocol identifier */ + while (*p && *p == ' ') p++; /* strip trailing spaces */ + + while (rtsp_next_attr_and_value(&p, attr, sizeof(attr), value, sizeof(value))) { + if (!strcmp(attr, "octet-align")) + octet_align = atoi(value); + else if (!strcmp(attr, "crc")) + crc = atoi(value); + else if (!strcmp(attr, "interleaving")) + interleaving = atoi(value); + else if (!strcmp(attr, "channels")) + channels = atoi(value); + } + if (!octet_align || crc || interleaving || channels != 1) { + av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n"); + return -1; + } + } + return 0; +} + +RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler = { + .enc_name = "AMR", + .codec_type = CODEC_TYPE_AUDIO, + .codec_id = CODEC_ID_AMR_NB, + .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 = CODEC_TYPE_AUDIO, + .codec_id = CODEC_ID_AMR_WB, + .parse_sdp_a_line = amr_parse_sdp_line, + .parse_packet = amr_handle_packet, +}; + -- cgit v1.2.3