Can't receive RTP stream on FreeBSD

[Andrey Zholos]

I'm trying to transmit a simple point-to-point RTP audio stream on FreeBSD.

Command to send the stream (codec parameters match one of the static RTP payload types):

$ ffmpeg -f lavfi -i 'sine=440:4:r=8000' -f rtp -acodec pcm_mulaw -ac 1 -ar 8000 rtp://127.0.0.1:20000

Command to receive the stream:

$ ffplay -f rtp rtp://127.0.0.1:20000

The send command works. The receive command receives the first packet and correctly detects the stream format, but doesn't receive the actual stream or even open a UDP socket for it.

The same thing happens trying to receive through the SDP file printed by the send command.

Logs attached.

I traced the reason to a failing getnameinfo() call. The call has a salen parameter which is passed sizeof(struct sockaddr_storage), but should be passed sizeof(struct sockaddr_in) (or whatever the actual address struct is). I guess Linux accepts this but FreeBSD doesn't. The call returns EAI_FAIL ("non-recoverable failure in name resolution").

Relevant quote from the ​FreeBSD manpage:

The sockaddr structure sa should point to either a sockaddr_in,
sockaddr_in6 or sockaddr_dl structure (for IPv4, IPv6 or link-layer
respectively) that is salen bytes long.

And from ​POSIX:

The salen argument contains the length of the address pointed to by sa.

Patch that fixes the issue above attached, but there are other similar calls to getnameinfo().

[Michael Niedermayer]

sockaddr_storage does not have a ss_len field. Aka this solution seems not portable