1 // SPDX-License-Identifier: GPL-2.0
3 * Vidtv serves as a reference DVB driver and helps validate the existing APIs
4 * in the media subsystem. It can also aid developers working on userspace
7 * This file contains the code for an AES3 (also known as AES/EBU) encoder.
8 * It is based on EBU Tech 3250 and SMPTE 302M technical documents.
10 * This encoder currently supports 16bit AES3 subframes using 16bit signed
13 * Note: AU stands for Access Unit, and AAU stands for Audio Access Unit
15 * Copyright (C) 2020 Daniel W. S. Almeida
18 #define pr_fmt(fmt) KBUILD_MODNAME ":%s, %d: " fmt, __func__, __LINE__
20 #include <linux/bug.h>
21 #include <linux/crc32.h>
22 #include <linux/fixp-arith.h>
23 #include <linux/jiffies.h>
24 #include <linux/kernel.h>
25 #include <linux/math64.h>
26 #include <linux/printk.h>
27 #include <linux/ratelimit.h>
28 #include <linux/slab.h>
29 #include <linux/string.h>
30 #include <linux/types.h>
31 #include <linux/vmalloc.h>
33 #include "vidtv_common.h"
34 #include "vidtv_encoder.h"
35 #include "vidtv_s302m.h"
37 #define S302M_SAMPLING_RATE_HZ 48000
38 #define PES_PRIVATE_STREAM_1 0xbd /* PES: private_stream_1 */
39 #define S302M_BLOCK_SZ 192
40 #define S302M_SIN_LUT_NUM_ELEM 1024
42 /* these are retrieved empirically from ffmpeg/libavcodec */
43 #define FF_S302M_DEFAULT_NUM_FRAMES 1115
44 #define FF_S302M_DEFAULT_PTS_INCREMENT 2090
45 #define FF_S302M_DEFAULT_PTS_OFFSET 100000
47 /* Used by the tone generator: number of samples for PI */
50 static const u8 reverse[256] = {
52 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0,
53 0x30, 0xB0, 0x70, 0xF0, 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
54 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, 0x04, 0x84, 0x44, 0xC4,
55 0x24, 0xA4, 0x64, 0xE4, 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
56 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, 0x1C, 0x9C, 0x5C, 0xDC,
57 0x3C, 0xBC, 0x7C, 0xFC, 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
58 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, 0x0A, 0x8A, 0x4A, 0xCA,
59 0x2A, 0xAA, 0x6A, 0xEA, 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
60 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56, 0xD6,
61 0x36, 0xB6, 0x76, 0xF6, 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
62 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, 0x01, 0x81, 0x41, 0xC1,
63 0x21, 0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
64 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, 0x19, 0x99, 0x59, 0xD9,
65 0x39, 0xB9, 0x79, 0xF9, 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
66 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, 0x0D, 0x8D, 0x4D, 0xCD,
67 0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
68 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, 0x13, 0x93, 0x53, 0xD3,
69 0x33, 0xB3, 0x73, 0xF3, 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
70 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, 0x07, 0x87, 0x47, 0xC7,
71 0x27, 0xA7, 0x67, 0xE7, 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
72 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, 0x1F, 0x9F, 0x5F, 0xDF,
73 0x3F, 0xBF, 0x7F, 0xFF,
76 struct tone_duration {
77 enum musical_notes note;
81 #define COMPASS 120 /* beats per minute (Allegro) */
82 static const struct tone_duration beethoven_fur_elise[] = {
83 { NOTE_E_6, 128}, { NOTE_DS_6, 128}, { NOTE_E_6, 128},
84 { NOTE_DS_6, 128}, { NOTE_E_6, 128}, { NOTE_B_5, 128},
85 { NOTE_D_6, 128}, { NOTE_C_6, 128}, { NOTE_A_3, 128},
