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
33 #include "libavutil/intreadwrite.h"
34 #include "libavutil/intfloat.h"
35 #include "libavutil/dict.h"
39 int bytes_per_packet; ///< bytes in a packet, or 0 if variable
40 int frames_per_packet; ///< frames in a packet, or 0 if variable
41 int64_t num_bytes; ///< total number of bytes in stream
43 int64_t packet_cnt; ///< packet counter
44 int64_t frame_cnt; ///< frame counter
46 int64_t data_start; ///< data start position, in bytes
47 int64_t data_size; ///< raw data size, in bytes
50 static int probe(AVProbeData *p)
52 if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
53 return AVPROBE_SCORE_MAX;
57 /** Read audio description chunk */
58 static int read_desc_chunk(AVFormatContext *s)
60 AVIOContext *pb = s->pb;
61 CaffContext *caf = s->priv_data;
65 /* new audio stream */
66 st = avformat_new_stream(s, NULL);
68 return AVERROR(ENOMEM);
70 /* parse format description */
71 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
72 st->codec->sample_rate = av_int2double(avio_rb64(pb));
73 st->codec->codec_tag = avio_rl32(pb);
74 flags = avio_rb32(pb);
75 caf->bytes_per_packet = avio_rb32(pb);
76 st->codec->block_align = caf->bytes_per_packet;
77 caf->frames_per_packet = avio_rb32(pb);
78 st->codec->channels = avio_rb32(pb);
79 st->codec->bits_per_coded_sample = avio_rb32(pb);
81 /* calculate bit rate for constant size packets */
82 if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
83 st->codec->bit_rate = (uint64_t)st->codec->sample_rate * (uint64_t)caf->bytes_per_packet * 8
84 / (uint64_t)caf->frames_per_packet;
86 st->codec->bit_rate = 0;
90 if (st->codec->codec_tag == MKTAG('l','p','c','m'))
91 st->codec->codec_id = ff_mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, (flags ^ 0x2) | 0x4);
93 st->codec->codec_id = ff_codec_get_id(ff_codec_caf_tags, st->codec->codec_tag);
97 /** Read magic cookie chunk */
98 static int read_kuki_chunk(AVFormatContext *s, int64_t size)
100 AVIOContext *pb = s->pb;
101 AVStream *st = s->streams[0];
103 if (size < 0 || size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
106 if (st->codec->codec_id == CODEC_ID_AAC) {
107 /* The magic cookie format for AAC is an mp4 esds atom.
108 The lavc AAC decoder requires the data from the codec specific
109 description as extradata input. */
113 strt = avio_tell(pb);
114 ff_mov_read_esds(s, pb, atom);
115 skip = size - (avio_tell(pb) - strt);
116 if (skip < 0 || !st->codec->extradata ||
117 st->codec->codec_id != CODEC_ID_AAC) {
118 av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
119 return AVERROR_INVALIDDATA;
122 } else if (st->codec->codec_id == CODEC_ID_ALAC) {
123 #define ALAC_PREAMBLE 12
124 #define ALAC_HEADER 36
125 #define ALAC_NEW_KUKI 24
126 uint8_t preamble[12];
127 if (size < ALAC_NEW_KUKI) {
128 av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
130 return AVERROR_INVALIDDATA;
132 avio_read(pb, preamble, ALAC_PREAMBLE);
134 st->codec->extradata = av_mallocz(ALAC_HEADER + FF_INPUT_BUFFER_PADDING_SIZE);
135 if (!st->codec->extradata)
136 return AVERROR(ENOMEM);
138 /* For the old style cookie, we skip 12 bytes, then read 36 bytes.
139 * The new style cookie only contains the last 24 bytes of what was
140 * 36 bytes in the old style cookie, so we fabricate the first 12 bytes
141 * in that case to maintain compatibility. */
142 if (!memcmp(&preamble[4], "frmaalac", 8)) {
143 if (size < ALAC_PREAMBLE + ALAC_HEADER) {
144 av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
145 av_freep(&st->codec->extradata);
146 return AVERROR_INVALIDDATA;
148 avio_read(pb, st->codec->extradata, ALAC_HEADER);
149 avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
151 AV_WB32(st->codec->extradata, 36);
152 memcpy(&st->codec->extradata[4], "alac", 4);
153 AV_WB32(&st->codec->extradata[8], 0);
154 memcpy(&st->codec->extradata[12], preamble, 12);
155 avio_read(pb, &st->codec->extradata[24], ALAC_NEW_KUKI - 12);
156 avio_skip(pb, size - ALAC_NEW_KUKI);
158 st->codec->extradata_size = ALAC_HEADER;
160 st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
161 if (!st->codec->extradata)
162 return AVERROR(ENOMEM);
163 avio_read(pb, st->codec->extradata, size);
164 st->codec->extradata_size = size;
170 /** Read packet table chunk */
171 static int read_pakt_chunk(AVFormatContext *s, int64_t size)
173 AVIOContext *pb = s->pb;
174 AVStream *st = s->streams[0];
175 CaffContext *caf = s->priv_data;
176 int64_t pos = 0, ccount, num_packets;
179 ccount = avio_tell(pb);
181 num_packets = avio_rb64(pb);
182 if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
183 return AVERROR_INVALIDDATA;
185 st->nb_frames = avio_rb64(pb); /* valid frames */
186 st->nb_frames += avio_rb32(pb); /* priming frames */
187 st->nb_frames += avio_rb32(pb); /* remainder frames */
