STRUCT V4L2_H264_REFLIST_BUILDER(9)

💅 struct v4l2_...list_builder(9) — Kernel API Manual 💅

okay so bestie, you're reading the manual page for struct v4l2_...list_builder(9) from the Kernel API Manual, and it's literally the reference list builder object. no cap, this is the struct that handles all the H.264 reference list vibes. 🎀

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✨ NAME ✨

struct v4l2_h264_reflist_builder — Reference list builder object

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🌸 SYNOPSIS 🌸

struct v4l2_h264_reflist_builder {
    struct {
      s32 top_field_order_cnt;
      s32 bottom_field_order_cnt;
      int frame_num;
      u16 longterm : 1;
    } refs[V4L2_H264_NUM_DPB_ENTRIES];
    s32 cur_pic_order_count;
    u8 cur_pic_fields;
    struct v4l2_h264_reference
unordered_reflist[V4L2_H264_REF_LIST_LEN];
    u8 num_valid;
 };

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🎀 Members 🎀

• refs — array of references. the whole squad of reference pics, lowkey.
• refs.top_field_order_cnt — top field order count. it's giving top-field energy.
• refs.bottom_field_order_cnt — bottom field order count. bottom-field vibes fr fr.
• refs.frame_num — reference frame number. the number that identifies the frame, no cap.
• refs.longterm — set to true for a long term reference. when it's true, that's a long-term relationship with this reference, periodt.
• cur_pic_order_count — picture order count of the frame being decoded. the POC of the frame you're decoding rn.
• cur_pic_fields — fields present in the frame being decoded. which fields are showing up in the frame being decoded.
• unordered_reflist — unordered list of references. Will be used to generate ordered P/B0/B1 lists. it's the chaotic group chat before someone makes the ordered list.
• num_valid — number of valid references in the refs array. how many of the refs are actually valid, bestie.

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🔥 Description 🔥

okay so this object is literally storing the context of the P/B0/B1 reference list builder. the way it works is described in section '8.2.4 Decoding process for reference picture lists construction' of the H264 spec — iykyk. 🧚

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👑 SEE ALSO 👑

• Kernel file ./include/media/v4l2-h264.h
• v4l2_h264_build_b_ref_lists(9)
• v4l2_h264_build_p_ref_list(9)

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source: ./include/media · date: October 2026 · that's the tea, bestie 🍓💖