aud: fix time stamp calculation for ADPCM IMA WS
[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_stream_index;
46 } WsAudDemuxContext;
47
48 static int wsaud_probe(AVProbeData *p)
49 {
50 int field;
51
52 /* Probabilistic content detection strategy: There is no file signature
53 * so perform sanity checks on various header parameters:
54 * 8000 <= sample rate (16 bits) <= 48000 ==> 40001 acceptable numbers
55 * flags <= 0x03 (2 LSBs are used) ==> 4 acceptable numbers
56 * compression type (8 bits) = 1 or 99 ==> 2 acceptable numbers
57 * first audio chunk signature (32 bits) ==> 1 acceptable number
58 * The number space contains 2^64 numbers. There are 40001 * 4 * 2 * 1 =
59 * 320008 acceptable number combinations.
60 */
61
62 if (p->buf_size < AUD_HEADER_SIZE + AUD_CHUNK_PREAMBLE_SIZE)
63 return 0;
64
65 /* check sample rate */
66 field = AV_RL16(&p->buf[0]);
67 if ((field < 8000) || (field > 48000))
68 return 0;
69
70 /* enforce the rule that the top 6 bits of this flags field are reserved (0);
71 * this might not be true, but enforce it until deemed unnecessary */
72 if (p->buf[10] & 0xFC)
73 return 0;
74
75 /* note: only check for WS IMA (type 99) right now since there is no
76 * support for type 1 */
77 if (p->buf[11] != 99 && p->buf[11] != 1)
78 return 0;
79
80 /* read ahead to the first audio chunk and validate the first header signature */
81 if (AV_RL32(&p->buf[16]) != AUD_CHUNK_SIGNATURE)
82 return 0;
83
84 /* return 1/2 certainty since this file check is a little sketchy */
85 return AVPROBE_SCORE_MAX / 2;
86 }
87
88 static int wsaud_read_header(AVFormatContext *s,
89 AVFormatParameters *ap)
90 {
91 WsAudDemuxContext *wsaud = s->priv_data;
92 AVIOContext *pb = s->pb;
93 AVStream *st;
94 unsigned char header[AUD_HEADER_SIZE];
95 int sample_rate, channels, codec;
96
97 if (avio_read(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE)
98 return AVERROR(EIO);
99
100 sample_rate = AV_RL16(&header[0]);
101 channels = (header[10] & 0x1) + 1;
102 codec = header[11];
103
104 /* initialize the audio decoder stream */
105 st = avformat_new_stream(s, NULL);
106 if (!st)
107 return AVERROR(ENOMEM);
108
109 switch (codec) {
110 case 1:
111 if (channels != 1) {
112 av_log_ask_for_sample(s, "Stereo WS-SND1 is not supported.\n");
113 return AVERROR_PATCHWELCOME;
114 }
115 st->codec->codec_id = CODEC_ID_WESTWOOD_SND1;
116 break;
117 case 99:
118 st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS;
119 st->codec->bits_per_coded_sample = 4;
120 st->codec->bit_rate = channels * sample_rate * 4;
121 break;
122 default:
123 av_log_ask_for_sample(s, "Unknown codec: %d\n", codec);
124 return AVERROR_PATCHWELCOME;
125 }
126 avpriv_set_pts_info(st, 64, 1, sample_rate);
127 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
128 st->codec->channels = channels;
129 st->codec->sample_rate = sample_rate;
130
131 wsaud->audio_stream_index = st->index;
132
133 return 0;
134 }
135
136 static int wsaud_read_packet(AVFormatContext *s,
137 AVPacket *pkt)
138 {
139 WsAudDemuxContext *wsaud = s->priv_data;
140 AVIOContext *pb = s->pb;
141 unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE];
142 unsigned int chunk_size;
143 int ret = 0;
144 AVStream *st = s->streams[wsaud->audio_stream_index];
145
146 if (avio_read(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) !=
147 AUD_CHUNK_PREAMBLE_SIZE)
148 return AVERROR(EIO);
149
150 /* validate the chunk */
151 if (AV_RL32(&preamble[4]) != AUD_CHUNK_SIGNATURE)
152 return AVERROR_INVALIDDATA;
153
154 chunk_size = AV_RL16(&preamble[0]);
155
156 if (st->codec->codec_id == CODEC_ID_WESTWOOD_SND1) {
157 /* For Westwood SND1 audio we need to add the output size and input
158 size to the start of the packet to match what is in VQA.
159 Specifically, this is needed to signal when a packet should be
160 decoding as raw 8-bit pcm or variable-size ADPCM. */
161 int out_size = AV_RL16(&preamble[2]);
162 if ((ret = av_new_packet(pkt, chunk_size + 4)))
163 return ret;
164 if ((ret = avio_read(pb, &pkt->data[4], chunk_size)) != chunk_size)
165 return ret < 0 ? ret : AVERROR(EIO);
166 AV_WL16(&pkt->data[0], out_size);
167 AV_WL16(&pkt->data[2], chunk_size);
168
169 pkt->duration = out_size;
170 } else {
171 ret = av_get_packet(pb, pkt, chunk_size);
172 if (ret != chunk_size)
173 return AVERROR(EIO);
174
175 /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
176 pkt->duration = (chunk_size * 2) / st->codec->channels;
177 }
178 pkt->stream_index = st->index;
179
180 return ret;
181 }
182
183 AVInputFormat ff_wsaud_demuxer = {
184 .name = "wsaud",
185 .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio format"),
186 .priv_data_size = sizeof(WsAudDemuxContext),
187 .read_probe = wsaud_probe,
188 .read_header = wsaud_read_header,
189 .read_packet = wsaud_read_packet,
190 };