7/26/2019 Raspberry Pi View Topic - Multicast GPU Decoding
1/3
FAQ Register Login
8 posts
by dbrb2 Thu Dec 13, 2012 10:32 am
Hi,
I have been trying to decode multicast video using my pi.
VLC can do this, but doesn't currently use the GPU
OMX player uses the GPU, but doesn't seem to support multicast
video
I imagine eventually tVLC will support GPU decoding...? In the
meantime is this a problemthat anyone else has encountered and/or
solved?
Cheers,
Ben
Posts:36
Joined:Sun Nov 25, 2012
6:15 pm
by RomanNV Thu Dec 13, 2012 12:02 pm
Try this:
Code: Select all
omxplayer udp://multicast address or IP:port
for example:
Code: Select all
omxplayer udp://238.1.1.15:1234
Posts:19
Joined:Sat Aug 25, 2012
11:39 am
by dbrb2 Thu Dec 13, 2012 3:35 pm
Hi,
No joy - but I think I know why:
When using VLC, I join my multicast group by providing an SDP
file of the form:
v=0
m=video RTP/AVP 96
c=IN IP4
a=rtpmap:96 RTP/AVP
a=source-filter: incl IN IP4
My first suspicion was that the problem I was having with the
suggested solution was the
source-specific-multicast on the last line of the SDP.
However, whilst trying to launch vlc with the above sdp works,
trying to launch either VLC or
omxplayer with:
vlc/omxplayer udp/rtp://@: does not
So there is some other key bit of info in the sdp file I am not
passing into the players via the
command line. I'll keep trying
Posts:36
Joined:Sun Nov 25, 2012
6:15 pm
by dbrb2 Thu Dec 13, 2012 4:58 pm
Ok....calling at the command line does, according to tshark,
bring me video when using vlc
(just testing omx) - but no video. So there is something missing
between that call and the full
Posts:36
Quick Start Downloads Buy Codecs Forum FAQs About
Raspberry Pi View topic - Multicast GPU decoding
http://www.raspberrypi.org/forums/viewtopic.php?f=63&t=25543
1 of 3 7/25/2014 12:40 PM
7/26/2019 Raspberry Pi View Topic - Multicast GPU Decoding
2/3
by dbrb2 Thu Dec 13, 2012 5:32 pm
...omxplayer with the following:
omxplayer udp://@:
from the pi quits immediately with "have a nice day"
vlc udp://@:
From either the pi or my local machine brings the multicast
traffic to the machine, but does
not play it.
In the formate case, pwerhaps omx does not support SSM?
In the latter, something missing from the command line call that
is provided when using the
full sdp...
Posts:36
Joined:Sun Nov 25, 2012
6:15 pm
by dbrb2 Fri Dec 14, 2012 11:03 am
Ok....I'm making some progress. It seems there is some problem
with IGMP requests issued
from the raspberry pi not reaching remote switches...but if the
local switch has the multicast
stream we are OK.
I wonder what the ttl is on IGMP requests....
Also, the omxplayer latency is ~10 seconds. This might be
inevitable given the hardware -
does anyone have any experience of expected behaviour of the
cache, and how/if it can be
tweaked?
Posts:36
Joined:Sun Nov 25, 2012
6:15 pm
by dom Fri Dec 14, 2012 11:43 am
dbrb2 wrote:Ok....I'm making some progress. It
seems there is some problem with IGMP
requests issued from the raspberry pi not
reaching remote switches...but if the local switch
has the multicast stream we are OK.
I wonder what the ttl is on IGMP requests....
Also, the omxplayer latency is ~10 seconds.
This might be inevitable given the hardware -does anyone have
any experience of expected
behaviour of the cache, and how/if it can be
tweaked?
These determine how much data is cached on GPU (video buffers
are 80K each).
#define AUDIO_BUFFER_SECONDS 2
#define VIDEO_BUFFERS 60
These determine how much data is cached on the ARM:
#define MAX_DATA_SIZE_VIDEO 8 * 1024 * 1024
#define MAX_DATA_SIZE_AUDIO 2 * 1024 * 1024
#define MAX_DATA_SIZE 10 * 1024 * 1024
Raspberry Pi Engineer &
Forum Moderator
Posts:3992
Joined:Wed Aug 17, 2011
7:41 pm
Location:Cambridge
by dbrb2 Fri Dec 14, 2012 12:13 pm
Ah - so I have to recompile at present. Doable
I don't actually need audio at all....I guess it will just be a
matter of seeing how low I can take
the buffers before things stop working
Posts:36
Joined:Sun Nov 25, 2012
6:15 pm
Quick Start Downloads Buy Codecs Forum FAQs About
Raspberry Pi View topic - Multicast GPU decoding
http://www.raspberrypi.org/forums/viewtopic.php?f=63&t=25543
2 of 3 7/25/2014 12:40 PM
