diff --git a/pytchat/downloader/downloader.py b/pytchat/downloader/downloader.py
index b2bb385..7257759 100644
--- a/pytchat/downloader/downloader.py
+++ b/pytchat/downloader/downloader.py
@@ -1,167 +1,32 @@
 import asyncio
 import aiohttp,async_timeout
 import json
-from tqdm import tqdm
 import traceback,time
-from requests.exceptions import ConnectionError
 from urllib.parse import quote
-from multiprocessing import Process,  Queue
 
-from . import dictquery
+from . import parser
 from .. import config
+from .. import util
 from .. paramgen import arcparam
 
-
-
-
 logger = config.logger(__name__)
+headers=config.headers
 
 REPLAY_URL = "https://www.youtube.com/live_chat_replay/" \
              "get_live_chat_replay?continuation="
 
-async def _dl_piece(_session,queue,movie_id,offset_ms,duration_ms,pbar_pos,is_lastpiece,dl_end):
-    #print(f'_dl_piece:{movie_id},{offset_ms},{duration_ms},{pbar_pos},{is_lastpiece}')
-    
-    chat_data=[]
-    if pbar_pos == 0:
-        #continue_url = construct.encoder.encode(construct.construct_seekinit(movie_id,filter='all'))
-        continuation = arcparam.getparam(movie_id,-1)
-    else:
-        continuation = arcparam.getparam(movie_id,offset_ms/1000)
-    next_url = f"{REPLAY_URL}{quote(continuation)}&pbj=1"
-        
-    #print(pbar_pos,next_url)
-    chat_data = await _dl(session=_session,
-                        queue = queue,
-                        next_url =next_url,
-                        absolute_start = offset_ms,
-                        duration = duration_ms,
-                        pbar_pos = pbar_pos,
-                        is_lastpiece = is_lastpiece,
-                        dl_end = dl_end)
-    return chat_data
-
-def get_init_offset_ms(dics: dict):
-    n = 0
-    while(True):
-        init_offset_ms = dics["response"]["continuationContents"]["liveChatContinuation"]["actions"][n].get("replayChatItemAction")['videoOffsetTimeMsec']
-        if init_offset_ms is None:
-            n += 1
-            continue
-        else:
-            return int(init_offset_ms)
-
-def get_last_offset_ms(dics: dict):
-    m = -1                    
-    while(True):
-        last_offset_ms = dics["response"]["continuationContents"]["liveChatContinuation"]["actions"][m].get("replayChatItemAction")['videoOffsetTimeMsec']
-        if last_offset_ms is None:
-            m -= 1
-            continue
-        else:
-            return int(last_offset_ms)
-        
-
-async def _dl(session,queue, next_url, absolute_start,duration,pbar_pos,is_lastpiece,dl_end):
-    async with async_timeout.timeout(1000):
-        chat_data = []
-        #print('absolute',absolute_start,'duration',duration,'pos',pbar_pos)
-        dlerror=False
-        first = True
-        rqerr=0
-        jserr=0
-        while(True):
-
-            try:
-                #json形式のchatデータのダウンロードと読み込み
-                async with session.get(next_url,headers=config.headers) as response:
-                    text = await response.text()
-                    dics = json.loads(text)
-
-                    continuation = dics["response"]["continuationContents"]["liveChatContinuation"]["continuations"][0]["liveChatReplayContinuationData"]["continuation"]
-                    #次のlive_chat_replayのurl
-                    next_url =f"{REPLAY_URL}{continuation}&pbj=1"
-
-                    init_offset_ms = get_init_offset_ms(dics)
-                    last_offset_ms = get_last_offset_ms(dics)
-                    length_ms      = last_offset_ms - init_offset_ms
-                    #print(f'[{pbar_pos}] length_ms = {length_ms}, total={last_offset_ms}')
-                    if length_ms < 0:
-                        raise Exception('length_ms < 0')
-                    queue.put(length_ms)
-                    if first:
-                        #print(dics["response"]["continuationContents"]["liveChatContinuation"]["actions"][0])
-                        #with open(str(pbar_pos)+'FIRST') as f:
-                        #    f.writelines(dics)##############################
-                        if pbar_pos > 0:
-                            #print(f'Reset dl_end[{pbar_pos - 1}]:{dl_end[pbar_pos - 1]} -> {init_offset_ms} ({init_offset_ms-dl_end[pbar_pos - 1]})')
-                            dl_end[pbar_pos - 1] = init_offset_ms
-                        first = False
-                    #print(dics["response"]["continuationContents"]["liveChatContinuation"]["actions"][0])
-                    chat_data.extend(dics["response"]["continuationContents"]["liveChatContinuation"]["actions"])
-                    #print(chat_data)
-                    if (last_offset_ms >= dl_end[pbar_pos]) and not(is_lastpiece):
-                        #save(pbar_pos,'LAST ',init_offset_ms,last_offset_ms,dics)###############################
-                        #print(f'break:pbar_pos ={pbar_pos}')
-                        queue.put('quit')
-                        break
-
-            # next_urlが入手できなくなったら終わり
-            except KeyError:
-                queue.put('quit')
-                break
-            # JSONDecodeErrorが発生した場合はデータを取得しなおす。
-            except json.decoder.JSONDecodeError:
-                time.sleep(1)
-                jserr+=1
-                if jserr<20:
-                    continue
-                else:
-                    logger.error('JSONDecodeError at piece %d' % (pbar_pos))
-                    queue.put(quit)
-                    dlerror = True
-                    break
-            except ConnectionError:
-                time.sleep(1)
-                rqerr+=1
-                if rqerr<20:
-                    continue
-                else:
-                    logger.error('ConnectionError at piece %d' % (pbar_pos))
-                    queue.put(quit)
-                    dlerror = True
-                    break
-            #except KeyboardInterrupt:
-            #    pass
-            except UnicodeDecodeError as e:
-                logger.error(f"{type(e)}, {str(e)}")
-                logger.error(f"{str(e.object)}")
-                with open('unicodeerror.txt', mode ="w", encoding='utf-8') as f:
-                    f.writelines(str(e.object))
-                break
-            except:
-                logger.error('\n不明なエラーが発生しました%d at:' % (pbar_pos))
-                logger.error('%s\n' % (next_url))
-                traceback.print_exc()
-                try:
-                    with open('error.json', mode ="w", encoding='utf-8') as f:
-                        f.writelines(text)
-                except UnboundLocalError as ule:
-                    pass
-                queue.put('quit')
-                dlerror = True
-                break
-        #session.close()
-        if dlerror:
-            return 'error'
-        else:
-            return chat_data  
 
