[gst-devel] Getting the complete caps from rtph264pay

[Farah Akhtar]

Thanks Jyoti. What I'm trying to do is this:

I am using gstreamer to stream h.264 files from a server to a client over RTP. The pipelines I create are:

Sender:
gst-launch-0.10 filesrc location=akiyo.264 ! video/x-h264 ! rtph264pay pt=96 mtu=1024! udpsink host=203.12.12.12 port=42050 sync=false
Receiver:
gst-launch-0.10 udpsrc port=" +this.port + " ! rtph264depay ! h264parse  ! filesink location=rec_akiyo.264

I encode the sent file using the H.264 reference software with 'Slice mode' enabled and different schemes of slice-structures used. I want that each of the packets should contain one slice of the encoded video. Also, all the slices are not in the raster-scan order and so, packets wont be received to the receiver in the decoding order. The RFC 3984 specifies that I should use STAP-B packets with 'interleaved mode' of RTP enabled when NAL units are out of the decoding order.


Now, 'rtph264pay' does not expose any of the properties that could specify to the payloader the NAL unit type (STAP-B) or set the 'interleaved mode' even though running the commands with -v param does give some caps that contain 'sprop-parameter-set'. Since 'interleave mode' is also a part of the 'sprop-parameter-set', I was wondering if there is a way to SET these parameters instead of just GETing them with -v. Also, I'm not sure if the functionality is even implemented in the 'rtph264pay' for interleave mode. So, I wanted to ask if this payloader implements the whole of rfc 3984 or not. 

Please note that I am using gstreamer from linux shell (as can be seen from the pipelines). I would like best not to have to go into changing the gstreamer but if it is necessary, please guide me.

Thanks.



________________________________
From: Jyoti <jyoti.d at allaboutif.com>
To: Discussion of the development of GStreamer <gstreamer-devel at lists.sourceforge.net>
Sent: Sat, December 19, 2009 3:13:56 PM
Subject: Re: [gst-devel] Getting the complete caps from rtph264pay

Within the notify::caps callback function try print the caps as below.

caps = GST_PAD_CAPS (pad);
g_print ("Caps = %s\n, gst_caps_to_string (caps));

Refer the link below for more info:
http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html#gst-pad-get-caps


On Sat, Dec 19, 2009 at 1:55 PM, Farah <farahakhtar_24c at yahoo.com> wrote:


>
>>Can you please tell how exactly you got those caps from a command line
>>shell? I'm new to gstreamer.  Say, I can create a pipeline fine but dont
>>know how to access or modify RTP params like 'sprop-paramater-set' etc.
>>Also, can I find the 'rtph264pay' help or documentation somewhere?
>
>
>
>
>>> I'm not sure if this will solve your issue but I'd been getting the caps
>>> from the udpsink linked to the payloader. However, some recent changes to
>>> gst-plugins-bad (in git) have made it so these caps are always null, and I
>>> haven't had the chance to diagnose the issue further. But at least with
>>> the
>>> last release, calling gst_pad_get_negotiated_caps on the udpsink's sink
>>> pad
>>> worked for me.
>
>>For me, get_negociated_caps returns None when used inside my
>>application. It does return the correct caps when i do it using an
>>interactive shell.
>
>
>--
>>View this message in context: http://n4.nabble.com/Getting-the-complete-caps-from-rtph264pay-tp972686p975288.html
>
>Sent from the GStreamer-devel mailing list archive at Nabble.com.
>
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