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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Vidtv serves as a reference DVB driver and helps validate the existing APIs
* in the media subsystem. It can also aid developers working on userspace
* applications.
*
* This file contains the code for an AES3 (also known as AES/EBU) encoder.
* It is based on EBU Tech 3250 and SMPTE 302M technical documents.
*
* This encoder currently supports 16bit AES3 subframes using 16bit signed
* integers.
*
* Note: AU stands for Access Unit, and AAU stands for Audio Access Unit
*
* Copyright (C) 2020 Daniel W. S. Almeida
*/
#ifndef VIDTV_S302M_H
#define VIDTV_S302M_H
#include <linux/types.h>
#include "vidtv_encoder.h"
/* see SMPTE 302M 2007 clause 7.3 */
#define VIDTV_S302M_BUF_SZ 65024
/* see ETSI TS 102 154 v.1.2.1 clause 7.3.5 */
#define VIDTV_S302M_FORMAT_IDENTIFIER 0x42535344
/**
* struct vidtv_s302m_ctx - s302m encoder context.
* @enc: A pointer to the containing encoder structure.
* @frame_index: The current frame in a block
* @au_count: The total number of access units encoded up to now
* @last_duration: Duration of the tone currently being played
* @note_offset: Position at the music tone array
* @last_tone: Tone currently being played
*/
struct vidtv_s302m_ctx {
struct vidtv_encoder *enc;
u32 frame_index;
u32 au_count;
int last_duration;
unsigned int note_offset;
enum musical_notes last_tone;
};
/*
* struct vidtv_smpte_s302m_es - s302m MPEG Elementary Stream header.
*
* See SMPTE 302M 2007 table 1.
*/
struct vidtv_smpte_s302m_es {
/*
*
* audio_packet_size:16;
* num_channels:2;
* channel_identification:8;
* bits_per_sample:2; // 0x0 for 16bits
* zero:4;
*/
__be32 bitfield;
} __packed;
struct vidtv_s302m_frame_16 {
u8 data[5];
} __packed;
/**
* struct vidtv_s302m_encoder_init_args - Args for the s302m encoder.
*
* @name: A name to identify this particular instance
* @src_buf: The source buffer, encoder will default to a sine wave if this is NULL.
* @src_buf_sz: The size of the source buffer.
* @es_pid: The MPEG Elementary Stream PID to use.
* @sync: Attempt to synchronize audio with this video encoder, if not NULL.
* @last_sample_cb: A callback called when the encoder runs out of data.
* @head: Add to this chain
*/
struct vidtv_s302m_encoder_init_args {
char *name;
void *src_buf;
u32 src_buf_sz;
u16 es_pid;
struct vidtv_encoder *sync;
void (*last_sample_cb)(u32 sample_no);
struct vidtv_encoder *head;
};
struct vidtv_encoder
*vidtv_s302m_encoder_init(struct vidtv_s302m_encoder_init_args args);
void vidtv_s302m_encoder_destroy(struct vidtv_encoder *encoder);
#endif /* VIDTV_S302M_H */
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