+class Block:
+    def __init__(self, pos=0, init_offset=0, last_offset=0,
+                 continuation='', chat_data=[]):
+        self.pos = pos
+        self.init_offset = init_offset
+        self.last_offset = last_offset
+        self.stop_offset = 0
+        self.continuation = continuation
+        self.chat_data = chat_data
 
 def _debug_save(_pbar_pos,prefix,init_offset_ms,last_offset_ms,dics):
-    '''
-    例外が発生したときのチャットデータを保存する。
-    '''
     chat_data =[]
     init = '{:0>8}'.format(str(init_offset_ms))
     last = '{:0>8}'.format(str(last_offset_ms))
@@ -170,121 +35,255 @@ def _debug_save(_pbar_pos,prefix,init_offset_ms,last_offset_ms,dics):
     with open(f"[{_pbar_pos}]-{prefix}-from_{init}_to_{last}.data",mode ='w',encoding='utf-8') as f:
         f.writelines(chat_data)
 
-def _debug_chatblock():
-    pass
+        
+def dump(o):
+    for key, value in o.__dict__.items():
+        if key != "chat_data":
+            print(key, ':', value)
 
+def dumpt(blocks,mes = None):
+    print(f"{'-'*40}\n{mes}")
+    [print(f"pos:{b.pos:>2}   |init:{b.init_offset: >12,}   |last:{b.last_offset: >12,}   |stop:{b.stop_offset :>12,} ")
+        for b in blocks]
 