86 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_C_5, 128},
87 { NOTE_E_5, 128}, { NOTE_A_5, 128}, { NOTE_E_3, 128},
88 { NOTE_E_4, 128}, { NOTE_GS_4, 128}, { NOTE_E_5, 128},
89 { NOTE_GS_5, 128}, { NOTE_B_5, 128}, { NOTE_A_3, 128},
90 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_E_5, 128},
91 { NOTE_E_6, 128}, { NOTE_DS_6, 128}, { NOTE_E_6, 128},
92 { NOTE_DS_6, 128}, { NOTE_E_6, 128}, { NOTE_B_5, 128},
93 { NOTE_D_6, 128}, { NOTE_C_6, 128}, { NOTE_A_3, 128},
94 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_C_5, 128},
95 { NOTE_E_5, 128}, { NOTE_A_5, 128}, { NOTE_E_3, 128},
96 { NOTE_E_4, 128}, { NOTE_GS_4, 128}, { NOTE_E_5, 128},
97 { NOTE_C_6, 128}, { NOTE_B_5, 128}, { NOTE_A_3, 128},
98 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_SILENT, 128},
100 { NOTE_E_6, 128}, { NOTE_DS_6, 128}, { NOTE_E_6, 128},
101 { NOTE_DS_6, 128}, { NOTE_E_6, 128}, { NOTE_B_5, 128},
102 { NOTE_D_6, 128}, { NOTE_C_6, 128}, { NOTE_A_3, 128},
103 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_C_5, 128},
104 { NOTE_E_5, 128}, { NOTE_A_5, 128}, { NOTE_E_3, 128},
105 { NOTE_E_4, 128}, { NOTE_GS_4, 128}, { NOTE_E_5, 128},
106 { NOTE_GS_5, 128}, { NOTE_B_5, 128}, { NOTE_A_3, 128},
107 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_E_5, 128},
108 { NOTE_E_6, 128}, { NOTE_DS_6, 128}, { NOTE_E_6, 128},
109 { NOTE_DS_6, 128}, { NOTE_E_6, 128}, { NOTE_B_5, 128},
110 { NOTE_D_6, 128}, { NOTE_C_6, 128}, { NOTE_A_3, 128},
111 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_C_5, 128},
112 { NOTE_E_5, 128}, { NOTE_A_5, 128}, { NOTE_E_3, 128},
113 { NOTE_E_4, 128}, { NOTE_GS_4, 128}, { NOTE_E_5, 128},
114 { NOTE_C_6, 128}, { NOTE_B_5, 128}, { NOTE_A_3, 128},
115 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_B_4, 128},
116 { NOTE_C_5, 128}, { NOTE_D_5, 128}, { NOTE_C_4, 128},
117 { NOTE_G_4, 128}, { NOTE_C_5, 128}, { NOTE_G_4, 128},
118 { NOTE_F_5, 128}, { NOTE_E_5, 128}, { NOTE_G_3, 128},
119 { NOTE_G_4, 128}, { NOTE_B_3, 128}, { NOTE_F_4, 128},
120 { NOTE_E_5, 128}, { NOTE_D_5, 128}, { NOTE_A_3, 128},
121 { NOTE_E_4, 128}, { NOTE_A_4, 128}, { NOTE_E_4, 128},
122 { NOTE_D_5, 128}, { NOTE_C_5, 128}, { NOTE_E_3, 128},
123 { NOTE_E_4, 128}, { NOTE_E_5, 255}, { NOTE_E_6, 128},
124 { NOTE_E_5, 128}, { NOTE_E_6, 128}, { NOTE_E_5, 255},
125 { NOTE_DS_5, 128}, { NOTE_E_5, 128}, { NOTE_DS_6, 128},
126 { NOTE_E_6, 128}, { NOTE_DS_5, 128}, { NOTE_E_5, 128},
127 { NOTE_DS_6, 128}, { NOTE_E_6, 128}, { NOTE_DS_6, 128},
128 { NOTE_E_6, 128}, { NOTE_DS_6, 128}, { NOTE_E_6, 128},
129 { NOTE_B_5, 128}, { NOTE_D_6, 128}, { NOTE_C_6, 128},
130 { NOTE_A_3, 128}, { NOTE_E_4, 128}, { NOTE_A_4, 128},
131 { NOTE_C_5, 128}, { NOTE_E_5, 128}, { NOTE_A_5, 128},
132 { NOTE_E_3, 128}, { NOTE_E_4, 128}, { NOTE_GS_4, 128},
133 { NOTE_E_5, 128}, { NOTE_GS_5, 128}, { NOTE_B_5, 128},
134 { NOTE_A_3, 128}, { NOTE_E_4, 128}, { NOTE_A_4, 128},
135 { NOTE_E_5, 128}, { NOTE_E_6, 128}, { NOTE_DS_6, 128},
136 { NOTE_E_6, 128}, { NOTE_DS_6, 128}, { NOTE_E_6, 128},
137 { NOTE_B_5, 128}, { NOTE_D_6, 128}, { NOTE_C_6, 128},
138 { NOTE_A_3, 128}, { NOTE_E_4, 128}, { NOTE_A_4, 128},
139 { NOTE_C_5, 128}, { NOTE_E_5, 128}, { NOTE_A_5, 128},
140 { NOTE_E_3, 128}, { NOTE_E_4, 128}, { NOTE_GS_4, 128},
141 { NOTE_E_5, 128}, { NOTE_C_6, 128}, { NOTE_B_5, 128},
142 { NOTE_C_5, 255}, { NOTE_C_5, 255}, { NOTE_SILENT, 512},
145 static struct vidtv_access_unit *vidtv_s302m_access_unit_init(struct vidtv_access_unit *head)
147 struct vidtv_access_unit *au;
