FFmpeg
acedec.c
Go to the documentation of this file.
1 /*
2  * ACE demuxer
3  * Copyright (c) 2020 Paul B Mahol
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/intreadwrite.h"
23 #include "avformat.h"
24 #include "internal.h"
25 
26 static int ace_probe(const AVProbeData *p)
27 {
28  uint32_t asc;
29 
30  if (AV_RB32(p->buf) != MKBETAG('A','A','C',' '))
31  return 0;
32  if (p->buf_size < 0x44)
33  return 0;
34  asc = AV_RB32(p->buf + 0x40);
35  if (asc < 0x44 || asc > p->buf_size - 4)
36  return 0;
37  if (AV_RB32(p->buf + asc) != MKBETAG('A','S','C',' '))
38  return 0;
39 
40  return AVPROBE_SCORE_MAX / 2 + 1;
41 }
42 
44 {
45  AVIOContext *pb = s->pb;
46  AVCodecParameters *par;
47  int ret, codec, rate, nb_channels;
48  uint32_t asc_pos, size;
49  AVStream *st;
50 
51  avio_skip(pb, 0x40);
52  asc_pos = avio_rb32(pb);
53  if (asc_pos < 0x44)
54  return AVERROR_INVALIDDATA;
55  avio_skip(pb, asc_pos - 0x44);
56  if (avio_rb32(pb) != MKBETAG('A','S','C',' '))
57  return AVERROR_INVALIDDATA;
58  avio_skip(pb, 0xec);
59  codec = avio_rb32(pb);
60  nb_channels = avio_rb32(pb);
61  if (nb_channels <= 0 || nb_channels > 8)
62  return AVERROR_INVALIDDATA;
63  size = avio_rb32(pb);
64  if (size == 0)
65  return AVERROR_INVALIDDATA;
66  rate = avio_rb32(pb);
67  if (rate <= 0)
68  return AVERROR_INVALIDDATA;
69  avio_skip(pb, 16);
70 
71  st = avformat_new_stream(s, NULL);
72  if (!st)
73  return AVERROR(ENOMEM);
74  st->start_time = 0;
75  par = st->codecpar;
77  par->channels = nb_channels;
78  par->sample_rate = rate;
79  par->block_align = (codec == 4 ? 0x60 : codec == 5 ? 0x98 : 0xC0) * nb_channels;
80  st->duration = (size / par->block_align) * 1024LL;
82 
83  ret = ff_alloc_extradata(par, 14);
84  if (ret < 0)
85  return ret;
86 
87  AV_WL16(st->codecpar->extradata, 1);
88  AV_WL16(st->codecpar->extradata+2, 2048 * par->channels);
89  AV_WL16(st->codecpar->extradata+4, 0);
90  AV_WL16(st->codecpar->extradata+6, codec == 4 ? 1 : 0);
91  AV_WL16(st->codecpar->extradata+8, codec == 4 ? 1 : 0);
92  AV_WL16(st->codecpar->extradata+10, 1);
93  AV_WL16(st->codecpar->extradata+12, 0);
94 
95  avpriv_set_pts_info(st, 64, 1, par->sample_rate);
96 
97  return 0;
98 }
99 
101 {
102  AVCodecParameters *par = s->streams[0]->codecpar;
103 
104  return av_get_packet(s->pb, pkt, par->block_align);
105 }
106 
108  .name = "ace",
109  .long_name = NULL_IF_CONFIG_SMALL("tri-Ace Audio Container"),
110  .read_probe = ace_probe,
111  .read_header = ace_read_header,
112  .read_packet = ace_read_packet,
113  .flags = AVFMT_GENERIC_INDEX,
114 };
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4893
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:341
static AVPacket pkt
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
Format I/O context.
Definition: avformat.h:1239
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:785
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4477
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:91
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1307
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:307
ptrdiff_t size
Definition: opengl_enc.c:100
static int ace_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: acedec.c:100
static int ace_read_header(AVFormatContext *s)
Definition: acedec.c:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:115
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
static int ace_probe(const AVProbeData *p)
Definition: acedec.c:26
int block_align
Audio only.
Definition: codec_par.h:177
int ff_alloc_extradata(AVCodecParameters *par, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0...
Definition: utils.c:3282
#define s(width, name)
Definition: cbs_vp9.c:257
Stream structure.
Definition: avformat.h:880
AVIOContext * pb
I/O context.
Definition: avformat.h:1281
AVInputFormat ff_ace_demuxer
Definition: acedec.c:107
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:463
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:929
int sample_rate
Audio only.
Definition: codec_par.h:170
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
Main libavformat public API header.
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:919
#define AV_WL16(p, v)
Definition: intreadwrite.h:412
#define MKBETAG(a, b, c, d)
Definition: common.h:406
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:74
int channels
Audio only.
Definition: codec_par.h:166
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:652
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1045
int nb_channels
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
Definition: packet.h:340