-async def _asyncdl(argslist):
-    promises=[]
-    async with aiohttp.ClientSession() as session:
-        promises = [_dl_piece(session,*args) for args in argslist]
-        return await asyncio.gather(*promises)
-
-def _listener(q,duration,div):
-    duration_ms =int(duration/1000)
-    ret = int(div)
-    pbar = tqdm(total = duration_ms, ncols=80,unit_scale = 1,
-         bar_format='{desc}{percentage:3.0f}%|{bar}|[{n_fmt:>7}/{total_fmt}]{elapsed}<{remaining}')
-    #Noneを見つけるまでgetし続ける。
+def _divide_(start, end, count):
+    min_interval = 120
+    if (not isinstance(start,int) or 
+        not isinstance(end,int) or 
+        not isinstance(count,int)):
+        raise ValueError("start/end/count must be int")
+    if start>end:
+        raise ValueError("end must be equal to or greater than start.")
+    if count<1:
+        raise ValueError("count must be equal to or greater than 1.")
+    if (end-start)/count < min_interval:
+        count = int((end-start)/min_interval) 
+        if count == 0 : count = 1
+    interval= (end-start)/count 
     
-    for item in iter(q.get, None):
-        if(item=='quit'):
-            ret=ret-1
-            if(ret==0):
-                if duration_ms>0:
-                    pbar.update(duration_ms)
-                pbar.close()
+    if count == 1:
+        return [start]
+    return sorted(list(set([int(start+interval*j)
+        for j in range(count) ])))
+
+
+def ready_blocks(video_id:str, div:int, duration:int):
+    if div <= 0: raise ValueError
+
+    def _divide(start, end, count):
+        if (not isinstance(start,int) or 
+            not isinstance(end,int) or 
+            not isinstance(count,int)):
+            raise ValueError("start/end/count must be int")
+        if start>end:
+            raise ValueError("end must be equal to or greater than start.")
+        if count<1:
+            raise ValueError("count must be equal to or greater than 1.")
+
+        interval= (end-start)/(count) 
+        if interval < 120 :
+            interval=120
+            count = int((end-start)/interval)+1
+        if count == 1:
+            return [start]
+        return sorted(list(set([int(start+interval*j)
+            if j < count else end 
+            for j in range(count) ])))
+
+    async def _get_blocks(duration,div):
+        async with aiohttp.ClientSession() as session:
+            futures = [_create_block(session, pos, seektime)
+                for pos, seektime in enumerate(_divide(-1, duration , div))]
+            return await asyncio.gather(*futures,return_exceptions=True)
+
+    async def _create_block(session, pos, seektime):
+        continuation = arcparam.getparam(video_id,seektime=seektime)
+        url = f"{REPLAY_URL}{quote(continuation)}&pbj=1"
+
+        async with session.get(url,headers = headers) as resp:
+            text = await resp.text()
+        #util.save(text,f"v:/~~/pre_{pos}_",".json")
+        next_continuation, actions = parser.parse(json.loads(text))
+        block = Block(
+            pos = pos,
+            continuation = next_continuation,
+            chat_data = actions,
+            init_offset = parser.get_offset(actions[0]),
+            last_offset = parser.get_offset(actions[-1])
+        )
+        return block
+
+    blocks=[]
+    loop = asyncio.get_event_loop()
+    blocks = loop.run_until_complete(_get_blocks(duration,div))
+    return blocks  
+
+def remove_duplicate_head(blocks):
+    def is_same_offset(index):
+        return (blocks[index].init_offset == blocks[index+1].init_offset)
+
+    def is_same_id(index):
+        id_0 = parser.get_id(blocks[index].chat_data[0])
+        id_1 = parser.get_id(blocks[index+1].chat_data[0])
+        return (id_0 == id_1)
+
+    def is_same_type(index):
+        type_0 = parser.get_type(blocks[index].chat_data[0])
+        type_1 = parser.get_type(blocks[index+1].chat_data[0])
+        return (type_0 == type_1)
+
+    ret = []
+    [ret.append(blocks[i]) for i in range(len(blocks)-1)
+        if (len(blocks[i].chat_data)>0 and 
+        not ( is_same_offset(i) and is_same_id(i) and is_same_type(i)))]
+    ret.append(blocks[-1])
+    blocks = None
+    return ret
+
+def remove_overwrap(blocks):
+    def is_overwrap(a, b):
+        print(f"comparing({a}, {b})....overwrap ({(blocks[a].last_offset > blocks[b].init_offset)})")
+        return (blocks[a].last_offset > blocks[b].init_offset)
+    
+    ret = []
+    a = 0
+    b=1
+    jmp = False
+    ret.append(blocks[0])
+    while a < len(blocks)-2:
+
+        while is_overwrap(a,b):
+            b+=1
+            print("forward")
+            if b == len(blocks)-2:
+                jmp=True    
+                break
+        if jmp: break
+        if b-a == 1:
+            print(f"next  ret.append(blocks[{b}]")
+            ret.append(blocks[b])
+            a = b
+            b+=1
+
+            continue
         else:
-            item =int(item/1000)
-            if duration_ms - item >= 0 and  item >= 0:
-                duration_ms -= item
-                pbar.update(item) 
+            print(f"apart ret.append(blocks[{b-1}]")
+            ret.append(blocks[b-1])
+            a=b-1
+            b=a+1
+    ret.append(blocks[-1])            
+    return ret
+
+def remove_duplicate_tail(blocks):
+    def is_same_offset(index):
+        return blocks[index-1].init_offset == blocks[index].init_offset
+
+    def is_same_id(index):
+        id_0 = parser.get_id(blocks[index-1].chat_data[-1])
+        id_1 = parser.get_id(blocks[index].chat_data[-1])
+        return id_0 == id_1
+
+    def is_same_type(index):
+        type_0 = parser.get_type(blocks[index-1].chat_data[-1])
+        type_1 = parser.get_type(blocks[index].chat_data[-1])
+        return type_0 == type_1
+
+    ret = []
+    [ret.append(blocks[i]) for i in range(len(blocks)-1)
+        if not ( is_same_offset(i) and is_same_id(i) and is_same_type(i) )]
+    ret.append(blocks[-1])
+    blocks = None
+    return ret
+    
+
+def set_stop_offset(blocks):
+    for i in range(len(blocks)-1):
+        blocks[i].stop_offset = blocks[i+1].init_offset
+    blocks[-1].stop_offset = -1
+    return blocks
 
