FFmpeg: libavformat/rtpdec_qdm2.c Source File

00001 /*
00002  * QDesign Music 2 (QDM2) payload for RTP
00003  * Copyright (c) 2010 Ronald S. Bultje
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00028 #include <string.h>
00029 #include "libavutil/intreadwrite.h"
00030 #include "libavcodec/avcodec.h"
00031 #include "rtp.h"
00032 #include "rtpdec.h"
00033 #include "rtpdec_formats.h"
00034 
00035 struct PayloadContext {
00038     int block_type;            
00039     int block_size;            
00040     int subpkts_per_block;     
00041 
00042 
00045     uint16_t len[0x80];        
00046     uint8_t  buf[0x80][0x800]; 
00047 
00048     unsigned int cache;        
00049     unsigned int n_pkts;       
00050     uint32_t timestamp;        
00051 
00052 };
00053 
00075 static int qdm2_parse_config(PayloadContext *qdm, AVStream *st,
00076                              const uint8_t *buf, const uint8_t *end)
00077 {
00078     const uint8_t *p = buf;
00079 
00080     while (end - p >= 2) {
00081         unsigned int item_len = p[0], config_item = p[1];
00082 
00083         if (item_len < 2 || end - p < item_len || config_item > 4)
00084             return AVERROR_INVALIDDATA;
00085 
00086         switch (config_item) {
00087             case 0: /* end of config block */
00088                 return p - buf + item_len;
00089             case 1: /* stream without extradata */
00090                 /* FIXME: set default qdm->block_size */
00091                 break;
00092             case 2: 
00093                 if (item_len < 3)
00094                     return AVERROR_INVALIDDATA;
00095                 qdm->subpkts_per_block = p[2];
00096                 break;
00097             case 3: /* superblock type */
00098                 if (item_len < 4)
00099                     return AVERROR_INVALIDDATA;
00100                 qdm->block_type = AV_RB16(p + 2);
00101                 break;
00102             case 4: /* stream with extradata */
00103                 if (item_len < 30)
00104                     return AVERROR_INVALIDDATA;
00105                 av_freep(&st->codec->extradata);
00106                 st->codec->extradata_size = 26 + item_len;
00107                 if (!(st->codec->extradata = av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE))) {
00108                     st->codec->extradata_size = 0;
00109                     return AVERROR(ENOMEM);
00110                 }
00111                 AV_WB32(st->codec->extradata, 12);
00112                 memcpy(st->codec->extradata + 4, "frma", 4);
00113                 memcpy(st->codec->extradata + 8, "QDM2", 4);
00114                 AV_WB32(st->codec->extradata + 12, 6 + item_len);
00115                 memcpy(st->codec->extradata + 16, "QDCA", 4);
00116                 memcpy(st->codec->extradata + 20, p + 2, item_len - 2);
00117                 AV_WB32(st->codec->extradata + 18 + item_len, 8);
00118                 AV_WB32(st->codec->extradata + 22 + item_len, 0);
00119 
00120                 qdm->block_size = AV_RB32(p + 26);
00121                 break;
00122         }
00123 
00124         p += item_len;
00125     }
00126 
00127     return AVERROR(EAGAIN); /* not enough data */
00128 }
00129 
00152 static int qdm2_parse_subpacket(PayloadContext *qdm, AVStream *st,
00153                                 const uint8_t *buf, const uint8_t *end)
00154 {
00155     const uint8_t *p = buf;
00156     unsigned int id, len, type, to_copy;
00157 
00158     /* parse header so we know the size of the header/data */
00159     id       = *p++;
00160     type     = *p++;
00161     if (type & 0x80) {
00162         len   = AV_RB16(p);
00163         p    += 2;
00164         type &= 0x7F;
00165     } else
00166         len = *p++;
00167 
00168     if (end - p < len + (type == 0x7F) || id >= 0x80)
00169         return AVERROR_INVALIDDATA;
00170     if (type == 0x7F)
00171         type |= *p++ << 8;
00172 
00173     /* copy data into a temporary buffer */
00174     to_copy = FFMIN(len + (p - &buf[1]), 0x800 - qdm->len[id]);
00175     memcpy(&qdm->buf[id][qdm->len[id]], buf + 1, to_copy);
00176     qdm->len[id] += to_copy;
00177 
00178     return p + len - buf;
00179 }
00180 
00186 static int qdm2_restore_block(PayloadContext *qdm, AVStream *st, AVPacket *pkt)
00187 {
00188     int to_copy, n, res, include_csum;
00189     uint8_t *p, *csum_pos = NULL;
00190 
00191     /* create packet to hold subpkts into a superblock */
