STRUCT DVB_DEMUX(9)

💅 struct dvb_demux(9)

okay bestie, so this is struct dvb_demux — it represents a digital TV demux, and it is literally the main character of the DVB demux world. Let's get into it ✨

✨ SYNOPSIS ✨

struct dvb_demux {
    struct dmx_demux dmx;
    void *priv;
    int filternum;
    int feednum;
    int (*start_feed)(struct dvb_demux_feed *feed);
    int (*stop_feed)(struct dvb_demux_feed *feed);
    int (*write_to_decoder)(struct dvb_demux_feed *feed, const u8 *buf,
size_t len);
    u32 (*check_crc32)(struct dvb_demux_feed *feed, const u8 *buf,
size_t len);
    void (*memcopy)(struct dvb_demux_feed *feed, u8 *dst, const u8 *src,
size_t len);
    int users;
  #define MAX_DVB_DEMUX_USERS 10;
    struct dvb_demux_filter *filter;
    struct dvb_demux_feed *feed;
    struct list_head frontend_list;
    struct dvb_demux_feed *pesfilter[DMX_PES_OTHER];
    u16 pids[DMX_PES_OTHER];
  #define DMX_MAX_PID 0x2000;
    struct list_head feed_list;
    u8 tsbuf[204];
    int tsbufp;
    struct mutex mutex;
    spinlock_t lock;
    uint8_t *cnt_storage;
    ktime_t speed_last_time;
    uint32_t speed_pkts_cnt;
};

🎀 Members 🎀

okay so every field is about to get its moment, no skipping, we're doing all of them 💖

• dmx — the embedded struct dmx_demux that carries the demux capabilities and callbacks. it's the whole reason this thing can demux at all, so yeah, kind of a big deal 👑
• priv — private data, and it's optional — a DVB driver can use it if it wants. no pressure, no cap 🫶
• filternum — maximum amount of DVB filters.
• feednum — maximum amount of DVB feeds.
• start_feed — callback routine that gets called to start a DVB feed. go little feed go ✨
• stop_feed — callback routine that gets called to stop a DVB feed. bye bestie 😭
• write_to_decoder — callback routine that gets called when a new TS packet arrives, but only if the feed is TS and it's routed to an A/V decoder. and ngl it's used only on av7110-av.c — that's it, one file, iconic behavior 💅
• check_crc32 — callback routine to check CRC. if you don't initialize it, dvb_demux just uses an internal one. it's giving self-sufficient 🌸
• memcopy — callback routine to memcopy received data. if you don't initialize it, dvb_demux defaults to memcpy. defaults really said "i got you" 🦋
• users — counter for the number of demux opened file descriptors. currently it's limited to 10 users. ten. that's the whole capacity. MAX_DVB_DEMUX_USERS said what she said 💀
• filter — pointer to struct dvb_demux_filter.
• feed — pointer to struct dvb_demux_feed.
• frontend_list — a struct list_head with the frontends used by the demux.
• pesfilter — array of struct dvb_demux_feed with the PES types that will be filtered. it's sized DMX_PES_OTHER, which is right there in the synopsis, don't come for me 🍓
• pids — list of filtered program IDs.
• feed_list — a struct list_head with feeds.
• tsbuf — temporary buffer used internally to store TS packets. u8 tsbuf[204], yes the 204 is real.
• tsbufp — temporary buffer index, used internally.
• mutex — pointer to struct mutex used to protect feed set logic. lock it down, queen 🔒
• lock — pointer to spinlock_t, used to protect buffer handling.
• cnt_storage — buffer used for TS/TEI continuity check.
• speed_last_time — ktime_t used for TS speed check.
• speed_pkts_cnt — packets count used for TS speed check. ⚡

quick vibe check bestie: the members block above keeps mutex and lock described as pointers, and write_to_decoder described as being used only on av7110-av.c — both of those are straight from the source, so don't @ me, I'm just the messenger 🙈

🌈 SEE ALSO 🌈

Kernel file ./include/media/dvb_demux.h, plus the whole friend group:

• enum dvb_dmx_filter_type(9)
• enum dvb_dmx_state(9)
• struct dvb_demux_filter(9)
• struct dvb_demux_feed(9)
• dvb_dmx_init(9)
• dvb_dmx_release(9)
• dvb_dmx_swfilter_packets(9)
• dvb_dmx_swfilter(9)
• dvb_dmx_swfilter_204(9)
• dvb_dmx_swfilter_raw(9)

and that's the whole page, bestie, you ate that 🫶💜

this lil beauty lives in ./include/media, dated October 2026, and it's filed under struct dvb_demux(9) — periodt. ⭐