VLC的一些接口

其他参考链接：

1、https://www.cnblogs.com/smartsensor/p/4343769.html

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/*Set the video scaling factor。

Zero is a special value; it will adjust the video to the output
window/drawable (in windowed mode) or the entire screen.

*/

设置缩放系数

void libvlc_video_set_scale( libvlc_media_player_t *p_mi, float f_factor );

/*Set new video aspect ratio.*/

设置视频长宽比

void libvlc_video_set_aspect_ratio( libvlc_media_player_t *p_mi, const char *psz_aspect );