I'm attempting to use libVLC as a video decoder for a motion detection project. Previously I was using ffmpeg libraries, but some issues with Matroska files brought me here. Along with playing video back at the correct rate, I also want to be able to get one frame after another at the fastest rate my system can handle, as once the user sets up some parameters, I want the motion detection algorithm to run through the video as quickly as it can. My libVLC setup code looks like this (error handling and minor details omitted for brevity):
const char* vlc_argv =
"--no-audio", /* skip any audio track */
libvlc_instance_t* inst = libvlc_new(sizeof(vlc_argv) / sizeof(*vlc_argv), vlc_argv);
auto media = libvlc_media_new_path (inst, filename.c_str());
player = libvlc_media_player_new_from_media(media);
// Needed to initialize the player ?
fps = libvlc_media_player_get_fps(player);
length = libvlc_media_player_get_length(player);
width = libvlc_video_get_width(player);
height = libvlc_video_get_height(player);
// TODO: Add libvlc_video_set_callbacks to set up callbacks to render to memory buffer
However, I am left with the following questions:
1. Is there a more straightforward way to initialize the media player without starting playback besides calling `libvlc_media_player_play` then `libvlc_media_player_pause`?
2. All of the `get` functions (`fps, length, width, height`) all return zero. Do I need to do something like read the first frame to get these values, and if so, how am I supposed to know how large my decoded frame buffer must be? Hi, just wondering, on which OS are you?
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