3 * Copyright (c) 2010 Google, Inc.
4 * Copyright (c) 2013 Darryl Wallace <wallacdj@gmail.com>
6 * This file is part of FFmpeg.
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.
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.
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
23 #include "libavutil/channel_layout.h"
24 #include "libavutil/reverse.h"
26 #include "codec_internal.h"
31 #define AES3_HEADER_LEN 4
33 typedef struct S302MEncContext {
34 uint8_t framing_index; /* Set for even channels on multiple of 192 samples */
37 static av_cold int s302m_encode_init(AVCodecContext *avctx)
39 S302MEncContext *s = avctx->priv_data;
41 if (avctx->ch_layout.nb_channels & 1 || avctx->ch_layout.nb_channels > 8) {
42 av_log(avctx, AV_LOG_ERROR,
43 "Encoding %d channel(s) is not allowed. Only 2, 4, 6 and 8 channels are supported.\n",
44 avctx->ch_layout.nb_channels);
45 return AVERROR(EINVAL);
48 switch (avctx->sample_fmt) {
49 case AV_SAMPLE_FMT_S16:
50 avctx->bits_per_raw_sample = 16;
52 case AV_SAMPLE_FMT_S32:
53 if (avctx->bits_per_raw_sample > 20) {
54 if (avctx->bits_per_raw_sample > 24)
55 av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n");
56 avctx->bits_per_raw_sample = 24;
57 } else if (!avctx->bits_per_raw_sample) {
58 avctx->bits_per_raw_sample = 24;
59 } else if (avctx->bits_per_raw_sample <= 20) {
60 avctx->bits_per_raw_sample = 20;
64 avctx->frame_size = 0;
65 avctx->bit_rate = 48000 * avctx->ch_layout.nb_channels *
66 (avctx->bits_per_raw_sample + 4);
72 static int s302m_encode2_frame(AVCodecContext *avctx, AVPacket *avpkt,
73 const AVFrame *frame, int *got_packet_ptr)
75 S302MEncContext *s = avctx->priv_data;
76 const int nb_channels = avctx->ch_layout.nb_channels;
77 const int buf_size = AES3_HEADER_LEN +
78 (frame->nb_samples * nb_channels *
79 (avctx->bits_per_raw_sample + 4)) / 8;
84 if (buf_size - AES3_HEADER_LEN > UINT16_MAX) {
85 av_log(avctx, AV_LOG_ERROR, "number of samples in frame too big\n");
86 return AVERROR(EINVAL);
89 if ((ret = ff_get_encode_buffer(avctx, avpkt, buf_size, 0)) < 0)
93 init_put_bits(&pb, o, buf_size);
94 put_bits(&pb, 16, buf_size - AES3_HEADER_LEN);
95 put_bits(&pb, 2, (nb_channels - 2) >> 1); // number of channels
96 put_bits(&pb, 8, 0); // channel ID
97 put_bits(&pb, 2, (avctx->bits_per_raw_sample - 16) / 4); // bits per samples (0 = 16bit, 1 = 20bit, 2 = 24bit)
98 put_bits(&pb, 4, 0); // alignments
100 o += AES3_HEADER_LEN;
102 if (avctx->bits_per_raw_sample == 24) {
103 const uint32_t *samples = (uint32_t *)frame->data[0];
105 for (c = 0; c < frame->nb_samples; c++) {
106 uint8_t vucf = s->framing_index == 0 ? 0x10: 0;
108 for (channels = 0; channels < nb_channels; channels += 2) {
109 o[0] = ff_reverse[(samples[0] & 0x0000FF00) >> 8];
110 o[1] = ff_reverse[(samples[0] & 0x00FF0000) >> 16];
111 o[2] = ff_reverse[(samples[0] & 0xFF000000) >> 24];
112 o[3] = ff_reverse[(samples[1] & 0x00000F00) >> 4] | vucf;
113 o[4] = ff_reverse[(samples[1] & 0x000FF000) >> 12];
114 o[5] = ff_reverse[(samples[1] & 0x0FF00000) >> 20];
115 o[6] = ff_reverse[(samples[1] & 0xF0000000) >> 28];
121 if (s->framing_index >= 192)
122 s->framing_index = 0;
124 } else if (avctx->bits_per_raw_sample == 20) {
125 const uint32_t *samples = (uint32_t *)frame->data[0];
127 for (c = 0; c < frame->nb_samples; c++) {
128 uint8_t vucf = s->framing_index == 0 ? 0x80: 0;
130 for (channels = 0; channels < nb_channels; channels += 2) {
131 o[0] = ff_reverse[ (samples[0] & 0x000FF000) >> 12];
132 o[1] = ff_reverse[ (samples[0] & 0x0FF00000) >> 20];
133 o[2] = ff_reverse[((samples[0] & 0xF0000000) >> 28) | vucf];
134 o[3] = ff_reverse[ (samples[1] & 0x000FF000) >> 12];
135 o[4] = ff_reverse[ (samples[1] & 0x0FF00000) >> 20];
136 o[5] = ff_reverse[ (samples[1] & 0xF0000000) >> 28];
142 if (s->framing_index >= 192)
143 s->framing_index = 0;
145 } else if (avctx->bits_per_raw_sample == 16) {
146 const uint16_t *samples = (uint16_t *)frame->data[0];
148 for (c = 0; c < frame->nb_samples; c++) {
149 uint8_t vucf = s->framing_index == 0 ? 0x10 : 0;
151 for (channels = 0; channels < nb_channels; channels += 2) {
152 o[0] = ff_reverse[ samples[0] & 0xFF];
153 o[1] = ff_reverse[(samples[0] & 0xFF00) >> 8];
154 o[2] = ff_reverse[(samples[1] & 0x0F) << 4] | vucf;
155 o[3] = ff_reverse[(samples[1] & 0x0FF0) >> 4];
156 o[4] = ff_reverse[(samples[1] & 0xF000) >> 12];
163 if (s->framing_index >= 192)
164 s->framing_index = 0;
173 const FFCodec ff_s302m_encoder = {
175 CODEC_LONG_NAME("SMPTE 302M"),
176 .p.type = AVMEDIA_TYPE_AUDIO,
177 .p.id = AV_CODEC_ID_S302M,
178 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_EXPERIMENTAL |
179 AV_CODEC_CAP_VARIABLE_FRAME_SIZE |
180 AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
181 .priv_data_size = sizeof(S302MEncContext),
182 .init = s302m_encode_init,
183 FF_CODEC_ENCODE_CB(s302m_encode2_frame),
184 .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32,
186 AV_SAMPLE_FMT_NONE },
187 .p.supported_samplerates = (const int[]) { 48000, 0 },