vidtv_mux.h (5638B)
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 muxer logic for TS packets from different 8 * elementary streams. 9 * 10 * Loosely based on libavcodec/mpegtsenc.c 11 * 12 * Copyright (C) 2020 Daniel W. S. Almeida 13 */ 14 15#ifndef VIDTV_MUX_H 16#define VIDTV_MUX_H 17 18#include <linux/hashtable.h> 19#include <linux/types.h> 20#include <linux/workqueue.h> 21 22#include <media/dvb_frontend.h> 23 24#include "vidtv_psi.h" 25 26/** 27 * struct vidtv_mux_timing - Timing related information 28 * 29 * This is used to decide when PCR or PSI packets should be sent. This will also 30 * provide storage for the clock, which is used to compute the value for the PCR. 31 * 32 * @start_jiffies: The value of 'jiffies' when we started the mux thread. 33 * @current_jiffies: The value of 'jiffies' for the current iteration. 34 * @past_jiffies: The value of 'jiffies' for the past iteration. 35 * @clk: A 27Mhz clock from which we will drive the PCR. Updated proportionally 36 * on every iteration. 37 * @pcr_period_usecs: How often we should send PCR packets. 38 * @si_period_usecs: How often we should send PSI packets. 39 */ 40struct vidtv_mux_timing { 41 u64 start_jiffies; 42 u64 current_jiffies; 43 u64 past_jiffies; 44 45 u64 clk; 46 47 u64 pcr_period_usecs; 48 u64 si_period_usecs; 49}; 50 51/** 52 * struct vidtv_mux_si - Store the PSI context. 53 * 54 * This is used to store the PAT, PMT sections and SDT in use by the muxer. 55 * 56 * The muxer acquire these by looking into the hardcoded channels in 57 * vidtv_channel and then periodically sends the TS packets for them> 58 * 59 * @pat: The PAT in use by the muxer. 60 * @pmt_secs: The PMT sections in use by the muxer. One for each program in the PAT. 61 * @sdt: The SDT in use by the muxer. 62 * @nit: The NIT in use by the muxer. 63 * @eit: the EIT in use by the muxer. 64 */ 65struct vidtv_mux_si { 66 /* the SI tables */ 67 struct vidtv_psi_table_pat *pat; 68 struct vidtv_psi_table_pmt **pmt_secs; /* the PMT sections */ 69 struct vidtv_psi_table_sdt *sdt; 70 struct vidtv_psi_table_nit *nit; 71 struct vidtv_psi_table_eit *eit; 72}; 73 74/** 75 * struct vidtv_mux_pid_ctx - Store the context for a given TS PID. 76 * @pid: The TS PID. 77 * @cc: The continuity counter for this PID. It is incremented on every TS 78 * pack and it will wrap around at 0xf0. If the decoder notices a sudden jump in 79 * this counter this will trigger a discontinuity state. 80 * @h: This is embedded in a hash table, mapping pid -> vidtv_mux_pid_ctx 81 */ 82struct vidtv_mux_pid_ctx { 83 u16 pid; 84 u8 cc; /* continuity counter */ 85 struct hlist_node h; 86}; 87 88/** 89 * struct vidtv_mux - A muxer abstraction loosely based in libavcodec/mpegtsenc.c 90 * @fe: The frontend structure allocated by the muxer. 91 * @dev: pointer to struct device. 92 * @timing: Keeps track of timing related information. 93 * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes. 94 * @pid_ctx: A hash table to keep track of per-PID metadata. 95 * @on_new_packets_available_cb: A callback to inform of new TS packets ready. 96 * @mux_buf: A pointer to a buffer for this muxer. TS packets are stored there 97 * and then passed on to the bridge driver. 98 * @mux_buf_sz: The size for 'mux_buf'. 99 * @mux_buf_offset: The current offset into 'mux_buf'. 100 * @channels: The channels associated with this muxer. 101 * @si: Keeps track of the PSI context. 102 * @num_streamed_pcr: Number of PCR packets streamed. 103 * @num_streamed_si: The number of PSI packets streamed. 104 * @mpeg_thread: Thread responsible for the muxer loop. 105 * @streaming: whether 'mpeg_thread' is running. 106 * @pcr_pid: The TS PID used for the PSI packets. All channels will share the 107 * same PCR. 108 * @transport_stream_id: The transport stream ID 109 * @network_id: The network ID 110 * @network_name: The network name 111 * @priv: Private data. 112 */ 113struct vidtv_mux { 114 struct dvb_frontend *fe; 115 struct device *dev; 116 117 struct vidtv_mux_timing timing; 118 119 u32 mux_rate_kbytes_sec; 120 121 DECLARE_HASHTABLE(pid_ctx, 3); 122 123 void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets); 124 125 u8 *mux_buf; 126 u32 mux_buf_sz; 127 u32 mux_buf_offset; 128 129 struct vidtv_channel *channels; 130 131 struct vidtv_mux_si si; 132 u64 num_streamed_pcr; 133 u64 num_streamed_si; 134 135 struct work_struct mpeg_thread; 136 bool streaming; 137 138 u16 pcr_pid; 139 u16 transport_stream_id; 140 u16 network_id; 141 char *network_name; 142 void *priv; 143}; 144 145/** 146 * struct vidtv_mux_init_args - Arguments used to inix the muxer. 147 * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes. 148 * @on_new_packets_available_cb: A callback to inform of new TS packets ready. 149 * @mux_buf_sz: The size for 'mux_buf'. 150 * @pcr_period_usecs: How often we should send PCR packets. 151 * @si_period_usecs: How often we should send PSI packets. 152 * @pcr_pid: The TS PID used for the PSI packets. All channels will share the 153 * same PCR. 154 * @transport_stream_id: The transport stream ID 155 * @channels: an optional list of channels to use 156 * @network_id: The network ID 157 * @network_name: The network name 158 * @priv: Private data. 159 */ 160struct vidtv_mux_init_args { 161 u32 mux_rate_kbytes_sec; 162 void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets); 163 u32 mux_buf_sz; 164 u64 pcr_period_usecs; 165 u64 si_period_usecs; 166 u16 pcr_pid; 167 u16 transport_stream_id; 168 struct vidtv_channel *channels; 169 u16 network_id; 170 char *network_name; 171 void *priv; 172}; 173 174struct vidtv_mux *vidtv_mux_init(struct dvb_frontend *fe, 175 struct device *dev, 176 struct vidtv_mux_init_args *args); 177void vidtv_mux_destroy(struct vidtv_mux *m); 178 179void vidtv_mux_start_thread(struct vidtv_mux *m); 180void vidtv_mux_stop_thread(struct vidtv_mux *m); 181 182#endif //VIDTV_MUX_H