Sizing a playback buffer to that of a video

[opensoar]

First time user of LibVLC. I have working code that opens a video file from a URL and renders it into a 256 x 256 buffer via an OpenGL texture.

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unsigned int texture_width = 256; unsigned int texture height = 256; unsigned int texture_depth = 4; libvlc_video_set_callbacks(media_player, lock, unlock, display, &context); libvlc_video_set_format(media_player, "RV32", texture_width, texture_height, texture_width * texture_depth); libvlc_media_player_play(media_player);

Now I want to optimize it so the buffer is sized to the actual dimensions of the video.

I realize you don't know the size of the video until after it starts playing so currently, I set an arbitrary size for the video at initialization and defer creation of the buffer until my "lock" method is called. I get the video size and set the format like this:

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static void* lock(void* data, void** p_pixels) { ... ... libvlc_video_get_size(context->mp, 0, &video_width, &video_height); libvlc_video_set_format(context->mp, "RV32", video_width, video_height, video_width * 4); ... ...

and create a buffer video_width x video_height x 4 in size. However, the video renders incorrectly - the line pitch is wrong and looks like VLC is still using the value I set at initialization.

Is this the right approach and if so, anyone know what I am doing wrong?

If there is a better way to do this, can you please share details.

[Rémi Denis-Courmont]

No, it is not. Refer to the Libvlc Doxygen.

[opensoar]

Isn't that more of a resource for looking up functions etc. vs a description of how one is supposed to structure an application?

Can you point me at some sample code?

[opensoar]

As a long time VLC developer, I imagine you know exactly how to do this. Care to elaborate or point me at some code?

[Rémi Denis-Courmont]

RTFM.

[opensoar]

Really? That's the best you can come up with.

Super helpful. Thank you.

[Rémi Denis-Courmont]

Would you care to explain why volunteer developers should help you debug your app on their free time, while you can evidently not be bothered to read the documentation?

[opensoar]

Yes of course.

My post wasn't one of those "hey guys - i need to make app that decodes video - please help. LOL. thanks".

I followed the instructions on your saite for an example that uses SDL, ported it to my Windows code base and got it working. After some experimentation, I discovered that the simple approach didn't appear to let me decode to a buffer that can change size at any point - a feature of the system I am working in and beyond my control.

I didn't post asking for debugging help - merely a pointer to an example snippet or at least a high level approach I can take to implement it. I was planning on releasing all the source code once I got it working for those Windows developers that come after me.

I'm not expecting anyone to spend a large amount of time on this - as experienced developers, I'm sure you know exactly how to do this and a quick list of the sorts of functions I need to string together or a pointer to some existing code - even an overview doc on how to implement this feature - would have been immensely helpful.

"RTFM" was not.