Merge d2344827c8 into eb15fd5a32

Closes #3937
Authored by: krichbanana, pzhlkj6612

Co-authored-by: Mozi <29089388+pzhlkj6612@users.noreply.github.com>

test/test_mp4parser.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python
+
+# Allow direct execution
+import os
+import sys
+import unittest
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+import io
+
+from yt_dlp.postprocessor.mp4direct import (
+    parse_mp4_boxes,
+    write_mp4_boxes,
+)
+
+TEST_SEQUENCE = [
+    ('test', b'123456'),
+    ('trak', b''),
+    ('helo', b'abcdef'),
+    ('1984', b'1q84'),
+    ('moov', b''),
+    ('keys', b'2022'),
+    (None, 'moov'),
+    ('topp', b'1991'),
+    (None, 'trak'),
+]
+
+# on-file reprensetation of the above sequence
+TEST_BYTES = b'\x00\x00\x00\x0etest123456\x00\x00\x00Btrak\x00\x00\x00\x0eheloabcdef\x00\x00\x00\x0c19841q84\x00\x00\x00\x14moov\x00\x00\x00\x0ckeys2022\x00\x00\x00\x0ctopp1991'
+
+
+class TestMP4Parser(unittest.TestCase):
+    def test_write_sequence(self):
+        with io.BytesIO() as w:
+            write_mp4_boxes(w, TEST_SEQUENCE)
+            bs = w.getvalue()
+        self.assertEqual(TEST_BYTES, bs)
+
+    def test_read_bytes(self):
+        with io.BytesIO(TEST_BYTES) as r:
+            result = list(parse_mp4_boxes(r))
+        self.assertListEqual(TEST_SEQUENCE, result)
+
+    def test_mismatched_box_end(self):
+        with io.BytesIO() as w, self.assertRaises(AssertionError):
+            write_mp4_boxes(w, [
+                ('moov', b''),
+                ('trak', b''),
+                (None, 'moov'),
+                (None, 'trak'),
+            ])

yt_dlp/YoutubeDL.py

@@ -58,6 +58,7 @@ from .postprocessor import (
     FFmpegPostProcessor,
     FFmpegVideoConvertorPP,
     MoveFilesAfterDownloadPP,
+    MP4FixupTimestampPP,
     get_postprocessor,
 )
 from .postprocessor.ffmpeg import resolve_mapping as resolve_recode_mapping
@@ -3548,8 +3549,11 @@ class YoutubeDL:
                                      and (info_dict.get('is_live') or info_dict.get('is_dash_periods')),
                                      'Possible duplicate MOOV atoms', FFmpegFixupDuplicateMoovPP)
 
+                    is_fmp4 = info_dict.get('protocol') == 'websocket_frag' and info_dict.get('container') == 'fmp4'
                     ffmpeg_fixup(downloader == 'web_socket_fragment', 'Malformed timestamps detected', FFmpegFixupTimestampPP)
                     ffmpeg_fixup(downloader == 'web_socket_fragment', 'Malformed duration detected', FFmpegFixupDurationPP)
+                    ffmpeg_fixup(downloader == 'web_socket_to_file' and is_fmp4, 'Malformed timestamps detected', MP4FixupTimestampPP)
+                    ffmpeg_fixup(downloader == 'web_socket_to_file' and is_fmp4, 'Possible duplicate MOOV atoms', FFmpegFixupDuplicateMoovPP)
 
                 fixup()
                 try:

yt_dlp/downloader/__init__.py

@@ -33,7 +33,7 @@ from .mhtml import MhtmlFD
 from .niconico import NiconicoDmcFD, NiconicoLiveFD
 from .rtmp import RtmpFD
 from .rtsp import RtspFD
-from .websocket import WebSocketFragmentFD
+from .websocket import WebSocketFragmentFD, WebSocketToFileFD
 from .youtube_live_chat import YoutubeLiveChatFD
 
 PROTOCOL_MAP = {
@@ -121,6 +121,9 @@ def _get_suitable_downloader(info_dict, protocol, params, default):
         elif params.get('hls_prefer_native') is False:
             return FFmpegFD
 
