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westwood_aud.c
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1 /*
2  * Westwood Studios AUD Format Demuxer
3  * Copyright (c) 2003 The FFmpeg Project
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  * Westwood Studios AUD file demuxer
25  * by Mike Melanson (melanson@pcisys.net)
26  * for more information on the Westwood file formats, visit:
27  * http://www.pcisys.net/~melanson/codecs/
28  * http://www.geocities.com/SiliconValley/8682/aud3.txt
29  *
30  * Implementation note: There is no definite file signature for AUD files.
31  * The demuxer uses a probabilistic strategy for content detection. This
32  * entails performing sanity checks on certain header values in order to
33  * qualify a file. Refer to wsaud_probe() for the precise parameters.
34  */
35 
37 #include "libavutil/intreadwrite.h"
38 #include "avformat.h"
39 #include "internal.h"
40 
41 #define AUD_HEADER_SIZE 12
42 #define AUD_CHUNK_PREAMBLE_SIZE 8
43 #define AUD_CHUNK_SIGNATURE 0x0000DEAF
44 
45 static int wsaud_probe(AVProbeData *p)
46 {
47  int field;
48 
49  /* Probabilistic content detection strategy: There is no file signature
50  * so perform sanity checks on various header parameters:
51  * 8000 <= sample rate (16 bits) <= 48000 ==> 40001 acceptable numbers
52  * flags <= 0x03 (2 LSBs are used) ==> 4 acceptable numbers
53  * compression type (8 bits) = 1 or 99 ==> 2 acceptable numbers
54  * first audio chunk signature (32 bits) ==> 1 acceptable number
55  * The number space contains 2^64 numbers. There are 40001 * 4 * 2 * 1 =
56  * 320008 acceptable number combinations.
57  */
58 
60  return 0;
61 
62  /* check sample rate */
63  field = AV_RL16(&p->buf[0]);
64  if ((field < 8000) || (field > 48000))
65  return 0;
66 
67  /* enforce the rule that the top 6 bits of this flags field are reserved (0);
68  * this might not be true, but enforce it until deemed unnecessary */
69  if (p->buf[10] & 0xFC)
70  return 0;
71 
72  if (p->buf[11] != 99 && p->buf[11] != 1)
73  return 0;
74 
75  /* read ahead to the first audio chunk and validate the first header signature */
76  if (AV_RL32(&p->buf[16]) != AUD_CHUNK_SIGNATURE)
77  return 0;
78 
79  /* return 1/2 certainty since this file check is a little sketchy */
81 }
82 
84 {
85  AVIOContext *pb = s->pb;
86  AVStream *st;
87  unsigned char header[AUD_HEADER_SIZE];
88  int sample_rate, channels, codec;
89 
90  if (avio_read(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE)
91  return AVERROR(EIO);
92 
93  sample_rate = AV_RL16(&header[0]);
94  channels = (header[10] & 0x1) + 1;
95  codec = header[11];
96 
97  /* initialize the audio decoder stream */
98  st = avformat_new_stream(s, NULL);
99  if (!st)
100  return AVERROR(ENOMEM);
101 
102  switch (codec) {
103  case 1:
104  if (channels != 1) {
105  avpriv_request_sample(s, "Stereo WS-SND1");
106  return AVERROR_PATCHWELCOME;
107  }
109  break;
110  case 99:
112  st->codec->bits_per_coded_sample = 4;
113  st->codec->bit_rate = channels * sample_rate * 4;
114  break;
115  default:
116  avpriv_request_sample(s, "Unknown codec: %d", codec);
117  return AVERROR_PATCHWELCOME;
118  }
119  avpriv_set_pts_info(st, 64, 1, sample_rate);
121  st->codec->channels = channels;
122  st->codec->channel_layout = channels == 1 ? AV_CH_LAYOUT_MONO :
125 
126  return 0;
127 }
128 
130  AVPacket *pkt)
131 {
132  AVIOContext *pb = s->pb;
133  unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE];
134  unsigned int chunk_size;
135  int ret = 0;
136  AVStream *st = s->streams[0];
137 
138  if (avio_read(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) !=
140  return AVERROR(EIO);
141 
142  /* validate the chunk */
143  if (AV_RL32(&preamble[4]) != AUD_CHUNK_SIGNATURE)
144  return AVERROR_INVALIDDATA;
145 
146  chunk_size = AV_RL16(&preamble[0]);
147 
149  /* For Westwood SND1 audio we need to add the output size and input
150  size to the start of the packet to match what is in VQA.
151  Specifically, this is needed to signal when a packet should be
152  decoding as raw 8-bit pcm or variable-size ADPCM. */
153  int out_size = AV_RL16(&preamble[2]);
154  if ((ret = av_new_packet(pkt, chunk_size + 4)) < 0)
155  return ret;
156  if ((ret = avio_read(pb, &pkt->data[4], chunk_size)) != chunk_size)
157  return ret < 0 ? ret : AVERROR(EIO);
158  AV_WL16(&pkt->data[0], out_size);
159  AV_WL16(&pkt->data[2], chunk_size);
160 
161  pkt->duration = out_size;
162  } else {
163  ret = av_get_packet(pb, pkt, chunk_size);
164  if (ret != chunk_size)
165  return AVERROR(EIO);
166 
167  /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
168  pkt->duration = (chunk_size * 2) / st->codec->channels;
169  }
170  pkt->stream_index = st->index;
171 
172  return ret;
173 }
174 
176  .name = "wsaud",
177  .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio"),
178  .read_probe = wsaud_probe,
179  .read_header = wsaud_read_header,
180  .read_packet = wsaud_read_packet,
181 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
Bytestream IO Context.
Definition: avio.h:111
#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:4006
int index
stream index in AVFormatContext
Definition: avformat.h:843
static AVPacket pkt
#define AV_CH_LAYOUT_STEREO
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:85
#define AUD_CHUNK_PREAMBLE_SIZE
Definition: westwood_aud.c:42
Format I/O context.
Definition: avformat.h:1272
static int wsaud_read_header(AVFormatContext *s)
Definition: westwood_aud.c:83
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:3672
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1340
uint8_t * data
Definition: avcodec.h:1173
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:241
static const uint8_t header[24]
Definition: sdr2.c:67
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:2748
int duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1191
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:538
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:83
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:175
#define AUD_CHUNK_SIGNATURE
Definition: westwood_aud.c:43
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2073
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:861
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:451
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
int bit_rate
the average bitrate
Definition: avcodec.h:1316
audio channel layout utility functions
ret
Definition: avfilter.c:974
#define AUD_HEADER_SIZE
Definition: westwood_aud.c:41
Stream structure.
Definition: avformat.h:842
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
sample_rate
enum AVMediaType codec_type
Definition: avcodec.h:1260
enum AVCodecID codec_id
Definition: avcodec.h:1269
AVInputFormat ff_wsaud_demuxer
Definition: westwood_aud.c:175
int sample_rate
samples per second
Definition: avcodec.h:2012
AVIOContext * pb
I/O context.
Definition: avformat.h:1314
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:458
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
Main libavformat public API header.
static int wsaud_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: westwood_aud.c:129
#define AV_WL16(p, v)
Definition: intreadwrite.h:412
static int wsaud_probe(AVProbeData *p)
Definition: westwood_aud.c:45
int channels
number of audio channels
Definition: avcodec.h:2013
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:628
int stream_index
Definition: avcodec.h:1175
#define AV_CH_LAYOUT_MONO
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:85
This structure stores compressed data.
Definition: avcodec.h:1150