2 * Core Audio Format demuxer
3 * Copyright (c) 2007 Justin Ruggles
4 * Copyright (c) 2009 Peter Ross
6 * This file is part of FFmpeg.
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.
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.
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
25 * Core Audio Format demuxer
32 #include "libavutil/intreadwrite.h"
33 #include "libavutil/intfloat.h"
34 #include "libavutil/dict.h"
38 int bytes_per_packet; ///< bytes in a packet, or 0 if variable
39 int frames_per_packet; ///< frames in a packet, or 0 if variable
40 int64_t num_bytes; ///< total number of bytes in stream
42 int64_t packet_cnt; ///< packet counter
43 int64_t frame_cnt; ///< frame counter
45 int64_t data_start; ///< data start position, in bytes
46 int64_t data_size; ///< raw data size, in bytes
49 static int probe(AVProbeData *p)
51 if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
52 return AVPROBE_SCORE_MAX;
56 /** Read audio description chunk */
57 static int read_desc_chunk(AVFormatContext *s)
59 AVIOContext *pb = s->pb;
60 CaffContext *caf = s->priv_data;
64 /* new audio stream */
65 st = avformat_new_stream(s, NULL);
67 return AVERROR(ENOMEM);
69 /* parse format description */
70 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
71 st->codec->sample_rate = av_int2double(avio_rb64(pb));
72 st->codec->codec_tag = avio_rl32(pb);
73 flags = avio_rb32(pb);
74 caf->bytes_per_packet = avio_rb32(pb);
75 st->codec->block_align = caf->bytes_per_packet;
76 caf->frames_per_packet = avio_rb32(pb);
77 st->codec->channels = avio_rb32(pb);
78 st->codec->bits_per_coded_sample = avio_rb32(pb);
80 /* calculate bit rate for constant size packets */
81 if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
82 st->codec->bit_rate = (uint64_t)st->codec->sample_rate * (uint64_t)caf->bytes_per_packet * 8
83 / (uint64_t)caf->frames_per_packet;
85 st->codec->bit_rate = 0;
89 if (st->codec->codec_tag == MKTAG('l','p','c','m'))
90 st->codec->codec_id = ff_mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, (flags ^ 0x2) | 0x4);
92 st->codec->codec_id = ff_codec_get_id(ff_codec_caf_tags, st->codec->codec_tag);
96 /** Read magic cookie chunk */
97 static int read_kuki_chunk(AVFormatContext *s, int64_t size)
99 AVIOContext *pb = s->pb;
100 AVStream *st = s->streams[0];
102 if (size < 0 || size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
105 if (st->codec->codec_id == AV_CODEC_ID_AAC) {
106 /* The magic cookie format for AAC is an mp4 esds atom.
107 The lavc AAC decoder requires the data from the codec specific
108 description as extradata input. */
112 strt = avio_tell(pb);
113 ff_mov_read_esds(s, pb, atom);
114 skip = size - (avio_tell(pb) - strt);
115 if (skip < 0 || !st->codec->extradata ||
116 st->codec->codec_id != AV_CODEC_ID_AAC) {
117 av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
118 return AVERROR_INVALIDDATA;
121 } else if (st->codec->codec_id == AV_CODEC_ID_ALAC) {
122 #define ALAC_PREAMBLE 12
123 #define ALAC_HEADER 36
124 #define ALAC_NEW_KUKI 24
125 uint8_t preamble[12];
126 if (size < ALAC_NEW_KUKI) {
127 av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
129 return AVERROR_INVALIDDATA;
131 avio_read(pb, preamble, ALAC_PREAMBLE);
133 if (ff_alloc_extradata(st->codec, ALAC_HEADER))
134 return AVERROR(ENOMEM);
136 /* For the old style cookie, we skip 12 bytes, then read 36 bytes.
