aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/cafdec.c
blob: abde78d56cc50c8405c62730a26cb4aaaa772381 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
/*
 * Core Audio Format demuxer
 * Copyright (c) 2007 Justin Ruggles
 * Copyright (c) 2009 Peter Ross
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Core Audio Format demuxer
 */

#include "avformat.h"
#include "internal.h"
#include "riff.h"
#include "isom.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/intfloat.h"
#include "libavutil/dict.h"
#include "caf.h"

typedef struct {
    int bytes_per_packet;           ///< bytes in a packet, or 0 if variable
    int frames_per_packet;          ///< frames in a packet, or 0 if variable
    int64_t num_bytes;              ///< total number of bytes in stream

    int64_t packet_cnt;             ///< packet counter
    int64_t frame_cnt;              ///< frame counter

    int64_t data_start;             ///< data start position, in bytes
    int64_t data_size;              ///< raw data size, in bytes
} CaffContext;

static int probe(AVProbeData *p)
{
    if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
        return AVPROBE_SCORE_MAX;
    return 0;
}

/** Read audio description chunk */
static int read_desc_chunk(AVFormatContext *s)
{
    AVIOContext *pb = s->pb;
    CaffContext *caf  = s->priv_data;
    AVStream *st;
    int flags;

    /* new audio stream */
    st = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);

    /* parse format description */
    st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
    st->codec->sample_rate = av_int2double(avio_rb64(pb));
    st->codec->codec_tag   = avio_rb32(pb);
    flags = avio_rb32(pb);
    caf->bytes_per_packet  = avio_rb32(pb);
    st->codec->block_align = caf->bytes_per_packet;
    caf->frames_per_packet = avio_rb32(pb);
    st->codec->channels    = avio_rb32(pb);
    st->codec->bits_per_coded_sample = avio_rb32(pb);

    /* calculate bit rate for constant size packets */
    if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
        st->codec->bit_rate = (uint64_t)st->codec->sample_rate * (uint64_t)caf->bytes_per_packet * 8
                              / (uint64_t)caf->frames_per_packet;
    } else {
        st->codec->bit_rate = 0;
    }

    /* determine codec */
    if (st->codec->codec_tag == MKBETAG('l','p','c','m'))
        st->codec->codec_id = ff_mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, (flags ^ 0x2) | 0x4);
    else
        st->codec->codec_id = ff_codec_get_id(ff_codec_caf_tags, st->codec->codec_tag);
    return 0;
}

/** Read magic cookie chunk */
static int read_kuki_chunk(AVFormatContext *s, int64_t size)
{
    AVIOContext *pb = s->pb;
    AVStream *st      = s->streams[0];

    if (size < 0 || size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
        return -1;

    if (st->codec->codec_id == CODEC_ID_AAC) {
        /* The magic cookie format for AAC is an mp4 esds atom.
           The lavc AAC decoder requires the data from the codec specific
           description as extradata input. */
        int strt, skip;
        MOVAtom atom;

        strt = avio_tell(pb);
        ff_mov_read_esds(s, pb, atom);
        skip = size - (avio_tell(pb) - strt);
        if (skip < 0 || !st->codec->extradata ||
            st->codec->codec_id != CODEC_ID_AAC) {
            av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
            return AVERROR_INVALIDDATA;
        }
        avio_skip(pb, skip);
    } else if (st->codec->codec_id == CODEC_ID_ALAC) {
#define ALAC_PREAMBLE 12
#define ALAC_HEADER   36
        if (size < ALAC_PREAMBLE + ALAC_HEADER) {
            av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
            avio_skip(pb, size);
            return AVERROR_INVALIDDATA;
        }
        avio_skip(pb, ALAC_PREAMBLE);
        st->codec->extradata = av_mallocz(ALAC_HEADER + FF_INPUT_BUFFER_PADDING_SIZE);
        if (!st->codec->extradata)
            return AVERROR(ENOMEM);
        avio_read(pb, st->codec->extradata, ALAC_HEADER);
        st->codec->extradata_size = ALAC_HEADER;
        avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
    } else {
        st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
        if (!st->codec->extradata)
            return AVERROR(ENOMEM);
        avio_read(pb, st->codec->extradata, size);
        st->codec->extradata_size = size;
    }

