westwood: split the AUD and VQA demuxers into separate files.
[libav.git] / libavformat / westwood_aud.c
1 /*
2 * Westwood Studios AUD Format Demuxer
3 * Copyright (c) 2003 The ffmpeg Project
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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
36 #include "libavutil/intreadwrite.h"
37 #include "avformat.h"
38 #include "internal.h"
39
40 #define AUD_HEADER_SIZE 12
41 #define AUD_CHUNK_PREAMBLE_SIZE 8
42 #define AUD_CHUNK_SIGNATURE 0x0000DEAF
43
44 typedef struct WsAudDemuxContext {
45 int audio_samplerate;
46 int audio_channels;
47 int audio_bits;
48 enum CodecID audio_type;
49 int audio_stream_index;
50 int64_t audio_frame_counter;
51 } WsAudDemuxContext;
52
53 static int wsaud_probe(AVProbeData *p)
54 {
55 int field;
56
57 /* Probabilistic content detection strategy: There is no file signature
58 * so perform sanity checks on various header parameters:
59 * 8000 <= sample rate (16 bits) <= 48000 ==> 40001 acceptable numbers
60 * flags <= 0x03 (2 LSBs are used) ==> 4 acceptable numbers
61 * compression type (8 bits) = 1 or 99 ==> 2 acceptable numbers
62 * first audio chunk signature (32 bits) ==> 1 acceptable number
63 * The number space contains 2^64 numbers. There are 40001 * 4 * 2 * 1 =
64 * 320008 acceptable number combinations.
65 */
66
67 if (p->buf_size < AUD_HEADER_SIZE + AUD_CHUNK_PREAMBLE_SIZE)
68 return 0;
69
70 /* check sample rate */
71 field = AV_RL16(&p->buf[0]);
72 if ((field < 8000) || (field > 48000))
73 return 0;
74
75 /* enforce the rule that the top 6 bits of this flags field are reserved (0);
76 * this might not be true, but enforce it until deemed unnecessary */
77 if (p->buf[10] & 0xFC)
78 return 0;
79
80 /* note: only check for WS IMA (type 99) right now since there is no
81 * support for type 1 */
82 if (p->buf[11] != 99)
83 return 0;
84
85 /* read ahead to the first audio chunk and validate the first header signature */
86 if (AV_RL32(&p->buf[16]) != AUD_CHUNK_SIGNATURE)
87 return 0;
88
89 /* return 1/2 certainty since this file check is a little sketchy */
90 return AVPROBE_SCORE_MAX / 2;
91 }
92
93 static int wsaud_read_header(AVFormatContext *s,
94 AVFormatParameters *ap)
95 {
96 WsAudDemuxContext *wsaud = s->priv_data;
97 AVIOContext *pb = s->pb;
98 AVStream *st;
99 unsigned char header[AUD_HEADER_SIZE];
100
101 if (avio_read(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE)
102 return AVERROR(EIO);
103 wsaud->audio_samplerate = AV_RL16(&header[0]);
104 if (header[11] == 99)
105 wsaud->audio_type = CODEC_ID_ADPCM_IMA_WS;
106 else
107 return AVERROR_INVALIDDATA;
108
109 /* flag 0 indicates stereo */
110 wsaud->audio_channels = (header[10] & 0x1) + 1;
111 /* flag 1 indicates 16 bit audio */
112 wsaud->audio_bits = (((header[10] & 0x2) >> 1) + 1) * 8;
113
114 /* initialize the audio decoder stream */
115 st = avformat_new_stream(s, NULL);
116 if (!st)
117 return AVERROR(ENOMEM);
118 avpriv_set_pts_info(st, 33, 1, wsaud->audio_samplerate);
119 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
120 st->codec->codec_id = wsaud->audio_type;
121 st->codec->codec_tag = 0; /* no tag */
122 st->codec->channels = wsaud->audio_channels;
123 st->codec->sample_rate = wsaud->audio_samplerate;
124 st->codec->bits_per_coded_sample = wsaud->audio_bits;
125 st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
126 st->codec->bits_per_coded_sample / 4;
127 st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;
128
129 wsaud->audio_stream_index = st->index;
130 wsaud->audio_frame_counter = 0;
131
132 return 0;
133 }
134
135 static int wsaud_read_packet(AVFormatContext *s,
136 AVPacket *pkt)
137 {
138 WsAudDemuxContext *wsaud = s->priv_data;
139 AVIOContext *pb = s->pb;
140 unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE];
141 unsigned int chunk_size;
142 int ret = 0;
143
144 if (avio_read(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) !=
145 AUD_CHUNK_PREAMBLE_SIZE)
146 return AVERROR(EIO);
147
148 /* validate the chunk */
149 if (AV_RL32(&preamble[4]) != AUD_CHUNK_SIGNATURE)
150 return AVERROR_INVALIDDATA;
151
152 chunk_size = AV_RL16(&preamble[0]);
153 ret= av_get_packet(pb, pkt, chunk_size);
154 if (ret != chunk_size)
155 return AVERROR(EIO);
156 pkt->stream_index = wsaud->audio_stream_index;
157 pkt->pts = wsaud->audio_frame_counter;
158 pkt->pts /= wsaud->audio_samplerate;
159
160 /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
161 wsaud->audio_frame_counter += (chunk_size * 2) / wsaud->audio_channels;
162
163 return ret;
164 }
165
166 AVInputFormat ff_wsaud_demuxer = {
167 .name = "wsaud",
168 .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio format"),
169 .priv_data_size = sizeof(WsAudDemuxContext),
170 .read_probe = wsaud_probe,
171 .read_header = wsaud_read_header,
172 .read_packet = wsaud_read_packet,
173 };