/* 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 muxer logic for TS packets from different * elementary streams. * * Loosely based on libavcodec/mpegtsenc.c * * Copyright (C) 2020 Daniel W. S. Almeida */ #ifndef VIDTV_MUX_H #define VIDTV_MUX_H #include #include #include #include #include "vidtv_psi.h" /** * struct vidtv_mux_timing - Timing related information * * This is used to decide when PCR or PSI packets should be sent. This will also * provide storage for the clock, which is used to compute the value for the PCR. * * @start_jiffies: The value of 'jiffies' when we started the mux thread. * @current_jiffies: The value of 'jiffies' for the current iteration. * @past_jiffies: The value of 'jiffies' for the past iteration. * @clk: A 27Mhz clock from which we will drive the PCR. Updated proportionally * on every iteration. * @pcr_period_usecs: How often we should send PCR packets. * @si_period_usecs: How often we should send PSI packets. */ struct vidtv_mux_timing { u64 start_jiffies; u64 current_jiffies; u64 past_jiffies; u64 clk; u64 pcr_period_usecs; u64 si_period_usecs; }; /** * struct vidtv_mux_si - Store the PSI context. * * This is used to store the PAT, PMT sections and SDT in use by the muxer. * * The muxer acquire these by looking into the hardcoded channels in * vidtv_channel and then periodically sends the TS packets for them> * * @pat: The PAT in use by the muxer. * @pmt_secs: The PMT sections in use by the muxer. One for each program in the PAT. * @sdt: The SDT in use by the muxer. */ struct vidtv_mux_si { /* the SI tables */ struct vidtv_psi_table_pat *pat; struct vidtv_psi_table_pmt **pmt_secs; /* the PMT sections */ struct vidtv_psi_table_sdt *sdt; }; /** * struct vidtv_mux_pid_ctx - Store the context for a given TS PID. * @pid: The TS PID. * @cc: The continuity counter for this PID. It is incremented on every TS * pack and it will wrap around at 0xf0. If the decoder notices a sudden jump in * this counter this will trigger a discontinuity state. * @h: This is embedded in a hash table, mapping pid -> vidtv_mux_pid_ctx */ struct vidtv_mux_pid_ctx { u16 pid; u8 cc; /* continuity counter */ struct hlist_node h; }; /** * struct vidtv_mux - A muxer abstraction loosely based in libavcodec/mpegtsenc.c * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes. * @timing: Keeps track of timing related information. * @pid_ctx: A hash table to keep track of per-PID metadata. * @on_new_packets_available_cb: A callback to inform of new TS packets ready. * @mux_buf: A pointer to a buffer for this muxer. TS packets are stored there * and then passed on to the bridge driver. * @mux_buf_sz: The size for 'mux_buf'. * @mux_buf_offset: The current offset into 'mux_buf'. * @channels: The channels associated with this muxer. * @si: Keeps track of the PSI context. * @num_streamed_pcr: Number of PCR packets streamed. * @num_streamed_si: The number of PSI packets streamed. * @mpeg_thread: Thread responsible for the muxer loop. * @streaming: whether 'mpeg_thread' is running. * @pcr_pid: The TS PID used for the PSI packets. All channels will share the * same PCR. * @transport_stream_id: The transport stream ID * @priv: Private data. */ struct vidtv_mux { struct dvb_frontend *fe; struct device *dev; struct vidtv_mux_timing timing; u32 mux_rate_kbytes_sec; DECLARE_HASHTABLE(pid_ctx, 3); void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets); u8 *mux_buf; u32 mux_buf_sz; u32 mux_buf_offset; struct vidtv_channel *channels; struct vidtv_mux_si si; u64 num_streamed_pcr; u64 num_streamed_si; struct work_struct mpeg_thread; bool streaming; u16 pcr_pid; u16 transport_stream_id; void *priv; }; /** * struct vidtv_mux_init_args - Arguments used to inix the muxer. * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes. * @on_new_packets_available_cb: A callback to inform of new TS packets ready. * @mux_buf_sz: The size for 'mux_buf'. * @pcr_period_usecs: How often we should send PCR packets. * @si_period_usecs: How often we should send PSI packets. * @pcr_pid: The TS PID used for the PSI packets. All channels will share the * same PCR. * @transport_stream_id: The transport stream ID * @channels: an optional list of channels to use * @priv: Private data. */ struct vidtv_mux_init_args { u32 mux_rate_kbytes_sec; void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets); u32 mux_buf_sz; u64 pcr_period_usecs; u64 si_period_usecs; u16 pcr_pid; u16 transport_stream_id; struct vidtv_channel *channels; void *priv; }; struct vidtv_mux *vidtv_mux_init(struct dvb_frontend *fe, struct device *dev, struct vidtv_mux_init_args args); void vidtv_mux_destroy(struct vidtv_mux *m); void vidtv_mux_start_thread(struct vidtv_mux *m); void vidtv_mux_stop_thread(struct vidtv_mux *m); #endif //VIDTV_MUX_H