path: root/libavcodec/dvaudiodec.c (plain)
blob: 5aa2a95553b8f9c1578caeb3e4c11a33914f1ede

1	/*
2	* Copyright (c) 2012 Laurent Aimar
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	#include "libavutil/intreadwrite.h"
22	#include "avcodec.h"
23	#include "internal.h"
24	#include "dvaudio.h"
25
26	typedef struct DVAudioContext {
27	int block_size;
28	int is_12bit;
29	int is_pal;
30	int16_t shuffle[2000];
31	} DVAudioContext;
32
33	static av_cold int decode_init(AVCodecContext *avctx)
34	{
35	DVAudioContext *s = avctx->priv_data;
36	int i;
37
38	if (avctx->channels != 2) {
39	av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
40	return AVERROR(EINVAL);
41	}
42
43	if (avctx->codec_tag == 0x0215) {
44	s->block_size = 7200;
45	} else if (avctx->codec_tag == 0x0216) {
46	s->block_size = 8640;
47	} else if (avctx->block_align == 7200 ||
48	avctx->block_align == 8640) {
49	s->block_size = avctx->block_align;
50	} else {
51	return AVERROR(EINVAL);
52	}
53
54	s->is_pal = s->block_size == 8640;
55	s->is_12bit = avctx->bits_per_coded_sample == 12;
56	avctx->sample_fmt = AV_SAMPLE_FMT_S16;
57	avctx->channel_layout = AV_CH_LAYOUT_STEREO;
58
59	for (i = 0; i < FF_ARRAY_ELEMS(s->shuffle); i++) {
60	const unsigned a = s->is_pal ? 18 : 15;
61	const unsigned b = 3 * a;
62
63	s->shuffle[i] = 80 * ((21 * (i % 3) + 9 * (i / 3) + ((i / a) % 3)) % b) +
64	(2 + s->is_12bit) * (i / b) + 8;
65	}
66
67	return 0;
68	}
69
70	static inline uint16_t dv_audio_12to16(uint16_t sample)
71	{
72	uint16_t shift, result;
73
74	sample = (sample < 0x800) ? sample : sample | 0xf000;
75	shift = (sample & 0xf00) >> 8;
76
77	if (shift < 0x2 || shift > 0xd) {
78	result = sample;
79	} else if (shift < 0x8) {
80	shift--;
81	result = (sample - (256 * shift)) << shift;
82	} else {
83	shift = 0xe - shift;
84	result = ((sample + ((256 * shift) + 1)) << shift) - 1;
85	}
86
87	return result;
88	}
89
90	static int decode_frame(AVCodecContext *avctx, void *data,
91	int *got_frame_ptr, AVPacket *pkt)
92	{
93	DVAudioContext *s = avctx->priv_data;
94	AVFrame *frame = data;
95	const uint8_t *src = pkt->data;
96	int16_t *dst;
97	int ret, i;
98
99	if (pkt->size < s->block_size)
100	return AVERROR_INVALIDDATA;
101
102	frame->nb_samples = dv_get_audio_sample_count(pkt->data + 244, s->is_pal);
103	if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
104	return ret;
105	dst = (int16_t *)frame->data[0];
106
107	for (i = 0; i < frame->nb_samples; i++) {
108	const uint8_t *v = &src[s->shuffle[i]];
109
110	if (s->is_12bit) {
111	*dst++ = dv_audio_12to16((v[0] << 4) | ((v[2] >> 4) & 0x0f));
112	*dst++ = dv_audio_12to16((v[1] << 4) | ((v[2] >> 0) & 0x0f));
113	} else {
114	*dst++ = AV_RB16(&v[0]);
115	*dst++ = AV_RB16(&v[s->is_pal ? 4320 : 3600]);
116	}
117	}
118
119	*got_frame_ptr = 1;
120
121	return s->block_size;
122	}
123
124	AVCodec ff_dvaudio_decoder = {
125	.name = "dvaudio",
126	.long_name = NULL_IF_CONFIG_SMALL("Ulead DV Audio"),
127	.type = AVMEDIA_TYPE_AUDIO,
128	.id = AV_CODEC_ID_DVAUDIO,
129	.init = decode_init,
130	.decode = decode_frame,
131	.capabilities = AV_CODEC_CAP_DR1,
132	.priv_data_size = sizeof(DVAudioContext),
133	};
134