BW_INFINITE (1 Gbps) affects higher bitrates

[maxsharabayko]

SRT v1.3.2 and lower had the default maxbw value is 30 Mbps. Since v1.3.3 the default value is 1 Gbps (#760).

The limitaion is not obvious for the end user.
v1.3.2 and earlier

const int64_t BW_INFINITE =  30000000/8;         //Infinite=> 30Mbps

Since v1.3.3

const int64_t BW_INFINITE =  1000000000/8;         //Infinite=> 1Gbps

This value affects the sending period of the packets.

void updatePktSndPeriod()
{
   // packet = payload + header
   double pktsize = m_iSndAvgPayloadSize + CPacket::SRT_DATA_HDR_SIZE;
   m_dPktSndPeriod = 1000*1000.0 * (pktsize/m_llSndMaxBW);
}

• Suggested default value: -1. Zero packet send period.
• If the sender skips packet due to the bandwidth, a proper message should be shown to the user, that the packet is dropped due to MAXBW is less the sending rate tries to use.

[rmsoto]

Hello @maxlovic

I´m facing a problem when I try to send more than 80Mbps into one SRT session. DEspite of I´ve changed some parameters inside core.cpp file to avoid crashes in srt-live-transmit with high bandwidht streams:

m_iFlightFlagSize = 100000;
m_iSndBufSize = 100000;
m_iRcvBufSize = 98000;

I can´t find where it is const int64_t BW_INFINITE = 30000000/8;

Can you tell me where I can find it?

thanks!

[maxsharabayko]

@rmsoto
With srt-live-transmit you can simply specify the maximum bandwidth in the URI like
srt://ip:port?maxbw=bytes&sndbuf=bytes&rcvbuf=bytes
All this parameters are configurable via SRT socket options (SRTO_MAXBW, etc.).

[rmsoto]

@maxlovic

But....where is this sentence written?

const int64_t BW_INFINITE = 30000000/8; //Infinite=> 30Mbps

CAn I turn it to 100Mbps ?

[maxsharabayko]

@rmsoto In common.h.

[rmsoto]

thx! No improvement though.

[maxsharabayko]

@rmsoto What OS? Windows, Linux, Mac, etc.

[rmsoto]

Sorry.

libsrt v1.32 and the OS are mainly debian 8.6 and some ubuntu 18.04. I was trying to send 105Mbps Mpeg-TS with about 2-3Mbps of Null Packets....no matter which server I use (they all both have different networks) I cant send more than 83-84Mbps. I also tried with v.1.2.0 and 1.3.1.

Sender: ./srt-live-transmit -v -t:-1 -i "udp://@224.123.0.1:5001" -o "srt://:6001?latency=200&maxbw=15000000&inputbw=15000000"

./srt-live-transmit -v -r:30 -s:5 -t:-1 -i "srt://@80.84.129.197:6001" -o "udp://224.168.227.3:5013"

We have a system with 1.2.0 where we sent around 100Mbs to a customer which implemented his own srt receiver with the same version. I also copied the SRT compiled in that server and replicate the commands but no way to get more than 84Mbps...

Regards and have s good weekend.

[maxsharabayko]

@rmsoto Try to perform SRT bandwidth loop test, described here.
Please create a separate issue.