[libav-api] does setting the UDP receive buffer size for sdp streams require API change?

Bernd Pfrommer bernd.pfrommer at gmail.com
Fri Jan 2 14:54:31 CET 2015

You are right that it is straight forward to pass the receive buffer size when opening a udp url.

But I'm working with an sdp file.

I could not find a way to specify a udp url when using an sdp file. Would you mind explaining how to do that?

I actually looked at the sources quite a bit and could not see any way to accomplish it.

When the rtp url is generated in sdp_read_header(), there is no buffer_size parameter put on there

            ff_url_join(url, sizeof(url), "rtp", NULL,
                        namebuf, rtsp_st->sdp_port,
                        "?localport=%d&ttl=%d&connect=%d", rtsp_st->sdp_port,
                        rt->rtsp_flags & RTSP_FLAG_FILTER_SRC ? 1 : 0);
            if (ffurl_open(&rtsp_st->rtp_handle, url, AVIO_FLAG_READ_WRITE,
                           &s->interrupt_callback, NULL) < 0) {
                err = AVERROR_INVALIDDATA;
                goto fail;

Later, in rtp_open() there is also no option to specify the udp buffer size when
the udp url is generated: 

 build_udp_url(buf, sizeof(buf),
                  hostname, rtp_port, local_rtp_port, ttl, max_packet_size,

Message: 1
Date: Thu, 01 Jan 2015 14:49:59 +0100
From: Luca Barbato <lu_zero at gentoo.org>
To: libav-api at libav.org
Subject: Re: [libav-api] does setting the UDP receive buffer size for
	sdp streams require API change?
Message-ID: <54A55087.5040706 at gentoo.org>
Content-Type: text/plain; charset=utf-8; format=flowed

On 31/12/14 14:58, Bernd Pfrommer wrote:

> Does this issue indeed require an API change (e.g. add an AVOption), and
> if yes, what is the cleanest way? If some of the developers can offer
> guidance I'm willing to implement and test.

The `buffer_size` url option is there for you.


Should work.


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