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1 | /* |
2 | * SMPTE 302M encoder | |
3 | * Copyright (c) 2010 Google, Inc. | |
4 | * Copyright (c) 2013 Darryl Wallace <wallacdj@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 "avcodec.h" | |
24 | #include "internal.h" | |
25 | #include "mathops.h" | |
26 | #include "put_bits.h" | |
27 | ||
28 | #define AES3_HEADER_LEN 4 | |
29 | ||
30 | typedef struct S302MEncContext { | |
31 | uint8_t framing_index; /* Set for even channels on multiple of 192 samples */ | |
32 | } S302MEncContext; | |
33 | ||
34 | static av_cold int s302m_encode_init(AVCodecContext *avctx) | |
35 | { | |
36 | S302MEncContext *s = avctx->priv_data; | |
37 | ||
38 | if (avctx->channels & 1 || avctx->channels > 8) { | |
39 | av_log(avctx, AV_LOG_ERROR, | |
40 | "Encoding %d channel(s) is not allowed. Only 2, 4, 6 and 8 channels are supported.\n", | |
41 | avctx->channels); | |
42 | return AVERROR(EINVAL); | |
43 | } | |
44 | ||
45 | switch (avctx->sample_fmt) { | |
46 | case AV_SAMPLE_FMT_S16: | |
47 | avctx->bits_per_raw_sample = 16; | |
48 | break; | |
49 | case AV_SAMPLE_FMT_S32: | |
50 | if (avctx->bits_per_raw_sample > 20) { | |
51 | if (avctx->bits_per_raw_sample > 24) | |
52 | av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n"); | |
53 | avctx->bits_per_raw_sample = 24; | |
54 | } else if (!avctx->bits_per_raw_sample) { | |
55 | avctx->bits_per_raw_sample = 24; | |
56 | } else if (avctx->bits_per_raw_sample <= 20) { | |
57 | avctx->bits_per_raw_sample = 20; | |
58 | } | |
59 | } | |
60 | ||
61 | avctx->frame_size = 0; | |
62 | avctx->bit_rate = 48000 * avctx->channels * | |
63 | (avctx->bits_per_raw_sample + 4); | |
64 | s->framing_index = 0; | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
69 | static int s302m_encode2_frame(AVCodecContext *avctx, AVPacket *avpkt, | |
70 | const AVFrame *frame, int *got_packet_ptr) | |
71 | { | |
72 | S302MEncContext *s = avctx->priv_data; | |
73 | const int buf_size = AES3_HEADER_LEN + | |
74 | (frame->nb_samples * | |
75 | avctx->channels * | |
76 | (avctx->bits_per_raw_sample + 4)) / 8; | |
77 | int ret, c, channels; | |
78 | uint8_t *o; | |
79 | PutBitContext pb; | |
80 | ||
81 | if ((ret = ff_alloc_packet2(avctx, avpkt, buf_size)) < 0) | |
82 | return ret; | |
83 | ||
84 | o = avpkt->data; | |
85 | init_put_bits(&pb, o, buf_size * 8); | |
86 | put_bits(&pb, 16, buf_size - AES3_HEADER_LEN); | |
87 | put_bits(&pb, 2, (avctx->channels - 2) >> 1); // number of channels | |
88 | put_bits(&pb, 8, 0); // channel ID | |
89 | put_bits(&pb, 2, (avctx->bits_per_raw_sample - 16) / 4); // bits per samples (0 = 16bit, 1 = 20bit, 2 = 24bit) | |
90 | put_bits(&pb, 4, 0); // alignments | |
91 | flush_put_bits(&pb); | |
92 | o += AES3_HEADER_LEN; | |
93 | ||
94 | if (avctx->bits_per_raw_sample == 24) { | |
95 | const uint32_t *samples = (uint32_t *)frame->data[0]; | |
96 | ||
97 | for (c = 0; c < frame->nb_samples; c++) { | |
98 | uint8_t vucf = s->framing_index == 0 ? 0x10: 0; | |
99 | ||
100 | for (channels = 0; channels < avctx->channels; channels += 2) { | |
