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 "avcodec.h"
23 #include "bytestream.h"
24 #include "internal.h"
25
26 typedef struct PCMDVDContext {
27 uint8_t header[3]; // Header added to every frame
28 int block_size; // Size of a block of samples in bytes
29 int samples_per_block; // Number of samples per channel per block
30 int groups_per_block; // Number of 20/24-bit sample groups per block
31 uint8_t *extra_samples; // Pointer to leftover samples from a frame
32 int extra_sample_count; // Number of leftover samples in the buffer
33 } PCMDVDContext;
34
pcm_dvd_encode_init(AVCodecContext * avctx)35 static av_cold int pcm_dvd_encode_init(AVCodecContext *avctx)
36 {
37 PCMDVDContext *s = avctx->priv_data;
38 int quant, freq, frame_size;
39
40 switch (avctx->sample_rate) {
41 case 48000:
42 freq = 0;
43 break;
44 case 96000:
45 freq = 1;
46 break;
47 }
48
49 switch (avctx->sample_fmt) {
50 case AV_SAMPLE_FMT_S16:
51 avctx->bits_per_coded_sample = 16;
52 quant = 0;
53 break;
54 case AV_SAMPLE_FMT_S32:
55 avctx->bits_per_coded_sample = 24;
56 quant = 2;
57 break;
58 }
59
60 avctx->bits_per_coded_sample = 16 + quant * 4;
61 avctx->block_align = avctx->channels * avctx->bits_per_coded_sample / 8;
62 avctx->bit_rate = avctx->block_align * 8LL * avctx->sample_rate;
63 if (avctx->bit_rate > 9800000) {
64 av_log(avctx, AV_LOG_ERROR, "Too big bitrate: reduce sample rate, bitdepth or channels.\n");
65 return AVERROR(EINVAL);
66 }
67
68 if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
69 s->samples_per_block = 1;
70 s->block_size = avctx->channels * 2;
71 frame_size = 2008 / s->block_size;
72 } else {
73 switch (avctx->channels) {
74 case 1:
75 case 2:
76 case 4:
77 /* one group has all the samples needed */
78 s->block_size = 4 * avctx->bits_per_coded_sample / 8;
79 s->samples_per_block = 4 / avctx->channels;
80 s->groups_per_block = 1;
81 break;
82 case 8:
83 /* two groups have all the samples needed */
84 s->block_size = 8 * avctx->bits_per_coded_sample / 8;
85 s->samples_per_block = 1;
86 s->groups_per_block = 2;
87 break;
88 default:
89 /* need avctx->channels groups */
90 s->block_size = 4 * avctx->channels *
91 avctx->bits_per_coded_sample / 8;
92 s->samples_per_block = 4;
93 s->groups_per_block = avctx->channels;
94 break;
95 }
96
97 frame_size = FFALIGN(2008 / s->block_size, s->samples_per_block);
98 }
99
100 s->header[0] = 0x0c;
101 s->header[1] = (quant << 6) | (freq << 4) | (avctx->channels - 1);
102 s->header[2] = 0x80;
103
104 if (!avctx->frame_size)
105 avctx->frame_size = frame_size;
106
107 return 0;
108 }
109
pcm_dvd_encode_frame(AVCodecContext * avctx,AVPacket * avpkt,const AVFrame * frame,int * got_packet_ptr)110 static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
111 const AVFrame *frame, int *got_packet_ptr)
112 {
113 PCMDVDContext *s = avctx->priv_data;
114 int samples = frame->nb_samples * avctx->channels;
115 int64_t pkt_size = (frame->nb_samples / s->samples_per_block) * s->block_size + 3;
116 int blocks = (pkt_size - 3) / s->block_size;
117 const int16_t *src16;
118 const int32_t *src32;
119 PutByteContext pb;
120 int ret;
121
122 if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size, 0)) < 0)
123 return ret;
124
125 memcpy(avpkt->data, s->header, 3);
126
127 src16 = (const int16_t *)frame->data[0];
128 src32 = (const int32_t *)frame->data[0];
129
130 bytestream2_init_writer(&pb, avpkt->data + 3, avpkt->size - 3);
131
132 switch (avctx->sample_fmt) {
133 case AV_SAMPLE_FMT_S16:
134 do {
135 bytestream2_put_be16(&pb, *src16++);
136 } while (--samples);
137 break;
138 case AV_SAMPLE_FMT_S32:
139 if (avctx->channels == 1) {
140 do {
141 for (int i = 2; i; i--) {
142 bytestream2_put_be16(&pb, src32[0] >> 16);
143 bytestream2_put_be16(&pb, src32[1] >> 16);
144 bytestream2_put_byte(&pb, (*src32++) >> 24);
145 bytestream2_put_byte(&pb, (*src32++) >> 24);
146 }
147 } while (--blocks);
148 } else {
149 do {
150 for (int i = s->groups_per_block; i; i--) {
151 bytestream2_put_be16(&pb, src32[0] >> 16);
152 bytestream2_put_be16(&pb, src32[1] >> 16);
153 bytestream2_put_be16(&pb, src32[2] >> 16);
154 bytestream2_put_be16(&pb, src32[3] >> 16);
155 bytestream2_put_byte(&pb, (*src32++) >> 24);
156 bytestream2_put_byte(&pb, (*src32++) >> 24);
157 bytestream2_put_byte(&pb, (*src32++) >> 24);
158 bytestream2_put_byte(&pb, (*src32++) >> 24);
159 }
160 } while (--blocks);
161 }
162 break;
163 }
164
165 avpkt->pts = frame->pts;
166 avpkt->size = pkt_size;
167 avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
168 *got_packet_ptr = 1;
169
170 return 0;
171 }
172
173 AVCodec ff_pcm_dvd_encoder = {
174 .name = "pcm_dvd",
175 .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
176 .type = AVMEDIA_TYPE_AUDIO,
177 .id = AV_CODEC_ID_PCM_DVD,
178 .priv_data_size = sizeof(PCMDVDContext),
179 .init = pcm_dvd_encode_init,
180 .encode2 = pcm_dvd_encode_frame,
181 .capabilities = AV_CODEC_CAP_SMALL_LAST_FRAME,
182 .supported_samplerates = (const int[]) { 48000, 96000, 0},
183 .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
184 AV_CH_LAYOUT_STEREO,
185 AV_CH_LAYOUT_5POINT1,
186 AV_CH_LAYOUT_7POINT1,
187 0 },
188 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
189 AV_SAMPLE_FMT_S32,
190 AV_SAMPLE_FMT_NONE },
191 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
192 };
193