blob: 9c2d35cb8a30456bb8c911cfcc1c7489549241c1
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 | |
36 | #include "libavutil/channel_layout.h" |
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 | |
59 | if (p->buf_size < AUD_HEADER_SIZE + AUD_CHUNK_PREAMBLE_SIZE) |
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 */ |
80 | return AVPROBE_SCORE_EXTENSION; |
81 | } |
82 | |
83 | static int wsaud_read_header(AVFormatContext *s) |
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 | } |
108 | st->codecpar->codec_id = AV_CODEC_ID_WESTWOOD_SND1; |
109 | break; |
110 | case 99: |
111 | st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_WS; |
112 | st->codecpar->bits_per_coded_sample = 4; |
113 | st->codecpar->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); |
120 | st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; |
121 | st->codecpar->channels = channels; |
122 | st->codecpar->channel_layout = channels == 1 ? AV_CH_LAYOUT_MONO : |
123 | AV_CH_LAYOUT_STEREO; |
124 | st->codecpar->sample_rate = sample_rate; |
125 | |
126 | return 0; |
127 | } |
128 | |
129 | static int wsaud_read_packet(AVFormatContext *s, |
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) != |
139 | 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 | |
148 | if (st->codecpar->codec_id == AV_CODEC_ID_WESTWOOD_SND1) { |
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 | if (st->codecpar->channels <= 0) { |
168 | av_log(s, AV_LOG_ERROR, "invalid number of channels %d\n", |
169 | st->codecpar->channels); |
170 | return AVERROR_INVALIDDATA; |
171 | } |
172 | |
173 | /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */ |
174 | pkt->duration = (chunk_size * 2) / st->codecpar->channels; |
175 | } |
176 | pkt->stream_index = st->index; |
177 | |
178 | return ret; |
179 | } |
180 | |
181 | AVInputFormat ff_wsaud_demuxer = { |
182 | .name = "wsaud", |
183 | .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio"), |
184 | .read_probe = wsaud_probe, |
185 | .read_header = wsaud_read_header, |
186 | .read_packet = wsaud_read_packet, |
187 | }; |
188 |