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| 1 /* |
| 2 * RTP AMR Depacketizer, RFC 3267 |
| 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 "avformat.h" |
| 23 #include "rtpdec_amr.h" |
| 24 #include "libavutil/avstring.h" |
| 25 |
| 26 static 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 }; |
| 29 static 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 |
| 33 static int amr_handle_packet(AVFormatContext *ctx, |
| 34 PayloadContext *data, |
| 35 AVStream *st, |
| 36 AVPacket * pkt, |
| 37 uint32_t * timestamp, |
| 38 const uint8_t * buf, |
| 39 int len, int flags) |
| 40 { |
| 41 const uint8_t *frame_sizes = NULL; |
| 42 int frames; |
| 43 int i; |
| 44 const uint8_t *speech_data; |
| 45 uint8_t *ptr; |
| 46 |
| 47 if (st->codec->codec_id == CODEC_ID_AMR_NB) { |
| 48 frame_sizes = frame_sizes_nb; |
| 49 } else if (st->codec->codec_id == CODEC_ID_AMR_WB) { |
| 50 frame_sizes = frame_sizes_wb; |
| 51 } else { |
| 52 av_log(ctx, AV_LOG_ERROR, "Bad codec ID\n"); |
| 53 return AVERROR_INVALIDDATA; |
| 54 } |
| 55 |
| 56 if (st->codec->channels != 1) { |
| 57 av_log(ctx, AV_LOG_ERROR, "Only mono AMR is supported\n"); |
| 58 return AVERROR_INVALIDDATA; |
| 59 } |
| 60 |
| 61 /* The AMR RTP packet consists of one header byte, followed |
| 62 * by one TOC byte for each AMR frame in the packet, followed |
| 63 * by the speech data for all the AMR frames. |
| 64 * |
| 65 * The header byte contains only a codec mode request, for |
| 66 * requesting what kind of AMR data the sender wants to |
| 67 * receive. Not used at the moment. |
| 68 */ |
| 69 |
| 70 /* Count the number of frames in the packet. The highest bit |
| 71 * is set in a TOC byte if there are more frames following. |
| 72 */ |
| 73 for (frames = 1; frames < len && (buf[frames] & 0x80); frames++) ; |
| 74 |
| 75 if (1 + frames >= len) { |
| 76 /* We hit the end of the packet while counting frames. */ |
| 77 av_log(ctx, AV_LOG_ERROR, "No speech data found\n"); |
| 78 return AVERROR_INVALIDDATA; |
| 79 } |
| 80 |
| 81 speech_data = buf + 1 + frames; |
| 82 |
| 83 /* Everything except the codec mode request byte should be output. */ |
| 84 if (av_new_packet(pkt, len - 1)) { |
| 85 av_log(ctx, AV_LOG_ERROR, "Out of memory\n"); |
| 86 return AVERROR_NOMEM; |
| 87 } |
| 88 pkt->stream_index = st->index; |
| 89 ptr = pkt->data; |
| 90 |
| 91 for (i = 0; i < frames; i++) { |
| 92 uint8_t toc = buf[1 + i]; |
| 93 int frame_size = frame_sizes[(toc >> 3) & 0x0f]; |
| 94 |
| 95 if (speech_data + frame_size > buf + len) { |
| 96 /* Too little speech data */ |
| 97 av_log(ctx, AV_LOG_WARNING, "Too little speech data in the RTP packe
t\n"); |
| 98 /* Set the unwritten part of the packet to zero. */ |
| 99 memset(ptr, 0, pkt->data + pkt->size - ptr); |
| 100 pkt->size = ptr - pkt->data; |
| 101 return 0; |
| 102 } |
| 103 |
| 104 /* Extract the AMR frame mode from the TOC byte */ |
| 105 *ptr++ = toc & 0x7C; |
| 106 |
| 107 /* Copy the speech data */ |
| 108 memcpy(ptr, speech_data, frame_size); |
| 109 speech_data += frame_size; |
| 110 ptr += frame_size; |
| 111 } |
| 112 |
| 113 if (speech_data < buf + len) { |
| 114 av_log(ctx, AV_LOG_WARNING, "Too much speech data in the RTP packet?\n")
; |
| 115 /* Set the unwritten part of the packet to zero. */ |
| 116 memset(ptr, 0, pkt->data + pkt->size - ptr); |
| 117 pkt->size = ptr - pkt->data; |
| 118 } |
| 119 |
| 120 return 0; |
| 121 } |
| 122 |
| 123 static int amr_parse_sdp_line(AVFormatContext *s, int st_index, |
| 124 PayloadContext *data, const char *line) |
| 125 { |
| 126 const char *p; |
| 127 char attr[25], value[25]; |
| 128 |
| 129 /* Parse an fmtp line this one: |
| 130 * a=fmtp:97 octet-align=1; interleaving=0 |
| 131 * That is, a normal fmtp: line followed by semicolon & space |
| 132 * separated key/value pairs. |
| 133 */ |
| 134 if (av_strstart(line, "fmtp:", &p)) { |
| 135 int octet_align = 0; |
| 136 int crc = 0; |
| 137 int interleaving = 0; |
| 138 int channels = 1; |
| 139 |
| 140 while (*p && *p == ' ') p++; /* strip spaces */ |
| 141 while (*p && *p != ' ') p++; /* eat protocol identifier */ |
| 142 while (*p && *p == ' ') p++; /* strip trailing spaces */ |
| 143 |
| 144 while (ff_rtsp_next_attr_and_value(&p, attr, sizeof(attr), value, sizeof
(value))) { |
| 145 if (!strcmp(attr, "octet-align")) |
| 146 octet_align = atoi(value); |
| 147 else if (!strcmp(attr, "crc")) |
| 148 crc = atoi(value); |
| 149 else if (!strcmp(attr, "interleaving")) |
| 150 interleaving = atoi(value); |
| 151 else if (!strcmp(attr, "channels")) |
| 152 channels = atoi(value); |
| 153 } |
| 154 if (!octet_align || crc || interleaving || channels != 1) { |
| 155 av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n"); |
| 156 return -1; |
| 157 } |
| 158 } |
| 159 return 0; |
| 160 } |
| 161 |
| 162 RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler = { |
| 163 .enc_name = "AMR", |
| 164 .codec_type = CODEC_TYPE_AUDIO, |
| 165 .codec_id = CODEC_ID_AMR_NB, |
| 166 .parse_sdp_a_line = amr_parse_sdp_line, |
| 167 .parse_packet = amr_handle_packet, |
| 168 }; |
| 169 |
| 170 RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler = { |
| 171 .enc_name = "AMR-WB", |
| 172 .codec_type = CODEC_TYPE_AUDIO, |
| 173 .codec_id = CODEC_ID_AMR_WB, |
| 174 .parse_sdp_a_line = amr_parse_sdp_line, |
| 175 .parse_packet = amr_handle_packet, |
| 176 }; |
| 177 |
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