Audio/Video out of Sync (When video is over 60 mins)

[Adrian Edmonds]

I have read most of the issues regarding this matter. The "canned" answers are awful.

I sometimes download NEWs site videos to watch and review later. I have used this addon for a few years... never no issue. In the past few months it gets out of sync when a HLS video is OVER  an hour (e.g full movie, most videos have been 30-60 minutes).

BEFORE you say it could be bad video editing... I went to three (3) different video sites and downloaded full movies to confirm my suspicion. All was out of sync if you go to the last 10-15 minutes of the movies - You will find this problem (Movie lengths 1:45:00  to  2 horus).

IS IT THE VIDEO SITES... again, I went to 3 random googled "watch movie free" sites. SO NO...

SO LETS ISOLATE if its Video DownloadHelper...

I added "HLS Downloader" to to Firefox. I re-downloaded all the videos. ALL of them are perfectly in sync.

So where is the problem??? Possibly when you convert to MP4. "HLS Downloader" only downloads to .ts files. (I have to run conversion to get them to mp4, but it works for the few videos I needed).

WHILE you may not have designed it to download full movies - and may not be testing it for that... herein lies the problem people are finding. 1 Hour 30-45 minutes should see the error in the last 10-15 minutes of the movie/video.

FURTHER: I suspected DownloadHelper could have been corrupt. I removed the addon from Firefox. Shut down the system, reloaded firefox, re-added the addon. Problem still exist.

NOTE: I'm a systems analyst... all these test was to locate the problem instead of going with - "bad videos". ANY VIDEO from ANY SITE that is full movie length 1hr 30+ minutes the problem exist towards the last 15 minutes of the video/movie.

I hope you look into this. I enjoy this add on. Now I have to do conversion or check these others to get what I need.

[Wild Willy]

I don't often download such long content. Not much of a movie buff. But I have recorded
livestreams that have lasted 3-4 hours & longer & I have observed some small slippage of
the synchronization. This doesn't seem to be related to the location within the
download. There's slippage in the first 10 minutes, in the second hour, at the end of 4
hours. I have always thought this was due to the fact that livestreams go up in chunks.
You can observe this in the VDH download status menu you get from the blue dot. VDH will
say it's at 100% complete, 0:00 left to download. Then oops, here we need another minute
or two to download from 92%. Then VDH catches up again, and the server puts up more of
the stream, which VDH then downloads. I have speculated that each time there's one of
these steps, the audio & video can get slightly out of synch. My observation is that
throughout playback in VLC of the broadcast, I have to adjust the audio synch forward
some fraction of a second to get the sound of the golf club hitting the ball in synch
with the golfer swinging the club. And later I have to synch the audio back. It changes
throughout the broadcast, back & forth. It's never by more than a second. I'm talking
about livestreams from NBC Sports of Golf Channel tournament broadcasts. There's going
to be one tomorrow for the first time in over a month that I'm rather looking forward to.

I would like you to post an example URL of a movie where you see bad synchronization.
Tell me the time index where the bad synch first appears. I want to see if I observe the
same thing you do.

[Wild Willy]

I just remembered something that is perhaps relevant. I have noticed recently during NFL
broadcasts that I watch on my cable box, not online, not recorded, that the audio & video
are out of synch. I can't tell, of course, whether this failure of the synchronization
is introduced by the TV network, my cable system, or the cable box here in my home. But
it's quite noticeable when they switch to the booth during one of the (all too frequent)
pauses in play, pauses they surprisingly don't fill with advertising. You'll see the
play-by-play guy & the former player talking to each other & the audio doesn't match what
you can see on the screen of their lips moving. So maybe the problem I observe with my
Golf Channel recordings has nothing to do with livestream chunks & everything to do with
it being a recording of a channel on my cable TV system. If you are in the US & have a
cable subscription, you can get into the NBC Sports web site & watch their live content.
You just have to go to the minor trouble of getting on the web site of your cable
provider & creating a user ID & password. It's something you're entitled to as a paying
subscriber to the cable system. There is no additional cost beyond your cable
subscription to do this. When you try to watch anything on the NBC Sports web site, they
first ask you to authenticate with your cable provider. After that minor annoyance, you
can watch whatever they've got up there, other than the stuff that's behind the Peacock
paywall.

I'm still interested in looking at whatever movie you point me off to.

[Wild Willy]

As you can see from the deleted message notices above, our pal Adrian has been having
problems getting his posts to appear on the site. As an evasive maneuver, he created a
new thread over here:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/zJYAprBWk6k

Continue reading about this issue over there.