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 */ 40 struct 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 */ 54 struct 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 66 struct 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 */ 81 struct 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 92 struct vidtv_encoder 93 *vidtv_s302m_encoder_init(struct vidtv_s302m_encoder_init_args args); 94 95 void vidtv_s302m_encoder_destroy(struct vidtv_encoder *encoder); 96 97 #endif /* VIDTV_S302M_H */ 98