Sound and picture out of sync when downloading from Dailymotion

[dave...@mvps.org]

I'm trying to download the videos at:
https://www.dailymotion.com/video/x85cns0
https://www.dailymotion.com/video/x85ezaj

and
https://www.dailymotion.com/video/x85ino8

In all three cases, in the mp4 that Video DownloadHelper downloads, the sound and picture are slightly out of sync, whereas if you play the video at the url in a browser, the sound and picture are perfectly in sync. What's going on and is there are fix?

I get the same problem whether using Firefox or Chrome to do the downloads. I have the up to date versions of both browsers (and of VDH), and am running Windows 10.

Dave

[dave...@mvps.org]

PS - my post is displaying a very old and now non-existing email address for some reason, even though I'm logged into my Google account using my gmail address. Any idea why and how to fix that? I'm worried that I won't be notifed of replies if the email address is incorrect.

[mjs]

Where at what time does it become out of sync ? There is a problem in the way the .ts stream is downloaded to mp4. The developer has

acknowledged this but no fix coming. So the best solution for this problem is changing a setting: HLS as M2TS

It is not mp4 format, though it should keep the video in sync. The other benefit is that the file is stutter free. I tested it by downloading 5% of the

first link as mp4 and it is very jerky & shaky.

To reply : use Reply all and delete everything after clicking the show quoted text button.

--

A vdh user

[Wild Willy]

When was the last time you looked in your group membership settings? I'll bet you have
no idea. But you should check those to make sure everything in there is the way you want
it. There's a link to your group membership settings on the left side of every page of
Google Groups, this page, every VDH thread, the VDH root page, & every page in every
other group. You can't take care of this from inside GMail. You have to come onto the
web site in your browser & do it from here, while you are logged on, of course.

[Wild Willy]

I decided to take a different approach to this. You have already shown that there are
problems downloading this with VDH. So I didn't even attempt such a download. Instead,
I visited the page for the first URL you provided, with the Network Monitor open, &
looked around at what I could find. There was no entry in the Network Monitor for
anything of type x-mpegurl, which would have been an HLS master manifest. Nor was there
anything of type dash, which would have been a DASH master manifest. Looking at json
files, which is the next most likely place to find a manifest, didn't immediately turn up
anything.

So I just went to the top of the Network Monitor & started scrolling down, looking at the
Response data displayed in the right part of the Network Monitor. Every single entry.
One at a time. Tedious as can be. But when you're improvising, guessing, experimenting,
this is what you have to do.

Eventually, I came to the one shown in attached image #01. You can see from the scroll
button in the scroll bar that it's 2/3-3/4 of the way down the list. As with other items
I had already looked at, I expanded things in the right side of the display. There is no
method to this. There is no logic to this. I was guessing. I was asking myself at each
step, I wonder what's in here. What does this show? What if I click this? I have to
say there is very little obvious evidence that would have drawn my attention to the thing
labeled qualities in the right side of the Network Monitor. I was doing a thorough
drill-down. That's all. Like trawling for fish. When I saw Object 0 here was of type
application/x-mpegURL, I thought this has to be an HLS manifest. With any luck, it would
be a master manifest. There's only one way to find out. You know what it is. I've
posted it many times. Run the manifest URL through ffprobe. Those results are in
attached file ffprobe.txt. So it seems I was a bit lucky. I say persistence & patience
make for good luck. This did turn out to be an HLS master manifest.

There are 6 variants here represented by Programs 0-5. They are of various resolutions.
There is no timed_ID3 data here, which I was half expecting given that you are reporting
synch issues. It's a pretty ordinary manifest as these things go. It has the advantage
of providing English subtitles in WEBVTT format. So I downloaded the video in one ffmpeg
invocation & the subtitles in another. You can find my tutorial on ffmpeg by starting
here:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/BzPLK2YyL-s

Then look for "cannot download" within the text of that web page. That will show you the
link to the tutorial.

The captions, being just a small text file, completed downloading quickly. Those results
are in attached file Dailymotion Video vtt Log.txt. You can see in that log (look for
it) that the downloaded file was fairly small & the download speed was quite poor. But
even at that slow speed, the download went fairly quickly. I pulled up the downloaded
vtt file in Notepad++ & it looked to be reasonable captions.

