Accelerated video

[Joan Cros]

Hello, when I upload a video to a site, which may be secure, the output video is accelerated with normal speed audio. How to cure it ?

Thanx

[Wild Willy]

Oh brother. I have intermittently observed the inverse problem, which I have described
in entirely too much detail over here:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/w9993gUmxr4

That probably doesn't help you a lot but it may give you some ideas. My guess, and I
admit I'm guessing, is that there is something wrong with the file on your system before
you upload it. Does it play properly all the way through before you upload it? If it
does, then maybe simply retrying your upload might fix the problem. If not, I don't
think I can help you. I'm no expert at video editing. It's entirely possible that your
video player is silently correcting some problem in your input file. I can't advise you
on how to analyze the original input file. I would assume that ffprobe on the input file
shows the file is fine. If that's the case, I'm out of ideas.

This does not particularly sound like a VDH problem. VDH doesn't upload files to
servers. If the file you uploaded has this problem, VDH would most likely just download
it & preserve the problem. You need to figure out what's wrong with the file before you
upload it.

Good luck.

[Wild Willy]

We now have a collection of threads, most of them fairly recent, all of them sharing the distressing commonality that the original poster seems to have disappeared & lost interest in the discussion.  Moreover, not a single one of these cases includes a proper problem description.

https://groups.google.com/g/video-downloadhelper-q-and-a/c/xB1XQOFs0zo
https://groups.google.com/g/video-downloadhelper-q-and-a/c/WfQfhriLDNI
https://groups.google.com/g/video-downloadhelper-q-and-a/c/i8bP8DOVN00
https://groups.google.com/g/video-downloadhelper-q-and-a/c/4BaGtP_xbQY

In all of these cases, I have offered this thread as a workaround.  I admit it doesn't fix VDH.  I also have to say that it is unclear whether VDH is the cause of this problem.  But it is a problem I have observed & I have come up with a way to deal with the issue:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/w9993gUmxr4

This thread is new enough that I can't yet judge whether the original poster has lost interest.  Based on the trend, I am not optimistic:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/SSgY9oLoHdw

On the other hand, this user posted what is very close to a proper problem description.  So maybe I should be more optimistic.

Here is the problem description.  Something happens intermittently that causes the video to run at a ridiculously fast rate while the audio plays normally.  I first noticed this a year ago & I have seen this multiple times in the interim.  I get it with Golf Channel livestreamed tournaments.  But I get it maybe once every 10 or 15 rounds of golf.  The intermittency of the problem does make it nearly impossible to nail down.  I just wish one of these posters, I don't care which one, would follow up.  Try my approach.  Does it help?  Did it trigger a better idea you could be cajoled into sharing with us here in public?  This is a problem that I wish could be identified & I would welcome a workaround that is less of a kludge than the one I've been using.  But I've offered the kludge & nobody else has offered anything.  Nobody else has even said whether they can apply my kludge.  Nobody else has said whether they have a better idea.  I'm pretty sure this is not a problem with VDH but I'm not 100% certain.  Since it is intermittent, Michel probably can't replicate it so there isn't any hope a fix to VDH is forthcoming.  The assumption that this is caused by VDH is not entirely supported by the facts.  The fact is that most downloads with VDH DO NOT exhibit this too-fast-video problem.  So blaming VDH is a hard sell.  My suspicion is that there is some field in the control block of the video that indicates the video speed.  I believe this control block is known as the MOOV atom.  My suspicion is that one field in the MOOV atom needs to be repaired.  How did the field get corrupted?  Beats me.  Maybe there was momentary noise on the line.  I though TCP/IP had built-in safeguards to prevent such corruption but I believe it is not foolproof.  It can correct single-bit errors but it might not catch double-bit errors.  Maybe the video was encoded incorrectly by the serving web site.  Maybe this, maybe that.  Maybe maybe maybe.  How do you repair the damage?  Beats me.  I don't know the internal structure of a MOOV atom.  But you'll notice my repeated us of the word, "suspicion."  I'm guessing.  I'm not a guru in these matters.  I'm a guru only in watching golf tournaments.  I'm also a guru in railing against the deplorable state of apparent apathy among the people posting these problems . . . and problems in general in this forum.  All I know is that the video in these cases is not totally corrupted.  If you slow playback down by some factor, you will see a proper video.  The slow down factor is something you can determine only by trial & error.  Sometimes you can play it at 50%, sometimes 25%. sometimes it's some fraction that is probably an irrational number.  Irrational number.  A mathematical term.  If you don't know it, look it up.

Trying all the resolutions -- resolutions, not qualities -- offered by VDH is probably not productive.  For one thing, I see this problem with livestreams.  I don't know the problem has occurred until after the livestream ends.  You can't chase play the livestream while VDH is recording it.  I've tried.  You can't do it.  So you can't know you've got the too-fast-video problem until the recording is complete.  So by the time I might reach the decision of trying the other resolutions, the livestream is no longer available at any resolution, even the one I just recorded.  So that suggestion is a non-starter.  Besides, like I say, the problem usually does NOT occur.

All I can do is post this comment in each of the applicable threads & hope somebody sees it & progresses this discussion.