libavformat/cafdec.c

   1 /*
   2  * Core Audio Format demuxer
   3  * Copyright (c) 2007 Justin Ruggles
   4  * Copyright (c) 2009 Peter Ross
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file libavformat/cafdec.c
  25  * Core Audio Format demuxer
  26  */
  27
  28 #include "avformat.h"
  29 #include "riff.h"
  30 #include "isom.h"
  31 #include "libavutil/intreadwrite.h"
  32 #include "caf.h"
  33
  34 typedef struct {
  35     int bytes_per_packet;           ///< bytes in a packet, or 0 if variable
  36     int frames_per_packet;          ///< frames in a packet, or 0 if variable
  37     int64_t num_bytes;              ///< total number of bytes in stream
  38
  39     int64_t packet_cnt;             ///< packet counter
  40     int64_t frame_cnt;              ///< frame counter
  41
  42     int64_t data_start;             ///< data start position, in bytes
  43     int64_t data_size;              ///< raw data size, in bytes
  44 } CaffContext;
  45
  46 static int probe(AVProbeData *p)
  47 {
  48     if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
  49         return AVPROBE_SCORE_MAX;
  50     return 0;
  51 }
  52
  53 /** Read audio description chunk */
  54 static int read_desc_chunk(AVFormatContext *s)
  55 {
  56     ByteIOContext *pb = s->pb;
  57     CaffContext *caf  = s->priv_data;
  58     AVStream *st;
  59     int flags;
  60
  61     /* new audio stream */
  62     st = av_new_stream(s, 0);
  63     if (!st)
  64         return AVERROR_NOMEM;
  65
  66     /* parse format description */
  67     st->codec->codec_type  = CODEC_TYPE_AUDIO;
  68     st->codec->sample_rate = av_int2dbl(get_be64(pb));
  69     st->codec->codec_tag   = get_be32(pb);
  70     flags = get_be32(pb);
  71     caf->bytes_per_packet  = get_be32(pb);
  72     st->codec->block_align = caf->bytes_per_packet;
  73     caf->frames_per_packet = get_be32(pb);
  74     st->codec->channels    = get_be32(pb);
  75     st->codec->bits_per_coded_sample = get_be32(pb);
  76
  77     /* calculate bit rate for constant size packets */
  78     if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
  79         st->codec->bit_rate = (uint64_t)st->codec->sample_rate * (uint64_t)caf->bytes_per_packet * 8
  80                               / (uint64_t)caf->frames_per_packet;
  81     } else {
  82         st->codec->bit_rate = 0;
  83     }
  84
  85     /* determine codec */
  86     if (st->codec->codec_tag == MKBETAG('l','p','c','m'))
  87         st->codec->codec_id = ff_mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, (flags ^ 0x2) | 0x4);
  88     else
  89         st->codec->codec_id = ff_codec_get_id(ff_codec_caf_tags, st->codec->codec_tag);
  90     return 0;
  91 }
  92
  93 /** Read magic cookie chunk */
  94 static int read_kuki_chunk(AVFormatContext *s, int64_t size)
  95 {
  96     ByteIOContext *pb = s->pb;
  97     AVStream *st      = s->streams[0];
  98
  99     if (size < 0 || size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
 100         return -1;
 101
 102     if (st->codec->codec_id == CODEC_ID_AAC) {
 103         /* The magic cookie format for AAC is an mp4 esds atom.
