[vlc-devel] [PATCH 1/1] Supporting ONVIF PRofile-G recording playback

David R. Robison david.robison at openroadsconsulting.com
Tue Aug 5 01:30:51 CEST 2014

There are a few concerns I have. Looking at the src/input/var.c file I 
see a "time" variable but not a time-start/time-end. I do see a "length" 
variable so I assume "time" is start time and "time" + "length" is the 
end time. When it comes to the RTSP integration there are two ways to 
set the PLAY requests range header value. When playing live video the 
RTSP SendPlayCommand sens a "range: npt" tag, when playing recorded 
video it sends a "range: clock" value. I need a way to set the start/end 
time and also let the live555 module know its playing recorded not live 
video. I am also concerned about sending multiple PLAY request. If I use 
the variable callback and have separate variables then I will send a 
PLAY when the start time is set and again when the end time is set. I 
should be able to get around this, however.

I don't know if I am explaining this well. Am I understanding the code 
right? Any suggestions of how to let live555 know the difference between 
live and recorded video? Thanks for your input and suggestions.

David R Robison
Open Roads Consulting, Inc.
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On 8/4/2014 5:51 PM, Rémi Denis-Courmont wrote:
> Le lundi 4 août 2014, 15:15:40 David R. Robison a écrit :
>> My thoughts was to use a single variable which I now call "timerng" (but
>> I will change that) so that when I set the time range I get a single
>> callback for the one variable. However, I can get around this if I
>> create a time variable for "start-time" and one for "end-time". If I set
>> the end-time first then I can detect that the start-time has not been
>> set and not cause an extra PLAY request.
> Again: why do you need to use object variables AT ALL? This still looks like
> cargo cult programming to me.
>> I do think, however, that I need two new variables so I can determine if
>> I am requesting recorded video or live video from the RTSP source. The
>> difference is whether I send the "Range: npt" or the "Range: clock" header.
>> I could create two variables for recorded_playback_start and
>> recorded_playback_stop. Thoughts?
> What is it you are concerned about? Selecting the time base, selecting the end
> time or both?
> As per the previous thread, VLC can already deal with start-time and end-time,
> but internally only. (The live555 plugin cannot access the end-time currently,
> so it cannot put it in the PLAY request.)

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