+    if protocol == 'websocket_frag' and info_dict.get('container') == 'fmp4' and external_downloader != 'ffmpeg':
+        return WebSocketToFileFD
+
     return PROTOCOL_MAP.get(protocol, default)
 
 

yt_dlp/downloader/websocket.py

@@ -1,49 +1,25 @@
 import asyncio
 import contextlib
 import os
-import signal
 import threading
+import time
 
 from .common import FileDownloader
 from .external import FFmpegFD
 from ..dependencies import websockets
 
 
-class FFmpegSinkFD(FileDownloader):
+class _WebSocketFD(FileDownloader):
-    """ A sink to ffmpeg for downloading fragments in any form """
+    async def connect(self, stdin, info_dict):
+        try:
+            await self.real_connection(stdin, info_dict)
+        except OSError:
+            pass
+        finally:
+            with contextlib.suppress(OSError):
+                stdin.flush()
+                stdin.close()
 
-    def real_download(self, filename, info_dict):
-        info_copy = info_dict.copy()
-        info_copy['url'] = '-'
-
-        async def call_conn(proc, stdin):
-            try:
-                await self.real_connection(stdin, info_dict)
-            except OSError:
-                pass
-            finally:
-                with contextlib.suppress(OSError):
-                    stdin.flush()
-                    stdin.close()
-                os.kill(os.getpid(), signal.SIGINT)
-
-        class FFmpegStdinFD(FFmpegFD):
-            @classmethod
-            def get_basename(cls):
-                return FFmpegFD.get_basename()
-
-            def on_process_started(self, proc, stdin):
-                thread = threading.Thread(target=asyncio.run, daemon=True, args=(call_conn(proc, stdin), ))
-                thread.start()
-
-        return FFmpegStdinFD(self.ydl, self.params or {}).download(filename, info_copy)
-
-    async def real_connection(self, sink, info_dict):
-        """ Override this in subclasses """
-        raise NotImplementedError('This method must be implemented by subclasses')
-
-
-class WebSocketFragmentFD(FFmpegSinkFD):
     async def real_connection(self, sink, info_dict):
         async with websockets.connect(info_dict['url'], extra_headers=info_dict.get('http_headers', {})) as ws:
             while True:
@@ -51,3 +27,67 @@ class WebSocketFragmentFD(FFmpegSinkFD):
                 if isinstance(recv, str):
                     recv = recv.encode('utf8')
                 sink.write(recv)
+
+
+class WebSocketFragmentFD(_WebSocketFD):
+    """ A sink to ffmpeg for downloading fragments in any form """
+
+    def real_download(self, filename, info_dict):
+        info_copy = info_dict.copy()
+        info_copy['url'] = '-'
+        connect = self.connect
+
+        class FFmpegStdinFD(FFmpegFD):
+            @classmethod
+            def get_basename(cls):
+                return FFmpegFD.get_basename()
+
+            def on_process_started(self, proc, stdin):
+                thread = threading.Thread(target=asyncio.run, daemon=True, args=(connect(stdin, info_dict), ))
+                thread.start()
+
+        return FFmpegStdinFD(self.ydl, self.params or {}).download(filename, info_copy)
+
+
+class WebSocketToFileFD(_WebSocketFD):
+    """ A sink to a file for downloading fragments in any form """
+    def real_download(self, filename, info_dict):
+        tempname = self.temp_name(filename)
+        try:
+            with open(tempname, 'wb') as w:
+                started = time.time()
+                status = {
+                    'filename': info_dict.get('_filename'),
+                    'status': 'downloading',
+                    'elapsed': 0,
+                    'downloaded_bytes': 0,
+                }
+                self._hook_progress(status, info_dict)
+
+                thread = threading.Thread(target=asyncio.run, daemon=True, args=(self.connect(w, info_dict), ))
+                thread.start()
+                time_and_size, avg_len = [], 10
+                while thread.is_alive():
+                    time.sleep(0.1)
+
+                    downloaded, curr = w.tell(), time.time()
+                    # taken from ffmpeg attachment
+                    time_and_size.append((downloaded, curr))
+                    time_and_size = time_and_size[-avg_len:]
+                    if len(time_and_size) > 1:
+                        last, early = time_and_size[0], time_and_size[-1]
+                        average_speed = (early[0] - last[0]) / (early[1] - last[1])
+                    else:
+                        average_speed = None
+
+                    status.update({
+                        'downloaded_bytes': downloaded,
+                        'speed': average_speed,
+                        'elapsed': curr - started,
+                    })
+                    self._hook_progress(status, info_dict)
+        except KeyboardInterrupt:
+            pass
+        finally:
+            os.replace(tempname, filename)
+        return True

