VOD iOS playback freezes on first frame

Wowza Streaming Engine
1

Hi,

Some of my short VOD clips fail to play in iOS (iOS6, iPad, Simulator). The first frame loads, but the video never plays - the loading message and spinner stay forever. Other short videos play successfully. I can view the videos with no problem in Safari on Mac, in VLC on Windows, etc. It is only on iOS (Safari and native app) that the problem manifests itself.

playlist.m3u8:

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=256477,CODECS="avc1.66.30",RESOLUTION=640x480
chunklist.m3u8?wowzasessionid=1850863335

chunklist.m3u8:

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:1
#EXTINF:3.972,
media_1.ts?wowzasessionid=1850863335
#EXT-X-ENDLIST

mediavalidatortool:

mediastreamvalidator http://<url>/video_9ac61783a189a96cea3c93a3f995cae6db3ef7a2_1379387221.mp4/playlist.m3u8
mediastreamvalidator: Beta Version 1.1(130423)
Validating http://<url>/video_9ac61783a189a96cea3c93a3f995cae6db3ef7a2_1379387221.mp4/playlist.m3u8
Validating child playlist chunklist.m3u8?wowzasessionid=33067098 [256.48 kbits/sec]
--------------------------------------------------------------------------------
http://<url>/video_9ac61783a189a96cea3c93a3f995cae6db3ef7a2_1379387221.mp4/playlist.m3u8
--------------------------------------------------------------------------------
Playlist Syntax: 	OK
Alternate playlist(s):
--------------------------------------------------------------------------------
chunklist.m3u8?wowzasessionid=33067098
--------------------------------------------------------------------------------
Playlist Syntax: 	OK
Segments:	OK
Average segment duration: 3.02 seconds
Playlist target bitrate: 256.48 kbits/sec
Segment bitrate: Average: 243.85 kbits/sec, Max: 243.85 kbits/sec

We are using Amazon S3 and MediaCache. We have no issues with video playback except on iOS for certain (but not all) short video clips.

Any suggestions would be appreciated.

Thanks,

Dan

2

Dan,

Try setting the cupertinoPlaylistChunkCount shown in the Configuring HLS Packetizing article to “1”

And/or, depending on the actual length and encoding, if you can encode the file to have a key frame frequency of 1 second, then set cupertinoChunkDurationTarget to “1000” (1 second). Then if the video is at least 3 seconds long you might leave cupertinoPlaylistChunkCount at default setting or “3”. In any case, those are the settings I would work with in this case, along with key frame frequency, which gop (or key frame interval) / fps

Richard

3

edit: Try setting the cupertinoPlaylistChunkCount shown in the Configuring HLS Packetizing article to "1"

4

Dan,

Right, sorry, not for vod. All I can suggest is encoding the file with very short key frame interval, 1 second if possible, so Wowza breaks smaller chunks. Not sure if that will help. For reference, this is our video encoding guide

Richard

5

Hi Richard,

Does this setting apply to VOD? I found the following article, but it mostly looks like it’s related to live: https://www.wowza.com/docs/how-to-configure-apple-hls-packetization-cupertinostreaming

I’ll try adding to the HTTPStreamer/Properties container to see if it makes a difference:

<Property>
	<Name>cupertinoPlaylistChunkCount</Name>
	<Value>1</Value>
	<Type>Integer</Type>
</Property>

Thanks,

Dan

6

Hi Richard,

I don’t see any change in behaviour with this property setting in the VOD context.

Dan

7

Thanks Richard, I’ll look into the encoder side of things.

Dan