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1 | /* |
2 | * SMPTE 302M decoder | |
3 | * Copyright (c) 2008 Laurent Aimar <fenrir@videolan.org> | |
4 | * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com> | |
5 | * | |
6 | * This file is part of FFmpeg. | |
7 | * | |
8 | * FFmpeg is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * FFmpeg is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with FFmpeg; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
23 | #include "libavutil/intreadwrite.h" | |
24 | #include "libavutil/log.h" | |
25 | #include "avcodec.h" | |
26 | #include "internal.h" | |
27 | #include "mathops.h" | |
28 | ||
29 | #define AES3_HEADER_LEN 4 | |
30 | ||
31 | static int s302m_parse_frame_header(AVCodecContext *avctx, const uint8_t *buf, | |
32 | int buf_size) | |
33 | { | |
34 | uint32_t h; | |
35 | int frame_size, channels, bits; | |
36 | ||
37 | if (buf_size <= AES3_HEADER_LEN) { | |
38 | av_log(avctx, AV_LOG_ERROR, "frame is too short\n"); | |
39 | return AVERROR_INVALIDDATA; | |
40 | } | |
41 | ||
42 | /* | |
43 | * AES3 header : | |
44 | * size: 16 | |
45 | * number channels 2 | |
46 | * channel_id 8 | |
47 | * bits per samples 2 | |
48 | * alignments 4 | |
49 | */ | |
50 | ||
51 | h = AV_RB32(buf); | |
52 | frame_size = (h >> 16) & 0xffff; | |
53 | channels = ((h >> 14) & 0x0003) * 2 + 2; | |
54 | bits = ((h >> 4) & 0x0003) * 4 + 16; | |
55 | ||
56 | if (AES3_HEADER_LEN + frame_size != buf_size || bits > 24) { | |
57 | av_log(avctx, AV_LOG_ERROR, "frame has invalid header\n"); | |
58 | return AVERROR_INVALIDDATA; | |
59 | } | |
60 | ||
61 | /* Set output properties */ | |
62 | avctx->bits_per_raw_sample = bits; | |
63 | if (bits > 16) | |
64 | avctx->sample_fmt = AV_SAMPLE_FMT_S32; | |
65 | else | |
66 | avctx->sample_fmt = AV_SAMPLE_FMT_S16; | |
67 | ||
68 | avctx->channels = channels; | |
69 | switch(channels) { | |
70 | case 2: | |
71 | avctx->channel_layout = AV_CH_LAYOUT_STEREO; | |
72 | break; | |
73 | case 4: | |
74 | avctx->channel_layout = AV_CH_LAYOUT_QUAD; | |
75 | break; | |
76 | case 6: | |
77 | avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK; | |
78 | break; | |
79 | case 8: | |
80 | avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX; | |
81 | } | |
82 | avctx->sample_rate = 48000; | |
83 | avctx->bit_rate = 48000 * avctx->channels * (avctx->bits_per_raw_sample + 4) + | |
84 | 32 * (48000 / (buf_size * 8 / | |
85 | (avctx->channels * | |
86 | (avctx->bits_per_raw_sample + 4)))); | |
87 | ||
88 | return frame_size; | |
89 | } | |
90 | ||
91 | static int s302m_decode_frame(AVCodecContext *avctx, void *data, | |
92 | int *got_frame_ptr, AVPacket *avpkt) | |
93 | { | |
94 | AVFrame *frame = data; | |
95 | const uint8_t *buf = avpkt->data; | |
96 | int buf_size = avpkt->size; | |
97 | int block_size, ret; | |
98 | ||
99 | int frame_size = s302m_parse_frame_header(avctx, buf, buf_size); | |
100 | if (frame_size < 0) | |
101 | return frame_size; | |
102 | ||
103 | buf_size -= AES3_HEADER_LEN; | |
104 | buf += AES3_HEADER_LEN; | |
105 | ||
106 | /* get output buffer */ | |
107 | block_size = (avctx->bits_per_raw_sample + 4) / 4; | |
108 | frame->nb_samples = 2 * (buf_size / block_size) / avctx->channels; | |
109 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) | |
110 | return ret; | |
111 | ||
112 | buf_size = (frame->nb_samples * avctx->channels / 2) * block_size; | |
113 | ||
114 | if (avctx->bits_per_raw_sample == 24) { | |
115 | uint32_t *o = (uint32_t *)frame->data[0]; | |
116 | for (; buf_size > 6; buf_size -= 7) { | |
117 | *o++ = (ff_reverse[buf[2]] << 24) | | |
118 | (ff_reverse[buf[1]] << 16) | | |
119 | (ff_reverse[buf[0]] << 8); | |
120 | *o++ = (ff_reverse[buf[6] & 0xf0] << 28) | | |
121 | (ff_reverse[buf[5]] << 20) | | |
122 | (ff_reverse[buf[4]] << 12) | | |
123 | (ff_reverse[buf[3] & 0x0f] << 4); | |
124 | buf += 7; | |
125 | } | |
126 | } else if (avctx->bits_per_raw_sample == 20) { | |
127 | uint32_t *o = (uint32_t *)frame->data[0]; | |
128 | for (; buf_size > 5; buf_size -= 6) { | |
129 | *o++ = (ff_reverse[buf[2] & 0xf0] << 28) | | |
130 | (ff_reverse[buf[1]] << 20) | | |
131 | (ff_reverse[buf[0]] << 12); | |
132 | *o++ = (ff_reverse[buf[5] & 0xf0] << 28) | | |
133 | (ff_reverse[buf[4]] << 20) | | |
134 | (ff_reverse[buf[3]] << 12); | |
135 | buf += 6; | |
136 | } | |
137 | } else { | |
138 | uint16_t *o = (uint16_t *)frame->data[0]; | |
139 | for (; buf_size > 4; buf_size -= 5) { | |
140 | *o++ = (ff_reverse[buf[1]] << 8) | | |
141 | ff_reverse[buf[0]]; | |
142 | *o++ = (ff_reverse[buf[4] & 0xf0] << 12) | | |
143 | (ff_reverse[buf[3]] << 4) | | |
144 | (ff_reverse[buf[2]] >> 4); | |
145 | buf += 5; | |
146 | } | |
147 | } | |
148 | ||
149 | *got_frame_ptr = 1; | |
150 | ||
151 | return avpkt->size; | |
152 | } | |
153 | ||
154 | AVCodec ff_s302m_decoder = { | |
155 | .name = "s302m", | |
156 | .long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"), | |
157 | .type = AVMEDIA_TYPE_AUDIO, | |
158 | .id = AV_CODEC_ID_S302M, | |
159 | .decode = s302m_decode_frame, | |
160 | .capabilities = CODEC_CAP_DR1, | |
161 | }; |