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libavformat/cafdec.c

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00001 /*
00002  * Core Audio Format demuxer
00003  * Copyright (c) 2007 Justin Ruggles
00004  * Copyright (c) 2009 Peter Ross
00005  *
00006  * This file is part of Libav.
00007  *
00008  * Libav is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * Libav is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with Libav; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00028 #include "avformat.h"
00029 #include "internal.h"
00030 #include "riff.h"
00031 #include "isom.h"
00032 #include "libavutil/intreadwrite.h"
00033 #include "libavutil/intfloat.h"
00034 #include "libavutil/dict.h"
00035 #include "caf.h"
00036 
00037 typedef struct {
00038     int bytes_per_packet;           
00039     int frames_per_packet;          
00040     int64_t num_bytes;              
00041 
00042     int64_t packet_cnt;             
00043     int64_t frame_cnt;              
00044 
00045     int64_t data_start;             
00046     int64_t data_size;              
00047 } CaffContext;
00048 
00049 static int probe(AVProbeData *p)
00050 {
00051     if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
00052         return AVPROBE_SCORE_MAX;
00053     return 0;
00054 }
00055 
00057 static int read_desc_chunk(AVFormatContext *s)
00058 {
00059     AVIOContext *pb = s->pb;
00060     CaffContext *caf  = s->priv_data;
00061     AVStream *st;
00062     int flags;
00063 
00064     /* new audio stream */
00065     st = avformat_new_stream(s, NULL);
00066     if (!st)
00067         return AVERROR(ENOMEM);
00068 
00069     /* parse format description */
00070     st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
00071     st->codec->sample_rate = av_int2double(avio_rb64(pb));
00072     st->codec->codec_tag   = avio_rb32(pb);
00073     flags = avio_rb32(pb);
00074     caf->bytes_per_packet  = avio_rb32(pb);
00075     st->codec->block_align = caf->bytes_per_packet;
00076     caf->frames_per_packet = avio_rb32(pb);
00077     st->codec->channels    = avio_rb32(pb);
00078     st->codec->bits_per_coded_sample = avio_rb32(pb);
00079 
00080     /* calculate bit rate for constant size packets */
00081     if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
00082         st->codec->bit_rate = (uint64_t)st->codec->sample_rate * (uint64_t)caf->bytes_per_packet * 8
00083                               / (uint64_t)caf->frames_per_packet;
00084     } else {
00085         st->codec->bit_rate = 0;
00086     }
00087 
00088     /* determine codec */
00089     if (st->codec->codec_tag == MKBETAG('l','p','c','m'))
00090         st->codec->codec_id = ff_mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, (flags ^ 0x2) | 0x4);
00091     else
00092         st->codec->codec_id = ff_codec_get_id(ff_codec_caf_tags, st->codec->codec_tag);
00093     return 0;
00094 }
00095 
00097 static int read_kuki_chunk(AVFormatContext *s, int64_t size)
00098 {
00099     AVIOContext *pb = s->pb;
00100     AVStream *st      = s->streams[0];
00101 
00102     if (size < 0 || size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
00103         return -1;
00104 
00105     if (st->codec->codec_id == CODEC_ID_AAC) {
00106         /* The magic cookie format for AAC is an mp4 esds atom.
00107            The lavc AAC decoder requires the data from the codec specific
00108            description as extradata input. */
00109         int strt, skip;
00110         MOVAtom atom;
00111 
00112         strt = avio_tell(pb);
00113         ff_mov_read_esds(s, pb, atom);
00114         skip = size - (avio_tell(pb) - strt);
00115         if (skip < 0 || !st->codec->extradata ||
00116             st->codec->codec_id != CODEC_ID_AAC) {
00117             av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
00118             return AVERROR_INVALIDDATA;
00119         }
00120         avio_skip(pb, skip);
00121     } else if (st->codec->codec_id == CODEC_ID_ALAC) {
00122 #define ALAC_PREAMBLE 12
00123 #define ALAC_HEADER   36
00124         if (size < ALAC_PREAMBLE + ALAC_HEADER) {
00125             av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
00126             avio_skip(pb, size);
00127             return AVERROR_INVALIDDATA;
00128         }
00129         avio_skip(pb, ALAC_PREAMBLE);
00130         st->codec->extradata = av_mallocz(ALAC_HEADER + FF_INPUT_BUFFER_PADDING_SIZE);
00131         if (!st->codec->extradata)
00132             return AVERROR(ENOMEM);
00133         avio_read(pb, st->codec->extradata, ALAC_HEADER);
00134         st->codec->extradata_size = ALAC_HEADER;
00135         avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
00136     } else {
00137         st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
