1 /*
2 * LPCM codecs for PCM formats found in Video DVD streams
3 * Copyright (c) 2018 Paul B Mahol
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 "libavutil/channel_layout.h"
23 #include "avcodec.h"
24 #include "bytestream.h"
25 #include "codec_internal.h"
26 #include "encode.h"
27 #include "internal.h"
28
29 typedef struct PCMDVDContext {
30 uint8_t header[3]; // Header added to every frame
31 int block_size; // Size of a block of samples in bytes
32 int samples_per_block; // Number of samples per channel per block
33 int groups_per_block; // Number of 20/24-bit sample groups per block
34 } PCMDVDContext;
35
pcm_dvd_encode_init(AVCodecContext *avctx)36 static av_cold int pcm_dvd_encode_init(AVCodecContext *avctx)
37 {
38 PCMDVDContext *s = avctx->priv_data;
39 int quant, freq, frame_size;
40
41 switch (avctx->sample_rate) {
42 case 48000:
43 freq = 0;
44 break;
45 case 96000:
46 freq = 1;
47 break;
48 default:
49 av_assert1(0);
50 }
51
52 switch (avctx->sample_fmt) {
53 case AV_SAMPLE_FMT_S16:
54 avctx->bits_per_coded_sample = 16;
55 quant = 0;
56 break;
57 case AV_SAMPLE_FMT_S32:
58 avctx->bits_per_coded_sample = 24;
59 quant = 2;
60 break;
61 default:
62 av_assert1(0);
63 }
64
65 avctx->bits_per_coded_sample = 16 + quant * 4;
66 avctx->block_align = avctx->ch_layout.nb_channels * avctx->bits_per_coded_sample / 8;
67 avctx->bit_rate = avctx->block_align * 8LL * avctx->sample_rate;
68 if (avctx->bit_rate > 9800000) {
69 av_log(avctx, AV_LOG_ERROR, "Too big bitrate: reduce sample rate, bitdepth or channels.\n");
70 return AVERROR(EINVAL);
71 }
72
73 if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
74 s->samples_per_block = 1;
75 s->block_size = avctx->ch_layout.nb_channels * 2;
76 frame_size = 2008 / s->block_size;
77 } else {
78 switch (avctx->ch_layout.nb_channels) {
79 case 1:
80 case 2:
81 case 4:
82 /* one group has all the samples needed */
83 s->block_size = 4 * avctx->bits_per_coded_sample / 8;
84 s->samples_per_block = 4 / avctx->ch_layout.nb_channels;
85 s->groups_per_block = 1;
86 break;
87 case 8:
88 /* two groups have all the samples needed */
89 s->block_size = 8 * avctx->bits_per_coded_sample / 8;
90 s->samples_per_block = 1;
91 s->groups_per_block = 2;
92 break;
93 default:
94 /* need avctx->ch_layout.nb_channels groups */
95 s->block_size = 4 * avctx->ch_layout.nb_channels *
96 avctx->bits_per_coded_sample / 8;
97 s->samples_per_block = 4;
98 s->groups_per_block = avctx->ch_layout.nb_channels;
99 break;
100 }
101
102 frame_size = FFALIGN(2008 / s->block_size, s->samples_per_block);
103 }
104
105 s->header[0] = 0x0c;
106 s->header[1] = (quant << 6) | (freq << 4) | (avctx->ch_layout.nb_channels - 1);
107 s->header[2] = 0x80;
108
109 if (!avctx->frame_size)
110 avctx->frame_size = frame_size;
111
112 return 0;
113 }
114
pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)115 static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
116 const AVFrame *frame, int *got_packet_ptr)
117 {
118 PCMDVDContext *s = avctx->priv_data;
119 int samples = frame->nb_samples * avctx->ch_layout.nb_channels;
120 int64_t pkt_size = (int64_t)(frame->nb_samples / s->samples_per_block) * s->block_size + 3;
121 int blocks = (pkt_size - 3) / s->block_size;
122 const int16_t *src16;
123 const int32_t *src32;
124 PutByteContext pb;
125 int ret;
126
127 if ((ret = ff_get_encode_buffer(avctx, avpkt, pkt_size, 0)) < 0)
128 return ret;
129
130 memcpy(avpkt->data, s->header, 3);
131
132 src16 = (const int16_t *)frame->data[0];
133 src32 = (const int32_t *)frame->data[0];
134
135 bytestream2_init_writer(&pb, avpkt->data + 3, avpkt->size - 3);
136
137 switch (avctx->sample_fmt) {
138 case AV_SAMPLE_FMT_S16:
139 do {
140 bytestream2_put_be16(&pb, *src16++);
141 } while (--samples);
142 break;
143 case AV_SAMPLE_FMT_S32:
144 if (avctx->ch_layout.nb_channels == 1) {
145 do {
146 for (int i = 2; i; i--) {
147 bytestream2_put_be16(&pb, src32[0] >> 16);
148 bytestream2_put_be16(&pb, src32[1] >> 16);
149 bytestream2_put_byte(&pb, (uint8_t)((*src32++) >> 8));
150 bytestream2_put_byte(&pb, (uint8_t)((*src32++) >> 8));
151 }
152 } while (--blocks);
153 } else {
154 do {
155 for (int i = s->groups_per_block; i; i--) {
156 bytestream2_put_be16(&pb, src32[0] >> 16);
157 bytestream2_put_be16(&pb, src32[1] >> 16);
158 bytestream2_put_be16(&pb, src32[2] >> 16);
159 bytestream2_put_be16(&pb, src32[3] >> 16);
160 bytestream2_put_byte(&pb, (uint8_t)((*src32++) >> 8));
161 bytestream2_put_byte(&pb, (uint8_t)((*src32++) >> 8));
162 bytestream2_put_byte(&pb, (uint8_t)((*src32++) >> 8));
163 bytestream2_put_byte(&pb, (uint8_t)((*src32++) >> 8));
164 }
165 } while (--blocks);
166 }
167 break;
168 }
169
170 avpkt->pts = frame->pts;
171 avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
172 *got_packet_ptr = 1;
173
174 return 0;
175 }
176
177 const FFCodec ff_pcm_dvd_encoder = {
178 .p.name = "pcm_dvd",
179 .p.long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
180 .p.type = AVMEDIA_TYPE_AUDIO,
181 .p.id = AV_CODEC_ID_PCM_DVD,
182 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SMALL_LAST_FRAME,
183 .priv_data_size = sizeof(PCMDVDContext),
184 .init = pcm_dvd_encode_init,
185 FF_CODEC_ENCODE_CB(pcm_dvd_encode_frame),
186 .p.supported_samplerates = (const int[]) { 48000, 96000, 0},
187 #if FF_API_OLD_CHANNEL_LAYOUT
188 .p.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
189 AV_CH_LAYOUT_STEREO,
190 AV_CH_LAYOUT_5POINT1,
191 AV_CH_LAYOUT_7POINT1,
192 0 },
193 #endif
194 .p.ch_layouts = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_MONO,
195 AV_CHANNEL_LAYOUT_STEREO,
196 AV_CHANNEL_LAYOUT_5POINT1,
197 AV_CHANNEL_LAYOUT_7POINT1,
198 { 0 } },
199 .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
200 AV_SAMPLE_FMT_S32,
201 AV_SAMPLE_FMT_NONE },
202 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
203 };
204