| 1 | /* |
| 2 | * QDesign Music 2 (QDM2) payload for RTP |
| 3 | * Copyright (c) 2010 Ronald S. Bultje |
| 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 | /** |
| 23 | * @file |
| 24 | * @brief RTP support for the QDM2 payload (todo: wiki) |
| 25 | * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net> |
| 26 | */ |
| 27 | |
| 28 | #include <string.h> |
| 29 | #include "libavutil/avassert.h" |
| 30 | #include "libavutil/intreadwrite.h" |
| 31 | #include "libavcodec/avcodec.h" |
| 32 | #include "internal.h" |
| 33 | #include "rtp.h" |
| 34 | #include "rtpdec.h" |
| 35 | #include "rtpdec_formats.h" |
| 36 | |
| 37 | struct PayloadContext { |
| 38 | /** values read from the config header, used as packet headers */ |
| 39 | //@{ |
| 40 | int block_type; ///< superblock type, value 2 .. 8 |
| 41 | int block_size; ///< from extradata, used as pkt length |
| 42 | int subpkts_per_block; ///< max. nr. of subpackets to add per output buffer |
| 43 | //@} |
| 44 | |
| 45 | /** Temporary storage for superblock restoring, per packet ID (0x80 total) */ |
| 46 | //@{ |
| 47 | uint16_t len[0x80]; ///< how much the temporary buffer is filled |
| 48 | uint8_t buf[0x80][0x800]; ///< the temporary storage buffer |
| 49 | |
| 50 | unsigned int cache; ///< number of data packets that we have cached right now |
| 51 | unsigned int n_pkts; ///< number of RTP packets received since last packet output / config |
| 52 | uint32_t timestamp; ///< timestamp of next-to-be-returned packet |
| 53 | //@} |
| 54 | }; |
| 55 | |
| 56 | /** |
| 57 | * Parse configuration (basically the codec-specific extradata) from |
| 58 | * an RTP config subpacket (starts with 0xff). |
| 59 | * |
| 60 | * Layout of the config subpacket (in bytes): |
| 61 | * 1: 0xFF <- config ID |
| 62 | * then an array { |
| 63 | * 1: size <- of the current item |
| 64 | * 1: item type <- 0 .. 4 |
| 65 | * size-2: data <- data depends on the item type |
| 66 | * } |
| 67 | * |
| 68 | * Item 0 implies the end of the config subpacket, and has no data. |
| 69 | * Item 1 implies a stream configuration without extradata. |
| 70 | * Item 2 max. nr. of subpackets per superblock |
| 71 | * Item 3 superblock type for the stream |
| 72 | * Item 4 implies a stream configuration with extradata (size >= 0x1c). |
| 73 | * |
| 74 | * @return <0 on error, otherwise the number of bytes parsed from the |
| 75 | * input buffer. |
| 76 | */ |
| 77 | static int qdm2_parse_config(PayloadContext *qdm, AVStream *st, |
| 78 | const uint8_t *buf, const uint8_t *end) |
| 79 | { |
| 80 | const uint8_t *p = buf; |
| 81 | |
| 82 | while (end - p >= 2) { |
| 83 | unsigned int item_len = p[0], config_item = p[1]; |
| 84 | |
| 85 | if (item_len < 2 || end - p < item_len || config_item > 4) |
| 86 | return AVERROR_INVALIDDATA; |
| 87 | |
| 88 | switch (config_item) { |
| 89 | case 0: /* end of config block */ |
| 90 | return p - buf + item_len; |
| 91 | case 1: /* stream without extradata */ |
| 92 | /* FIXME: set default qdm->block_size */ |
| 93 | break; |
| 94 | case 2: /**< subpackets per block */ |
| 95 | if (item_len < 3) |
| 96 | return AVERROR_INVALIDDATA; |
| 97 | qdm->subpkts_per_block = p[2]; |
| 98 | break; |
| 99 | case 3: /* superblock type */ |
| 100 | if (item_len < 4) |
| 101 | return AVERROR_INVALIDDATA; |
| 102 | qdm->block_type = AV_RB16(p + 2); |
| 103 | break; |
| 104 | case 4: /* stream with extradata */ |
| 105 | if (item_len < 30) |
| 106 | return AVERROR_INVALIDDATA; |
| 107 | av_freep(&st->codec->extradata); |
| 108 | if (ff_alloc_extradata(st->codec, 26 + item_len)) { |
| 109 | return AVERROR(ENOMEM); |
| 110 | } |
