Http Live Streaming issues at lower frame rates

Wowza Streaming Engine
1

Hi,

I have been trying to get the lowest possible latency for http live stream into iPad. The delay is now around 5 sec for the streams with a frame rate 8 and above. I have set the key frame rate to be 1 in all cases.

The properties I have set are:

cupertinoChunkDurationTarget

1000

Integer

cupertinoMaxChunkCount

4

Integer

cupertinoPlaylistChunkCount

3

Integer

The index file I receive in this case is

#EXTM3U#EXT-X-VERSION:3#EXT-X-ALLOW-CACHE:NO

#EXT-X-TARGETDURATION:1#EXT-X-MEDIA-SEQUENCE:4002

#EXTINF:1,media_4002.ts?wowzasessionid=1339164348

#EXTINF:1,media_4003.ts?wowzasessionid=1339164348

#EXTINF:1,media_4004.ts?wowzasessionid=1339164348

and the video is fine.

However, when the frame rate of the stream is below 8, the video get stuck and some times go back and forth in time

The index file in this case (frame rate 1) is

#EXTM3U#EXT-X-VERSION:3#EXT-X-ALLOW-CACHE:NO#EXT-X-TARGETDURATION:3#EXT-X-MEDIA-SEQUENCE:5552

#EXTINF:3,media_5552.ts?wowzasessionid=22787889

#EXTINF:1,media_5553.ts?wowzasessionid=22787889

#EXTINF:3,media_5554.ts?wowzasessionid=22787889

Similar output is observer even if I set cupertinoChunkDurationTarget to 10 secs.

How can I get good video quality in lower frame rates?

Is there a minimum frame rate requirement for HLS?

Also, my Index file shows, CODECS=“avc1.66.41”. Does this mean that the H.264 profile and level is Baseline 4.1? If so, how can I change it to Baseline 3.0 so that it will be supported by all iOS devices

Regards,

Manu

2

Hi,

This is actually the Apple device which does not like the low frame rate and should play better in VLC player using the Apple HLS URL.

Generally the stream quality is based on the bitrate of the stream and resolution however if you’re stream has a lot of movement, then you will probably be able to it has a low frame rate.

To change the profile of a stream you will need to use the Wowza trasncoder

Jason

3

Hi,

Please see the “Preparing Media for Delivery to iOS-Based Devices” section of this Apple HLS article which should come in useful.

Jason