drivers/media/test-drivers/vidtv/vidtv_s302m.h

   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 */