 
-def _combine(chatblocks):
-    '''
-    分割DLしたチャットデータを結合する
-    1番目の固まり(chatblocks[0])に順次結合していく。
-    '''
-    line=''
+def download_each_block(blocks):
+    loop = asyncio.get_event_loop()
+    return loop.run_until_complete(_dl_block(blocks))
+
+async def _dl_block(blocks):
+    futures = []
+    async with aiohttp.ClientSession() as session:
+        futures = [_dl_chunk(session, block) for block in blocks]
+        return await asyncio.gather(*futures,return_exceptions=True)    
+
+async def _dl_chunk(session, block:Block):
+    if (block.stop_offset != -1 and
+        block.last_offset > block.stop_offset):
+        return 
+
+    def get_last_offset(actions):
+        return parser.get_offset(actions[-1])
+
+    continuation = block.continuation
+    while continuation:
+        print(block.pos)
+        url = f"{REPLAY_URL}{quote(continuation)}&pbj=1"
+        async with session.get(url,headers = config.headers) as resp:
+            text = await resp.text()
+        continuation, actions = parser.parse(json.loads(text))
+        if actions:
+            block.chat_data.extend(actions)
+            last_offset = get_last_offset(actions)
+            if block.stop_offset != -1:
+                if last_offset > block.stop_offset:
+                    block.last_offset = last_offset
+                    break
+            else:
+                block.last_offset = last_offset
+
+
+def combine(blocks):
+    line = ''
     try:
-        if len(chatblocks[0])>0:
-            lastline=chatblocks[0][-1]
-            #lastline_id = dictquery.getid_replay(json.loads(lastline))
-            lastline_id = dictquery.getid_replay(lastline)
+        if len(blocks[0].chat_data)>0:
+            lastline=blocks[0].chat_data[-1]
+            lastline_offset = parser.get_offset(lastline)
         else: return None
-        for i in range(1,len(chatblocks)):
-            f=chatblocks[i]
+        for i in range(1,len(blocks)):
+            f=blocks[i].chat_data
             if len(f)==0:
                 logger.error(f'zero size piece.:{str(i)}')
                 continue
-            #チャットデータの行を最初から走査して直前のデータの末尾との共通行を探す
             for row in range(len(f)):
-                #row行目のデータ
                 line = f[row]
-                #末尾が直前のデータの末尾行と等しい（ダウンロードタイミングが異なると
-                #trackingParamsが一致しないためidで判定）
-                #if dictquery.getid_replay(json.loads(line)) == lastline_id:
-                if dictquery.getid_replay(line) == lastline_id:
-                    #共通行が見つかったので、共通行以降を結合する
-                    #print(f'[{i}][{row}]Find common line {lastline_id}')
-                    chatblocks[0].extend(f[row+1:])
+                if parser.get_offset(line) > lastline_offset:
+                    blocks[0].chat_data.extend(f[row:])
                     break
                 if line =='error':
                     logger.error(f'Error file was saved.: piece:{str(i)}')
                     return['error']
-            else:#forの途中でbreakが発生しなかった場合ここに飛ぶ
-                #ファイルの結合点（共通ライン）の発見に失敗
-                logger.error(f'Missing common line.: piece:{str(i-1)}->{str(i)} lastline_id= {lastline_id}')
-                return ['combination failed']#---------------------------------test
-            #最終行のデータを更新する
-            lastline = f[-1]
-            #dic_lastline=json.loads(lastline)
-            dic_lastline=lastline
-            lastline_id = dictquery.getid_replay(dic_lastline)
-            #print(f'[{i}]lastline_id:{lastline_id}')
-        print(f"length:{len(chatblocks[0])}")
-        return chatblocks[0]
+            else:
+                logger.error(f'Missing common line.: piece:{str(i-1)}->{str(i)} lastline_id= {lastline_offset}')
+                return ['combination failed']
+            lastline_offset = parser.get_offset( f[-1])
+        return blocks[0].chat_data
     except Exception as e:
         logger.error(f"{type(e)} {str(e)} {line}")
         traceback.print_exc()
-        # p= json.loads(line)
-        # with open('v:/~~/error_dic.json',mode ='w',encoding='utf-8') as f:
-        #     f.write(line)
+        
 