00192     assert(qdm->cache > 0);
00193     for (n = 0; n < 0x80; n++)
00194         if (qdm->len[n] > 0)
00195             break;
00196     assert(n < 0x80);
00197 
00198     if ((res = av_new_packet(pkt, qdm->block_size)) < 0)
00199         return res;
00200     memset(pkt->data, 0, pkt->size);
00201     pkt->stream_index  = st->index;
00202     p                  = pkt->data;
00203 
00204     /* superblock header */
00205     if (qdm->len[n] > 0xff) {
00206         *p++ = qdm->block_type | 0x80;
00207         AV_WB16(p, qdm->len[n]);
00208         p   += 2;
00209     } else {
00210         *p++ = qdm->block_type;
00211         *p++ = qdm->len[n];
00212     }
00213     if ((include_csum = (qdm->block_type == 2 || qdm->block_type == 4))) {
00214         csum_pos = p;
00215         p       += 2;
00216     }
00217 
00218     /* subpacket data */
00219     to_copy = FFMIN(qdm->len[n], pkt->size - (p - pkt->data));
00220     memcpy(p, qdm->buf[n], to_copy);
00221     qdm->len[n] = 0;
00222 
00223     /* checksum header */
00224     if (include_csum) {
00225         unsigned int total = 0;
00226         uint8_t *q;
00227 
00228         for (q = pkt->data; q < &pkt->data[qdm->block_size]; q++)
00229             total += *q;
00230         AV_WB16(csum_pos, (uint16_t) total);
00231     }
00232 
00233     return 0;
00234 }
00235 
00237 static int qdm2_parse_packet(AVFormatContext *s, PayloadContext *qdm,
00238                              AVStream *st, AVPacket *pkt,
00239                              uint32_t *timestamp,
00240                              const uint8_t *buf, int len, int flags)
00241 {
00242     int res = AVERROR_INVALIDDATA, n;
00243     const uint8_t *end = buf + len, *p = buf;
00244 
00245     if (len > 0) {
00246         if (len < 2)
00247             return AVERROR_INVALIDDATA;
00248 
00249         /* configuration block */
00250         if (*p == 0xff) {
00251             if (qdm->n_pkts > 0) {
00252                 av_log(s, AV_LOG_WARNING,
00253                        "Out of sequence config - dropping queue\n");
00254                 qdm->n_pkts = 0;
00255                 memset(qdm->len, 0, sizeof(qdm->len));
00256             }
00257 
00258             if ((res = qdm2_parse_config(qdm, st, ++p, end)) < 0)
00259                 return res;
00260             p += res;
00261 
00262             /* We set codec_id to AV_CODEC_ID_NONE initially to
00263              * delay decoder initialization since extradata is
00264              * carried within the RTP stream, not SDP. Here,
00265              * by setting codec_id to AV_CODEC_ID_QDM2, we are signalling
00266              * to the decoder that it is OK to initialize. */
00267             st->codec->codec_id = AV_CODEC_ID_QDM2;
00268         }
00269         if (st->codec->codec_id == AV_CODEC_ID_NONE)
00270             return AVERROR(EAGAIN);
00271 
00272         /* subpackets */
00273         while (end - p >= 4) {
00274             if ((res = qdm2_parse_subpacket(qdm, st, p, end)) < 0)
00275                 return res;
00276             p += res;
00277         }
00278 
00279         qdm->timestamp = *timestamp;
00280         if (++qdm->n_pkts < qdm->subpkts_per_block)
00281             return AVERROR(EAGAIN);
00282         qdm->cache = 0;
00283         for (n = 0; n < 0x80; n++)
00284             if (qdm->len[n] > 0)
00285                 qdm->cache++;
00286     }
00287 
00288     /* output the subpackets into freshly created superblock structures */
00289     if (!qdm->cache || (res = qdm2_restore_block(qdm, st, pkt)) < 0)
00290         return res;
00291     if (--qdm->cache == 0)
00292         qdm->n_pkts = 0;
00293 
00294     *timestamp = qdm->timestamp;
00295     qdm->timestamp = RTP_NOTS_VALUE;
00296 
00297     return (qdm->cache > 0) ? 1 : 0;
00298 }
00299 
00300 static PayloadContext *qdm2_extradata_new(void)
00301 {
00302     return av_mallocz(sizeof(PayloadContext));
00303 }
00304 
00305 static void qdm2_extradata_free(PayloadContext *qdm)
00306 {
00307     av_free(qdm);
00308 }
00309 
00310 RTPDynamicProtocolHandler ff_qdm2_dynamic_handler = {
00311     .enc_name         = "X-QDM",
00312     .codec_type       = AVMEDIA_TYPE_AUDIO,
00313     .codec_id         = AV_CODEC_ID_NONE,
00314     .alloc            = qdm2_extradata_new,
00315     .free             = qdm2_extradata_free,
00316     .parse_packet     = qdm2_parse_packet,
00317 };