mpv-scripts/scripts/screenshot-duo.lua

-- screenshot-duo.lua
-- Press S to capture two screenshots at the current frame:
--   _normal.png   — raw frame via ffmpeg (no adjustments)
--   _modified.png — what you see on screen (gamma/brightness/etc baked in)
--
-- Suggested input.conf binding:
--   S    script-binding screenshot_duo/capture
--
-- Saves to ~/Videos/mpv-loops/.

local mp = require("mp")
local utils = require("mp.utils")

local OUTPUT_DIR = os.getenv("HOME") .. "/Videos/mpv-loops"
local ENABLE_OSD_MSG = true

local function osd_msg(text, duration)
    if ENABLE_OSD_MSG then
        mp.osd_message(text, duration or 3)
    end
end

local function format_label(seconds)
    local h = math.floor(seconds / 3600)
    local m = math.floor((seconds % 3600) / 60)
    local s = math.floor(seconds % 60)
    return string.format("%02d%02d%02d", h, m, s)
end

local function dedup_path(base_path, suffix, ext)
    local candidate = string.format("%s_%s.%s", base_path, suffix, ext)
    local counter = 1
    while true do
        local f = io.open(candidate, "r")
        if not f then return candidate end
        f:close()
        candidate = string.format("%s_%s_%d.%s", base_path, suffix, counter, ext)
        counter = counter + 1
    end
end

local function format_size(path)
    local info = utils.file_info(path)
    if not info or not info.size then return "" end
    local s = info.size
    if s > 1024 * 1024 then
        return string.format(" (%.1f MB)", s / 1024 / 1024)
    elseif s > 1024 then
        return string.format(" (%.0f KB)", s / 1024)
    else
        return string.format(" (%d B)", s)
    end
end

-- Build crop filter string for current zoom/pan.
-- Returns nil if no zoom/pan is active (no filter needed).
local function zoom_pan_crop()
    local zoom = mp.get_property_number("video-zoom", -999)
    local pan_x = mp.get_property_number("video-pan-x", -999)
    local pan_y = mp.get_property_number("video-pan-y", -999)
    mp.msg.warn(string.format("[zp] raw: zoom=%+5.2f pan_x=%+5.2f pan_y=%+5.2f", zoom, pan_x, pan_y))
    if zoom <= 0 then
        mp.msg.warn("[zp] zoom <= 0, skipping crop")
        return nil
    end
    if pan_x == -999 then pan_x = 0 end
    if pan_y == -999 then pan_y = 0 end
    local s = 2 ^ zoom
    local filter = string.format("crop=iw/%g:ih/%g:iw*(0.5-0.5/%g-%g):ih*(0.5-0.5/%g-%g)",
                                 s, s, s, pan_x, s, pan_y)
    mp.msg.warn(string.format("[zp] filter=%s", filter))
    mp.osd_message(string.format("ZOOM=%.2f PAN_X=%.2f PAN_Y=%.2f", zoom, pan_x, pan_y), 3)
    return filter
end

local function capture_pair()
    -- 1. Get current position and file path
    local time_pos = mp.get_property_number("time-pos")
    if not time_pos then
        osd_msg("No video position.", 2)
        return
    end

    local file_path = mp.get_property("path")
    if not file_path then
        osd_msg("No file loaded.", 2)
        return
    end

    -- 2. Build filenames
    local filename_stripped = mp.get_property("filename/no-ext") or "video"
    local basename = filename_stripped:gsub("[^%w._-]", "_")

    local label = format_label(time_pos)
    local stem = string.format("%s_%s", basename, label)
    local base_path = utils.join_path(OUTPUT_DIR, stem)

    local ext = "png"
    local normal_path   = dedup_path(base_path, "normal",   ext)
    local modified_path = dedup_path(base_path, "modified", ext)

    -- 3. Ensure output directory exists
    mp.command_native({"run", "mkdir", "-p", OUTPUT_DIR})

    -- 4. Build ffmpeg args for normal screenshot
    local crop_filter = zoom_pan_crop()
    local ffmpeg_args = {"ffmpeg", "-y"}
    local src = mp.get_property("stream-path") or mp.get_property("path", "")
    local mf_prefix = "mf:///tmp/mpv-webp-anim/"

    if src:sub(1, #mf_prefix) == mf_prefix or src:find("/tmp/mpv-webp-anim/") then
        -- mf:// from webp-anim-bridge: use specific frame
        local pattern = src
        if pattern:sub(1, 5) == "mf://" then pattern = pattern:sub(6) end
        local mf_fps = mp.get_property_number("mf-fps", 10)
        local frame_num = math.floor(time_pos * mf_fps)
        local frame_file = pattern:gsub("%%04d", string.format("%04d", frame_num))
        if frame_file == pattern then
            local dir = pattern:match("^(.*/)") or "."
            frame_file = dir .. string.format("frame_%04d.png", frame_num)
        end
        table.insert(ffmpeg_args, "-i"); table.insert(ffmpeg_args, frame_file)
        table.insert(ffmpeg_args, "-vframes"); table.insert(ffmpeg_args, "1")
        table.insert(ffmpeg_args, "-q:v"); table.insert(ffmpeg_args, "3")
    else
        table.insert(ffmpeg_args, "-ss"); table.insert(ffmpeg_args, string.format("%06.3f", time_pos))
        table.insert(ffmpeg_args, "-i"); table.insert(ffmpeg_args, src)
        table.insert(ffmpeg_args, "-vframes"); table.insert(ffmpeg_args, "1")
        table.insert(ffmpeg_args, "-q:v"); table.insert(ffmpeg_args, "3")
    end
    if crop_filter then
        table.insert(ffmpeg_args, "-vf")
        table.insert(ffmpeg_args, crop_filter)
    end
    table.insert(ffmpeg_args, normal_path)

    -- 5. Modified screenshot via mpv (captures current on-screen image with adjustments)
    mp.commandv("screenshot-to-file", modified_path)

    -- 6. Launch ffmpeg async (background, no flashing)
    osd_msg("Capturing screenshots ...", 2)
    print(string.format("[screenshot-duo] Normal:   %s", normal_path))
    print(string.format("[screenshot-duo] Modified: %s", modified_path))

    mp.command_native({
        name = "subprocess",
        args = ffmpeg_args,
        playback_only = false,
        capture_stdout = false,
        capture_stderr = false,
    }, function(success, result, err)
        if success then
            local mpv_info = utils.file_info(modified_path)
            local mpv_size = ""
            if mpv_info and mpv_info.size then
                if mpv_info.size > 1024 * 1024 then
                    mpv_size = string.format(" (%.1f MB)", mpv_info.size / 1024 / 1024)
                elseif mpv_info.size > 1024 then
                    mpv_size = string.format(" (%.0f KB)", mpv_info.size / 1024)
                else
                    mpv_size = string.format(" (%d B)", mpv_info.size)
                end
            end
            osd_msg(string.format("Screenshots: %s%s, %s%s",
                normal_path, format_size(normal_path),
                modified_path, mpv_size), 5)
            print(string.format("[screenshot-duo] Both saved: %s, %s", normal_path, modified_path))
        else
            -- mpv screenshot succeeded but ffmpeg failed
            osd_msg("Normal screenshot failed. Modified saved.", 4)
            print("[screenshot-duo] ffmpeg ERROR: " .. (err or "unknown"))
        end
    end)
end

mp.add_key_binding(nil, "capture", capture_pair)