00138         if (!st->codec->extradata)
00139             return AVERROR(ENOMEM);
00140         avio_read(pb, st->codec->extradata, size);
00141         st->codec->extradata_size = size;
00142     }
00143 
00144     return 0;
00145 }
00146 
00148 static int read_pakt_chunk(AVFormatContext *s, int64_t size)
00149 {
00150     AVIOContext *pb = s->pb;
00151     AVStream *st      = s->streams[0];
00152     CaffContext *caf  = s->priv_data;
00153     int64_t pos = 0, ccount;
00154     int num_packets, i;
00155 
00156     ccount = avio_tell(pb);
00157 
00158     num_packets = avio_rb64(pb);
00159     if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
00160         return AVERROR_INVALIDDATA;
00161 
00162     st->nb_frames  = avio_rb64(pb); /* valid frames */
00163     st->nb_frames += avio_rb32(pb); /* priming frames */
00164     st->nb_frames += avio_rb32(pb); /* remainder frames */
00165 
00166     st->duration = 0;
00167     for (i = 0; i < num_packets; i++) {
00168         av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
00169         pos += caf->bytes_per_packet ? caf->bytes_per_packet : ff_mp4_read_descr_len(pb);
00170         st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);
00171     }
00172 
00173     if (avio_tell(pb) - ccount != size) {
00174         av_log(s, AV_LOG_ERROR, "error reading packet table\n");
00175         return -1;
00176     }
00177 
00178     caf->num_bytes = pos;
00179     return 0;
00180 }
00181 
00183 static void read_info_chunk(AVFormatContext *s, int64_t size)
00184 {
00185     AVIOContext *pb = s->pb;
00186     unsigned int i;
00187     unsigned int nb_entries = avio_rb32(pb);
00188     for (i = 0; i < nb_entries; i++) {
00189         char key[32];
00190         char value[1024];
00191         avio_get_str(pb, INT_MAX, key,   sizeof(key));
00192         avio_get_str(pb, INT_MAX, value, sizeof(value));
00193         av_dict_set(&s->metadata, key, value, 0);
00194     }
00195 }
00196 
00197 static int read_header(AVFormatContext *s,
00198                        AVFormatParameters *ap)
00199 {
00200     AVIOContext *pb = s->pb;
00201     CaffContext *caf  = s->priv_data;
00202     AVStream *st;
00203     uint32_t tag = 0;
00204     int found_data, ret;
00205     int64_t size;
00206 
00207     avio_skip(pb, 8); /* magic, version, file flags */
00208 
00209     /* audio description chunk */
00210     if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {
00211         av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
00212         return AVERROR_INVALIDDATA;
00213     }
00214     size = avio_rb64(pb);
00215     if (size != 32)
00216         return AVERROR_INVALIDDATA;
00217 
00218     ret = read_desc_chunk(s);
00219     if (ret)
00220         return ret;
00221     st = s->streams[0];
00222 
00223     /* parse each chunk */
00224     found_data = 0;
00225     while (!pb->eof_reached) {
00226 
00227         /* stop at data chunk if seeking is not supported or
00228            data chunk size is unknown */
00229         if (found_data && (caf->data_size < 0 || !pb->seekable))
00230             break;
00231 
00232         tag  = avio_rb32(pb);
00233         size = avio_rb64(pb);
00234         if (pb->eof_reached)
00235             break;
00236 
00237         switch (tag) {
00238         case MKBETAG('d','a','t','a'):
00239             avio_skip(pb, 4); /* edit count */
00240             caf->data_start = avio_tell(pb);
00241             caf->data_size  = size < 0 ? -1 : size - 4;
00242             if (caf->data_size > 0 && pb->seekable)
00243                 avio_skip(pb, caf->data_size);
00244             found_data = 1;
00245             break;
00246 
00247         /* magic cookie chunk */
00248         case MKBETAG('k','u','k','i'):
00249             if (read_kuki_chunk(s, size))
00250                 return AVERROR_INVALIDDATA;
00251             break;
00252 
00253         /* packet table chunk */
00254         case MKBETAG('p','a','k','t'):
00255             if (read_pakt_chunk(s, size))
00256                 return AVERROR_INVALIDDATA;
00257             break;
00258 
00259         case MKBETAG('i','n','f','o'):
00260             read_info_chunk(s, size);
00261             break;
00262 
00263         default:
00264 #define _(x) ((x) >= ' ' ? (x) : ' ')
00265             av_log(s, AV_LOG_WARNING, "skipping CAF chunk: %08X (%c%c%c%c)\n",
00266                 tag, _(tag>>24), _((tag>>16)&0xFF), _((tag>>8)&0xFF), _(tag&0xFF));
00267 #undef _
00268         case MKBETAG('f','r','e','e'):
00269             if (size < 0)
00270                 return AVERROR_INVALIDDATA;
00271             avio_skip(pb, size);
00272             break;
00273         }
00274     }
00275 
00276     if (!found_data)