101 | o[0] = ff_reverse[(samples[0] & 0x0000FF00) >> 8]; | |
102 | o[1] = ff_reverse[(samples[0] & 0x00FF0000) >> 16]; | |
103 | o[2] = ff_reverse[(samples[0] & 0xFF000000) >> 24]; | |
104 | o[3] = ff_reverse[(samples[1] & 0x00000F00) >> 4] | vucf; | |
105 | o[4] = ff_reverse[(samples[1] & 0x000FF000) >> 12]; | |
106 | o[5] = ff_reverse[(samples[1] & 0x0FF00000) >> 20]; | |
107 | o[6] = ff_reverse[(samples[1] & 0xF0000000) >> 28]; | |
108 | o += 7; | |
109 | samples += 2; | |
110 | } | |
111 | ||
112 | s->framing_index++; | |
113 | if (s->framing_index >= 192) | |
114 | s->framing_index = 0; | |
115 | } | |
116 | } else if (avctx->bits_per_raw_sample == 20) { | |
117 | const uint32_t *samples = (uint32_t *)frame->data[0]; | |
118 | ||
119 | for (c = 0; c < frame->nb_samples; c++) { | |
120 | uint8_t vucf = s->framing_index == 0 ? 0x80: 0; | |
121 | ||
122 | for (channels = 0; channels < avctx->channels; channels += 2) { | |
123 | o[0] = ff_reverse[ (samples[0] & 0x000FF000) >> 12]; | |
124 | o[1] = ff_reverse[ (samples[0] & 0x0FF00000) >> 20]; | |
125 | o[2] = ff_reverse[((samples[0] & 0xF0000000) >> 28) | vucf]; | |
126 | o[3] = ff_reverse[ (samples[1] & 0x000FF000) >> 12]; | |
127 | o[4] = ff_reverse[ (samples[1] & 0x0FF00000) >> 20]; | |
128 | o[5] = ff_reverse[ (samples[1] & 0xF0000000) >> 28]; | |
129 | o += 6; | |
130 | samples += 2; | |
131 | } | |
132 | ||
133 | s->framing_index++; | |
134 | if (s->framing_index >= 192) | |
135 | s->framing_index = 0; | |
136 | } | |
137 | } else if (avctx->bits_per_raw_sample == 16) { | |
138 | const uint16_t *samples = (uint16_t *)frame->data[0]; | |
139 | ||
140 | for (c = 0; c < frame->nb_samples; c++) { | |
141 | uint8_t vucf = s->framing_index == 0 ? 0x10 : 0; | |
142 | ||
143 | for (channels = 0; channels < avctx->channels; channels += 2) { | |
144 | o[0] = ff_reverse[ samples[0] & 0xFF]; | |
145 | o[1] = ff_reverse[(samples[0] & 0xFF00) >> 8]; | |
146 | o[2] = ff_reverse[(samples[1] & 0x0F) << 4] | vucf; | |
147 | o[3] = ff_reverse[(samples[1] & 0x0FF0) >> 4]; | |
148 | o[4] = ff_reverse[(samples[1] & 0xF000) >> 12]; | |
149 | o += 5; | |
150 | samples += 2; | |
151 | ||
152 | } | |
153 | ||
154 | s->framing_index++; | |
155 | if (s->framing_index >= 192) | |
156 | s->framing_index = 0; | |
157 | } | |
158 | } | |
159 | ||
160 | *got_packet_ptr = 1; | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
165 | AVCodec ff_s302m_encoder = { | |
166 | .name = "s302m", | |
167 | .long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"), | |
168 | .type = AVMEDIA_TYPE_AUDIO, | |
169 | .id = AV_CODEC_ID_S302M, | |
170 | .priv_data_size = sizeof(S302MEncContext), | |
171 | .init = s302m_encode_init, | |
172 | .encode2 = s302m_encode2_frame, | |
173 | .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32, | |
174 | AV_SAMPLE_FMT_S16, | |
175 | AV_SAMPLE_FMT_NONE }, | |
176 | .capabilities = CODEC_CAP_VARIABLE_FRAME_SIZE | CODEC_CAP_EXPERIMENTAL, | |
177 | .supported_samplerates = (const int[]) { 48000, 0 }, | |
178 | }; |