create-sound-waveforms: create waveform from mp3 if ogg doesn't exist

emissions/management/commands/create-sound-waveforms.py

@@ -48,7 +48,12 @@ class Command(BaseCommand):
 
     def create(self, soundfile):
         # create a raw output, with a single channel and 4000Hz samples of 8bits
-        cmd = ['sox', soundfile.get_format_path('ogg'), '-t', 'raw', '-c', '1', '-r', '4000',
+        sound_filename = soundfile.get_format_path('ogg')
+        if not os.path.exists(sound_filename):
+            sound_filename = soundfile.get_format_path('mp3')
+        if not os.path.exists(sound_filename):
+            return
+        cmd = ['sox', sound_filename, '-t', 'raw', '-c', '1', '-r', '4000',
                 '-e' 'unsigned-integer', '-b', '8', '-']
         wave_array = subprocess.check_output(cmd)
         for filename, n_samples in (('waveform.json', 200), ('waveform-500.json', 500)):