[gst-devel] question about GstClock not set

[Wim Taymans]

On Tue, 2009-08-25 at 16:40 +0200, Julien Isorce wrote:
> Hi,
> 
> I attach to this mail a minimal test to provide a gstreamer behaviour
> that I do not understand.
> 
> Actually, I would like to know why the clock can be not set yet
> whereas some buffers are dispatched.
> I mean I put an identity element between a videotestsrc and a
> fakesink, 
> and I am checking the clock availability in the identity handoff
> callback.
> 
> Why am I able to get raw video buffers from handoff callback whereas
> no clock is set on identity yet ?
> Moreover in this case the timestamp buffer is valid, but I assume this
> timestamp was set by the internal clock.
> I can understand that the internal clock was already there before
> playing,
> and I can also understand that the internal clock is affected on
> elements only when going to playing state (or at least ready).
> But I think the clock should be always available from a handoff
> callback, at least if the buffer timestamp is valid.
> 

The first buffer is part of preroll in PAUSED. It is only after all
sinks receive a buffer that a clock is selected and the pipeline is set
to PLAYING. 

Wim

> ( to compile the test: gcc -Wall $(pkg-config --cflags --libs
> gstreamer-0.10) main.c -o main )
> 
> (output:
> 
> identity has clock: 0, timestamp is valid: 1
> pipeline is now playing
> new clock set from: pipeline
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> identity has clock: 1, timestamp is valid: 1
> End of stream
> 
> )
> 
> Sincerely
> 
> Julien
> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day 
> trial. Simplify your report design, integration and deployment - and focus on 
> what you do best, core application coding. Discover what's new with 
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
> _______________________________________________ gstreamer-devel mailing list gstreamer-devel at lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gstreamer-devel