[Live-devel] Any feedback re: Change to 'trick play' Transport Stream generation - reduces output bit rate ??

[Ross Finlayson]

Does anyone have any feedback about the following change (which was 
put into place for the most recent version of the code)?  A few 
months ago, several people were complaining about the high bitrate of 
'trick play' streams (fast-forward or reverse play) for Transport 
Stream data.  Does this new version of the code work better for you?

	Ross Finlayson
	Live Networks, Inc.


>Date: Mon, 23 Feb 2009 20:20:33 +1000
>To: live-devel at lists.live555.com
>From: Ross Finlayson <finlayson at live555.com>
>Subject: Change to 'trick play' Transport Stream generation - 
>reduces output bit rate
>
>Some people have reported having problems with 'trick play' 
>operations on Transport Streams, due to the high bitrate of the 
>'trick play' output streams.
>
>By popular demand, I have now released a new version (2009.02.23) of 
>the "LIVE555 Streaming Media" software that changes the way that 
>Transport Streams are generated for 'trick play' operations 
>(fast-forward or reverse play).  Now, each I-frame (i.e., key frame) 
>appears no more than once in the output Transport Stream for 'trick 
>play' operations.  This will have the effect of reducing the average 
>output bitrate for 'trick play' streams, except for high 'scale' 
>values.
>
>For those of you who have been having problems with the high bit 
>rate of 'trick play' Transport Stream data - please try this new 
>code, and let us know if this new version of the code improves 
>things.  Note that because these changes are experimental, I have 
>not yet changed the prebuilt binary versions of the "LIVE555 Media 
>Server" application - therefore, if you use this application, you 
>will need to build your own version from the new source code.
>
>If - for whatever reason - you wish to go back to the old behavior 
>(in which we always keep the original frame rate, even if it means 
>duplicating I-frames), then you can do so by changing the definition 
>of "KEEP_ORIGINAL_FRAME_RATE" in 
>"liveMedia/MPEG2TransportStreamTrickModeFilter.cpp" to "True". 
>However, if you find you need to do this, please let us know why. 
>This change to the code is experimental, and I will back it out if 
>people end up having problems with it.
>--
>
>
>Ross Finlayson
>Live Networks, Inc.
>http://www.live555.com/
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