Crash app when download video hasn't data in manifest

Describe the bug
A clear and concise description of what the bug is.
When check audio manifest hasn’t m3u8URL then crash app

To Reproduce
Download a video has multi audio and subtitle
Manifest file hasn’t m3u8URL
App is crashed

Expected behavior
Check nil with a serveral cases hasn’t data

Logs and Screenshots
If applicable, add log and/or screenshots to help explain your problem.

Platform

  • OS and version: IOS 13.3.1
  • Device type: Iphone/Ipad
  • Library version : v3.11.1

Vietnam VPN -> can play stream
Other location -> stream 404 error
Can you give me IP address or region to open VPN connection?
Tks

#EXTM3U
#EXT-X-VERSION:7

Created with Broadpeak BkS350 Origin Packager(version=1.9.5)

AUDIO groups

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID=“audio-aacl-128”,NAME=“Vietnamese”,LANGUAGE=“vi”,AUTOSELECT=YES,DEFAULT=YES,CHANNELS=“2”
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID=“audio-aacl-128”,NAME=“Korean”,LANGUAGE=“ko”,AUTOSELECT=YES,CHANNELS=“2”,URI=“player_test-audio_kor=128000.m3u8”

SUBTITLES groups

#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID=“textstream”,NAME=“Vietnamese”,LANGUAGE=“vi”,AUTOSELECT=YES,DEFAULT=YES,URI=“player_test-textstream_vie=1000.m3u8”

variants

#EXT-X-STREAM-INF:BANDWIDTH=452000,CODECS=“mp4a.40.2,avc1.4D4029”,RESOLUTION=426x240,FRAME-RATE=30,AUDIO=“audio-aacl-128”,SUBTITLES=“textstream”,CLOSED-CAPTIONS=NONE
player_test-audio_vie=128000-video=297000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=702000,CODECS=“mp4a.40.2,avc1.4D4029”,RESOLUTION=640x360,FRAME-RATE=30,AUDIO=“audio-aacl-128”,SUBTITLES=“textstream”,CLOSED-CAPTIONS=NONE
player_test-audio_vie=128000-video=533000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=1182000,CODECS=“mp4a.40.2,avc1.4D4029”,RESOLUTION=854x480,FRAME-RATE=30,AUDIO=“audio-aacl-128”,SUBTITLES=“textstream”,CLOSED-CAPTIONS=NONE
player_test-audio_vie=128000-video=986000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=2235000,CODECS="mp4a.