STRUCT V4L2_JPEG_FRAME_COMPONENT_SPEC(9)

💅 struct v4l2_jpeg_frame_component_spec 💅

okay so this is a page straight out of the Kernel API Manual, and today's main character is struct v4l2_jpeg_frame_component_spec — literally the frame component-specification. that's it, that's the vibe. it's giving "one little struct that knows exactly what it's about" ✨

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🎀 NAME 🎀

struct v4l2_jpeg_frame_component_spec — frame component-specification. yes bestie, that's the whole name, no notes, she said what she said 🫶

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✨ SYNOPSIS ✨

here's the glow-up, in code, exactly as she appears:

struct v4l2_jpeg_frame_component_spec {
    u8 component_identifier;
    u8 horizontal_sampling_factor;
    u8 vertical_sampling_factor;
    u8 quantization_table_selector;
 };

four little u8 fields, all in a row, all doing their thing. lowkey iconic 💜

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🦋 Members 🦋

so let's meet the cast, one by one, because they each have main character energy:

• component_identifier — this one is C[i]. that's it. that's the whole description. short king 🎀
• horizontal_sampling_factor — H[i]. the horizontal one. the way she samples horizontally… obsessed 💅
• vertical_sampling_factor — V[i]. same energy but vertical, and yeah, it's a whole mood 🌸
• quantization_table_selector — the quantization table destination selector, Tq[i]. fancy full name, no cap 👑

bestie note: those [i] brackets are just how the doc labels them — copy them exactly, don't go inventing new indices, iykyk 🙈

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🌈 SEE ALSO 🌈

go touch grass in the kernel file ./include/media/v4l2-jpeg.h and then go say hi to her friends:

• struct v4l2_jpeg_reference(9)
• struct v4l2_jpeg_frame_header(9)
• struct v4l2_jpeg_scan_component_spec(9)
• struct v4l2_jpeg_scan_header(9)
• enum v4l2_jpeg_app14_tf(9)
• struct v4l2_jpeg_header(9)

that's the whole friend group, they roll deep 🧚

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and that's the page, bestie!! muah 💖 this lil' gem lives over in ./include/media, it's stamped October 2026, and it's part of the Kernel API Manual — go drink some water, you read a whole manpage today, slay 🍓⭐