yt_dlp/extractor/_extractors.py

@@ -946,6 +946,10 @@ from .kaltura import KalturaIE
 from .kankanews import KankaNewsIE
 from .karaoketv import KaraoketvIE
 from .kelbyone import KelbyOneIE
+from .kenh14 import (
+    Kenh14PlaylistIE,
+    Kenh14VideoIE,
+)
 from .khanacademy import (
     KhanAcademyIE,
     KhanAcademyUnitIE,

yt_dlp/extractor/chaturbate.py

@@ -79,7 +79,7 @@ class ChaturbateIE(InfoExtractor):
             'formats': self._extract_m3u8_formats(m3u8_url, video_id, ext='mp4', live=True),
         }
 
-    def _extract_from_webpage(self, video_id, tld):
+    def _extract_from_html(self, video_id, tld):
         webpage = self._download_webpage(
             f'https://chaturbate.{tld}/{video_id}/', video_id,
             headers=self.geo_verification_headers(), impersonate=True)
@@ -151,4 +151,4 @@ class ChaturbateIE(InfoExtractor):
 
     def _real_extract(self, url):
         video_id, tld = self._match_valid_url(url).group('id', 'tld')
-        return self._extract_from_api(video_id, tld) or self._extract_from_webpage(video_id, tld)
+        return self._extract_from_api(video_id, tld) or self._extract_from_html(video_id, tld)

