FFmpeg
xa.c
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1 /*
2  * Maxis XA (.xa) File Demuxer
3  * Copyright (c) 2008 Robert Marston
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 /**
23  * @file
24  * Maxis XA File Demuxer
25  * by Robert Marston (rmarston@gmail.com)
26  * for more information on the XA audio format see
27  * http://wiki.multimedia.cx/index.php?title=Maxis_XA
28  */
29 
30 #include "libavutil/intreadwrite.h"
31 #include "avformat.h"
32 #include "demux.h"
33 #include "internal.h"
34 
35 #define XA00_TAG MKTAG('X', 'A', 0, 0)
36 #define XAI0_TAG MKTAG('X', 'A', 'I', 0)
37 #define XAJ0_TAG MKTAG('X', 'A', 'J', 0)
38 
39 typedef struct MaxisXADemuxContext {
40  uint32_t out_size;
41  uint32_t sent_bytes;
43 
44 static int xa_probe(const AVProbeData *p)
45 {
46  int channels, srate, bits_per_sample;
47  if (p->buf_size < 24)
48  return 0;
49  switch(AV_RL32(p->buf)) {
50  case XA00_TAG:
51  case XAI0_TAG:
52  case XAJ0_TAG:
53  break;
54  default:
55  return 0;
56  }
57  channels = AV_RL16(p->buf + 10);
58  srate = AV_RL32(p->buf + 12);
59  bits_per_sample = AV_RL16(p->buf + 22);
60  if (!channels || channels > 8 || !srate || srate > 192000 ||
61  bits_per_sample < 4 || bits_per_sample > 32)
62  return 0;
64 }
65 
67 {
68  MaxisXADemuxContext *xa = s->priv_data;
69  AVIOContext *pb = s->pb;
70  AVStream *st;
71 
72  /*Set up the XA Audio Decoder*/
73  st = avformat_new_stream(s, NULL);
74  if (!st)
75  return AVERROR(ENOMEM);
76 
79  avio_skip(pb, 4); /* Skip the XA ID */
80  xa->out_size = avio_rl32(pb);
81  avio_skip(pb, 2); /* Skip the tag */
83  st->codecpar->sample_rate = avio_rl32(pb);
84  avio_skip(pb, 4); /* Skip average byte rate */
85  avio_skip(pb, 2); /* Skip block align */
86  avio_skip(pb, 2); /* Skip bits-per-sample */
87 
89  return AVERROR_INVALIDDATA;
90 
91  st->codecpar->bit_rate = av_clip(15LL * st->codecpar->ch_layout.nb_channels * 8 *
92  st->codecpar->sample_rate / 28, 0, INT_MAX);
93 
94  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
95  st->start_time = 0;
96 
97  return 0;
98 }
99 
101  AVPacket *pkt)
102 {
103  MaxisXADemuxContext *xa = s->priv_data;
104  AVStream *st = s->streams[0];
105  AVIOContext *pb = s->pb;
106  unsigned int packet_size;
107  int ret;
108 
109  if (xa->sent_bytes >= xa->out_size)
110  return AVERROR_EOF;
111  /* 1 byte header and 14 bytes worth of samples * number channels per block */
112  packet_size = 15*st->codecpar->ch_layout.nb_channels;
113 
114  ret = av_get_packet(pb, pkt, packet_size);
115  if(ret < 0)
116  return ret;
117 
118  pkt->stream_index = st->index;
119  xa->sent_bytes += packet_size;
120  pkt->duration = 28;
121 
122  return ret;
123 }
124 
126  .p.name = "xa",
127  .p.long_name = NULL_IF_CONFIG_SMALL("Maxis XA"),
128  .priv_data_size = sizeof(MaxisXADemuxContext),
129  .read_probe = xa_probe,
132 };
av_clip
#define av_clip
Definition: common.h:99
AVERROR
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
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:538
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:454
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:321
MaxisXADemuxContext::out_size
uint32_t out_size
Definition: xa.c:40
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:853
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:714
xa_probe
static int xa_probe(const AVProbeData *p)
Definition: xa.c:44
pkt
AVPacket * pkt
Definition: movenc.c:60
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_read_callback.c:42
ff_xa_demuxer
const FFInputFormat ff_xa_demuxer
Definition: xa.c:125
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
channels
channels
Definition: aptx.h:31
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
xa_read_header
static int xa_read_header(AVFormatContext *s)
Definition: xa.c:66
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:550
NULL
#define NULL
Definition: coverity.c:32
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
MaxisXADemuxContext::sent_bytes
uint32_t sent_bytes
Definition: xa.c:41
AVCodecParameters::ch_layout
AVChannelLayout ch_layout
Audio only.
Definition: codec_par.h:180
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:461
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:184
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:730
AVIOContext
Bytestream IO Context.
Definition: avio.h:160
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:94
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
XA00_TAG
#define XA00_TAG
Definition: xa.c:35
AV_CODEC_ID_ADPCM_EA_MAXIS_XA
@ AV_CODEC_ID_ADPCM_EA_MAXIS_XA
Definition: codec_id.h:393
demux.h
av_get_packet
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:91
XAJ0_TAG
#define XAJ0_TAG
Definition: xa.c:37
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:743
MaxisXADemuxContext
Definition: xa.c:39
avformat.h
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
xa_read_packet
static int xa_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: xa.c:100
AVStream::index
int index
stream index in AVFormatContext
Definition: avformat.h:749
XAI0_TAG
#define XAI0_TAG
Definition: xa.c:36
AVPacket::stream_index
int stream_index
Definition: packet.h:522
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:318
read_probe
static int read_probe(const AVProbeData *p)
Definition: cdg.c:30
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:497
FFInputFormat
Definition: demux.h:37
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:97
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base.
Definition: avformat.h:792