[Live-devel] Confused about how to generate fmtp line for H.264 source for SDP

[Matt Schuckmannn]

Ok, thanks for the input. 

Matt S. 


On Wednesday, August 03, 2011 6:51:37 PM, Ross Finlayson wrote:
>>> Yes. Now, the SPS and PPS NAL units are assumed to be in the input 
>>> NAL unit stream (and are extracted from there).
>>
>> Is that a safe assumption, isn't optional to include the SPS and PPS 
>> NAL units in the stream? or at the very least make the very infrequent?
> 
> Yes, it's uncommon for a supplier of a H.264 stream to know the SPS and 
> PPS NAL units, but for those NAL units not to appear in the stream. Most 
> commonly, these NAL units appear in the stream, but you don't know what 
> they are - and can find them out only by scanning the stream. We now do 
> that for you.
> 
> 
>> Hmm, I'll look into it, but my encoder gives me the sps and pps when I 
>> initialize it, it seems like it would be easier to just hand the sps 
>> and pps to the rtp sink and just re-implement auxSDPLine in my class, 
>> pretty much like I used to do. Is there a reason your recomme
nding 
>> this approach
> 
> Yes, the reason was that it would probably save you work. If the SPS and 
> PPS NAL units also appear in the stream (which, for most encoders, they 
> will), then you don't have to do any extra work (except perhaps 
> duplicate some code that we already have in 
> "H264VideoFileServerMediaSubsession").
> 
> 
> Ross Finlayson
> Live Networks, Inc.
> http://www.live555.com/
> 
> 
> 
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