| 111 | AV_WB32(st->codec->extradata, 12); |
| 112 | memcpy(st->codec->extradata + 4, "frma", 4); |
| 113 | memcpy(st->codec->extradata + 8, "QDM2", 4); |
| 114 | AV_WB32(st->codec->extradata + 12, 6 + item_len); |
| 115 | memcpy(st->codec->extradata + 16, "QDCA", 4); |
| 116 | memcpy(st->codec->extradata + 20, p + 2, item_len - 2); |
| 117 | AV_WB32(st->codec->extradata + 18 + item_len, 8); |
| 118 | AV_WB32(st->codec->extradata + 22 + item_len, 0); |
| 119 | |
| 120 | qdm->block_size = AV_RB32(p + 26); |
| 121 | break; |
| 122 | } |
| 123 | |
| 124 | p += item_len; |
| 125 | } |
| 126 | |
| 127 | return AVERROR(EAGAIN); /* not enough data */ |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * Parse a single subpacket. We store this subpacket in an intermediate |
| 132 | * buffer (position depends on the ID (byte[0]). When called, at least |
| 133 | * 4 bytes are available for reading (see qdm2_parse_packet()). |
| 134 | * |
| 135 | * Layout of a single subpacket (RTP packets commonly contain multiple |
| 136 | * such subpackets) - length in bytes: |
| 137 | * 1: ordering ID <- 0 .. 0x7F |
| 138 | * 1: subpacket type <- 0 .. 0x7F; value & 0x80 means subpacket length = 2 bytes, else 1 byte |
| 139 | * 1/2: subpacket length <- length of the data following the flags/length fields |
| 140 | * if (subpacket type & 0x7F) == 0x7F |
| 141 | * 1: subpacket type, higher bits |
| 142 | * size: subpacket data |
| 143 | * |
| 144 | * The subpackets come in randomly, and should be encapsulated into 1 |
| 145 | * or more superblocks (containing qdm->subpkts_per_block subpackets |
| 146 | * each) per RTP packet, in order of ascending "ordering ID", see |
| 147 | * qdm2_restore_block(). |
| 148 | * |
| 149 | * @return <0 on error, otherwise the number of bytes parsed from the |
| 150 | * input buffer. |
| 151 | */ |
| 152 | static int qdm2_parse_subpacket(PayloadContext *qdm, AVStream *st, |
| 153 | const uint8_t *buf, const uint8_t *end) |
| 154 | { |
| 155 | const uint8_t *p = buf; |
| 156 | unsigned int id, len, type, to_copy; |
| 157 | |
| 158 | /* parse header so we know the size of the header/data */ |
| 159 | id = *p++; |
| 160 | type = *p++; |
| 161 | if (type & 0x80) { |
| 162 | len = AV_RB16(p); |
| 163 | p += 2; |
| 164 | type &= 0x7F; |
| 165 | } else |
| 166 | len = *p++; |
| 167 | |
| 168 | if (end - p < len + (type == 0x7F) || id >= 0x80) |
| 169 | return AVERROR_INVALIDDATA; |
| 170 | if (type == 0x7F) |
| 171 | type |= *p++ << 8; |
| 172 | |
| 173 | /* copy data into a temporary buffer */ |
| 174 | to_copy = FFMIN(len + (p - &buf[1]), 0x800 - qdm->len[id]); |
| 175 | memcpy(&qdm->buf[id][qdm->len[id]], buf + 1, to_copy); |
| 176 | qdm->len[id] += to_copy; |
| 177 | |
| 178 | return p + len - buf; |
| 179 | } |
| 180 | |
| 181 | /** |
| 182 | * Add a superblock header around a set of subpackets. |
| 183 | * |
| 184 | * @return <0 on error, else 0. |
| 185 | */ |
| 186 | static int qdm2_restore_block(PayloadContext *qdm, AVStream *st, AVPacket *pkt) |
| 187 | { |
| 188 | int to_copy, n, res, include_csum; |
| 189 | uint8_t *p, *csum_pos = NULL; |
| 190 | |
| 191 | /* create packet to hold subpkts into a superblock */ |
| 192 | assert(qdm->cache > 0); |
| 193 | for (n = 0; n < 0x80; n++) |
| 194 | if (qdm->len[n] > 0) |
| 195 | break; |
| 196 | av_assert0(n < 0x80); |
| 197 | |
| 198 | if ((res = av_new_packet(pkt, qdm->block_size)) < 0) |
| 199 | return res; |
| 200 | memset(pkt->data, 0, pkt->size); |
| 201 | pkt->stream_index = st->index; |
| 202 | p = pkt->data; |
| 203 | |
| 204 | /* superblock header */ |
| 205 | if (qdm->len[n] > 0xff) { |
| 206 | *p++ = qdm->block_type | 0x80; |
