> I have never quite got the advantage of frame fragmentation, i.e. let's
> consider a large intra frame and the two cases:
>
> 1) Sending the intra frame as a single huge packet
>
> 2) Sending the intra frame as a series of smaller packets
Your use of the word ‘packet’ here is strange (and, I presume, wrong), because
the word ‘packet’ usually means an atomic unit of data sent over a network. I
presume, instead, that you meant to ask about the difference between:
1) Sending an intra frame (i.e., ‘key frame’) as a single H.264 NAL
unit, versus
2) Sending an intra frame (i.e., ‘key frame’) as a sequence of H.264
‘slice’ NAL units
In each case, each NAL unit (unless it’s very small) will be fragmented into
several network (i.e., RTP/UDP/IP) packets - which can be up to 64 kBytes in
size, but are typically about 1500 bytes. The loss of *even one* of these
packets will make the whole NAL unit useless (i.e., unrenderable) for the
receiver.
> The behaviour for the two cases in the case of packet loss:
>
> 1) The whole intra frame is lost, must wait for the next one
Correct
> 2) A one slice of the intra frame is lost .. making the whole intra-frame
> useless.
Incorrect. The video decoder/renderer will be able to decode/render/display
the other slices of the frame - apart from the one that was lost. This might
look strange, but at least you’ll be able to see something.
Ross Finlayson
Live Networks, Inc.
http://www.live555.com/
_______________________________________________
live-devel mailing list
live-devel@lists.live555.com
http://lists.live555.com/mailman/listinfo/live-devel
