Non-fluid vision

[Andrea L]

Hello.

First I apologize for my English.

I am a subscriber to the service and I am very happy with this, but I would like to point out that some videos - depending on the platform - seem to contain many "B-Frames" that do not allow a fluid vision of the video, if downloaded.

However, viewing is without problems if you watch the video online.

Initially I thought it was a problem with the television station that publishes the video, but I downloaded the same tv show first through "Videodownloader helper" and then through "Pasty Link / Pasty Info".

In the first case the video is jerky, in the second case no problem.

The problem is present - for example - in the RSI.ch

https://www.rsi.ch/play/tv/storie/video/storie?urn=urn:rsi:video:15311842

I was already told that the problem was with Quick Time, but I don't use Quick Time. Then I replied again (always with e-mail) without receiving any other replies.

(Jeremy Gutierrez)

I also attach a screenshot of the "Avidemux" program when I try to edit the jerky video. This is the initial report (in any case, even following their indication, the problem is not solved).

My OS is Windows 10, with browser Mozilla Firefox or Google Chrome and VLC player (non-fluid also occurs with Windows Media Player).

Thanks for what you will be able to do. 

Andrea

 

[Wild Willy]

First, my setup is Windows 7 64-bit, Firefox 100.0 64-bit, licensed VDH 7.6.3a1 beta,
CoApp 1.6.3, VLC 3.0.16 Vetinari, ffmpeg downloaded from ffmpeg.org on 2022/3/17.

I am going to be throwing around some ideas that are covered in another thread. You can
find it by looking over here:

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

You can find the particular topic in question by doing a string search on "cannot
download" in there & clicking the link you'll find.

To start, I went to your rsi page. VDH presented me with what looked very much like
separate audio & video. I downloaded the 2 variants & indeed, I got a 1280x720
video-only file & an audio-only file of 48kHz sampling rate & 192kbps. They did play
fine in VLC using VLC's synchronous playback feature. It seemed like the audio was badly
out of synch near the start of the file but got a bit better within a couple of minutes.
I couldn't quite figure out whether the audio was ahead or behind the video. I'm sure
the fact that I don't speak Italian made things more difficult, although if I had Rachele
Bianchi Porro teaching me, I'm quite sure I'd learn Italian pretty quick. I didn't play
the thing all the way through. There did seem to be a bit of jumpiness in the video
(what you call non-fluid), but it didn't seem to me to be overly annoying.

Then I went looking in the Network Monitor to see what I could find. Not too
surprisingly, I found an HLS manifest, a .m3u8 file with the string "master" in its URL.
It did turn out to be the master manifest for this item. I ran the manifest through
ffprobe & got the results you can see in attached file ffprobe.txt. It turns out there's
3 Programs in this manifest. Each one consists of an audio stream, a video stream, & TWO
timed_ID3 data streams. Not one timed_ID3, like every other instance I've encountered of
this type of data, but two. Two, that's a first. I've posted about this type of data a
few times in here, discussions you can find by searching this forum. This type of data
is ignored by ffmpeg & it was my understanding that VDH ignored it now as well. Possibly
not. In any case, you can see from the ffprobe output that audio stream 0:0 is shared by
all 3 Programs. The video stream in each program has a different video resolution.
Curiously, stream 0:1 of timed_ID3 data is shared by all 3 Programs, while the second
timed_ID3 stream is unique to each program. I downloaded streams 0:2 & 0:0 via ffmpeg
into a single MP4 output file. Doing it this way avoids downloading the timed_ID3
streams. The resulting video looks much smoother & the audio synch seems pretty good.

If you look closely at the ffprobe output, you'll see it complaining about an unsupported
subtitle stream. This is inexplicable. Using the information provided in the ffprobe
output, I reconstructed the URL for the subtitle manifest. I then used ffmpeg to
download the subtitles. I don't know why ffprobe had any problem with this. As part of
my download of the subtitles with ffmpeg, I ran ffprobe on the resulting .vtt file.
There was no problem with that. I've encountered this before with subtitles. I can't
explain it. When I played the video I got with ffmpeg, VLC displayed the subtitles.
They were in Italian so they weren't helping me understand things any better. The
subtitles seemed to be in perfect synch with the audio I was hearing & with the lips of
the people speaking. Although I didn't understand any of it, the words of the subtitles
looked sort of like the words I was hearing. I didn't sit & watch it all the way
through. I just sampled it at intervals & it seemed to be good all the way to the end.

So. It appears that whatever solution Michel put into VDH to ignore timed_ID3 data isn't
complete. I think the fact that there's 2 streams of timed_ID3 data in each Program is
causing the problem. VDH needs to allow for the possibility that there could be multiple
streams of timed_ID3 data. I think my results point in this direction. So if you want
to get this video now, you're going to have to learn how to use ffmpeg. Or just continue
to use the tools you have already told us about. We'll just have to wait for a new VDH
to see whether it handles this any better.

Speaking of a new VDH, over the past several months, Michel has dropped little comments
here & there about small things he has fixed in some upcoming release. One thing that
was solved that I can think of is the glitch that displaying Details on an in-flight
download in the blue dot status display removes the percent completed & time remaining
from the display. But there have been a few other things. I'd like to see a new VDH
beta with these things fixed. Beta. I don't want an official release on the Mozilla
site. Their installer is brain dead. It still insists you uninstall VDH before you
install a new version. Garbage! A new beta is indicated.

[Wild Willy]

By the way, your English is fine. Much better than my Italian, which is no challenge,
but you shouldn't worry.

[Andrea L]

Thanks for the analysis. In the meantime the situation has worsened: now from the rsi.ch page the downloaded files are without audio :-( The situation is not pleasant :-(

[Wild Willy]

I have not checked your site again but it would not be surprising to discover that the site has changed something.  It is quite common for web sites to present their content in separate files, audio without video, and video without audio.  You can usually tell which is which in the VDH menu.  The video without audio variants will show a video resolution, 1920x1080, 1280x720, something like that.  But the audio without video variants will show almost the same information but they won't include a video resolution.  You need to download each variant separately.  Then click the link I gave in my earlier post.  Search for "audio without video" and "video without audio" in there.  There are multiple occurrences of these strings in there so don't stop at the first search hit.  You will find links to instructions explaining what to do with the separate files you download.  Since this site is including timed_ID3 data, you will probably get the most satisfactory results by avoiding VDH & instead using ffmpeg to download the files.  Using ffmpeg will allow you to avoid the timed_ID3 data AND get the video & audio into a single output file in one step.  If you want the captions as well, VDH can't do that at all.  You can get them with ffmpeg but that would be a separate step.  I like to keep my captions in a separate file so I can fix them if they contain errors.  Caption files are plain text files & you can edit them in a text editor (think Notepad).  If you are more serious about fixing captions, there are also special purpose caption editors out there that you can get.  (I have something called SubtitleEdit.  Google it.  It's freeware.)  If you don't care about fixing captions, you can use ffmpeg to put the video, the audio, AND the captions into a single file.

To summarize, you should be able to find the audio track to go with any video track through VDH.  But to eliminate the video jumpiness & the audio synch problem, you're going to have to learn how to use ffmpeg.  If you're also interested in getting the captions, VDH will be of no help.  You will have to learn how to use ffmpeg to get the captions.

[mjs]

From what I can see on this site,the audio is still there underneath the video variants. The audio variants have no video resolution but a time

that matches the duration of the video.

The jerky or non fluid video has been talked about on this forum, someone said on another post if you change a vdh setting it runs smoother.

Click settings then behavior tab, scroll down to HLS as M2TS - Download HLS streams as M2TS

Tick this box and click save button.

--

A vdh user