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List:       gstreamer-devel
Subject:    Re: [gst-devel] Help with videorate and qos usage
From:       Nguyen Thanh Trung <trungnt_hut () yahoo ! com>
Date:       2009-07-29 10:20:38
Message-ID: 51862.83136.qm () web63102 ! mail ! re1 ! yahoo ! com
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Thanks for your answer.

So, I won't use videorate any more. I think I'll calculate the probability that a \
frame can be dropped based on qos event, cause I'm comparing the effection of \
difference codecs. Do you think is there any thing else that I should get ? 

P/S: I also get jitter and frame rate.

Thanks and best regards.



trungnt

--- Ngà y Thứ 4, 29/07/09, Tim-Philipp Müller <t.i.m@zen.co.uk> đã viết:

Từ: Tim-Philipp Müller <t.i.m@zen.co.uk>
Chủ Ä‘á»: Re: [gst-devel] Help with videorate and qos usage
Äến: gstreamer-devel@lists.sourceforge.net
Ngà y: Thứ Tư, 29 tháng 7, 2009, 16:17

On Tue, 2009-07-28 at 22:01 -0700, Nguyen Thanh Trung wrote:
> Hi, I'm new here, and I want to ask something about gstreamer:
> 
> I'm working with a gstreamer application to get the number of dropped
> frames from a video stream. I use videorate to get the value. But, the
> result is alway 0, no matter what I tried.
> 
> The gstreamer qos document says that qos is enabled by default for
> video, so why I did not get any dropped frame ?
> 
> I wrote an event prob function to put after the video decoder and
> found that there's many frame have positive jitter (the diff value got
> from gst_event_parse_qos()) but they are still not dropped event I set
> max_lateness for video sink to 100.

The drop property on videorate will only tell you how many frames
videorate dropped in the process of trying to convert the upstream
framerate / input stream to the desired downstream framerate (usually
configured by using a capsfilter after the videorate element). It does
not really handle or take into account QoS-related things at all. It
merely tries to create a perfectly timestamped/spaced output stream
according to the desired output framerate. If you have a decoder
upstream that handles QoS events and skips the decoding of some frames,
videorate most likely will just fill the gaps with duplicate frames
(which would then later be dropped again by the sink because they're too
late).

I don't think we have a way to query this kind of information at the
moment. There's a bug for it though:
http://bugzilla.gnome.org/show_bug.cgi?id=353680

 Cheers
   -Tim



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[Attachment #5 (text/html)]

<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: \
inherit;">Thanks for your answer.<br><br>So, I won't use videorate any more. I think \
I'll calculate the probability that a frame can be dropped based on qos event, cause \
I'm comparing the effection of difference codecs.<br>Do you think is there any thing \
else that I should get ? <br><br>P/S: I also get jitter and frame rate.<br><br>Thanks \
and best regards.<br> <br>
trungnt<br><br>--- Ngà y <b>Thứ 4, 29/07/09, Tim-Philipp Müller \
<i>&lt;t.i.m@zen.co.uk&gt;</i></b> đã viết:<br><blockquote style="border-left: \
2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>Từ: \
Tim-Philipp Müller &lt;t.i.m@zen.co.uk&gt;<br>Chủ Ä‘á»: Re: [gst-devel] Help with \
videorate and qos usage<br>Äến: gstreamer-devel@lists.sourceforge.net<br>Ngà y: \
Thứ Tư, 29 tháng 7, 2009, 16:17<br><br><div class="plainMail">On Tue, 2009-07-28 \
at 22:01 -0700, Nguyen Thanh Trung wrote:<br>&gt; Hi, I'm new here, and I want to ask \
something about gstreamer:<br>&gt; <br>&gt; I'm working with a gstreamer application \
to get the number of dropped<br>&gt; frames from a video stream. I use videorate to \
get the value. But, the<br>&gt; result is alway 0, no matter what I tried.<br>&gt; \
<br>&gt; The gstreamer qos document says that qos is enabled by default for<br>&gt; \
video, so why I did not get any dropped frame ?<br>&gt; <br>&gt; I  wrote an event \
prob function to put after the video decoder and<br>&gt; found that there's many \
frame have positive jitter (the diff value got<br>&gt; from gst_event_parse_qos()) \
but they are still not dropped event I set<br>&gt; max_lateness for video sink to \
100.<br><br>The drop property on videorate will only tell you how many \
frames<br>videorate dropped in the process of trying to convert the \
upstream<br>framerate / input stream to the desired downstream framerate \
(usually<br>configured by using a capsfilter after the videorate element). It \
does<br>not really handle or take into account QoS-related things at all. \
It<br>merely tries to create a perfectly timestamped/spaced output \
stream<br>according to the desired output framerate. If you have a \
decoder<br>upstream that handles QoS events and skips the decoding of some \
frames,<br>videorate most likely will just fill the gaps with duplicate \
frames<br>(which would then later be dropped again by the  sink because they're \
too<br>late).<br><br>I don't think we have a way to query this kind of information at \
the<br>moment. There's a bug for it though:<br><a \
href="http://bugzilla.gnome.org/show_bug.cgi?id=353680" \
target="_blank">http://bugzilla.gnome.org/show_bug.cgi?id=353680</a><br><br> \
Cheers<br>&nbsp; -Tim<br><br><br><br>------------------------------------------------------------------------------<br>Let \
Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day <br>trial. \
Simplify your report design, integration and deployment - and focus on <br>what you \
do best, core application coding. Discover what's new with <br>Crystal Reports \
now.&nbsp; <a href="http://p.sf.net/sfu/bobj-july" \
target="_blank">http://p.sf.net/sfu/bobj-july</a><br>_______________________________________________<br>gstreamer-devel \
mailing list<br><a ymailto="mailto:gstreamer-devel@lists.sourceforge.net"  \
href="/mc/compose?to=gstreamer-devel@lists.sourceforge.net">gstreamer-devel@lists.sourceforge.net</a><br><a \
href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" \
target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a><br></div></blockquote></td></tr></table><br>
                
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