[Lazarus] Can LazVlc update the length of a file while playing?

[Marc Weustink]

Hi,
Why using a file as intermediate transport and not some network stream. Vlc can play a rtsp or raw ts stream without problem. And what is the purpose of ffmpeg (iow can't it be done by vlc itself)
Marc

On November 11, 2024 9:08:24 AM GMT+01:00, Bo Berglund via lazarus <lazarus at lists.lazarus-ide.org> wrote:
>I have created a video player/editor based on PasLibVlc some 5-6 years ago and
>it works for the original purposes. This is on Windows 10. It was created to
>handle mp4 files, but it can open other video file formats as well, thanks to
>the VLC back-end.
>
>Now I have a new use which it cannot perform properly:
>
>In order to be able to view an Internet video stream when it is being downloaded
>using ffmpeg I could not use mp4 format since such a file is not playable until
>it has been closed by ffmpeg. At close ffmpeg writes crucial information to the
>file which allows playback.
>
>So I tested to set the ffmpeg output format to be a ts (transport stream) file
>which I want to view before the download ends. This type of file should be
>playable at all times.
>
>But if I open the file for viewing the PasLibVlc library reads the current
>length at that time into some internal property, which never changes...
>
>I.e. the length of the playing video is not increasing as the donwnload
>progresses.
>
>This means that only that part which was present at the time of opening the file
>for viewing will be available since the player exits when it reaches the
>percieved "end".
>
>I have tried adding a refresh function to my player but it does not work.
>
>And it does not even help to close and re-open the video file, somehow the
>information has been cached somewhere and the old length data reappears.
>
>The only way I have found to actually get a new length is to open a completely
>different video file and then re-open the original file, then the length
>updates...
>
>So it seems like there is some caching being done by VLC, which affects playing
>of the same file and giving the erroneous file length....
>
>QUESTION:
>---------
>So my question is if I would try to use the LazVlc package instead of PasLibVlc,
>is there a command to clear any cached VLC data so a re-opening of a file during
>recording will get the correct current length of it?
>
>
>Notice that the VLC Player itself behaves in the same way, open the ts file at
>some time and note the length, then close it, wait a bit and then re-open the
>file and the OLD length is again shown!
>
>So I cannot use that player either, I need to build my own viwer if the existing
>player/editor cannot be made to work for this scenario...
>
>