Check and use correct paths for generating HLS playlist

This also should prevent generating the playlist if it already exists
and uses a better ffmpeg command for transcoding the video.

src/video.rs

@@ -1,19 +1,30 @@
 use std::process::Command;
+use std::path::Path;
 
 // ffmpeg -i test.mp4 -c:v h264 -flags +cgop -g 30 -hls_time 3 out.m3u8
+// ffmpeg -i "filename.mp4" -preset veryfast -c:v libx264 -f hls -hls_list_size 100 -hls_time 2 -crf 24 -vf scale=1080:-2,setsar=1:1 attempt/vid_out.m3u8
 
 pub fn create_playlist(video_path: &str, playlist_file: &str) {
+    if Path::new(playlist_file).exists() {
+        println!("Playlist already exists: {}", playlist_file);
+        return;
+    }
+
     let result = Command::new("ffmpeg")
         .arg("-i")
         .arg(video_path)
         .arg("-c:v")
         .arg("h264")
-        .arg("-flags")
-        .arg("+cgop")
-        .arg("-g")
-        .arg("30")
+        .arg("-crf")
+        .arg("23")
+        .arg("-preset")
+        .arg("veryfast")
         .arg("-hls_time")
-        .arg("5")
+        .arg("3")
+        .arg("-hls_list_size")
+        .arg("100")
+        .arg("-vf")
+        .arg("scale=1080:-2,setsar=1:1")
         .arg(playlist_file)
         .output()
         .expect("Expected this to work..");