yt_dlp/extractor/kenh14.py

@@ -0,0 +1,160 @@
+from .common import InfoExtractor
+from ..utils import (
+    clean_html,
+    extract_attributes,
+    get_element_by_class,
+    get_element_html_by_attribute,
+    get_elements_html_by_class,
+    int_or_none,
+    parse_duration,
+    parse_iso8601,
+    remove_start,
+    strip_or_none,
+    unescapeHTML,
+    update_url,
+    url_or_none,
+)
+from ..utils.traversal import traverse_obj
+
+
+class Kenh14VideoIE(InfoExtractor):
+    _VALID_URL = r'https?://video\.kenh14\.vn/(?:video/)?[\w-]+-(?P<id>[0-9]+)\.chn'
+    _TESTS = [{
+        'url': 'https://video.kenh14.vn/video/mo-hop-iphone-14-pro-max-nguon-unbox-therapy-316173.chn',
+        'md5': '1ed67f9c3a1e74acf15db69590cf6210',
+        'info_dict': {
+            'id': '316173',
+            'ext': 'mp4',
+            'title': 'Video mở hộp iPhone 14 Pro Max (Nguồn: Unbox Therapy)',
+            'description': 'Video mở hộp iPhone 14 Pro MaxVideo mở hộp iPhone 14 Pro Max (Nguồn: Unbox Therapy)',
+            'thumbnail': r're:^https?://videothumbs\.mediacdn\.vn/.*\.jpg$',
+            'tags': [],
+            'uploader': 'Unbox Therapy',
+            'upload_date': '20220517',
+            'view_count': int,
+            'duration': 722.86,
+            'timestamp': 1652764468,
+        },
+    }, {
+        'url': 'https://video.kenh14.vn/video-316174.chn',
+        'md5': '2b41877d2afaf4a3f487ceda8e5c7cbd',
+        'info_dict': {
+            'id': '316174',
+            'ext': 'mp4',
+            'title': 'Khoảnh khắc VĐV nằm gục khóc sau chiến thắng: 7 năm trời Việt Nam mới có HCV kiếm chém nữ, chỉ có 8 tháng để khổ luyện trước khi lên sàn đấu',
+            'description': 'md5:de86aa22e143e2b277bce8ec9c6f17dc',
+            'thumbnail': r're:^https?://videothumbs\.mediacdn\.vn/.*\.jpg$',
+            'tags': [],
+            'upload_date': '20220517',
+            'view_count': int,
+            'duration': 70.04,
+            'timestamp': 1652766021,
+        },
+    }, {
+        'url': 'https://video.kenh14.vn/0-344740.chn',
+        'md5': 'b843495d5e728142c8870c09b46df2a9',
+        'info_dict': {
+            'id': '344740',
+            'ext': 'mov',
+            'title': 'Kỳ Duyên đầy căng thẳng trong buổi ra quân đi Miss Universe, nghi thức tuyên thuệ lần đầu xuất hiện gây nhiều tranh cãi',
+            'description': 'md5:2a2dbb4a7397169fb21ee68f09160497',
+            'thumbnail': r're:^https?://kenh14cdn\.com/.*\.jpg$',
+            'tags': ['kỳ duyên', 'Kỳ Duyên tuyên thuệ', 'miss universe'],
+            'uploader': 'Quang Vũ',
+            'upload_date': '20241024',
+            'view_count': int,
+            'duration': 198.88,
+            'timestamp': 1729741590,
+        },
+    }]
+
+    def _real_extract(self, url):
+        video_id = self._match_id(url)
+        webpage = self._download_webpage(url, video_id)
+
+        attrs = extract_attributes(get_element_html_by_attribute('type', 'VideoStream', webpage) or '')
+        direct_url = attrs['data-vid']
+
+        metadata = self._download_json(
+            'https://api.kinghub.vn/video/api/v1/detailVideoByGet?FileName={}'.format(
+                remove_start(direct_url, 'kenh14cdn.com/')), video_id, fatal=False)
+
+        formats = [{'url': f'https://{direct_url}', 'format_id': 'http', 'quality': 1}]
+        subtitles = {}
+        video_data = self._download_json(
+            f'https://{direct_url}.json', video_id, note='Downloading video data', fatal=False)
+        if hls_url := traverse_obj(video_data, ('hls', {url_or_none})):
