[vlc-devel] MPEG Duration/Playback Ending?

[Developer]

I have a question to which I am hoping I can be enlightened on.

1. During an acquisition via HTTP (eg:  http://www.xyz.com/movie.mpg), 
VLC inititially requests the file from 0-, then does a secondary request 
200,000 bytes less then size.  I am assuming this is so it can determine 
the estimated time length.  What specifically is it looking for in that 
second request?  It doesnt seem to be a TIMESTAMP_PACKET, so I am 
assuming a VIDEO packet, or an AUDIO packet to which to read the 
timestamp from?

I ask because  am attempting to build a pseudo-live streaming server for 
MPEG2 (VOB), using a live source.  In the initial request I pass back in 
the HTML a length of "x", which is actually 1/2 of 1% bigger than the 
what the resulting file will be.  I need to also now send back in that 
2nd request request appropriate frames with timestamps matching my 
estimated length.

This in fact works - somewhat - in that, on a a live stream, when I get 
that 2nd request, I am serving the last 10,000 bytes of a previous 5 
minutes long MPEG video.  I add 0xFF to the rest of it matching the 
request i got (so if VLC asked for the last 200,000 bytes, i send my 
10,000 + 190,000 0xFF) and VLC accepts this, and in the playback window 
i see it has estimated the video at 5 minutes (as that is what the 
length is of the video i clipped the ending from).  I of course need to 
dynamically be able to set the timestamps or whatever in that chunk to 
whatever my real estimated time is going to be.  So needing to know what 
it is VLC is looking for.

2nd issue.  Event though the above works, when I fast forward say 2/3 
(3.5 minutes) into the slider scale, and say only having 1/3 (90 
seconds) the file available, when I get the HTTP Request moving to that 
position, I just serve data from the point at which I am in the live 
feed.  VLC accepts this, adjusts the CURRENT POSITION TIMESTAMP NUMBER 
in the lower right corner correct, so if i really served data from 90 
seconds on, it displays that appropriately, BUT (1) the slider bar does 
not correctly adjust to 90 seconds, it stays at where I moved it to.  
This is a problem because it seems when the BAR reaches the end (not the 
stream), VLC stops playing, even though I am still streaming the data to it.

I know this is probably (not even a little) but a lot off kilter, but 
being able to play LIVE (meaning truly live, not recorded and streams, 
but live video streaming) streams, with fast forward/rewind is  real 
important, and using a web based solution (http progressive) for this 
solves a lot of interop. issues, and removes the need for FLASH RTMP, or 
other realtime solutions.

Any feedback would be really appreciated
Shawn