STRUCT V4L2_VP8_ENTROPY_CODER_STATE(9)

✨ struct v4l2_vp8_entropy_coder_state(9) ✨

okay so this is a page straight out of the Kernel API Manual, and we're talking about one very specific little struct — the VP8 boolean entropy coder state. it's tiny. it's four bytes. it's lowkey iconic 💅

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🌸 NAME 🌸

struct v4l2_vp8_entropy_coder_state — the VP8 boolean coder state, bestie. that's the whole vibe.

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🎀 SYNOPSIS 🎀

here's the whole thing, look how small she is:

struct v4l2_vp8_entropy_coder_state {
    __u8 range;
    __u8 value;
    __u8 bit_count;
    __u8 padding;
 };

four __u8s and not a single one more. no cap.

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🦋 Members 🦋

okay let's meet the cast, one by one 🫶

• range — the coder state value for "Range". yes, it's literally called Range. main character field tbh.
• value — the coder state value for "Value". matching set, we love a duo ✨
• bit_count — how many bits are left in the range "Value". that's her whole job.
• padding — purely a padding field, fr fr. applications gotta zero it out — that's not optional, that's the rule 🙈

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💜 Description 💜

so what even is this? it's a struct that holds the state for the boolean coder — and if you wanna know the full lore, it's all explained in section '7. Boolean Entropy Decoder' of the VP8 specification. go read that section, iykwim 📖

tl;dr: it's a snapshot of where the boolean decoder is at. nothing more, nothing less. slay 💅

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🌈 SEE ALSO 🌈

buckle up bestie, this is the long list — the kernel file is at ./include/uapi/linux/v4l2-controls.h, and it's adjacent to all of these:

• enum v4l2_mpeg_video_av1_profile(9)
• enum v4l2_mpeg_video_av1_level(9)
• enum v4l2_stateless_h264_decode_mode(9)
• enum v4l2_stateless_h264_start_code(9)
• struct v4l2_ctrl_h264_sps(9)
• struct v4l2_ctrl_h264_pps(9)
• struct v4l2_ctrl_h264_scaling_matrix(9)
• struct v4l2_ctrl_h264_pred_weights(9)
• struct v4l2_h264_reference(9)
• struct v4l2_ctrl_h264_slice_params(9)
• struct v4l2_h264_dpb_entry(9)
• struct v4l2_ctrl_h264_decode_params(9)
• struct v4l2_ctrl_fwht_params(9)
• struct v4l2_vp8_segment(9)
• struct v4l2_vp8_loop_filter(9)
• struct v4l2_vp8_quantization(9)
• struct v4l2_vp8_entropy(9)
• struct v4l2_ctrl_vp8_frame(9)
• struct v4l2_ctrl_mpeg2_sequence(9)
• struct v4l2_ctrl_mpeg2_picture(9)
• struct v4l2_ctrl_mpeg2_quantisation(9)
• struct v4l2_ctrl_hevc_sps(9)
• struct v4l2_ctrl_hevc_pps(9)
• struct v4l2_hevc_dpb_entry(9)
• struct v4l2_hevc_pred_weight_table(9)
• struct v4l2_ctrl_hevc_slice_params(9)
• struct v4l2_ctrl_hevc_decode_params(9)
• struct v4l2_ctrl_hevc_scaling_matrix(9)
• struct v4l2_vp9_loop_filter(9)
• struct v4l2_vp9_quantization(9)
• struct v4l2_vp9_segmentation(9)
• struct v4l2_ctrl_vp9_frame(9)
• struct v4l2_vp9_mv_probs(9)
• struct v4l2_ctrl_vp9_compressed_hdr(9)
• struct v4l2_ctrl_av1_sequence(9)
• struct v4l2_ctrl_av1_tile_group_entry(9)
• enum v4l2_av1_warp_model(9)
• enum v4l2_av1_reference_frame(9)
• struct v4l2_av1_global_motion(9)
• enum v4l2_av1_frame_restoration_type(9)
• struct v4l2_av1_loop_restoration(9)
• struct v4l2_av1_cdef(9)
• enum v4l2_av1_segment_feature(9)
• struct v4l2_av1_segmentation(9)
• struct v4l2_av1_loop_filter(9)
• struct v4l2_av1_quantization(9)
• struct v4l2_av1_tile_info(9)
• enum v4l2_av1_frame_type(9)
• enum v4l2_av1_interpolation_filter(9)
• enum v4l2_av1_tx_mode(9)
• struct v4l2_ctrl_av1_frame(9)
• struct v4l2_ctrl_av1_film_grain(9)

like i said. long list. but you got this 💪

friendly reminder that the padding field has to be zeroed by applications — don't leave it vibing with garbage in it, that's not the move 🙅‍♀️

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alright bestie, that's the whole page 💖 this one came from ./include/uapi/linux, dated October 2026, and it lives in the Kernel API Manual — go forth and decode those booleans, you absolute icon 👑✨🎀