VisualHMI video playback: play_video/on_video_notify and format requirements

The HMI series supports MP4 video playback, using LUA API to specify the playback file and control the playback area. This routine serves as a complete video player: SD card traversal for .mp4 files → list paging → previous/next track → play/pause/resume → automatically play the next track after completion → display progress and time. Applicable to HMI&M series & DH series.

1. Video format hard requirements (exceeding which playback cannot be supported or may be stuttering)

2. Picture Control Address Table

3. API

4. Lua implementation

4.1 Traverse SD card MP4s

Trigger on_sd_inserted by card insertion → list_dir traversal → filter .mp4 files in on_list_dir callback and store them in video.NameTb:

function on_list_dir(path, filename, type, fsize)
  if type == 1 then                      -- 文件
    local cur_file_type = get_extension(filename)
    if cur_file_type == "mp4" then
      video.allCnt = video.allCnt + 1
      video.NameTb[video.allCnt] = path.."/"..filename
    end
  end
end

function on_sd_inserted(dir)
  sd_dir = dir
  list_dir(sd_dir)
  if video.allCnt > 0 then
    video.allPage = math.modf(video.allCnt / 5)
    if video.allCnt % 5 > 0 then video.allPage = video.allPage + 1 end
    set_uint16(VT_LW, 0x1003, 1)         -- 当前页
    set_uint16(VT_LW, 0x1004, video.allPage)
    set_uint16(VT_LW, 0x1005, 1)         -- 有视频标志
    set_string(VT_LW, 0x1240, "00:00")
    set_string(VT_LW, 0x1250, "00:00")
    updatVideoList(video.curPage)
    updatVideoPlayName(0)
  end
end

function on_sd_removed()
  video.NameTb = {}; video.allCnt = 0
  video.curPage = 1; video.allPage = 1; video.playIndex = 0
  set_uint16(VT_LW, 0x1003, 0)
  set_uint16(VT_LW, 0x1004, 0)
  set_uint16(VT_LW, 0x1005, 0)
  for i = 1, 5 do
    set_string(VT_LW, 0x1100 + (i-1)*0x40, "")
    set_uint16(VT_LW, 0x1500 + (i-1), 0)
  end
end

4.2 Playback control (distributed via on_update)

function on_update(slave, vtype, addr)
  if VT_LW == vtype then
    if addr == 0x1000 then                -- 列表翻页
      local val = get_uint16(VT_LW, 0x1000)
      local cur_page = get_uint16(VT_LW, 0x1003)
      local all_page = get_uint16(VT_LW, 0x1004)
      if val == 0 then                    -- 上一页
        cur_page = cur_page - 1
        if cur_page  all_page then cur_page = all_page end
      end
      set_uint16(VT_LW, 0x1003, cur_page)
      updatVideoList(cur_page)
    elseif addr == 0x1001 then            -- 上下首
      local val = get_uint16(VT_LW, 0x1001)
      set_uint16(VT_LW, 0x1002, 1)
      if val == 0 then                    -- 上一首，到头回绕到最后一首
        video.playIndex = video.playIndex - 1
        if video.playIndex  video.allCnt then video.playIndex = 1 end
      end
      local cur_play_page = math.modf(video.playIndex / 5)
      if video.playIndex % 5 > 0 then cur_play_page = cur_play_page + 1 end
      set_uint16(VT_LW, 0x1003, cur_play_page)
      stop_video()
      play_video(video.NameTb[video.playIndex], play.x, play.y, play.w, play.h)
      updatVideoList(cur_play_page)
      updatVideoPlayName(video.playIndex)
    elseif addr == 0x1002 then            -- 播放/暂停按钮
      local val = get_uint16(VT_LW, 0x1002)
      if val == 0 then pause_video()
      elseif val == 1 then resume_video() end
    elseif addr == 0x1505 then            -- 点击列表某一项播放
      local val = get_uint16(VT_LW, 0x1505)
      local cur_page = get_uint16(VT_LW, 0x1003)
      local temp = video.playIndex
      video.playIndex = (cur_page - 1) * 5 + val
      if video.playIndex  0 then
          updatVideoPlayName(video.playIndex)
          stop_video()
          play_video(video.NameTb[video.playIndex], play.x, play.y, play.w, play.h)
        end
      else
        video.playIndex = temp
      end
    end
  end
end

4.3 Automatically play the next song after finishing + progress display

function on_video_notify(msg, v1, v2)
  local SysSndState = msg          -- 播放状态
  local SysSndPlayTime = v1        -- 当前已播秒数
  local SysSndTotalTime = v2       -- 总秒数
  if SysSndState == 0x01 then      -- 播放中（周期通知）
    set_uint16(VT_LW, 0x1006, (v1*100)//v2)   -- 进度条 0~100
    set_string(VT_LW, 0x1240, string.format("%02d", SysSndPlayTime//60)..":"..
                              string.format("%02d", SysSndPlayTime%60))
    set_string(VT_LW, 0x1250, string.format("%02d", SysSndTotalTime//60)..":"..
                              string.format("%02d", SysSndTotalTime%60))
  elseif SysSndState == 0x00 then  -- 播放完毕（仅一次）
    video.playIndex = video.playIndex + 1
    if video.playIndex > video.allCnt then video.playIndex = 1 end
    local cur_play_page = math.modf(video.playIndex / 5)
    if video.playIndex % 5 > 0 then cur_play_page = cur_play_page + 1 end
    local cur_page = get_uint16(VT_LW, 0x1003)
    if cur_play_page == cur_page then
      updatVideoPlayName(video.playIndex)
    else
      updatVideoPlayName(0)
    end
    stop_video()
    play_video(video.NameTb[video.playIndex], play.x, play.y, play.w, play.h)
  end
  redraw()
end

Compiled from Guangzhou Dacai Technology VisualHMI development documentation (hmi-doc.gz-dc.com) LUA tutorial "Video Playback", copyright reserved by Dacai Technology.