 104            The lavc AAC decoder requires the data from the codec specific
 105            description as extradata input. */
 106         int strt, skip;
 107         MOVAtom atom;
 108
 109         strt = url_ftell(pb);
 110         ff_mov_read_esds(s, pb, atom);
 111         skip = size - (url_ftell(pb) - strt);
 112         if (skip < 0 || !st->codec->extradata ||
 113             st->codec->codec_id != CODEC_ID_AAC) {
 114             av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
 115             return AVERROR_INVALIDDATA;
 116         }
 117         url_fskip(pb, skip);
 118     } else {
 119         st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
 120         if (!st->codec->extradata)
 121             return AVERROR(ENOMEM);
 122         get_buffer(pb, st->codec->extradata, size);
 123         st->codec->extradata_size = size;
 124     }
 125
 126     return 0;
 127 }
 128
 129 /** Read packet table chunk */
 130 static int read_pakt_chunk(AVFormatContext *s, int64_t size)
 131 {
 132     ByteIOContext *pb = s->pb;
 133     AVStream *st      = s->streams[0];
 134     CaffContext *caf  = s->priv_data;
 135     int64_t pos = 0, ccount;
 136     int num_packets, i;
 137
 138     ccount = url_ftell(pb);
 139
 140     num_packets = get_be64(pb);
 141     if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
 142         return AVERROR_INVALIDDATA;
 143
 144     st->nb_frames  = get_be64(pb); /* valid frames */
 145     st->nb_frames += get_be32(pb); /* priming frames */
 146     st->nb_frames += get_be32(pb); /* remainder frames */
 147
 148     st->duration = 0;
 149     for (i = 0; i < num_packets; i++) {
 150         av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
 151         pos += caf->bytes_per_packet ? caf->bytes_per_packet : ff_mp4_read_descr_len(pb);
 152         st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);
 153     }
 154
 155     if (url_ftell(pb) - ccount != size) {
 156         av_log(s, AV_LOG_ERROR, "error reading packet table\n");
 157         return -1;
 158     }
 159
 160     caf->num_bytes = pos;
 161     return 0;
 162 }
 163
 164 /** Read information chunk */
 165 static void read_info_chunk(AVFormatContext *s, int64_t size)
 166 {
 167     ByteIOContext *pb = s->pb;
 168     unsigned int i;
 169     unsigned int nb_entries = get_be32(pb);
 170     for (i = 0; i < nb_entries; i++) {
 171         char key[32];
 172         char value[1024];
 173         get_strz(pb, key, sizeof(key));
 174         get_strz(pb, value, sizeof(value));
 175         av_metadata_set(&s->metadata, key, value);
 176     }
 177 }
 178
 179 static int read_header(AVFormatContext *s,
 180                        AVFormatParameters *ap)
 181 {
 182     ByteIOContext *pb = s->pb;
 183     CaffContext *caf  = s->priv_data;
 184     AVStream *st;
 185     uint32_t tag = 0;
 186     int found_data, ret;
 187     int64_t size;
 188
 189     url_fskip(pb, 8); /* magic, version, file flags */
 190
 191     /* audio description chunk */
 192     if (get_be32(pb) != MKBETAG('d','e','s','c')) {
 193         av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
 194         return AVERROR_INVALIDDATA;
 195     }
 196     size = get_be64(pb);
 197     if (size != 32)
 198         return AVERROR_INVALIDDATA;
 199
 200     ret = read_desc_chunk(s);
 201     if (ret)
 202         return ret;
 203     st = s->streams[0];
 204
 205     /* parse each chunk */
 206     found_data = 0;
 207     while (!url_feof(pb)) {
 208
 209         /* stop at data chunk if seeking is not supported or
 210            data chunk size is unknown */
 211         if (found_data && (caf->data_size < 0 || url_is_streamed(pb)))
 212             break;
 213
 214         tag  = get_be32(pb);
 215         size = get_be64(pb);
 216         if (url_feof(pb))
 217             break;
 218
 219         switch (tag) {
 220         case MKBETAG('d','a','t','a'):
 221             url_fskip(pb, 4); /* edit count */
 222             caf->data_start = url_ftell(pb);
 223             caf->data_size  = size < 0 ? -1 : size - 4;
 224             if (caf->data_size > 0 && !url_is_streamed(pb))
 225                 url_fskip(pb, caf->data_size);
 226             found_data = 1;
 227             break;
 228
 229         /* magic cookie chunk */
 230         case MKBETAG('k','u','k','i'):
 231             if (read_kuki_chunk(s, size))
 232                 return AVERROR_INVALIDDATA;
 233             break;
 234
 235         /* packet table chunk */
 236         case MKBETAG('p','a','k','t'):
 237             if (read_pakt_chunk(s, size))
 238                 return AVERROR_INVALIDDATA;
 239             break;
 240
 241         case MKBETAG('i','n','f','o'):
 242             read_info_chunk(s, size);
 243             break;
 244
 245         default:
 246 #define _(x) ((x) >= ' ' ? (x) : ' ')
 247             av_log(s, AV_LOG_WARNING, "skipping CAF chunk: %08X (%c%c%c%c)\n",
