The VideoLAN Forums

Hello,

We have been using libvlc for a few years, with the official release, and it was working fine, until recently when we were unable to play some files containing custom tracks (more on this at https://code.videolan.org/videolan/vlc/-/issues/26505). So we ended up compiling the 4.0.0 version with our simple fix; the lib has been compiled from linux following the suggested cross-compilation approach.

The VLC player compiled plays the movie correctly, both video and audio are played.

When I try to play the video from our application with libVLC integrated, audio is being played appropriately, and also seek is working fine, but I video is not being displayed.

I checked the output on the console, and did a little bit of comparisons between the output of the command-line vlc compiled, and the console output in Visual Studio, and I observe that apparently the libVLC is unable to create the video output display.

Following is the output of commandline VLC [WORKING]:

...
[0000026327f40030] d3d11va generic: Using D3D11VA (NVIDIA GeForce RTX 2060, vendor 10de(NVIDIA), device 1f11, revision a1)
[0000026327f4b0c0] main decoder debug: vout change: chroma
[0000026329078fc0] main video output debug: requested window size: 1920x1080
[0000026327e8fa20] main window debug: resized to 1920x1080
[0000026327e8fa20] main window debug: resized to 1920x1080
[0000026329078fc0] main video output debug: deinterlace -1, mode auto, is_needed 0
[0000026329078fc0] main video output debug: Opening vout display wrapper
[00000263290a9170] main vout display debug: looking for vout display module matching "any": 5 candidates
...

while the following is what is being printed from our application [FAILING]:

d3d11va generic: Using D3D11VA (NVIDIA GeForce RTX 2060, vendor 10de(NVIDIA), device 1f11, revision a1)
main decoder debug: vout change: chroma
main video output debug: requested window size: 1920x1080
main video output debug: deinterlace -1, mode auto, is_needed 0
main video output debug: Opening vout display wrapper
main video output error: video output display creation failed
main player debug: saving a free vout
avcodec decoder debug: trying format dxva2_vld
main decoder debug: vout change: decoder size
main decoder debug: vout change: visible size
main decoder debug: vout change: decoder size

lines in bold in the above snippet repeat themselves while the file is being played.

Could it be that I need to pass to the library some initialization option?
As I side note, when creating an instance of the library with libvlc_new, it is loading ALL the modules (many of which are not required) in the plugin directory taking forever, and I cant find a way to control the startup process appropriately.

Any kind of suggestion would be greatly appreciated, and if you need any further details I'll do my best to provide them.

Thanks in advance

have a Nice Day

Slow libvlc_new() is a symptom of the combination of two things: running on a platform with relocation instead of PIC, and missing the VLC plugin cache.

Tomorrow as I get back to the office I'll check out to make sure that libraries are compiled with PIC.

As for the missing VLC plugin cache, that is definately the case. I get the following message when creating the instance:

main libvlc debug: loading plugins cache file D:\AiM-GIT\AiM.Software.RaceStudio3\aim_exe\32\RS3\64/plugins\plugins.dat
main libvlc warning: cannot read [...]/plugins\plugins.dat: No such file or directory
main libvlc debug: recursively browsing `[...]/plugins'

I noticed the existance of vlc-cache-gen, I tried to run it with --help or without arguments, but no usage or help is being shown. Is there a place where some details are about cache creation is listed? Can the plugin cache be generated and shared among different machines?

Any hint/suggestion on the main subject regarding the failed creation of video output display?

Thanks

Just a quick update

at least problems with the long loading time of plugins has been solved by generating the plugins.dat appropriately

I still get no video output

Can you share a small C/C++ sample app that reproduces the issue please?

I'll be try to make up one, which will a nice test in itself

Regarding the video output failure, if you are using a recent-ish version of libvlc, you'll need to rebase onto a version including https://code.videolan.org/videolan/vlc/ ... uests/1327.

Regarding the video output failure, if you are using a recent-ish version of libvlc, you'll need to rebase onto a version including https://code.videolan.org/videolan/vlc/ ... uests/1327.

Will check into this as well

Regarding the video output failure, if you are using a recent-ish version of libvlc, you'll need to rebase onto a version including https://code.videolan.org/videolan/vlc/ ... uests/1327.

Integrating the mentioned patch fixed the issue.

I'll take the chance to ask one final question: I am struggling to find out how to control the logging level of libVLC 4.0.0 once it integrated into our application.
As of now, it looks like LIBVLC is initialized with DEBUG logging enabled; this was very helpful when we were investigating. At the moment I am trying to figure out if I should add arguments to the initialization of lb vlc, or if I should enable/disable logging levels through APIs.

Thanks for all the help so far!

It's up to your callback to filter log on levels. There is no longer an option to disable debug logs from the builds, if that's what you mean.