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ffmpeg/libavformat/cafdec.c

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/*
* Core Audio Format demuxer
* Copyright (c) 2007 Justin Ruggles
* Copyright (c) 2009 Peter Ross
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; 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 "isom.h"
#include "mov_chan.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_rl32(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 == MKTAG('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 == AV_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 != AV_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 == AV_CODEC_ID_ALAC) {
#define ALAC_PREAMBLE 12
#define ALAC_HEADER 36
#define ALAC_NEW_KUKI 24
uint8_t preamble[12];
if (size < ALAC_NEW_KUKI) {
av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
avio_skip(pb, size);
return AVERROR_INVALIDDATA;
}
avio_read(pb, preamble, ALAC_PREAMBLE);
st->codec->extradata = av_mallocz(ALAC_HEADER + FF_INPUT_BUFFER_PADDING_SIZE);
if (!st->codec->extradata)
return AVERROR(ENOMEM);
/* For the old style cookie, we skip 12 bytes, then read 36 bytes.
* The new style cookie only contains the last 24 bytes of what was
* 36 bytes in the old style cookie, so we fabricate the first 12 bytes
* in that case to maintain compatibility. */
if (!memcmp(&preamble[4], "frmaalac", 8)) {
if (size < ALAC_PREAMBLE + ALAC_HEADER) {
av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
av_freep(&st->codec->extradata);
return AVERROR_INVALIDDATA;
}
avio_read(pb, st->codec->extradata, ALAC_HEADER);
avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
} else {
AV_WB32(st->codec->extradata, 36);
memcpy(&st->codec->extradata[4], "alac", 4);
AV_WB32(&st->codec->extradata[8], 0);
memcpy(&st->codec->extradata[12], preamble, 12);
avio_read(pb, &st->codec->extradata[24], ALAC_NEW_KUKI - 12);
avio_skip(pb, size - ALAC_NEW_KUKI);
}
st->codec->extradata_size = 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, num_packets;
int 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 AVERROR_INVALIDDATA;
}
avio_skip(pb, ccount + size - avio_tell(pb));
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, pos;
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 (!url_feof(pb)) {
/* 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);
pos = avio_tell(pb);
if (url_feof(pb))
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;
case MKBETAG('c','h','a','n'):
if ((ret = ff_mov_read_chan(s, s->pb, st, size)) < 0)
return ret;
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), size %"PRId64"\n",
tag, _(tag>>24), _((tag>>16)&0xFF), _((tag>>8)&0xFF), _(tag&0xFF), size);
#undef _
case MKBETAG('f','r','e','e'):
if (size < 0)
return AVERROR_INVALIDDATA;
break;
}
if (size > 0) {
if (pos + size < pos)
return AVERROR_INVALIDDATA;
avio_skip(pb, FFMAX(0, pos + size - avio_tell(pb)));
}
}
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->duration > 0) {
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 (url_feof(pb))
return AVERROR_EOF;
/* 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)
return AVERROR_EOF;
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, packet_cnt, frame_cnt;
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);
packet_cnt = pos / caf->bytes_per_packet;
frame_cnt = caf->frames_per_packet * packet_cnt;
} else if (st->nb_index_entries) {
packet_cnt = av_index_search_timestamp(st, timestamp, flags);
frame_cnt = st->index_entries[packet_cnt].timestamp;
pos = st->index_entries[packet_cnt].pos;
} else {
return -1;
}
if (avio_seek(s->pb, pos + caf->data_start, SEEK_SET) < 0)
return -1;
caf->packet_cnt = packet_cnt;
caf->frame_cnt = frame_cnt;
return 0;
}
AVInputFormat ff_caf_demuxer = {
.name = "caf",
.long_name = NULL_IF_CONFIG_SMALL("Apple CAF (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* const []){ ff_codec_caf_tags, 0 },
};
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