STRUCT V4L2_JPEG_SCAN_COMPONENT_SPEC(9)

✨ struct v4l2_jpeg_scan_component_spec ✨

okay so bestie, we're in the Kernel API Manual section, and this little icon is struct v4l2_jpeg_scan_component_spec — literally just the scan component-specification. that's it, that's the whole vibe. you're not here for a novel, you're here for the spec of one component in a scan, and she delivers. 💅

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🌸 SYNOPSIS 🌸

the whole thing. the entire struct. not a single field more:

struct v4l2_jpeg_scan_component_spec {
    u8 component_selector;
    u8 dc_entropy_coding_table_selector;
    u8 ac_entropy_coding_table_selector;
};

three u8s. tiny. compact. main character energy in the smallest possible package. 🎀

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💖 Members 💖

• component_selector — this one's Cs[j] and no, I will not be elaborating further, because that's genuinely all the manpage says and I refuse to make stuff up on main. 🫶
• dc_entropy_coding_table_selector — Td[j]. the DC one. that j in brackets is doing a LOT of work and we respect her. ⭐
• ac_entropy_coding_table_selector — Ta[j]. the AC one. yes they're sibling-coded with the one above, no we will not be separating them. 🌸

ngl these three are giving "three besties who all show up in matching fits" — same type (u8), same vibe, same [j] energy. iykyk. 💜

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🦋 SEE ALSO 🦋

so if you want the full lore, the kernel file lives at ./include/media/v4l2-jpeg.h and it's lowkey the mothership. go read these, they're all connected, it's a whole cinematic universe:

• struct v4l2_jpeg_reference(9)
• struct v4l2_jpeg_frame_component_spec(9)
• struct v4l2_jpeg_frame_header(9)
• struct v4l2_jpeg_scan_header(9)
• enum v4l2_jpeg_app14_tf(9)
• struct v4l2_jpeg_header(9)

fr fr, clicking through these is the actual move. it's giving "the extended universe and you're only on chapter one". 🔥

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and that's the page!! 🎉

cute little sign-off for you: this one ships from ./include/media and it's dated October 2026 — so mark your calendars bestie, and remember the title up top was struct v4l2_...mponent_spec(9) if you ever need to cite her. go forth and parse those scans. 👑🌈