Please describe how segmentators parametres (http://www.wowza.com/forums/content....rameters-(iOS)) influence to latency from capture to playback.
First, packets incoming like a continious stream to wowza server and segmente here into chunks based on time. Duration of each chunk is control by the cupertinoChunkDurationTarget setting (in millseconds). As the chunks are completed they are added to the available chunk list. The maximum number of chunks stored in the available chunk list is control by the cupertinoMaxChunkCount setting. When a stream is requested by an iOS device a playlist is returned that contains the [n] most recently added chunks. The number of items returned in the playlist [n] is control by the cupertinoPlaylistChunkCount setting.
So as I understand here are 3 parametres which can increase or decrease latency: cupertinoChunkDurationTarget, cupertinoMaxChunkCount, cupertinoPlaylistChunkCount.
From my experiments I can't understand how they really influencing to latency.
My experiment: I use live Application setup. I set cupertinoChunkDurationTarget to constant value of 8 sec. (this is not matters because it's constant), and cupertinoMaxChunkCount cupertinoPlaylistChunkCount were parameters which I modified and than I follow to stream.
And I can't find direct dependence between changing this parametres and latency.
If I set big (300) value to cupertinoMaxChunkCount (so 300 chunks will be available in chunk list) and big value (100) to cupertinoPlaylistChunkCount so 100 chunks will returned in playlist. So 300 chunks * 8 sec (chunk duration) = 2400 sec buffer that wowza keep in memory. And 100 * 8 = 800 sec duration of playlist. I assume that wowza add as first chunk into playlist the first chunk from available in chunk list so I think that client device like iPad should playback video with latency 2400 sec from live stream. BUT IT'S NOT! I can't calculate really latency but it something like 30 sec. Why? What I misunderstood? Is it client logic or server logic that indicates the correct start time to client? I'm asking because if try to wget first chunk it seems that its really far from live.
If I set small value to cupertinoMaxChunkCount (5) and cupertinoPlaylistChunkCount had value 3. And 5 * 8 = 40 sec will be latency and 3 * 8 = 24 sec duration of whole playlist. In such case I've get latency around 8-15 sec. This value is good but how it can be calculated?
Please point me out how latency can be calculated and why this settings not work as I expect.
Or describe more deeply of stream flow through wowza and maybe I answer to my questions by myself.