encoding question for h.264 everywhere

[bill99]

Hi all,

I'm try to understand what file we need to make fully to take advantage of the h.264 everywhere idea. Currently we encode most of our video content to .flv formats and rely on progrressive download for display on websites. We are currently looking to upgrade to a streaming server solution for content delivery and need to make this content compatible with iphone / ipad etc. We will also be adding a live stream from an h.264 compatible IP camera.

So, to make a VOD file available to play frpom a website and an iphone can someone point me in the right direction as to what type of file we create?

How do we cater for the different screen sizes of iphone versus web playback?

How do we cater for intelligent bitrate delivery of the media stream depending on the network conditions / playback device etc.

We use sorenson squeeze 6 to encode our media so I'd really appreciate any information / settings that may exist which I can try in sorenson 6 to make test files.

Many thanks in advance.

Bill

[rrlanham]

To deliver the same stream to a Flash application and IPhone, incuding older model IPhones, you should encode h.264 format Baseline 3 profile or lower, wiith AAC or MP3 audio. For delivery to mobile over cellular connection, a low bitrate is good idea. For multiple bitrate, you have to encode multiple version with different bitrates that are keyframe/timecode aligned, and play a smil file. See the multi-bitrate section of the Video on Demand tutorial, which includes sample files and smil file, and a set of sample files especially encoded for IPhone:
http://www.wowzamedia.com/forums/showthread.php?t=6466

To encode sets with keyframe/timecode alignment we have found that MS Expression Encoder is a good choice for encoding sets of for this purpose.

Richard

[bill99]

Many thanks Richard.

I think I should also be able to produce the synchronised multibit streams using Sorenson - as long as we keep the frame rate set and apply key frames at a fixed number of frames ( say every 25 ). Hopefully key frames added on scene change will be detected and added the same in each stream.

Adding multi bitrate playback to flash seems fairly involved so I'l leave that til last but I'll try out making a few streams at different bitrates for the iphone to cater for cellular connections and broadband. For the flash player I'll just point it at a VOD app for one of these streams and point the iphone at the SMIL app.

I'm assumming that the iphone automatically detects bandwidth and switches bitrates if they are available? Is there any way I can tell what the iphone is doing and which stream it is playing while I am testing?

Best,

Bill

[rrlanham]

Yes, IPhone does the switching, or at least requests the switch. Wowza delivers the new stream, and you can see this in the log files.

Richard