generate previews for songs

app.py

@@ -1,10 +1,13 @@
 #!/usr/bin/env python2
 
+from __future__ import division
+
 import json
 import sqlite3
 import re
 import os
-from flask import Flask, g, jsonify, render_template
+from flask import Flask, g, jsonify, render_template, request, abort, redirect
+from ffmpy import FFmpeg
 
 app = Flask(__name__)
 DATABASE = 'taiko.db'
@@ -60,6 +63,21 @@ def get_osu_key(osu, section, key, default=None):
     return default
 
 
+def get_preview(song_id, song_type):
+    preview = 0
+
+    if song_type == "tja":
+        if os.path.isfile('public/songs/%s/main.tja' % song_id):
+            preview = get_tja_preview('public/songs/%s/main.tja' % song_id)
+    else:
+        osus = [osu for osu in os.listdir('public/songs/%s' % song_id) if osu in ['easy.osu', 'normal.osu', 'hard.osu', 'oni.osu']]
+        if osus:
+            osud = parse_osu('public/songs/%s/%s' % (song_id, osus[0]))
+            preview = int(get_osu_key(osud, 'General', 'PreviewTime', 0))
+
+    return preview
+
+
 def get_tja_preview(tja):
     tja_lines = open(tja, 'r').read().replace('\x00', '').split('\n')
     
@@ -95,6 +113,24 @@ def route_index():
     return render_template('index.html', version=version)
 
 
+@app.route('/api/preview')
+def route_api_preview():
+    song_id = request.args.get('id', None)
+    if not song_id or not re.match('^[0-9]+$', song_id):
+        abort(400)
+
+    song_row = query_db('select * from songs where id = ? and enabled = 1', (song_id,))
+    if not song_row:
+        abort(400)
+
+    song_type = song_row[0][10]
+    prev_path = make_preview(song_id, song_type)
+    if not prev_path:
+        return redirect(''.join([request.host_url, '/songs/%s/main.mp3' % song_id]))
+
+    return redirect(''.join([request.host_url, '/songs/%s/preview.mp3' % song_id]))
+
+
 @app.route('/api/songs')
 def route_api_songs():
     songs = query_db('select * from songs where enabled = 1')
@@ -107,18 +143,7 @@ def route_api_songs():
     for song in songs:
         song_id = song[0]
         song_type = song[10]
-        if song_type == "tja":
-            if os.path.isfile('public/songs/%s/main.tja' % song_id):
-                preview = get_tja_preview('public/songs/%s/main.tja' % song_id)
-            else:
-                preview = 0
-        else:
-            osus = [osu for osu in os.listdir('public/songs/%s' % song_id) if osu in ['easy.osu', 'normal.osu', 'hard.osu', 'oni.osu']]
-            if osus:
-                osud = parse_osu('public/songs/%s/%s' % (song_id, osus[0]))
-                preview = int(get_osu_key(osud, 'General', 'PreviewTime', 0))
-            else:
-                preview = 0
+        preview = get_preview(song_id, song_type)
         category_out = categories[song[9]] if song[9] in categories else def_category
         
         songs_out.append({
@@ -138,5 +163,34 @@ def route_api_songs():
     return jsonify(songs_out)
 
 
+def make_preview(song_id, song_type):
+    song_path = 'public/songs/%s/main.mp3' % song_id
+    prev_path = 'public/songs/%s/preview.mp3' % song_id
+
+    if os.path.isfile(song_path) and not os.path.isfile(prev_path):
+        preview = get_preview(song_id, song_type) / 1000
+        if not preview or preview <= 0.1:
+            print 'Skipping #%s due to no preview' % song_id
+            return False
+
+        print 'Making preview.mp3 for song #%s' % song_id
+        ff = FFmpeg(inputs={song_path: '-ss %s' % preview},
+                    outputs={prev_path: '-codec:a libmp3lame -b:a 128k -y -loglevel panic'})
+        ff.run()
+
+    return prev_path
+
+
+def check_song_previews():
+    with app.app_context():
+        songs = query_db('select * from songs where enabled = 1')
+
+    for song in songs:
+        make_preview(song[0], song[10])
+
+
+check_song_previews()
+
+
 if __name__ == '__main__':
     app.run(port=34801)

public/src/js/songselect.js

@@ -1263,16 +1263,17 @@ class SongSelect{
 			}
 			var songObj = assets.songs.find(song => song.id == id)
 			
-			if(songObj.sound){
+			if(songObj.preview_sound){
 				if(!loadOnly){
-					this.preview = songObj.sound
+					this.preview = songObj.preview_sound
 					this.preview.gain = snd.previewGain
 					this.previewLoaded(startLoad, prvTime)
 				}
 			}else{
-				snd.previewGain.load("/songs/" + id + "/main.mp3").then(sound => {
+				var previewFilename = prvTime > 0.1 ? "/preview.mp3" : "/main.mp3"
+				snd.previewGain.load("/songs/" + id + previewFilename).then(sound => {
 					if(currentId === this.previewId){
-						songObj.sound = sound
+						songObj.preview_sound = sound
 						this.preview = sound
 						this.previewLoaded(startLoad, prvTime)
 					}
@@ -1285,7 +1286,7 @@ class SongSelect{
 		var difference = endLoad - startLoad
 		var minDelay = 300
 		var delay = minDelay - Math.min(minDelay, difference)
-		this.preview.playLoop(delay / 1000, false, prvtime / 1000)
+		this.preview.playLoop(delay / 1000, false, 0)
 	}
 	endPreview(){
 		this.previewId++