149 au = kzalloc(sizeof(*au), GFP_KERNEL);
163 static void vidtv_s302m_access_unit_destroy(struct vidtv_encoder *e)
165 struct vidtv_access_unit *head = e->access_units;
166 struct vidtv_access_unit *tmp = NULL;
174 e->access_units = NULL;
177 static void vidtv_s302m_alloc_au(struct vidtv_encoder *e)
179 struct vidtv_access_unit *sync_au = NULL;
180 struct vidtv_access_unit *temp = NULL;
182 if (e->sync && e->sync->is_video_encoder) {
183 sync_au = e->sync->access_units;
186 temp = vidtv_s302m_access_unit_init(e->access_units);
187 if (!e->access_units)
188 e->access_units = temp;
190 sync_au = sync_au->next;
196 e->access_units = vidtv_s302m_access_unit_init(NULL);
200 vidtv_s302m_compute_sample_count_from_video(struct vidtv_encoder *e)
202 struct vidtv_access_unit *au = e->access_units;
203 struct vidtv_access_unit *sync_au = e->sync->access_units;
204 u32 vau_duration_usecs;
205 u32 sample_duration_usecs;
208 vau_duration_usecs = USEC_PER_SEC / e->sync->sampling_rate_hz;
209 sample_duration_usecs = USEC_PER_SEC / e->sampling_rate_hz;
211 while (au && sync_au) {
212 s = DIV_ROUND_UP(vau_duration_usecs, sample_duration_usecs);
215 sync_au = sync_au->next;
219 static void vidtv_s302m_compute_pts_from_video(struct vidtv_encoder *e)
221 struct vidtv_access_unit *au = e->access_units;
222 struct vidtv_access_unit *sync_au = e->sync->access_units;
224 /* use the same pts from the video access unit*/
225 while (au && sync_au) {
226 au->pts = sync_au->pts;
228 sync_au = sync_au->next;
232 static u16 vidtv_s302m_get_sample(struct vidtv_encoder *e)
236 struct vidtv_s302m_ctx *ctx = e->ctx;
240 * Simple tone generator: play the tones at the
241 * beethoven_fur_elise array.
243 if (ctx->last_duration <= 0) {
244 if (e->src_buf_offset >= ARRAY_SIZE(beethoven_fur_elise))
245 e->src_buf_offset = 0;
247 ctx->last_tone = beethoven_fur_elise[e->src_buf_offset].note;
248 ctx->last_duration = beethoven_fur_elise[e->src_buf_offset].duration *
249 S302M_SAMPLING_RATE_HZ / COMPASS / 5;
251 ctx->note_offset = 0;
253 ctx->last_duration--;
256 /* Handle pause notes */
260 pos = (2 * PI * ctx->note_offset * ctx->last_tone) / S302M_SAMPLING_RATE_HZ;
263 return (fixp_sin32(pos % (2 * PI)) >> 16) + 0x8000;
267 if (e->src_buf_offset > e->src_buf_sz) {
268 pr_err_ratelimited("overflow detected: %d > %d, wrapping.\n",
272 e->src_buf_offset = 0;
275 if (e->src_buf_offset >= e->src_buf_sz) {
276 /* let the source know we are out of data */
277 if (e->last_sample_cb)
278 e->last_sample_cb(e->sample_count);
280 e->src_buf_offset = 0;
283 sample = *(u16 *)(e->src_buf + e->src_buf_offset);
288 static u32 vidtv_s302m_write_frame(struct vidtv_encoder *e,
292 struct vidtv_s302m_frame_16 f = {};
293 struct vidtv_s302m_ctx *ctx = e->ctx;
295 /* from ffmpeg: see s302enc.c */
297 u8 vucf = ctx->frame_index == 0 ? 0x10 : 0;
299 f.data[0] = sample & 0xFF;
300 f.data[1] = (sample & 0xFF00) >> 8;
301 f.data[2] = ((sample & 0x0F) << 4) | vucf;
302 f.data[3] = (sample & 0x0FF0) >> 4;
303 f.data[4] = (sample & 0xF000) >> 12;
305 f.data[0] = reverse[f.data[0]];
306 f.data[1] = reverse[f.data[1]];
307 f.data[2] = reverse[f.data[2]];
308 f.data[3] = reverse[f.data[3]];
309 f.data[4] = reverse[f.data[4]];
311 nbytes += vidtv_memcpy(e->encoder_buf,
312 e->encoder_buf_offset,
317 e->encoder_buf_offset += nbytes;
320 if (ctx->frame_index >= S302M_BLOCK_SZ)
321 ctx->frame_index = 0;
326 static u32 vidtv_s302m_write_h(struct vidtv_encoder *e, u32 p_sz)
328 struct vidtv_smpte_s302m_es h = {};
331 /* 2 channels, ident: 0, 16 bits per sample */