137 * The new style cookie only contains the last 24 bytes of what was
138 * 36 bytes in the old style cookie, so we fabricate the first 12 bytes
139 * in that case to maintain compatibility. */
140 if (!memcmp(&preamble[4], "frmaalac", 8)) {
141 if (size < ALAC_PREAMBLE + ALAC_HEADER) {
142 av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
143 av_freep(&st->codec->extradata);
144 return AVERROR_INVALIDDATA;
146 avio_read(pb, st->codec->extradata, ALAC_HEADER);
147 avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
149 AV_WB32(st->codec->extradata, 36);
150 memcpy(&st->codec->extradata[4], "alac", 4);
151 AV_WB32(&st->codec->extradata[8], 0);
152 memcpy(&st->codec->extradata[12], preamble, 12);
153 avio_read(pb, &st->codec->extradata[24], ALAC_NEW_KUKI - 12);
154 avio_skip(pb, size - ALAC_NEW_KUKI);
157 if (ff_get_extradata(st->codec, pb, size) < 0)
158 return AVERROR(ENOMEM);
164 /** Read packet table chunk */
165 static int read_pakt_chunk(AVFormatContext *s, int64_t size)
167 AVIOContext *pb = s->pb;
168 AVStream *st = s->streams[0];
169 CaffContext *caf = s->priv_data;
170 int64_t pos = 0, ccount, num_packets;
173 ccount = avio_tell(pb);
175 num_packets = avio_rb64(pb);
176 if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
177 return AVERROR_INVALIDDATA;
179 st->nb_frames = avio_rb64(pb); /* valid frames */
180 st->nb_frames += avio_rb32(pb); /* priming frames */
181 st->nb_frames += avio_rb32(pb); /* remainder frames */
184 for (i = 0; i < num_packets; i++) {
185 av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
186 pos += caf->bytes_per_packet ? caf->bytes_per_packet : ff_mp4_read_descr_len(pb);
187 st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);
190 if (avio_tell(pb) - ccount > size) {
191 av_log(s, AV_LOG_ERROR, "error reading packet table\n");
192 return AVERROR_INVALIDDATA;
194 avio_skip(pb, ccount + size - avio_tell(pb));
196 caf->num_bytes = pos;
200 /** Read information chunk */
201 static void read_info_chunk(AVFormatContext *s, int64_t size)
203 AVIOContext *pb = s->pb;
205 unsigned int nb_entries = avio_rb32(pb);
206 for (i = 0; i < nb_entries; i++) {
209 avio_get_str(pb, INT_MAX, key, sizeof(key));
210 avio_get_str(pb, INT_MAX, value, sizeof(value));
211 av_dict_set(&s->metadata, key, value, 0);
215 static int read_header(AVFormatContext *s)
217 AVIOContext *pb = s->pb;
218 CaffContext *caf = s->priv_data;
224 avio_skip(pb, 8); /* magic, version, file flags */
226 /* audio description chunk */
227 if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {
228 av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
229 return AVERROR_INVALIDDATA;
231 size = avio_rb64(pb);
233 return AVERROR_INVALIDDATA;
235 ret = read_desc_chunk(s);
240 /* parse each chunk */
242 while (!url_feof(pb)) {
244 /* stop at data chunk if seeking is not supported or
245 data chunk size is unknown */
246 if (found_data && (caf->data_size < 0 || !pb->seekable))
250 size = avio_rb64(pb);
256 case MKBETAG('d','a','t','a'):
257 avio_skip(pb, 4); /* edit count */
258 caf->data_start = avio_tell(pb);
259 caf->data_size = size < 0 ? -1 : size - 4;
260 if (caf->data_size > 0 && pb->seekable)
261 avio_skip(pb, caf->data_size);
265 case MKBETAG('c','h','a','n'):
266 if ((ret = ff_mov_read_chan(s, s->pb, st, size)) < 0)
270 /* magic cookie chunk */
271 case MKBETAG('k','u','k','i'):
272 if (read_kuki_chunk(s, size))
273 return AVERROR_INVALIDDATA;
276 /* packet table chunk */
277 case MKBETAG('p','a','k','t'):
278 if (read_pakt_chunk(s, size))
279 return AVERROR_INVALIDDATA;
282 case MKBETAG('i','n','f','o'):
283 read_info_chunk(s, size);
287 #define _(x) ((x) >= ' ' ? (x) : ' ')