+            fmts, subs = self._extract_m3u8_formats_and_subtitles(
+                hls_url, video_id, m3u8_id='hls', fatal=False)
+            formats.extend(fmts)
+            self._merge_subtitles(subs, target=subtitles)
+        if dash_url := traverse_obj(video_data, ('mpd', {url_or_none})):
+            fmts, subs = self._extract_mpd_formats_and_subtitles(
+                dash_url, video_id, mpd_id='dash', fatal=False)
+            formats.extend(fmts)
+            self._merge_subtitles(subs, target=subtitles)
+
+        return {
+            **traverse_obj(metadata, {
+                'duration': ('duration', {parse_duration}),
+                'uploader': ('author', {strip_or_none}),
+                'timestamp': ('uploadtime', {parse_iso8601(delimiter=' ')}),
+                'view_count': ('views', {int_or_none}),
+            }),
+            'id': video_id,
+            'title': (
+                traverse_obj(metadata, ('title', {strip_or_none}))
+                or clean_html(self._og_search_title(webpage))
+                or clean_html(get_element_by_class('vdbw-title', webpage))),
+            'formats': formats,
+            'subtitles': subtitles,
+            'description': (
+                clean_html(self._og_search_description(webpage))
+                or clean_html(get_element_by_class('vdbw-sapo', webpage))),
+            'thumbnail': (self._og_search_thumbnail(webpage) or attrs.get('data-thumb')),
+            'tags': traverse_obj(self._html_search_meta('keywords', webpage), (
+                {lambda x: x.split(';')}, ..., filter)),
+        }
+
+
+class Kenh14PlaylistIE(InfoExtractor):
+    _VALID_URL = r'https?://video\.kenh14\.vn/playlist/[\w-]+-(?P<id>[0-9]+)\.chn'
+    _TESTS = [{
+        'url': 'https://video.kenh14.vn/playlist/tran-tinh-naked-love-mua-2-71.chn',
+        'info_dict': {
+            'id': '71',
+            'title': 'Trần Tình (Naked love) mùa 2',
+            'description': 'md5:e9522339304956dea931722dd72eddb2',
+            'thumbnail': r're:^https?://kenh14cdn\.com/.*\.png$',
+        },
+        'playlist_count': 9,
+    }, {
+        'url': 'https://video.kenh14.vn/playlist/0-72.chn',
+        'info_dict': {
+            'id': '72',
+            'title': 'Lau Lại Đầu Từ',
+            'description': 'Cùng xem xưa và nay có gì khác biệt nhé!',
+            'thumbnail': r're:^https?://kenh14cdn\.com/.*\.png$',
+        },
+        'playlist_count': 6,
+    }]
+
+    def _real_extract(self, url):
+        playlist_id = self._match_id(url)
+        webpage = self._download_webpage(url, playlist_id)
+
+        category_detail = get_element_by_class('category-detail', webpage) or ''
+        embed_info = traverse_obj(
+            self._yield_json_ld(webpage, playlist_id),
+            (lambda _, v: v['name'] and v['alternateName'], any)) or {}
+
+        return self.playlist_from_matches(
+            get_elements_html_by_class('video-item', webpage), playlist_id,
+            (clean_html(get_element_by_class('name', category_detail)) or unescapeHTML(embed_info.get('name'))),
+            getter=lambda x: 'https://video.kenh14.vn/video/video-{}.chn'.format(extract_attributes(x)['data-id']),
+            ie=Kenh14VideoIE, playlist_description=(
+                clean_html(get_element_by_class('description', category_detail))
+                or unescapeHTML(embed_info.get('alternateName'))),
+            thumbnail=traverse_obj(
+                self._og_search_thumbnail(webpage),
+                ({url_or_none}, {update_url(query=None)})))