| 207 | AV_WB16(p, qdm->len[n]); |
| 208 | p += 2; |
| 209 | } else { |
| 210 | *p++ = qdm->block_type; |
| 211 | *p++ = qdm->len[n]; |
| 212 | } |
| 213 | if ((include_csum = (qdm->block_type == 2 || qdm->block_type == 4))) { |
| 214 | csum_pos = p; |
| 215 | p += 2; |
| 216 | } |
| 217 | |
| 218 | /* subpacket data */ |
| 219 | to_copy = FFMIN(qdm->len[n], pkt->size - (p - pkt->data)); |
| 220 | memcpy(p, qdm->buf[n], to_copy); |
| 221 | qdm->len[n] = 0; |
| 222 | |
| 223 | /* checksum header */ |
| 224 | if (include_csum) { |
| 225 | unsigned int total = 0; |
| 226 | uint8_t *q; |
| 227 | |
| 228 | for (q = pkt->data; q < &pkt->data[qdm->block_size]; q++) |
| 229 | total += *q; |
| 230 | AV_WB16(csum_pos, (uint16_t) total); |
| 231 | } |
| 232 | |
| 233 | return 0; |
| 234 | } |
| 235 | |
| 236 | /** return 0 on packet, no more left, 1 on packet, -1 on partial packet... */ |
| 237 | static int qdm2_parse_packet(AVFormatContext *s, PayloadContext *qdm, |
| 238 | AVStream *st, AVPacket *pkt, |
| 239 | uint32_t *timestamp, |
| 240 | const uint8_t *buf, int len, uint16_t seq, |
| 241 | int flags) |
| 242 | { |
| 243 | int res = AVERROR_INVALIDDATA, n; |
| 244 | const uint8_t *end = buf + len, *p = buf; |
| 245 | |
| 246 | if (len > 0) { |
| 247 | if (len < 2) |
| 248 | return AVERROR_INVALIDDATA; |
| 249 | |
| 250 | /* configuration block */ |
| 251 | if (*p == 0xff) { |
| 252 | if (qdm->n_pkts > 0) { |
| 253 | av_log(s, AV_LOG_WARNING, |
| 254 | "Out of sequence config - dropping queue\n"); |
| 255 | qdm->n_pkts = 0; |
| 256 | memset(qdm->len, 0, sizeof(qdm->len)); |
| 257 | } |
| 258 | |
| 259 | if ((res = qdm2_parse_config(qdm, st, ++p, end)) < 0) |
| 260 | return res; |
| 261 | p += res; |
| 262 | |
| 263 | /* We set codec_id to AV_CODEC_ID_NONE initially to |
| 264 | * delay decoder initialization since extradata is |
| 265 | * carried within the RTP stream, not SDP. Here, |
| 266 | * by setting codec_id to AV_CODEC_ID_QDM2, we are signalling |
| 267 | * to the decoder that it is OK to initialize. */ |
| 268 | st->codec->codec_id = AV_CODEC_ID_QDM2; |
| 269 | } |
| 270 | if (st->codec->codec_id == AV_CODEC_ID_NONE) |
| 271 | return AVERROR(EAGAIN); |
| 272 | |
| 273 | /* subpackets */ |
| 274 | while (end - p >= 4) { |
| 275 | if ((res = qdm2_parse_subpacket(qdm, st, p, end)) < 0) |
| 276 | return res; |
| 277 | p += res; |
| 278 | } |
| 279 | |
| 280 | qdm->timestamp = *timestamp; |
| 281 | if (++qdm->n_pkts < qdm->subpkts_per_block) |
| 282 | return AVERROR(EAGAIN); |
| 283 | qdm->cache = 0; |
| 284 | for (n = 0; n < 0x80; n++) |
| 285 | if (qdm->len[n] > 0) |
| 286 | qdm->cache++; |
| 287 | } |
| 288 | |
| 289 | /* output the subpackets into freshly created superblock structures */ |
| 290 | if (!qdm->cache || (res = qdm2_restore_block(qdm, st, pkt)) < 0) |
| 291 | return res; |
| 292 | if (--qdm->cache == 0) |
| 293 | qdm->n_pkts = 0; |
| 294 | |
| 295 | *timestamp = qdm->timestamp; |
| 296 | qdm->timestamp = RTP_NOTS_VALUE; |
| 297 | |
| 298 | return (qdm->cache > 0) ? 1 : 0; |
| 299 | } |
| 300 | |
| 301 | static PayloadContext *qdm2_extradata_new(void) |
| 302 | { |
| 303 | return av_mallocz(sizeof(PayloadContext)); |
| 304 | } |
| 305 | |
| 306 | static void qdm2_extradata_free(PayloadContext *qdm) |
| 307 | { |
| 308 | av_free(qdm); |
| 309 | } |
| 310 | |
| 311 | RTPDynamicProtocolHandler ff_qdm2_dynamic_handler = { |
| 312 | .enc_name = "X-QDM", |
| 313 | .codec_type = AVMEDIA_TYPE_AUDIO, |
| 314 | .codec_id = AV_CODEC_ID_NONE, |
| 315 | .alloc = qdm2_extradata_new, |
| 316 | .free = qdm2_extradata_free, |
| 317 | .parse_packet = qdm2_parse_packet, |
| 318 | }; |