332 h.bitfield = cpu_to_be32((p_sz << 16));
334 nbytes += vidtv_memcpy(e->encoder_buf,
335 e->encoder_buf_offset,
340 e->encoder_buf_offset += nbytes;
344 static void vidtv_s302m_write_frames(struct vidtv_encoder *e)
346 struct vidtv_access_unit *au = e->access_units;
347 struct vidtv_s302m_ctx *ctx = e->ctx;
348 u32 nbytes_per_unit = 0;
355 au_sz = au->num_samples *
356 sizeof(struct vidtv_s302m_frame_16);
358 nbytes_per_unit = vidtv_s302m_write_h(e, au_sz);
360 for (j = 0; j < au->num_samples; ++j) {
361 sample = vidtv_s302m_get_sample(e);
362 nbytes_per_unit += vidtv_s302m_write_frame(e, sample);
365 e->src_buf_offset += sizeof(u16);
370 au->nbytes = nbytes_per_unit;
372 if (au_sz + sizeof(struct vidtv_smpte_s302m_es) != nbytes_per_unit) {
373 pr_warn_ratelimited("write size was %u, expected %zu\n",
375 au_sz + sizeof(struct vidtv_smpte_s302m_es));
378 nbytes += nbytes_per_unit;
379 au->offset = nbytes - nbytes_per_unit;
388 static void *vidtv_s302m_encode(struct vidtv_encoder *e)
391 * According to SMPTE 302M, an audio access unit is specified as those
392 * AES3 words that are associated with a corresponding video frame.
393 * Therefore, there is one audio access unit for every video access unit
394 * in the corresponding video encoder ('sync'), using the same values
395 * for PTS as used by the video encoder.
397 * Assuming that it is also possible to send audio without any
398 * associated video, as in a radio-like service, a single audio access unit
399 * is created with values for 'num_samples' and 'pts' taken empirically from
403 struct vidtv_s302m_ctx *ctx = e->ctx;
405 vidtv_s302m_access_unit_destroy(e);
406 vidtv_s302m_alloc_au(e);
408 if (e->sync && e->sync->is_video_encoder) {
409 vidtv_s302m_compute_sample_count_from_video(e);
410 vidtv_s302m_compute_pts_from_video(e);
412 e->access_units->num_samples = FF_S302M_DEFAULT_NUM_FRAMES;
413 e->access_units->pts = (ctx->au_count * FF_S302M_DEFAULT_PTS_INCREMENT) +
414 FF_S302M_DEFAULT_PTS_OFFSET;
417 vidtv_s302m_write_frames(e);
419 return e->encoder_buf;
422 static u32 vidtv_s302m_clear(struct vidtv_encoder *e)
424 struct vidtv_access_unit *au = e->access_units;
432 vidtv_s302m_access_unit_destroy(e);
433 memset(e->encoder_buf, 0, VIDTV_S302M_BUF_SZ);
434 e->encoder_buf_offset = 0;
440 *vidtv_s302m_encoder_init(struct vidtv_s302m_encoder_init_args args)
442 struct vidtv_encoder *e;
443 u32 priv_sz = sizeof(struct vidtv_s302m_ctx);
444 struct vidtv_s302m_ctx *ctx;
446 e = kzalloc(sizeof(*e), GFP_KERNEL);
453 e->name = kstrdup(args.name, GFP_KERNEL);
455 e->encoder_buf = vzalloc(VIDTV_S302M_BUF_SZ);
456 e->encoder_buf_sz = VIDTV_S302M_BUF_SZ;
457 e->encoder_buf_offset = 0;
461 e->src_buf = (args.src_buf) ? args.src_buf : NULL;
462 e->src_buf_sz = (args.src_buf) ? args.src_buf_sz : 0;
463 e->src_buf_offset = 0;
465 e->is_video_encoder = false;
467 ctx = kzalloc(priv_sz, GFP_KERNEL);
472 ctx->last_duration = 0;
474 e->encode = vidtv_s302m_encode;
475 e->clear = vidtv_s302m_clear;
477 e->es_pid = cpu_to_be16(args.es_pid);
478 e->stream_id = cpu_to_be16(PES_PRIVATE_STREAM_1);
481 e->sampling_rate_hz = S302M_SAMPLING_RATE_HZ;
483 e->last_sample_cb = args.last_sample_cb;
485 e->destroy = vidtv_s302m_encoder_destroy;
488 while (args.head->next)
489 args.head = args.head->next;
499 void vidtv_s302m_encoder_destroy(struct vidtv_encoder *e)
501 if (e->id != S302M) {
502 pr_err_ratelimited("Encoder type mismatch, skipping.\n");
506 vidtv_s302m_access_unit_destroy(e);
508 vfree(e->encoder_buf);