The video itself took longer. See attached file Dailymotion Video mp4 Log.txt. I chose
the 1280x720 variant since it was the highest resolution on offer here. This file was
considerably larger than the captions file but it wasn't even 1M. However, I was getting
a rather mediocre download speed (again, look for that information in the log). So after
grinding along for a while, I did get a perfectly watchable video.

It turns out that Program 4 & Program 5 are both 1280x720. They have the same bit rate.
In other words, they appear to be the exact same stream. I chose Program 5 to download.
It was basically a random choice.


I did not sit & watch this, just sampled it at intervals. Since a vtt file was in the
same directory as the video & the vtt file had the same name as the video (except for the
extension .vtt), VLC automatically displayed the captions. It turned out that the
subtitles were a few seconds in advance of what you could hear on the sound track. They
did appear to be accurate, just not in synch. This is a problem that is easily corrected
with caption editing tools. I was not sufficiently motivated to bother doing that. As
for video & audio being in synch, it was. Perfectly. I went to the end & backed up to
the last place you can see somebody on screen who is talking. It's a bit over a minute
from the end. The movement of his lips was perfectly in synch with the sound track.

So if I could get this with ffmpeg, why can't VDH? I can't even speculate on an answer
to that. I'm impressed that VDH apparently was able to fish the master manifest out of
the sea of debris in the Network Monitor much more easily than I did. I don't know
enough to do it quickly. Like I say, I just took the bull in the china shop approach
until I found something. I must say it was in a rather unlikely place under descriptors
I have not encountered before. But it was there & you can get a perfect video with no
synch problems using ffmpeg if you are sufficiently motivated. I never launched playback
of this so the VDH menu remained empty. I suspect that if I had launched playback, VDH
would have detected something. Then I imagine I could have looked in the Hit Details
provided by VDH & the URL for the master manifest would have been displayed there,
shortening my task considerably. But what I did worked well enough.

[Dave Rado]

Hi mjs.

"Where at what time does it become out of sync ?" 

When I download it.

" So the best solution for this problem is changing a setting: HLS as M2TS"

I've no idea what that means but I found the setting on the Behaviour tab of the VDH settings, changed it as you advised, and that did indeed solve the problem. But it's weird in that case that that isn't the default setting!

Anyway,  many thanks.

Dave 

[Dave Rado]

" When was the last time you looked in your group membership settings?"

I had no idea that such a thing existed. I assumed Google groups got your details from your login as most other forums do. Anyway, thanks for the pointer - that worked.

Dave

[Dave Rado]

Hi Wild Willy

Your post went right over my head but thanks for putting the time in.

Dave 

[Dave Rado]

hi again mjs

I thought at first that your solution of switching on the setting "HLS as M2TS" had worked but on watching the downloaded MP4 more carefully, it's still out of sync.

The only solution I can find is to import the MP4 into a video editor and move the sound file slightly relative to the video. 

Dave

[mjs]

I'm wondering if you forgot to click save after changing the setting. There is a save button to bottom right of settings page.

The resulting file should not be MP4 but M2TS.

[Dave Rado]

I guess I must have although I thought I'd saved it.

I wish you'd told me that the resulting file should be M2TS before (it's not a format I've ever heard of until now) - I've just spent hours tweaking the sound file of the MP4 file in a video editor to sync it with the picture.

Oh well ... I've burnt the DVDs now so not worth redoing it all but at least I know for next time.

I wish the developer would make this setting the default given that it's the only workaround that doesn't waste hours.

Thanks again.

Dave     

[Wild Willy]

Dave, it's too bad you just passed off what I said as being "over your head." It would
save you hours of tweaking in a video editor. Chase down that tutorial I mentioned
above. It looks more complicated than it is because there's a lot of steps. But when
you make the effort to understand each step, it's easy. It's just that it's not one or
two steps. Once you have ffmpeg in your bag of tricks, you can handle most cases that
VDH can't.

As for the HLS as M2TS setting, it does result in the unexpected m2ts format. That may
not play well in all cases, requiring a conversion. That is probably why it's not the
default. Downloading with ffmpeg gives you an mp4 from the outset without the need for
any post-processing, like tweaking audio tracks or converting formats or merging separate
audio & video tracks. You may think you're saving time now. But next time you hit a
site that VDH can't handle, you'll be glad you already know ffmpeg. If you can spend
hours in a video editor tweaking the audio, you have to be easily capable of learning
ffmpeg.