Video files that do not play properly. PTS (presentation time stamp) error?

[Lestat]

The video of the downloaded video file does not play smoothly.
Other download tools are fine.

I tried passing it to Avidemux and it showed a PTS error.
After correcting this error, the video can now be played normally.
This problem is not specific to a particular site and is rare.
Also, the problem has been occurring since about December 2022.

[Lestat]

[jcv...@gmail.com]

Hi,

Is it reproducible ?

Do you have a URL as an example ?

jerome

On Sunday, 26 February 2023 at 03:50:16 UTC+1 Lestat wrote:

[Lestat]

Cannot enter URL due to possible copyright issues.
Can you give me a few sites to test?

2023年2月26日日曜日 17:05:43 UTC+9 jcv...@gmail.com:

[Wild Willy]

It's nearly impossible to diagnose this if you can't give us examples. As for sites you
can test, you yourself said this is rare. This implies you have already tested this
yourself & found VDH to be flawless most of the time. I have not seen this error myself.
The closest I've come is the often reported issue that the audio of a multimedia item is
fine but the video is compressed into a few seconds at the beginning of the item, or the
item will be fine for a certain duration when suddenly, the video track speeds up to
twice normal speed (or faster) while the audio continues to play fine. Perhaps this
thread offers some things you can try:

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

But if you can't post samples for us to test, you're probably not going to get much
satisfaction here. You say other tools work fine on the items VDH damages. Well, use
those other tools in those cases.

I'm curious about your copyright worry. If this is an item that's behind a user ID &
password, then nobody here can access the content to test it. But if anybody could play
the content if they knew the URL, then I don't see where there could be a copyright
issue. If I don't have to identify myself before I access the material, then I can't see
where there is anything to worry about for copyright infringement. It's not like we
would be taking the content in order to offer it up again for a price. You already have
the content yourself so you are already in a position to infringe the copyright. If this
isn't password protected content, I question your worry about copyrights.

By the way, I don't work for VDH. I'm just another user, like you. On the other hand,
Jérôme does work for VDH. So pay attention to whoever you think will help you.

[mjs]

I searched the forum for  pts and found just a few posts. There were two sites I saw  for the Lestat to test.

https://tubitv.com/home

https://www.arte.tv/en/

It may not be exclusive to these sites but when I look in the VDH menu , they show as HLS streams.

And since they are HLS streams , I have it set to Download HLS streams as M2TS in the settings page because the video looks and plays

much better than if that setting wasn't enabled. So maybe the problem is with HLS streams.

[Wild Willy]

Tubi uses DRM to protect its content so you can forget about downloading from there.
Perhaps not all of their content is DRM protected so it might be hit & miss. But the
thing I picked at random just now was under DRM. Seems to me I've been to that site
before & hit DRM then, too. I think it was for World Cup matches. Tubi is owned by Fox
TV, isn't it? Not that that is particularly relevant. Just something I recall noticing.

If you want to just run a bunch of downloads as a test of VDH, try YouTube.

[Wild Willy]

Oh. Wait. That was dumb. YouTube doesn't use HLS. Try https://www.medici.tv/en. Or
https://www.medici.tv/xx where xx is your preferred language. They use HLS. Medici is a
subscription site but you don't need a subscription to test HLS on it. They have lots of
short preview clips that are HLS items that you can test VDH on without having a user ID
& without logging in. You don't generally even need tto launch playback on the clips.
VDH usually recognizes something on their pages. Their free preview clips are usually
only about 3 minutes long so it's a good site for exercising VDH.

[Wild Willy]

I picked something at random on Arte. You can see it in the 2 attached images. I needed
to take 2 screenshots to show the entire VDH menu because there's enough on there to make
it scrollable. Looking it over, I thought the bottom item in the second image looked
like it might be the video. It's about the right duration according to what you can read
on that web page. I decided to look at the Hit Details on that variant. It looked like
it might be a video but I ran the m3u8 HLS manifest in the Hit Details through ffprobe.
I was rather surprised to discover that this was an HLS manifest for WEBVTT captions. I
didn't try it but maybe VDH could download these captions. I hit something like this a
couple of weeks ago when I accidentally got VDH to download some captions for me. I
wasn't sufficiently motivated to try it here.

Everything else on the menu -- everything else showing a duration -- says it's only 6
seconds long. So I went to the first 2 items you can see in the first attached image.
The hit details on the top variant showed it was a straight MP4, not HLS. Running its
URL through ffprobe showed it was video without audio at 1920x1080 resolution. Doing the
same thing on the second variant showed it was an MP4 of audio without video, once again
not HLS. They were both of the expected duration quoted on the web page. I remained
insufficiently motivated to actually download either of these variants.

Maybe other content on this site is actual HLS but I wouldn't count on it. I worked on
this thread a couple of years ago:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/1d2Lz6hBST4

I even mention it in the Table of Contents. A user in France was having trouble getting
both tracks of an item on Arte. That one also had separate video & audio. So I'm not so
sure Arte is a good test site.

I further decided to look at the Hit Details for 2 of the 6-second items you can see in
my attached images. The first one (marked 1920x1080) turned out to give me an HLS master
manifest that included 5 video tracks at various resolutions, 1920x1080 among them, & the
others being the other resolutions reported on the VDH menu. But the 5 video tracks
shared a common audio track. We already know VDH has problems associating the video &
the audio correctly when the HLS manifest is built like this. The next to last variant
on the VDH menu (marked HLS streaming - 0:06 - MP4) turned out to have Hit Details that
referred to an HLS master manifest that included only 1 track, which appeared to be the
audio track. Curiously, despite VDH reporting the duration as 6 seconds in both cases,
ffprobe reported the duration as just over 43 minutes in both manifests. I am still not
sufficiently motivated to download any of this to verify it. Maybe you can as an
exercise. But I'm even more strongly recommending you not mess with Arte. That site
seems to point up the bug in VDH that makes it incorrectly process HLS manifests that
show an audio track shared among several video tracks.