[Live-devel] 答复: question about the live555 RTP sending speed

[Aiden_Coomo]

Sorry I can't grasp "properly set".  ^_^
Another question about "fPresentationTime".
The sending rate depends on "fDurationInMicroseconds", Then ,what is
"fPresentationTime" related to ?  timestamp, right ???


-----邮件原件-----
发件人: Ross Finlayson [mailto:finlayson at live555.com] 
发送时间: 2008年9月24日 15:26
收件人: LIVE555 Streaming Media - development & use
主题: Re: [Live-devel] question about the live555 RTP sending speed


>>The transmission speed is determined by the value of the
>>"fDurationInMicroseconds" variable.  Your "*Framer* object (in this
>>case, your "H264VideoStreamFramer" subclass) needs to properly set
>>this for each H.264 NAL unit that it delivers.
>
>I suppose this is correct. However, "properly set" doesn't necessarily
>mean what you first think it means.

Since I wrote the software, I'm the person who gets to define what 
"properly set" means :-)

>These are my findings:
>
>- all NAL units that belong to the same frame, except the last NAL
>   unit in that frame, should have a duration of 0 (zero).
>
>- the last NAL unit in each frame should have a duration matching
>   that of its frame.
>
>- all NAL units in a frame should have the same presentation time.

None of this is inconsistent with what I said earlier.  Your 
"H264VideoStreamFramer" subclass implementation should set the 
"fPresentationTime" and "fDurationInMicroseconds" variables in 
accordance with what you just said.


	Ross Finlayson
	Live Networks, Inc. (LIVE555.COM)
	<http://www.live555.com/>