 248                 tag, _(tag>>24), _((tag>>16)&0xFF), _((tag>>8)&0xFF), _(tag&0xFF));
 249 #undef _
 250         case MKBETAG('f','r','e','e'):
 251             if (size < 0)
 252                 return AVERROR_INVALIDDATA;
 253             url_fskip(pb, size);
 254             break;
 255         }
 256     }
 257
 258     if (!found_data)
 259         return AVERROR_INVALIDDATA;
 260
 261     if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
 262         if (caf->data_size > 0)
 263             st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;
 264     } else if (st->nb_index_entries) {
 265         st->codec->bit_rate = st->codec->sample_rate * caf->data_size * 8 /
 266                               st->duration;
 267     } else {
 268         av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "
 269                                 "block size or frame size are variable.\n");
 270         return AVERROR_INVALIDDATA;
 271     }
 272     s->file_size = url_fsize(pb);
 273     s->file_size = FFMAX(0, s->file_size);
 274
 275     av_set_pts_info(st, 64, 1, st->codec->sample_rate);
 276     st->start_time = 0;
 277
 278     /* position the stream at the start of data */
 279     if (caf->data_size >= 0)
 280         url_fseek(pb, caf->data_start, SEEK_SET);
 281
 282     return 0;
 283 }
 284
 285 #define CAF_MAX_PKT_SIZE 4096
 286
 287 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 288 {
 289     ByteIOContext *pb = s->pb;
 290     AVStream *st      = s->streams[0];
 291     CaffContext *caf  = s->priv_data;
 292     int res, pkt_size = 0, pkt_frames = 0;
 293     int64_t left      = CAF_MAX_PKT_SIZE;
 294
 295     if (url_feof(pb))
 296         return AVERROR_IO;
 297
 298     /* don't read past end of data chunk */
 299     if (caf->data_size > 0) {
 300         left = (caf->data_start + caf->data_size) - url_ftell(pb);
 301         if (left <= 0)
 302             return AVERROR_IO;
 303     }
 304
 305     pkt_frames = caf->frames_per_packet;
 306     pkt_size   = caf->bytes_per_packet;
 307
 308     if (pkt_size > 0 && pkt_frames == 1) {
 309         pkt_size   = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;
 310         pkt_size   = FFMIN(pkt_size, left);
 311         pkt_frames = pkt_size / caf->bytes_per_packet;
 312     } else if (st->nb_index_entries) {
 313         if (caf->packet_cnt < st->nb_index_entries - 1) {
 314             pkt_size   = st->index_entries[caf->packet_cnt + 1].pos       - st->index_entries[caf->packet_cnt].pos;
 315             pkt_frames = st->index_entries[caf->packet_cnt + 1].timestamp - st->index_entries[caf->packet_cnt].timestamp;
 316         } else if (caf->packet_cnt == st->nb_index_entries - 1) {
 317             pkt_size   = caf->num_bytes - st->index_entries[caf->packet_cnt].pos;
 318             pkt_frames = st->duration   - st->index_entries[caf->packet_cnt].timestamp;
 319         } else {
 320             return AVERROR_IO;
 321         }
 322     }
 323
 324     if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
 325         return AVERROR_IO;
 326
 327     res = av_get_packet(pb, pkt, pkt_size);
 328     if (res < 0)
 329         return res;
 330
 331     pkt->size           = res;
 332     pkt->stream_index   = 0;
 333     pkt->dts = pkt->pts = caf->frame_cnt;
 334
 335     caf->packet_cnt++;
 336     caf->frame_cnt += pkt_frames;
 337
 338     return 0;
 339 }
 340
 341 static int read_seek(AVFormatContext *s, int stream_index,
 342                      int64_t timestamp, int flags)
 343 {
 344     AVStream *st = s->streams[0];
 345     CaffContext *caf = s->priv_data;
 346     int64_t pos;
 347
 348     timestamp = FFMAX(timestamp, 0);
 349
 350     if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
 351         /* calculate new byte position based on target frame position */
 352         pos = caf->bytes_per_packet * timestamp / caf->frames_per_packet;
 353         if (caf->data_size > 0)
 354             pos = FFMIN(pos, caf->data_size);
 355         caf->packet_cnt = pos / caf->bytes_per_packet;
 356         caf->frame_cnt  = caf->frames_per_packet * caf->packet_cnt;
 357     } else if (st->nb_index_entries) {
 358         caf->packet_cnt = av_index_search_timestamp(st, timestamp, flags);
 359         caf->frame_cnt  = st->index_entries[caf->packet_cnt].timestamp;
 360         pos             = st->index_entries[caf->packet_cnt].pos;
 361     } else {
 362         return -1;
 363     }
 364
 365     url_fseek(s->pb, pos + caf->data_start, SEEK_SET);
 366     return 0;
 367 }
 368
 369 AVInputFormat caf_demuxer = {
 370     "caf",
 371     NULL_IF_CONFIG_SMALL("Apple Core Audio Format"),
 372     sizeof(CaffContext),
 373     probe,
 374     read_header,
 375     read_packet,
 376     NULL,
 377     read_seek,
 378     .codec_tag = (const AVCodecTag*[]){ff_codec_caf_tags, 0},
 379 };