00277         return AVERROR_INVALIDDATA;
00278 
00279     if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
00280         if (caf->data_size > 0)
00281             st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;
00282     } else if (st->nb_index_entries) {
00283         st->codec->bit_rate = st->codec->sample_rate * caf->data_size * 8 /
00284                               st->duration;
00285     } else {
00286         av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "
00287                                 "block size or frame size are variable.\n");
00288         return AVERROR_INVALIDDATA;
00289     }
00290 
00291     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
00292     st->start_time = 0;
00293 
00294     /* position the stream at the start of data */
00295     if (caf->data_size >= 0)
00296         avio_seek(pb, caf->data_start, SEEK_SET);
00297 
00298     return 0;
00299 }
00300 
00301 #define CAF_MAX_PKT_SIZE 4096
00302 
00303 static int read_packet(AVFormatContext *s, AVPacket *pkt)
00304 {
00305     AVIOContext *pb = s->pb;
00306     AVStream *st      = s->streams[0];
00307     CaffContext *caf  = s->priv_data;
00308     int res, pkt_size = 0, pkt_frames = 0;
00309     int64_t left      = CAF_MAX_PKT_SIZE;
00310 
00311     if (pb->eof_reached)
00312         return AVERROR(EIO);
00313 
00314     /* don't read past end of data chunk */
00315     if (caf->data_size > 0) {
00316         left = (caf->data_start + caf->data_size) - avio_tell(pb);
00317         if (left <= 0)
00318             return AVERROR(EIO);
00319     }
00320 
00321     pkt_frames = caf->frames_per_packet;
00322     pkt_size   = caf->bytes_per_packet;
00323 
00324     if (pkt_size > 0 && pkt_frames == 1) {
00325         pkt_size   = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;
00326         pkt_size   = FFMIN(pkt_size, left);
00327         pkt_frames = pkt_size / caf->bytes_per_packet;
00328     } else if (st->nb_index_entries) {
00329         if (caf->packet_cnt < st->nb_index_entries - 1) {
00330             pkt_size   = st->index_entries[caf->packet_cnt + 1].pos       - st->index_entries[caf->packet_cnt].pos;
00331             pkt_frames = st->index_entries[caf->packet_cnt + 1].timestamp - st->index_entries[caf->packet_cnt].timestamp;
00332         } else if (caf->packet_cnt == st->nb_index_entries - 1) {
00333             pkt_size   = caf->num_bytes - st->index_entries[caf->packet_cnt].pos;
00334             pkt_frames = st->duration   - st->index_entries[caf->packet_cnt].timestamp;
00335         } else {
00336             return AVERROR(EIO);
00337         }
00338     }
00339 
00340     if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
00341         return AVERROR(EIO);
00342 
00343     res = av_get_packet(pb, pkt, pkt_size);
00344     if (res < 0)
00345         return res;
00346 
00347     pkt->size           = res;
00348     pkt->stream_index   = 0;
00349     pkt->dts = pkt->pts = caf->frame_cnt;
00350 
00351     caf->packet_cnt++;
00352     caf->frame_cnt += pkt_frames;
00353 
00354     return 0;
00355 }
00356 
00357 static int read_seek(AVFormatContext *s, int stream_index,
00358                      int64_t timestamp, int flags)
00359 {
00360     AVStream *st = s->streams[0];
00361     CaffContext *caf = s->priv_data;
00362     int64_t pos;
00363 
00364     timestamp = FFMAX(timestamp, 0);
00365 
00366     if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
00367         /* calculate new byte position based on target frame position */
00368         pos = caf->bytes_per_packet * timestamp / caf->frames_per_packet;
00369         if (caf->data_size > 0)
00370             pos = FFMIN(pos, caf->data_size);
00371         caf->packet_cnt = pos / caf->bytes_per_packet;
00372         caf->frame_cnt  = caf->frames_per_packet * caf->packet_cnt;
00373     } else if (st->nb_index_entries) {
00374         caf->packet_cnt = av_index_search_timestamp(st, timestamp, flags);
00375         caf->frame_cnt  = st->index_entries[caf->packet_cnt].timestamp;
00376         pos             = st->index_entries[caf->packet_cnt].pos;
00377     } else {
00378         return -1;
00379     }
00380 
00381     avio_seek(s->pb, pos + caf->data_start, SEEK_SET);
00382     return 0;
00383 }
00384 
00385 AVInputFormat ff_caf_demuxer = {
00386     .name           = "caf",
00387     .long_name      = NULL_IF_CONFIG_SMALL("Apple Core Audio Format"),
00388     .priv_data_size = sizeof(CaffContext),
00389     .read_probe     = probe,
00390     .read_header    = read_header,
00391     .read_packet    = read_packet,
00392     .read_seek      = read_seek,
00393     .codec_tag = (const AVCodecTag*[]){ff_codec_caf_tags, 0},
00394 };
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