288 av_log(s, AV_LOG_WARNING, "skipping CAF chunk: %08X (%c%c%c%c), size %"PRId64"\n",
289 tag, _(tag>>24), _((tag>>16)&0xFF), _((tag>>8)&0xFF), _(tag&0xFF), size);
291 case MKBETAG('f','r','e','e'):
293 return AVERROR_INVALIDDATA;
298 if (pos > INT64_MAX - size)
299 return AVERROR_INVALIDDATA;
300 avio_skip(pb, FFMAX(0, pos + size - avio_tell(pb)));
305 return AVERROR_INVALIDDATA;
307 if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
308 if (caf->data_size > 0)
309 st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;
310 } else if (st->nb_index_entries && st->duration > 0) {
311 st->codec->bit_rate = st->codec->sample_rate * caf->data_size * 8 /
314 av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "
315 "block size or frame size are variable.\n");
316 return AVERROR_INVALIDDATA;
319 avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
322 /* position the stream at the start of data */
323 if (caf->data_size >= 0)
324 avio_seek(pb, caf->data_start, SEEK_SET);
329 #define CAF_MAX_PKT_SIZE 4096
331 static int read_packet(AVFormatContext *s, AVPacket *pkt)
333 AVIOContext *pb = s->pb;
334 AVStream *st = s->streams[0];
335 CaffContext *caf = s->priv_data;
336 int res, pkt_size = 0, pkt_frames = 0;
337 int64_t left = CAF_MAX_PKT_SIZE;
342 /* don't read past end of data chunk */
343 if (caf->data_size > 0) {
344 left = (caf->data_start + caf->data_size) - avio_tell(pb);
351 pkt_frames = caf->frames_per_packet;
352 pkt_size = caf->bytes_per_packet;
354 if (pkt_size > 0 && pkt_frames == 1) {
355 pkt_size = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;
356 pkt_size = FFMIN(pkt_size, left);
357 pkt_frames = pkt_size / caf->bytes_per_packet;
358 } else if (st->nb_index_entries) {
359 if (caf->packet_cnt < st->nb_index_entries - 1) {
360 pkt_size = st->index_entries[caf->packet_cnt + 1].pos - st->index_entries[caf->packet_cnt].pos;
361 pkt_frames = st->index_entries[caf->packet_cnt + 1].timestamp - st->index_entries[caf->packet_cnt].timestamp;
362 } else if (caf->packet_cnt == st->nb_index_entries - 1) {
363 pkt_size = caf->num_bytes - st->index_entries[caf->packet_cnt].pos;
364 pkt_frames = st->duration - st->index_entries[caf->packet_cnt].timestamp;
370 if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
373 res = av_get_packet(pb, pkt, pkt_size);
378 pkt->stream_index = 0;
379 pkt->dts = pkt->pts = caf->frame_cnt;
382 caf->frame_cnt += pkt_frames;
387 static int read_seek(AVFormatContext *s, int stream_index,
388 int64_t timestamp, int flags)
390 AVStream *st = s->streams[0];
391 CaffContext *caf = s->priv_data;
392 int64_t pos, packet_cnt, frame_cnt;
394 timestamp = FFMAX(timestamp, 0);
396 if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
397 /* calculate new byte position based on target frame position */
398 pos = caf->bytes_per_packet * (timestamp / caf->frames_per_packet);
399 if (caf->data_size > 0)
400 pos = FFMIN(pos, caf->data_size);
401 packet_cnt = pos / caf->bytes_per_packet;
402 frame_cnt = caf->frames_per_packet * packet_cnt;
403 } else if (st->nb_index_entries) {
404 packet_cnt = av_index_search_timestamp(st, timestamp, flags);
405 frame_cnt = st->index_entries[packet_cnt].timestamp;
406 pos = st->index_entries[packet_cnt].pos;
411 if (avio_seek(s->pb, pos + caf->data_start, SEEK_SET) < 0)
414 caf->packet_cnt = packet_cnt;
415 caf->frame_cnt = frame_cnt;
420 AVInputFormat ff_caf_demuxer = {
422 .long_name = NULL_IF_CONFIG_SMALL("Apple CAF (Core Audio Format)"),
423 .priv_data_size = sizeof(CaffContext),
425 .read_header = read_header,
426 .read_packet = read_packet,
427 .read_seek = read_seek,
428 .codec_tag = (const AVCodecTag* const []){ ff_codec_caf_tags, 0 },