+def download(video_id, duration, div):
+    blocks = ready_blocks(video_id=video_id, duration=duration, div=div)
+    dumpt(blocks,"ready_blocks")
 
-def download(movie_id, duration, divisions):
-    #動画の長さ（ミリ秒）
-    duration_ms=duration*1000
-    #分割DL数
-    div = divisions
-    #プログレスバー用のQueue
-    queue= Queue()
-    #プログレスバー用のプロセス
-    proc = Process(target=_listener,args=(queue,duration_ms,div))
-    proc.start()
-    #チャットデータの分割間隔(ミリ秒）
-    term_ms = int(duration_ms / div)
-    #チャットデータの取得開始時間
-    start_ms = 0
-    #分割したピースが最後かどうか
-    is_lastpiece  = False
-    argslist=[]
-    dl_end=[]
-    #分割DL用の引数を用意
-    for i in range(0,div):
-        if i==div-1:
-            is_lastpiece =True
-        args = (queue, movie_id, start_ms, term_ms, i, is_lastpiece,dl_end)
-        argslist.append(args)
-        start_ms+=term_ms
-        dl_end.append(start_ms)
+    selected = remove_duplicate_head(blocks)
+    dumpt(selected,"removed duplicate_head")
+    
+    
+    set_stop_offset(selected)
+    dumpt(selected,"set stop_offset")
+    #set_stop_offset(selected)
+    removed = remove_overwrap(selected)
+    dumpt(removed,"removed overwrap")   
+     
+    download_each_block(removed)
+    dumpt(removed,"downloaded each_block")
 
-    loop = asyncio.get_event_loop()  
-    chatlist =loop.run_until_complete(_asyncdl(argslist))
-    #プログレスバーのプロセスを終了させるためQueueにNoneを送る
-    queue.put(None)
-    #分割DLされたチャットデータを結合して返す
-
-    return _combine(chatlist)
- 
\ No newline at end of file
+    return combine(removed)
\ No newline at end of file
diff --git a/pytchat/downloader/downloader_test.py b/pytchat/downloader/downloader_old.py
similarity index 90%
rename from pytchat/downloader/downloader_test.py
rename to pytchat/downloader/downloader_old.py
index 67ae41e..1c5c75b 100644
--- a/pytchat/downloader/downloader_test.py
+++ b/pytchat/downloader/downloader_old.py
@@ -10,7 +10,7 @@ from multiprocessing import Process,  Queue
 from . import dictquery
 from .. import config
 from .. paramgen import arcparam
-
+from .. import util
 
