RTSP SETUP

[videoicu]

Is there a simple way to control the RTSP SETUP command in VLC...

I need to set Blocksize to a specific value in the SETUP that the VLC client (player) sends to the server but I do not see how to do that in VLC

Thanks, I attempted a search to locate such information but did not find answer...I apologize if it overlooked it.

R

[Rémi Denis-Courmont]

No, to my knowledge live555 does not implement this.

[videoicu]

The SETUP command Blocksize is to adjust parameters on an Axis video encoder to allow streaming of h.264 RTP/RTSP over a 3G cellular connect. We are having some better success when adjusting the MTU of the encoder but Axis suggests changing this SETUP Blocksize also...Remi, I see you have some experience with 3G cellular...would you have an opinion on this....

The video starts normally via RTP?RTSP but then stops and restarts often...the carrier and router manufacturer suggests that the MTU is the problem but just adjusting MTU alone has not resolved the problem...hence my original question.

Also anyone else's input would be appreciated. We view the video with multiple different viewers but all show similar response (VLC, CorePlayer, Wowza, etc). Video sets up normally, starts streaming then stops and restarts.

Thanks

[Rémi Denis-Courmont]

In GPRS networks, the MTU is typically 1400 bytes, so I can see why you'd want to shrink the blocksize. But on the client side of VLC things, this would need to be implemented in live555, not in VLC. And IMHO, it should be inferred from the MTU automatically; adding a configuration option is backward.

[videoicu]

Remi,

Again thanks for the discussion...it is a CDMA 3G network that as you state specifies an MTU of 1400. The 3G router is set to 1400 and the Axis encoder is set to MTU of 1400. I personally at this time do not understand if the Blocksize setting is a direct relationship to the MTU setting or not. For example, if we set the MTU to 1400, would it follow the Blocksize should be 1400?

Axis RTSP SETUP Blocksize is around 64,000 no where near the 1400 MTU if it is a direct relationship....as shown in Wireshark Protocol Analyzer in the SETUP command.

So in essence, I have not found a player that ingests h.264 RTP/RTSP that can set the Blocksize...it seems hard coded or left for device default and not specified at all. The router manufacturer, Cradlepoint, has suggested that the MTU and blocksize are not related much to each other...Axis disagrees and suggests both should be set in this special circumstance of 3G streaming upstream.

SETUP rtsp://IP/axis-media/media.amp/trackID=1?videocodec=h264
RTSP/1.0
CSeq: 2
User-Agent: Axis AMC
Blocksize: 65535 <--------------BLOCKSIZE
Transport: RTP/AVP/TCP;unicast
RTSP/1.0 200 OK
CSeq: 2Session: B58B7EBD; timeout=60
Transport: RTP/AVP/TCP;unicast;interleaved=0-1;ssrc=7FF55105;mode="PLAY"

The IP stream h.264 RTP/RTSP must orginate and be transmitted via the 3G network which is giving us fits right now. If we eliminate the 3G network the RTP/RTSP streams beautifully across normal WAN dsl or cable internet. But we can't eliminate the 3G, it is the critical link.

Any further thoughts again appreciated.

Richard

[Rémi Denis-Courmont]

As I said, live555 does not support custom Blocksize. First live555 needs to be modified. Then VLC needs to be modified. Then (and only then) the user needs to configure the block size manually.