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
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
34typedef 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
46static 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 */
54static 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(ENOMEM);
65
66    /* parse format description */
67    st->codec->codec_type  = AVMEDIA_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 */
94static 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 */
130static 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 */
165static 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_set2(&s->metadata, key, value, 0);
176    }
177}
178
179static 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
287static 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(EIO);
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(EIO);
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(EIO);
321        }
322    }
323
324    if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
325        return AVERROR(EIO);
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
341static 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
369AVInputFormat 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};
380