path: root/libavformat/redspark.c (plain)
blob: c247046584e0770e2c64bd98af4e96d6d8a5035d

1	/*
2	* RedSpark demuxer
3	* Copyright (c) 2013 James Almer
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	#include "libavcodec/bytestream.h"
23	#include "libavutil/intreadwrite.h"
24	#include "avformat.h"
25	#include "avio.h"
26	#include "internal.h"
27
28	#define HEADER_SIZE 4096
29	#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
30
31	typedef struct RedSparkContext {
32	int samples_count;
33	} RedSparkContext;
34
35	static int redspark_probe(AVProbeData *p)
36	{
37	uint32_t key, data;
38	uint8_t header[8];
39
40	/* Decrypt first 8 bytes of the header */
41	data = AV_RB32(p->buf);
42	key = data ^ 0x52656453;
43	data ^= key;
44	AV_WB32(header, data);
45	key = rol(key, 11);
46
47	key += rol(key, 3);
48	data = AV_RB32(p->buf + 4) ^ key;
49	AV_WB32(header + 4, data);
50
51	if (AV_RB64(header) == AV_RB64("RedSpark"))
52	return AVPROBE_SCORE_MAX;
53
54	return 0;
55	}
56
57	static int redspark_read_header(AVFormatContext *s)
58	{
59	AVIOContext *pb = s->pb;
60	RedSparkContext *redspark = s->priv_data;
61	AVCodecParameters *par;
62	GetByteContext gbc;
63	int i, coef_off, ret = 0;
64	uint32_t key, data;
65	uint8_t header[HEADER_SIZE];
66	AVStream *st;
67
68	st = avformat_new_stream(s, NULL);
69	if (!st)
70	return AVERROR(ENOMEM);
71	par = st->codecpar;
72
73	/* Decrypt header */
74	data = avio_rb32(pb);
75	key = data ^ 0x52656453;
76	data ^= key;
77	AV_WB32(header, data);
78	key = rol(key, 11);
79
80	for (i = 4; i < HEADER_SIZE; i += 4) {
81	key += rol(key, 3);
82	data = avio_rb32(pb) ^ key;
83	AV_WB32(header + i, data);
84	}
85
86	par->codec_id = AV_CODEC_ID_ADPCM_THP;
87	par->codec_type = AVMEDIA_TYPE_AUDIO;
88
89	bytestream2_init(&gbc, header, HEADER_SIZE);
90	bytestream2_seek(&gbc, 0x3c, SEEK_SET);
91	par->sample_rate = bytestream2_get_be32u(&gbc);
92	if (par->sample_rate <= 0 || par->sample_rate > 96000) {
93	av_log(s, AV_LOG_ERROR, "Invalid sample rate: %d\n", par->sample_rate);
94	return AVERROR_INVALIDDATA;
95	}
96
97	st->duration = bytestream2_get_be32u(&gbc) * 14;
98	redspark->samples_count = 0;
99	bytestream2_skipu(&gbc, 10);
100	par->channels = bytestream2_get_byteu(&gbc);
101	if (!par->channels) {
102	return AVERROR_INVALIDDATA;
103	}
104
105	coef_off = 0x54 + par->channels * 8;
106	if (bytestream2_get_byteu(&gbc)) // Loop flag
107	coef_off += 16;
108
109	if (coef_off + par->channels * (32 + 14) > HEADER_SIZE) {
110	return AVERROR_INVALIDDATA;
111	}
112
113	if (ff_alloc_extradata(par, 32 * par->channels)) {
114	return AVERROR_INVALIDDATA;
115	}
116
117	/* Get the ADPCM table */
118	bytestream2_seek(&gbc, coef_off, SEEK_SET);
119	for (i = 0; i < par->channels; i++) {
120	if (bytestream2_get_bufferu(&gbc, par->extradata + i * 32, 32) != 32) {
121	return AVERROR_INVALIDDATA;
122	}
123	bytestream2_skipu(&gbc, 14);
124	}
125
126	avpriv_set_pts_info(st, 64, 1, par->sample_rate);
127
128	return ret;
129	}
130
131	static int redspark_read_packet(AVFormatContext *s, AVPacket *pkt)
132	{
133	AVCodecParameters *par = s->streams[0]->codecpar;
134	RedSparkContext *redspark = s->priv_data;
135	uint32_t size = 8 * par->channels;
136	int ret;
137
138	if (avio_feof(s->pb) || redspark->samples_count == s->streams[0]->duration)
139	return AVERROR_EOF;
140
141	ret = av_get_packet(s->pb, pkt, size);
142	if (ret != size) {
143	av_packet_unref(pkt);
144	return AVERROR(EIO);
145	}
146
147	pkt->duration = 14;
148	redspark->samples_count += pkt->duration;
149	pkt->stream_index = 0;
150
151	return ret;
152	}
153
154	AVInputFormat ff_redspark_demuxer = {
155	.name = "redspark",
156	.long_name = NULL_IF_CONFIG_SMALL("RedSpark"),
157	.priv_data_size = sizeof(RedSparkContext),
158	.read_probe = redspark_probe,
159	.read_header = redspark_read_header,
160	.read_packet = redspark_read_packet,
161	.extensions = "rsd",
162	};
163