yt_dlp/extractor/twitcasting.py

@@ -195,6 +195,7 @@ class TwitCastingIE(InfoExtractor):
                         'source_preference': -10,
                         # TwitCasting simply sends moof atom directly over WS
                         'protocol': 'websocket_frag',
+                        'container': 'fmp4',
                     })
 
             infodict = {

yt_dlp/postprocessor/__init__.py

@@ -30,6 +30,7 @@ from .metadataparser import (
 )
 from .modify_chapters import ModifyChaptersPP
 from .movefilesafterdownload import MoveFilesAfterDownloadPP
+from .mp4direct import MP4FixupTimestampPP
 from .sponskrub import SponSkrubPP
 from .sponsorblock import SponsorBlockPP
 from .xattrpp import XAttrMetadataPP

yt_dlp/postprocessor/mp4direct.py

@@ -0,0 +1,277 @@
+import os
+import struct
+
+from io import BytesIO, RawIOBase
+from math import inf
+from typing import Tuple
+
+from .common import PostProcessor
+from ..utils import prepend_extension
+
+
+class LengthLimiter(RawIOBase):
+    """
+    A bytes IO to limit length to be read.
+    """
+
+    def __init__(self, r: RawIOBase, size: int):
+        self.r = r
+        self.remaining = size
+
+    def read(self, sz: int = None) -> bytes:
+        if self.remaining == 0:
+            return b''
+        if sz in (-1, None):
+            sz = self.remaining
+        sz = min(sz, self.remaining)
+        ret = self.r.read(sz)
+        if ret:
+            self.remaining -= len(ret)
+        return ret
+
+    def readall(self) -> bytes:
+        if self.remaining == 0:
+            return b''
+        ret = self.read(self.remaining)
+        if ret:
+            self.remaining -= len(ret)
+        return ret
+
+    def readable(self) -> bool:
+        return bool(self.remaining)
+
+
+def read_harder(r, size):
+    """
+    Try to read from the stream.
+
+    @params r    byte stream to read
+    @params size Number of bytes to read in total
+    """
+
+    retry = 0
+    buf = b''
+    while len(buf) < size and retry < 3:
+        ret = r.read(size - len(buf))
+        if not ret:
+            retry += 1
+            continue
+        retry = 0
+        buf += ret
+
+    return buf
+
+
+def pack_be32(value: int) -> bytes:
+    """ Pack value to 4-byte-long bytes in the big-endian byte order """
+    return struct.pack('>I', value)
+
+
+def pack_be64(value: int) -> bytes:
+    """ Pack value to 8-byte-long bytes in the big-endian byte order """
+    return struct.pack('>L', value)
+
+
+def unpack_be32(value: bytes) -> int:
+    """ Convert 4-byte-long bytes in the big-endian byte order, to an integer value """
+    return struct.unpack('>I', value)[0]
+
+
+def unpack_be64(value: bytes) -> int:
+    """ Convert 8-byte-long bytes in the big-endian byte order, to an integer value """
+    return struct.unpack('>L', value)[0]
+
+
+def unpack_ver_flags(value: bytes) -> Tuple[int, int]:
+    """
+    Unpack 4-byte-long value into version and flags.
+    @returns (version, flags)
+    """
+
+    ver, up_flag, down_flag = struct.unpack('>BBH', value)
+    return ver, (up_flag << 16 | down_flag)
+
+
+# https://github.com/gpac/mp4box.js/blob/4e1bc23724d2603754971abc00c2bd5aede7be60/src/box.js#L13-L40
+MP4_CONTAINER_BOXES = ('moov', 'trak', 'edts', 'mdia', 'minf', 'dinf', 'stbl', 'mvex', 'moof', 'traf', 'vttc', 'tref', 'iref', 'mfra', 'meco', 'hnti', 'hinf', 'strk', 'strd', 'sinf', 'rinf', 'schi', 'trgr', 'udta', 'iprp', 'ipco')
+""" List of boxes that nests the other boxes """
+
+
+def parse_mp4_boxes(r: RawIOBase):
+    """
+    Parses an ISO BMFF (which MP4 follows) and yields its boxes as a sequence.
+    This does not interpret content of these boxes.
+
+    Sequence details:
+    ('atom', b'blablabla'): A box, with content (not container boxes)
+    ('atom', b''):          Possibly container box (must check MP4_CONTAINER_BOXES) or really an empty box
+    (None, 'atom'):         End of a container box
+
+    Example:            Path:
+    ('test', b'123456') /test
+    ('moov', b'')       /moov           (start of container box)
+    ('helo', b'abcdef') /moov/helo
+    ('1984', b'1q84')   /moov/1984
+    ('trak', b'')       /moov/trak      (start of container box)
+    ('keys', b'2022')   /moov/trak/keys
+    (None  , 'trak')    /moov/trak      (end of container box)
+    ('topp', b'1991')   /moov/topp
+    (None  , 'moov')    /moov           (end of container box)
+    """
+
+    while True:
+        size_b = read_harder(r, 4)
+        if not size_b:
+            break
+        type_b = r.read(4)
+        # 00 00 00 20 is big-endian
+        box_size = unpack_be32(size_b)
+        type_s = type_b.decode()
+        if type_s in MP4_CONTAINER_BOXES:
+            yield (type_s, b'')
+            yield from parse_mp4_boxes(LengthLimiter(r, box_size - 8))
+            yield (None, type_s)
+            continue
+        # subtract by 8
+        full_body = read_harder(r, box_size - 8)
+        yield (type_s, full_body)
+
+
+def write_mp4_boxes(w: RawIOBase, box_iter):
+    """
+    Writes an ISO BMFF file from a given sequence to a given writer.
+    The iterator to be passed must follow parse_mp4_boxes's protocol.
+    """
+
+    stack = [
+        (None, w),  # parent box, IO
+    ]
+    for btype, content in box_iter:
+        if btype in MP4_CONTAINER_BOXES:
+            bio = BytesIO()