    return 0;
}

/** Read packet table chunk */
static int read_pakt_chunk(AVFormatContext *s, int64_t size)
{
    AVIOContext *pb = s->pb;
    AVStream *st      = s->streams[0];
    CaffContext *caf  = s->priv_data;
    int64_t pos = 0, ccount;
    int num_packets, i;

    ccount = avio_tell(pb);

    num_packets = avio_rb64(pb);
    if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
        return AVERROR_INVALIDDATA;

    st->nb_frames  = avio_rb64(pb); /* valid frames */
    st->nb_frames += avio_rb32(pb); /* priming frames */
    st->nb_frames += avio_rb32(pb); /* remainder frames */

    st->duration = 0;
    for (i = 0; i < num_packets; i++) {
        av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
        pos += caf->bytes_per_packet ? caf->bytes_per_packet : ff_mp4_read_descr_len(pb);
        st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);
    }

    if (avio_tell(pb) - ccount != size) {
        av_log(s, AV_LOG_ERROR, "error reading packet table\n");
        return -1;
    }

    caf->num_bytes = pos;
    return 0;
}

/** Read information chunk */
static void read_info_chunk(AVFormatContext *s, int64_t size)
{
    AVIOContext *pb = s->pb;
    unsigned int i;
    unsigned int nb_entries = avio_rb32(pb);
    for (i = 0; i < nb_entries; i++) {
        char key[32];
        char value[1024];
        avio_get_str(pb, INT_MAX, key,   sizeof(key));
        avio_get_str(pb, INT_MAX, value, sizeof(value));
        av_dict_set(&s->metadata, key, value, 0);
    }
}

static int read_header(AVFormatContext *s)
{
    AVIOContext *pb = s->pb;
    CaffContext *caf  = s->priv_data;
    AVStream *st;
    uint32_t tag = 0;
    int found_data, ret;
    int64_t size;

    avio_skip(pb, 8); /* magic, version, file flags */

    /* audio description chunk */
    if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {
        av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
        return AVERROR_INVALIDDATA;
    }
    size = avio_rb64(pb);
    if (size != 32)
        return AVERROR_INVALIDDATA;

    ret = read_desc_chunk(s);
    if (ret)
        return ret;
    st = s->streams[0];

    /* parse each chunk */
    found_data = 0;
    while (!pb->eof_reached) {

        /* stop at data chunk if seeking is not supported or
           data chunk size is unknown */
        if (found_data && (caf->data_size < 0 || !pb->seekable))
            break;

        tag  = avio_rb32(pb);
        size = avio_rb64(pb);
        if (pb->eof_reached)
            break;

        switch (tag) {
        case MKBETAG('d','a','t','a'):
            avio_skip(pb, 4); /* edit count */
            caf->data_start = avio_tell(pb);
            caf->data_size  = size < 0 ? -1 : size - 4;
            if (caf->data_size > 0 && pb->seekable)
                avio_skip(pb, caf->data_size);
            found_data = 1;
            break;

        /* magic cookie chunk */
        case MKBETAG('k','u','k','i'):
            if (read_kuki_chunk(s, size))
                return AVERROR_INVALIDDATA;
            break;

        /* packet table chunk */
        case MKBETAG('p','a','k','t'):
            if (read_pakt_chunk(s, size))
                return AVERROR_INVALIDDATA;
            break;

        case MKBETAG('i','n','f','o'):
            read_info_chunk(s, size);
            break;

        default:
#define _(x) ((x) >= ' ' ? (x) : ' ')
            av_log(s, AV_LOG_WARNING, "skipping CAF chunk: %08X (%c%c%c%c)\n",
                tag, _(tag>>24), _((tag>>16)&0xFF), _((tag>>8)&0xFF), _(tag&0xFF));
#undef _
        case MKBETAG('f','r','e','e'):
            if (size < 0)
                return AVERROR_INVALIDDATA;
            avio_skip(pb, size);
            break;
        }
    }

    if (!found_data)
        return AVERROR_INVALIDDATA;

    if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
        if (caf->data_size > 0)
            st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;
    } else if (st->nb_index_entries) {
        st->codec->bit_rate = st->codec->sample_rate * caf->data_size * 8 /
                              st->duration;
    } else {
        av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "
                                "block size or frame size are variable.\n");
        return AVERROR_INVALIDDATA;
    }

