# VOD iOS playback freezes on first frame **URL:** \ **Category:** Wowza Streaming Engine\ **Created:** [September 18, 2013, 10:55am UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119 "2013-09-18T10:55:28Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Dan\_Burkett](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@Dan\_Burkett](https://community.wowza.com/u/Dan_Burkett)\ **Post date:** [September 18, 2013, 10:55am UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119/1 "2013-09-18T10:55:28Z")
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: ```auto #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: ```auto #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: ```auto mediastreamvalidator http:///video_9ac61783a189a96cea3c93a3f995cae6db3ef7a2_1379387221.mp4/playlist.m3u8 mediastreamvalidator: Beta Version 1.1(130423) Validating http:///video_9ac61783a189a96cea3c93a3f995cae6db3ef7a2_1379387221.mp4/playlist.m3u8 Validating child playlist chunklist.m3u8?wowzasessionid=33067098 [256.48 kbits/sec] -------------------------------------------------------------------------------- http:///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 ---
**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\ **Post date:** [September 18, 2013, 4:03pm UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119/2 "2013-09-18T16:03:17Z")
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 ---
**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\ **Post date:** [September 18, 2013, 4:04pm UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119/3 "2013-09-18T16:04:18Z")
edit: Try setting the cupertinoPlaylistChunkCount shown in the Configuring HLS Packetizing article **to "1"** ---
**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\ **Post date:** [September 19, 2013, 2:01am UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119/4 "2013-09-19T02:01:23Z")
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](https://www.wowza.com/docs/how-to-encode-video-on-demand-content) Richard ---
**Author:** ![Dan\_Burkett](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@Dan\_Burkett](https://community.wowza.com/u/Dan_Burkett)\ **Post date:** [September 18, 2013, 12:33pm UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119/5 "2013-09-18T12:33:04Z")
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](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: ```auto cupertinoPlaylistChunkCount 1 Integer ``` Thanks, Dan ---
**Author:** ![Dan\_Burkett](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@Dan\_Burkett](https://community.wowza.com/u/Dan_Burkett)\ **Post date:** [September 18, 2013, 12:41pm UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119/6 "2013-09-18T12:41:21Z")
Hi Richard, I don’t see any change in behaviour with this property setting in the VOD context. Dan ---
**Author:** ![Dan\_Burkett](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@Dan\_Burkett](https://community.wowza.com/u/Dan_Burkett)\ **Post date:** [September 19, 2013, 5:40am UTC](https://community.wowza.com/t/vod-ios-playback-freezes-on-first-frame/37119/7 "2013-09-19T05:40:56Z")
Thanks Richard, I’ll look into the encoder side of things. Dan