 
 
@@ -45,12 +45,10 @@ def get_init_offset_ms(dics: dict):
     n = 0
     while(True):
         init_offset_ms = dics["response"]["continuationContents"]["liveChatContinuation"]["actions"][n].get("replayChatItemAction")['videoOffsetTimeMsec']
-
         if init_offset_ms is None:
             n += 1
             continue
         else:
-
             return int(init_offset_ms)
 
 def get_last_offset_ms(dics: dict):
@@ -67,7 +65,7 @@ def get_last_offset_ms(dics: dict):
 async def _dl(session,queue, next_url, absolute_start,duration,pbar_pos,is_lastpiece,dl_end):
     async with async_timeout.timeout(1000):
         chat_data = []
-        print('absolute',absolute_start,'duration',duration,'pos',pbar_pos)
+        #print('absolute',absolute_start,'duration',duration,'pos',pbar_pos)
         dlerror=False
         first = True
         rqerr=0
@@ -78,6 +76,7 @@ async def _dl(session,queue, next_url, absolute_start,duration,pbar_pos,is_lastp
                 #json形式のchatデータのダウンロードと読み込み
                 async with session.get(next_url,headers=config.headers) as response:
                     text = await response.text()
+                    util.save(text,"v:/~~/test_",".json")
                     dics = json.loads(text)
 
                     continuation = dics["response"]["continuationContents"]["liveChatContinuation"]["continuations"][0]["liveChatReplayContinuationData"]["continuation"]
@@ -85,28 +84,26 @@ async def _dl(session,queue, next_url, absolute_start,duration,pbar_pos,is_lastp
                     next_url =f"{REPLAY_URL}{continuation}&pbj=1"
 
                     init_offset_ms = get_init_offset_ms(dics)
-
                     last_offset_ms = get_last_offset_ms(dics)
-
                     length_ms      = last_offset_ms - init_offset_ms
                     #print(f'[{pbar_pos}] length_ms = {length_ms}, total={last_offset_ms}')
                     if length_ms < 0:
                         raise Exception('length_ms < 0')
                     queue.put(length_ms)
                     if first:
-                        print(f"[{pbar_pos}]Init_offset:",init_offset_ms)
-                        #save(pbar_pos,'FIRST',init_offset_ms,last_offset_ms,dics)##############################
+                        #print(dics["response"]["continuationContents"]["liveChatContinuation"]["actions"][0])
+                        #with open(str(pbar_pos)+'FIRST') as f:
+                        #    f.writelines(dics)##############################
                         if pbar_pos > 0:
                             #print(f'Reset dl_end[{pbar_pos - 1}]:{dl_end[pbar_pos - 1]} -> {init_offset_ms} ({init_offset_ms-dl_end[pbar_pos - 1]})')
                             dl_end[pbar_pos - 1] = init_offset_ms
                         first = False
-
+                    #print(dics["response"]["continuationContents"]["liveChatContinuation"]["actions"][0])
                     chat_data.extend(dics["response"]["continuationContents"]["liveChatContinuation"]["actions"])
                     #print(chat_data)
                     if (last_offset_ms >= dl_end[pbar_pos]) and not(is_lastpiece):
                         #save(pbar_pos,'LAST ',init_offset_ms,last_offset_ms,dics)###############################
                         #print(f'break:pbar_pos ={pbar_pos}')
-                        print(f"[{pbar_pos}]last_offset",last_offset_ms)
                         queue.put('quit')
                         break
 
