[streaming] Re: Streaming from raw MPEG-4

[Nico Sabbi]

Jeff Poole wrote:

>On Wed, November 22, 2006 4:44 pm, Nico Sabbi wrote:
>  
>
>>Jeff Poole wrote:
>>
>>    
>>
>>>nc -l -p 3975 -u | mplayer -
>>>(tell netcat to listen for udp traffic on port 3975, and then pipe that
>>>to
>>>mplayer which reads from stdin)
>>>
>>>
>>>      
>>>
>>twisted
>>
>>    
>>
>>>It usually spits out a few errors until it actually detects a header (I
>>>believe it's VOL headers that keep getting sent) and then it starts
>>>playing the video perfectly.  But I don't know of a way to get MPlayer to
>>>stream it back out.
>>>
>>>      
>>>
>>mplayer udp://ip:port
>>
>>    
>>
>
>I thought that just made mplayer read the data from UDP, not stream it
>back out?  
>
indeed

>If you are trying to give me an easier way to get the data into
>mplayer, I should point out that I tried that and it didn't seem to work. 
>Looking at the data more, it appears that the data stream starts with a
>VideoObject, containing a VideoObjectLayer...and those headers repeat
>regularly, presumably to allow one to connect in the middle of a stream. 
>But there is no VisualObject header, and I believe that is a problem.  I
>think mplayer seeks until it finds some sort of header it can use, and
>then tries to make the best of it.  But a more strict decoder would
>probably look for the VisualObject header, ensure that the type is "0001"
>(video), and then move from there. 
>
it's what mplayer does

> Especially since the spec says you can
>only repeat VideoObjectLayer headers in video, a decoder would want to see
>that before it would think the stream looked valid.  At least, that's my
>view -- I'm no expert.  Maybe I need to wrap this thing in a VisualObject
>and maybe try to put it in an RTP stream for VLC to take in?  Would RTP be
>the easiest? 
>

mot needed

> Any ideas?
>
>
>Jeff
>
>  
>

can you upload a sample somewhere please?

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