1/* SPDX-License-Identifier: GPL-2.0 */
2/*
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
5 * applications.
6 *
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.
9 *
10 * This encoder currently supports 16bit AES3 subframes using 16bit signed
11 * integers.
12 *
13 * Note: AU stands for Access Unit, and AAU stands for Audio Access Unit
14 *
15 * Copyright (C) 2020 Daniel W. S. Almeida
16 */
17
18#ifndef VIDTV_S302M_H
19#define VIDTV_S302M_H
20
21#include <linux/types.h>
22
23#include "vidtv_encoder.h"
24
25/* see SMPTE 302M 2007 clause 7.3 */
26#define VIDTV_S302M_BUF_SZ 65024
27
28/* see ETSI TS 102 154 v.1.2.1 clause 7.3.5 */
29#define VIDTV_S302M_FORMAT_IDENTIFIER 0x42535344
30
31/**
32 * struct vidtv_s302m_ctx - s302m encoder context.
33 * @enc: A pointer to the containing encoder structure.
34 * @frame_index: The current frame in a block
35 * @au_count: The total number of access units encoded up to now
36 * @last_duration: Duration of the tone currently being played
37 * @note_offset: Position at the music tone array
38 * @last_tone: Tone currently being played
39 */
40struct vidtv_s302m_ctx {
41	struct vidtv_encoder *enc;
42	u32 frame_index;
43	u32 au_count;
44	int last_duration;
45	unsigned int note_offset;
46	enum musical_notes last_tone;
47};
48
49/*
50 * struct vidtv_smpte_s302m_es - s302m MPEG Elementary Stream header.
51 *
52 * See SMPTE 302M 2007 table 1.
53 */
54struct vidtv_smpte_s302m_es {
55	/*
56	 *
57	 * audio_packet_size:16;
58	 * num_channels:2;
59	 * channel_identification:8;
60	 * bits_per_sample:2; // 0x0 for 16bits
61	 * zero:4;
62	 */
63	__be32 bitfield;
64} __packed;
65
66struct vidtv_s302m_frame_16 {
67	u8 data[5];
68} __packed;
69
70/**
71 * struct vidtv_s302m_encoder_init_args - Args for the s302m encoder.
72 *
73 * @name: A name to identify this particular instance
74 * @src_buf: The source buffer, encoder will default to a sine wave if this is NULL.
75 * @src_buf_sz: The size of the source buffer.
76 * @es_pid: The MPEG Elementary Stream PID to use.
77 * @sync: Attempt to synchronize audio with this video encoder, if not NULL.
78 * @last_sample_cb: A callback called when the encoder runs out of data.
79 * @head: Add to this chain
80 */
81struct vidtv_s302m_encoder_init_args {
82	char *name;
83	void *src_buf;
84	u32 src_buf_sz;
85	u16 es_pid;
86	struct vidtv_encoder *sync;
87	void (*last_sample_cb)(u32 sample_no);
88
89	struct vidtv_encoder *head;
90};
91
92struct vidtv_encoder
93*vidtv_s302m_encoder_init(struct vidtv_s302m_encoder_init_args args);
94
95void vidtv_s302m_encoder_destroy(struct vidtv_encoder *encoder);
96
97#endif /* VIDTV_S302M_H */
98