@@ -215,8 +212,7 @@ def _combine(chatblocks):
         if len(chatblocks[0])>0:
             lastline=chatblocks[0][-1]
             #lastline_id = dictquery.getid_replay(json.loads(lastline))
-            lastline_offsettime = dictquery.get_offsettime(lastline)
-            print('lastline_offsettime',lastline_offsettime)
+            lastline_id = dictquery.getid_replay(lastline)
         else: return None
         for i in range(1,len(chatblocks)):
             f=chatblocks[i]
@@ -230,23 +226,23 @@ def _combine(chatblocks):
                 #末尾が直前のデータの末尾行と等しい（ダウンロードタイミングが異なると
                 #trackingParamsが一致しないためidで判定）
                 #if dictquery.getid_replay(json.loads(line)) == lastline_id:
-                if dictquery.get_offsettime(line) > lastline_offsettime:
+                if dictquery.getid_replay(line) == lastline_id:
                     #共通行が見つかったので、共通行以降を結合する
-                    print(f'[{i}][{row}]Find common line {lastline_offsettime}')
-                    chatblocks[0].extend(f[row:])
+                    #print(f'[{i}][{row}]Find common line {lastline_id}')
+                    chatblocks[0].extend(f[row+1:])
                     break
                 if line =='error':
                     logger.error(f'Error file was saved.: piece:{str(i)}')
                     return['error']
             else:#forの途中でbreakが発生しなかった場合ここに飛ぶ
                 #ファイルの結合点（共通ライン）の発見に失敗
-                logger.error(f'Missing common line.: piece:{str(i-1)}->{str(i)} lastline_id= {lastline_offsettime}')
+                logger.error(f'Missing common line.: piece:{str(i-1)}->{str(i)} lastline_id= {lastline_id}')
                 return ['combination failed']#---------------------------------test
             #最終行のデータを更新する
             lastline = f[-1]
             #dic_lastline=json.loads(lastline)
             dic_lastline=lastline
-            lastline_offsettime = dictquery.get_offsettime(dic_lastline)
+            lastline_id = dictquery.getid_replay(dic_lastline)
             #print(f'[{i}]lastline_id:{lastline_id}')
         print(f"length:{len(chatblocks[0])}")
         return chatblocks[0]
@@ -290,15 +286,6 @@ def download(movie_id, duration, divisions):
     #プログレスバーのプロセスを終了させるためQueueにNoneを送る
     queue.put(None)
     #分割DLされたチャットデータを結合して返す
+
     return _combine(chatlist)
-
-def check():
-    #先頭のブロックから、offsettimeを調べる
-    #offsettimeが等しい場合はIDを調べ、ＩＤも一致していたら、
-    #比較元以下を連結対象から外す
-    for  i in range(0,len(blocks)-1):
-        if (offset(i)==offset(i+1)):
-            if(id(i)==id(i+1)):
-                discard(i+1)
-
  
\ No newline at end of file
diff --git a/pytchat/downloader/parser.py b/pytchat/downloader/parser.py
new file mode 100644
index 0000000..37bb6fd
--- /dev/null
+++ b/pytchat/downloader/parser.py
@@ -0,0 +1,58 @@
+import json
+from .. import config
+from .. exceptions import ( 
+    ResponseContextError, 
+    NoContentsException, 
+    NoContinuationsException )
+
+
+logger = config.logger(__name__)
+
+def parse(jsn):
+    """
+    Parse replay chat data.
+    Parameter:
+    ----------
+    jsn : dict
+        JSON of replay chat data.
+    Returns:
+    ------
+        continuation : str
+        actions : list
+
+    """
+    if jsn is None: 
+        raise ValueError("parameter JSON is None")
+    if jsn['response']['responseContext'].get('errors'):
+        raise ResponseContextError('動画に接続できません。'
+    '動画IDが間違っているか、動画が削除／非公開の可能性があります。')
+    contents=jsn['response'].get('continuationContents')
+    #配信が終了した場合、もしくはチャットデータが取得できない場合
+    if contents is None:
+        raise NoContentsException('チャットデータを取得できませんでした。')
+
+    cont = contents['liveChatContinuation']['continuations'][0]
+    if cont is None:
+        raise NoContinuationsException('Continuationがありません。')
+    metadata = cont.get('liveChatReplayContinuationData')
+    if metadata:
+        continuation = metadata.get("continuation")
+        actions = contents['liveChatContinuation'].get('actions')
+        return continuation, actions
+    return None, []
+
+    # if actions is None:
+    #     return {"continuation":None,"chatdata":[]}
+    
+
+def get_offset(item):
+    return int(item['replayChatItemAction']["videoOffsetTimeMsec"])
+
+def get_id(item):
+    #return list((list(item['replayChatItemAction']["actions"][0].values())[0])['item'].values())[0]['id']
+    return list(item['replayChatItemAction']['actions'][0]['addChatItemAction']['item'].values())[0]['id']
+
+def get_type(item):
+    return list(item['replayChatItemAction']["actions"][0]['addChatItemAction']['item'].keys())[0]
+
+