STRUCT V4L2_CTRL_MPEG2_PICTURE(9)

💅 struct v4l2_ctrl_mpeg2_picture(9) — the Kernel API Manual, bestie edition 🎀

okay so you're deep in the kernel docs (iconic of you, honestly) and you've stumbled into the Kernel API Manual page for struct v4l2_ctrl_mpeg2_picture — say it with me, it's the MPEG-2 picture header 🦋. yes it's a mouthful. no we're not skipping it. let's go ✨

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🌸 NAME 🌸

struct v4l2_ctrl_mpeg2_picture — MPEG-2 picture header, literally exactly what it says on the tin 💖

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⭐ SYNOPSIS ⭐

here's the whole struct, bestie, character for character, no edits no cap 👑

struct v4l2_ctrl_mpeg2_picture {
    __u64 backward_ref_ts;
    __u64 forward_ref_ts;
    __u32 flags;
    __u8 f_code[2][2];
    __u8 picture_coding_type;
    __u8 picture_structure;
    __u8 intra_dc_precision;
    __u8 reserved[5];
 };

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🫶 Members 🫶

• backward_ref_ts — timestamp of the V4L2 capture buffer you're using as the reference for backward prediction. that's your time-travel-in-reverse buddy ⏪
• forward_ref_ts — timestamp of the V4L2 capture buffer you're using as the reference for forward prediction. heads up (this is the important bit 🙈): these timestamps refer to the timestamp field in struct v4l2_buffer. use v4l2_timeval_to_ns to convert the struct timeval to a __u64 — do not freestyle this, fr fr.
• flags — see V4L2_MPEG2_PIC_FLAG_{}. the curly braces are the manpage being mysterious, not me, i promise 💀
• f_code — see MPEG-2 specification. that's the whole vibe. the spec has the tea ☕
• picture_coding_type — also see MPEG-2 specification ✨
• picture_structure — see V4L2_MPEG2_PIC_{}_FIELD 🎀
• intra_dc_precision — see MPEG-2 specification (again, yes, it's a spec household here) 📖
• reserved — padding field. Should be zeroed by applications. that's not a suggestion, bestie, zero it out 🙏

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🔥 Description 🔥

all of the members on this structure match the picture header and picture coding extension syntaxes as specified by the MPEG-2 specification. that's it. that's the whole description. it's giving "the spec is the spec" and honestly? respect. 👑

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🌈 SEE ALSO 🌈

the reading list is long, but every single one of these is here because you deserve the full set, no gatekeeping in this house 💜

first up, the file itself: Kernel file ./include/uapi/linux/v4l2-controls.h

then, alphabetically-ish by video-codec friend group:

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_vp8_entropy_coder_state(9), struct v4l2_ctrl_vp8_frame(9), struct v4l2_ctrl_mpeg2_sequence(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)

ngl that's a lot of cross-references but every one of them is real and every one of them is staying. iykyk 🧚

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and that's the whole page, bestie — you ate 💅

this cutie came out of ./include/uapi/linux, dated October 2026, which is honestly future energy of the highest order ⭐🌸🍓 go forth and decode your picture headers, main character 🫶💖👑