1 /*
2 * Copyright (c) 2021 Aidan Richmond
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 /**
22 * @file
23 * Westwood Studios AUD file muxer
24 * by Aidan Richmond (aidan.is@hotmail.co.uk)
25 *
26 * This muxer supports IMA ADPCM packed in westwoods format.
27 *
28 * @see http://xhp.xwis.net/documents/aud3.txt
29 */
30
31 #include "avformat.h"
32 #include "avio_internal.h"
33 #include "internal.h"
34 #include <stdint.h>
35
36 #define AUD_CHUNK_SIGNATURE 0x0000DEAF
37
38 typedef struct AUDMuxContext {
39 int uncomp_size;
40 int size;
41 } AUDMuxContext;
42
wsaud_write_init(AVFormatContext * ctx)43 static int wsaud_write_init(AVFormatContext *ctx)
44 {
45 AVStream *st = ctx->streams[0];
46 AVIOContext *pb = ctx->pb;
47
48 /* Stream must be seekable to correctly write the file. */
49 if (!(pb->seekable & AVIO_SEEKABLE_NORMAL)) {
50 av_log(ctx->streams[0], AV_LOG_ERROR, "Cannot write Westwood AUD to"
51 " non-seekable stream.\n");
52 return AVERROR(EINVAL);
53 }
54
55 if (st->codecpar->codec_id != AV_CODEC_ID_ADPCM_IMA_WS) {
56 av_log(st, AV_LOG_ERROR, "%s codec not supported for Westwood AUD.\n",
57 avcodec_get_name(st->codecpar->codec_id));
58 return AVERROR(EINVAL);
59 }
60
61 if (ctx->nb_streams != 1) {
62 av_log(st, AV_LOG_ERROR, "AUD files have exactly one stream\n");
63 return AVERROR(EINVAL);
64 }
65
66 return 0;
67 }
68
wsaud_write_header(AVFormatContext * ctx)69 static int wsaud_write_header(AVFormatContext *ctx)
70 {
71 AVStream *st = ctx->streams[0];
72 AVIOContext *pb = ctx->pb;
73 AUDMuxContext *a = ctx->priv_data;
74 unsigned char flags = 0;
75
76 a->uncomp_size = 0;
77 a->size = 0;
78
79 /* Flag if we have stereo data. */
80 if (st->codecpar->ch_layout.nb_channels == 2)
81 flags |= 1;
82
83 /* This flags that the file contains 16 bit samples rather than 8 bit
84 since the encoder only encodes 16 bit samples this should be set. */
85 if (av_get_bits_per_sample(st->codecpar->codec_id) == 4)
86 flags |= 2;
87
88 avio_wl16(pb, st->codecpar->sample_rate);
89 /* We don't know the file size yet, so just zero 8 bytes */
90 ffio_fill(pb, 0, 8);
91 avio_w8(pb, flags);
92 /* 99 indicates the ADPCM format. Other formats not supported. */
93 avio_w8(pb, 99);
94
95 return 0;
96 }
97
wsaud_write_packet(AVFormatContext * ctx,AVPacket * pkt)98 static int wsaud_write_packet(AVFormatContext *ctx, AVPacket *pkt)
99 {
100 AVIOContext *pb = ctx->pb;
101 AUDMuxContext *a = ctx->priv_data;
102
103 if (pkt->size > UINT16_MAX / 4)
104 return AVERROR_INVALIDDATA;
105 /* Assumes ADPCM since this muxer doesn't support SND1 or PCM format. */
106 avio_wl16(pb, pkt->size);
107 avio_wl16(pb, pkt->size * 4);
108 avio_wl32(pb, AUD_CHUNK_SIGNATURE);
109 avio_write(pb, pkt->data, pkt->size);
110 a->size += pkt->size + 8;
111 a->uncomp_size += pkt->size * 4;
112
113 return 0;
114 }
115
wsaud_write_trailer(AVFormatContext * ctx)116 static int wsaud_write_trailer(AVFormatContext *ctx)
117 {
118 AVIOContext *pb = ctx->pb;
119 AUDMuxContext *a = ctx->priv_data;
120
121 avio_seek(pb, 2, SEEK_SET);
122 avio_wl32(pb, a->size);
123 avio_wl32(pb, a->uncomp_size);
124
125 return 0;
126 }
127
128 const AVOutputFormat ff_wsaud_muxer = {
129 .name = "wsaud",
130 .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio"),
131 .extensions = "aud",
132 .priv_data_size = sizeof(AUDMuxContext),
133 .audio_codec = AV_CODEC_ID_ADPCM_IMA_WS,
134 .video_codec = AV_CODEC_ID_NONE,
135 .init = wsaud_write_init,
136 .write_header = wsaud_write_header,
137 .write_packet = wsaud_write_packet,
138 .write_trailer = wsaud_write_trailer,
139 };
140