190 for (i = 0; i < num_packets; i++) {
191 av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
192 pos += caf->bytes_per_packet ? caf->bytes_per_packet : ff_mp4_read_descr_len(pb);
193 st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);
196 if (avio_tell(pb) - ccount > size) {
197 av_log(s, AV_LOG_ERROR, "error reading packet table\n");
198 return AVERROR_INVALIDDATA;
200 avio_skip(pb, ccount + size - avio_tell(pb));
202 caf->num_bytes = pos;
206 /** Read information chunk */
207 static void read_info_chunk(AVFormatContext *s, int64_t size)
209 AVIOContext *pb = s->pb;
211 unsigned int nb_entries = avio_rb32(pb);
212 for (i = 0; i < nb_entries; i++) {
215 avio_get_str(pb, INT_MAX, key, sizeof(key));
216 avio_get_str(pb, INT_MAX, value, sizeof(value));
217 av_dict_set(&s->metadata, key, value, 0);
221 static int read_header(AVFormatContext *s)
223 AVIOContext *pb = s->pb;
224 CaffContext *caf = s->priv_data;
230 avio_skip(pb, 8); /* magic, version, file flags */
232 /* audio description chunk */
233 if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {
234 av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
235 return AVERROR_INVALIDDATA;
237 size = avio_rb64(pb);
239 return AVERROR_INVALIDDATA;
241 ret = read_desc_chunk(s);
246 /* parse each chunk */
248 while (!url_feof(pb)) {
250 /* stop at data chunk if seeking is not supported or
251 data chunk size is unknown */
252 if (found_data && (caf->data_size < 0 || !pb->seekable))
256 size = avio_rb64(pb);
261 case MKBETAG('d','a','t','a'):
262 avio_skip(pb, 4); /* edit count */
263 caf->data_start = avio_tell(pb);
264 caf->data_size = size < 0 ? -1 : size - 4;
265 if (caf->data_size > 0 && pb->seekable)
266 avio_skip(pb, caf->data_size);
270 case MKBETAG('c','h','a','n'):
271 if ((ret = ff_mov_read_chan(s, st, size)) < 0)
275 /* magic cookie chunk */
276 case MKBETAG('k','u','k','i'):
277 if (read_kuki_chunk(s, size))
278 return AVERROR_INVALIDDATA;
281 /* packet table chunk */
282 case MKBETAG('p','a','k','t'):
283 if (read_pakt_chunk(s, size))
284 return AVERROR_INVALIDDATA;
287 case MKBETAG('i','n','f','o'):
288 read_info_chunk(s, size);
292 #define _(x) ((x) >= ' ' ? (x) : ' ')
293 av_log(s, AV_LOG_WARNING, "skipping CAF chunk: %08X (%c%c%c%c), size %"PRId64"\n",
294 tag, _(tag>>24), _((tag>>16)&0xFF), _((tag>>8)&0xFF), _(tag&0xFF), size);
296 case MKBETAG('f','r','e','e'):
298 return AVERROR_INVALIDDATA;
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) {
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);
349 pkt_frames = caf->frames_per_packet;
350 pkt_size = caf->bytes_per_packet;
352 if (pkt_size > 0 && pkt_frames == 1) {
353 pkt_size = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;
354 pkt_size = FFMIN(pkt_size, left);
355 pkt_frames = pkt_size / caf->bytes_per_packet;
356 } else if (st->nb_index_entries) {
357 if (caf->packet_cnt < st->nb_index_entries - 1) {
358 pkt_size = st->index_entries[caf->packet_cnt + 1].pos - st->index_entries[caf->packet_cnt].pos;
359 pkt_frames = st->index_entries[caf->packet_cnt + 1].timestamp - st->index_entries[caf->packet_cnt].timestamp;
360 } else if (caf->packet_cnt == st->nb_index_entries - 1) {
361 pkt_size = caf->num_bytes - st->index_entries[caf->packet_cnt].pos;
362 pkt_frames = st->duration - st->index_entries[caf->packet_cnt].timestamp;
368 if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
371 res = av_get_packet(pb, pkt, pkt_size);
376 pkt->stream_index = 0;
377 pkt->dts = pkt->pts = caf->frame_cnt;
380 caf->frame_cnt += pkt_frames;
385 static int read_seek(AVFormatContext *s, int stream_index,
386 int64_t timestamp, int flags)
388 AVStream *st = s->streams[0];
389 CaffContext *caf = s->priv_data;
390 int64_t pos, packet_cnt, frame_cnt;
392 timestamp = FFMAX(timestamp, 0);
394 if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
395 /* calculate new byte position based on target frame position */
396 pos = caf->bytes_per_packet * timestamp / caf->frames_per_packet;
397 if (caf->data_size > 0)
398 pos = FFMIN(pos, caf->data_size);
399 packet_cnt = pos / caf->bytes_per_packet;
400 frame_cnt = caf->frames_per_packet * packet_cnt;
401 } else if (st->nb_index_entries) {
402 packet_cnt = av_index_search_timestamp(st, timestamp, flags);
403 frame_cnt = st->index_entries[packet_cnt].timestamp;
404 pos = st->index_entries[packet_cnt].pos;
409 if (avio_seek(s->pb, pos + caf->data_start, SEEK_SET) < 0)
412 caf->packet_cnt = packet_cnt;
413 caf->frame_cnt = frame_cnt;
418 AVInputFormat ff_caf_demuxer = {
420 .long_name = NULL_IF_CONFIG_SMALL("Apple Core Audio Format"),
421 .priv_data_size = sizeof(CaffContext),
423 .read_header = read_header,
424 .read_packet = read_packet,
425 .read_seek = read_seek,
426 .codec_tag = (const AVCodecTag* const []){ ff_codec_caf_tags, 0 },