    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
    st->start_time = 0;

    /* position the stream at the start of data */
    if (caf->data_size >= 0)
        avio_seek(pb, caf->data_start, SEEK_SET);

    return 0;
}

#define CAF_MAX_PKT_SIZE 4096

static int read_packet(AVFormatContext *s, AVPacket *pkt)
{
    AVIOContext *pb = s->pb;
    AVStream *st      = s->streams[0];
    CaffContext *caf  = s->priv_data;
    int res, pkt_size = 0, pkt_frames = 0;
    int64_t left      = CAF_MAX_PKT_SIZE;

    if (pb->eof_reached)
        return AVERROR(EIO);

    /* don't read past end of data chunk */
    if (caf->data_size > 0) {
        left = (caf->data_start + caf->data_size) - avio_tell(pb);
        if (left <= 0)
            return AVERROR(EIO);
    }

    pkt_frames = caf->frames_per_packet;
    pkt_size   = caf->bytes_per_packet;

    if (pkt_size > 0 && pkt_frames == 1) {
        pkt_size   = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;
        pkt_size   = FFMIN(pkt_size, left);
        pkt_frames = pkt_size / caf->bytes_per_packet;
    } else if (st->nb_index_entries) {
        if (caf->packet_cnt < st->nb_index_entries - 1) {
            pkt_size   = st->index_entries[caf->packet_cnt + 1].pos       - st->index_entries[caf->packet_cnt].pos;
            pkt_frames = st->index_entries[caf->packet_cnt + 1].timestamp - st->index_entries[caf->packet_cnt].timestamp;
        } else if (caf->packet_cnt == st->nb_index_entries - 1) {
            pkt_size   = caf->num_bytes - st->index_entries[caf->packet_cnt].pos;
            pkt_frames = st->duration   - st->index_entries[caf->packet_cnt].timestamp;
        } else {
            return AVERROR(EIO);
        }
    }

    if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
        return AVERROR(EIO);

    res = av_get_packet(pb, pkt, pkt_size);
    if (res < 0)
        return res;

    pkt->size           = res;
    pkt->stream_index   = 0;
    pkt->dts = pkt->pts = caf->frame_cnt;

    caf->packet_cnt++;
    caf->frame_cnt += pkt_frames;

    return 0;
}

static int read_seek(AVFormatContext *s, int stream_index,
                     int64_t timestamp, int flags)
{
    AVStream *st = s->streams[0];
    CaffContext *caf = s->priv_data;
    int64_t pos;

    timestamp = FFMAX(timestamp, 0);

    if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
        /* calculate new byte position based on target frame position */
        pos = caf->bytes_per_packet * timestamp / caf->frames_per_packet;
        if (caf->data_size > 0)
            pos = FFMIN(pos, caf->data_size);
        caf->packet_cnt = pos / caf->bytes_per_packet;
        caf->frame_cnt  = caf->frames_per_packet * caf->packet_cnt;
    } else if (st->nb_index_entries) {
        caf->packet_cnt = av_index_search_timestamp(st, timestamp, flags);
        caf->frame_cnt  = st->index_entries[caf->packet_cnt].timestamp;
        pos             = st->index_entries[caf->packet_cnt].pos;
    } else {
        return -1;
    }

    avio_seek(s->pb, pos + caf->data_start, SEEK_SET);
    return 0;
}

AVInputFormat ff_caf_demuxer = {
    .name           = "caf",
    .long_name      = NULL_IF_CONFIG_SMALL("Apple Core Audio Format"),
    .priv_data_size = sizeof(CaffContext),
    .read_probe     = probe,
    .read_header    = read_header,
    .read_packet    = read_packet,
    .read_seek      = read_seek,
    .codec_tag = (const AVCodecTag*[]){ff_codec_caf_tags, 0},
};