Subtitle Text+ clips auto-placer for DaVinci Resolve. It needs to place audio clips manually, but automates corresponding subtitles from your template caption Text+ clip.

subtitle_placer.lua

-- Original: https://zenn.dev/kirimin/articles/3abcada2b1646f by kirimin https://github.com/kirimin

-- convention of voice/text file: "num_character_content" + ".wav" or ".txt"

-- Replace configs here
local TEXT_DIR    = "/Users/mikuroxina/Documents/Projects/Scripts/pencil-puzzles/05/voices/" -- folder contains txt and wav
local AUDIO_TRACK = 2 -- number of audio track placed character voices
local CHARACTERS  = { "中国うさぎ" } -- names of character, used in file name

-- --------------------------------------------------
local is_win      = package.config:sub(1, 1) == "\\"

local function list_files(dir, ext)
    local cmd = is_win
        and string.format('dir /b "%s\\*.%s"', dir, ext)
        or string.format('ls -1 "%s" | grep "\\.%s$"', dir, ext)
    local p   = io.popen(cmd)
    if p == nil then
        error("failed to open pipe to ls command")
    end
    local out = {}
    for line in p:lines() do table.insert(out, line) end
    p:close()
    return out
end

local function read_text(path)
    local f = io.open(path, "r")
    if f == nil then
        error(string.format("failed to open file: %s", path))
    end
    local t = f:read("*all"):gsub("\r?\n", " ")
    f:close()
    return t
end

-- find clips by name in the media pool
local function find_clip_by_name(folder, name)
    for _, clip in ipairs(folder:GetClipList()) do
        local clipName = clip:GetClipProperty("Clip Name")
        local clipType = clip:GetClipProperty("Type") or "--unknown--"
        print("clip name: " .. clipName .. ", type: " .. clipType)
        if clipName == name then
            return clip
        end
    end
    for _, subfolder in ipairs(folder:GetSubFolderList()) do
        local clip = find_clip_by_name(subfolder, name)
        if clip then
            return clip
        end
    end
    return nil
end

-- initialize Resolve API
resolve = Resolve()
projectManager = resolve:GetProjectManager()
project = projectManager:GetCurrentProject()
mediaPool = project:GetMediaPool()
folder = mediaPool:GetCurrentFolder()
tl = project:GetCurrentTimeline()

-- get Text+ clips for each character from the media pool
local textPlusClips = {}
for _, char in ipairs(CHARACTERS) do
    local clip = find_clip_by_name(folder, char)
    if not clip then
        error("clip not found in the media pool - " .. char)
    end
    textPlusClips[char] = clip
end

-- store of subtitle data
local subDict = {}

-- load text files in TEXT_DIR and store into subDict
local files = list_files(TEXT_DIR, "txt")
for _, file in ipairs(files) do
    --  use file basename as key
    local base = file:gsub("%.txt$", "")
    local char = file:match("^%d+%_(.+)%_.+%.txt$")
    if base and char then
        local path = TEXT_DIR .. "/" .. file
        local text = read_text(path)
        print(string.format("base: %s, char: %s, text: %s", base, char, text))
        subDict[base] = { char = char, text = text }
    else
        print("invalid file name - " .. file)
    end
end

-- add new video track to the timeline
tl:AddTrack("video")
local subIdx = tl:GetTrackCount("video")

-- get all clips in the audio track
local clips = tl:GetItemListInTrack("audio", AUDIO_TRACK)
for _, c in ipairs(clips) do
    -- get basename from the audio clip name
    local base = c:GetName():gsub("%.wav$", "")
    -- get metadata from subDict
    local meta = subDict[base]
    if not meta then
        error("not found subtitle txt file for - " .. base)
    end

    -- get template Text+ clip for the character
    local textPlusClip = textPlusClips[meta.char]
    if not textPlusClip then
        error("not found character Text+ clip for - " .. meta.char)
    end
    print("found Text+ clip:", textPlusClip)

    local timelineItem = nil
    -- add a new Text+ clip to the timeline
    local s = c:GetStart()        -- start frame
    local e = s + c:GetDuration() -- end frame

    local timeline_fps = tonumber(project:GetSetting("timelineFrameRate"))
    local clip_fps = textPlusClip:GetClipProperty("FPS")

    print("audio clip's start frame:", s, "end frame:", e)
    print(e - s, "length of frames")
    -- configuration of a new clip
    local item = {
        ["mediaPoolItem"] = textPlusClip,
        ["startFrame"] = 0,                                           -- seek position of source media, so it should be zero
        ["endFrame"] = math.floor((e - s) * clip_fps / timeline_fps), -- convert to frames in the timeline
        ["startTimecode"] = s,
        ["endTimecode"] = e,
        ["trackType"] = "video",
        ["trackIndex"] = subIdx,
        ["recordFrame"] = math.floor(s) -- starting position
    }

    local result = mediaPool:AppendToTimeline({ item }) -- note: pass item in an array
    print("AppendToTimeline result:", result)
    for _, to_place in ipairs(result) do
        timelineItem = to_place
    end

    if not timelineItem then
        error("failed to add a clip to the timeline - " .. meta.char)
    end
    -- get Fusion composition to style
    local fusionComp = timelineItem:GetFusionCompByIndex(1)
    if not fusionComp then
        error("expected Fusion composition")
    end
    local textNode = fusionComp:FindTool("Template")
    if not textNode then
        error("expected Text+ template")
    end
    -- apply Text+ character subtitle style
    textNode:SetInput("StyledText", meta.text)
end

print("subtitle placing complete")