+            stack.append((btype, bio))
+            continue
+        elif btype is None:
+            assert stack[-1][0] == content
+            btype, bio = stack.pop()
+            content = bio.getvalue()
+
+        wt = stack[-1][1]
+        wt.write(pack_be32(len(content) + 8))
+        wt.write(btype.encode()[:4])
+        wt.write(content)
+
+
+class MP4FixupTimestampPP(PostProcessor):
+
+    @property
+    def available(self):
+        return True
+
+    def analyze_mp4(self, filepath):
+        """ returns (baseMediaDecodeTime offset, sample duration cutoff) """
+        smallest_bmdt, known_sdur = inf, set()
+        with open(filepath, 'rb') as r:
+            for btype, content in parse_mp4_boxes(r):
+                if btype == 'tfdt':
+                    version, _ = unpack_ver_flags(content[0:4])
+                    # baseMediaDecodeTime always comes to the first
+                    if version == 0:
+                        bmdt = unpack_be32(content[4:8])
+                    else:
+                        bmdt = unpack_be64(content[4:12])
+                    if bmdt == 0:
+                        continue
+                    smallest_bmdt = min(bmdt, smallest_bmdt)
+                elif btype == 'tfhd':
+                    version, flags = unpack_ver_flags(content[0:4])
+                    if not flags & 0x08:
+                        # this box does not contain "sample duration"
+                        continue
+                    # https://github.com/gpac/mp4box.js/blob/4e1bc23724d2603754971abc00c2bd5aede7be60/src/box.js#L203-L209
+                    # https://github.com/gpac/mp4box.js/blob/4e1bc23724d2603754971abc00c2bd5aede7be60/src/parsing/tfhd.js
+                    sdur_start = 8  # header + track id
+                    if flags & 0x01:
+                        sdur_start += 8
+                    if flags & 0x02:
+                        sdur_start += 4
+                    # the next 4 bytes are "sample duration"
+                    sample_dur = unpack_be32(content[sdur_start:sdur_start + 4])
+                    known_sdur.add(sample_dur)
+
+        maximum_sdur = max(known_sdur)
+        for multiplier in (0.7, 0.8, 0.9, 0.95):
+            sdur_cutoff = maximum_sdur * multiplier
+            if len(set(x for x in known_sdur if x > sdur_cutoff)) < 3:
+                break
+        else:
+            sdur_cutoff = inf
+
+        return smallest_bmdt, sdur_cutoff
+
+    @staticmethod
+    def transform(r, bmdt_offset, sdur_cutoff):
+        for btype, content in r:
+            if btype == 'tfdt':
+                version, _ = unpack_ver_flags(content[0:4])
+                if version == 0:
+                    bmdt = unpack_be32(content[4:8])
+                else:
+                    bmdt = unpack_be64(content[4:12])
+                if bmdt == 0:
+                    yield (btype, content)
+                    continue
+                # calculate new baseMediaDecodeTime
+                bmdt = max(0, bmdt - bmdt_offset)
+                # pack everything again and insert as a new box
+                if version == 0:
+                    bmdt_b = pack_be32(bmdt)
+                else:
+                    bmdt_b = pack_be64(bmdt)
+                yield ('tfdt', content[0:4] + bmdt_b + content[8 + version * 4:])
+                continue
+            elif btype == 'tfhd':
+                version, flags = unpack_ver_flags(content[0:4])
+                if not flags & 0x08:
+                    yield (btype, content)
+                    continue
+                sdur_start = 8
+                if flags & 0x01:
+                    sdur_start += 8
+                if flags & 0x02:
+                    sdur_start += 4
+                sample_dur = unpack_be32(content[sdur_start:sdur_start + 4])
+                if sample_dur > sdur_cutoff:
+                    sample_dur = 0
+                sd_b = pack_be32(sample_dur)
+                yield ('tfhd', content[:sdur_start] + sd_b + content[sdur_start + 4:])
+                continue
+            yield (btype, content)
+
+    def modify_mp4(self, src, dst, bmdt_offset, sdur_cutoff):
+        with open(src, 'rb') as r, open(dst, 'wb') as w:
+            write_mp4_boxes(w, self.transform(parse_mp4_boxes(r)))
+
+    def run(self, information):
+        filename = information['filepath']
+        temp_filename = prepend_extension(filename, 'temp')
+
+        self.write_debug('Analyzing MP4')
+        bmdt_offset, sdur_cutoff = self.analyze_mp4(filename)
+        working = inf not in (bmdt_offset, sdur_cutoff)
+        # if any of them are Infinity, there's something wrong
+        # baseMediaDecodeTime = to shift PTS
+        # sample duration = to define duration in each segment
+        self.write_debug(f'baseMediaDecodeTime offset = {bmdt_offset}, sample duration cutoff = {sdur_cutoff}')
+        if bmdt_offset == inf:
+            # safeguard
+            bmdt_offset = 0
+        self.modify_mp4(filename, temp_filename, bmdt_offset, sdur_cutoff)
+        if working:
+            self.to_screen('Duration of the file has been fixed')
+        else:
+            self.report_warning(f'Failed to fix duration of the file. (baseMediaDecodeTime offset = {bmdt_offset}, sample duration cutoff = {sdur_cutoff})')
+
+        os.replace(temp_filename, filename)
+
+        return [], information