ffserver: set the sample aspect ratio

Hi.

It seems that ffserver sets sample_aspect_ratio to an invalid value and lavf
rejects it.

I am not sure what I am doing here, but the attached patch actually solves
something: using the following config:

CustomLog -
NoDaemon
RTSPPort 5454
<Stream test1-rtsp.mpg>
Format rtp
File "/tmp/test1-rtsp.mpg"
</Stream>

it allows a somewhat old ffplay (unaffected by the content-base issue I
spoke of in another thread) to play the stream.

Without it, ffserver logs this and closes the stream:

Wed Feb 16 14:52:14 2011 [rtp @ 0x1399de0]Aspect ratio mismatch between encoder and muxer layer

Regards,

--
  Nicolas George

From 1b89c3c2164335060e87567b27deb0d354e0a814 Mon Sep 17 00:00:00 2001
From: Nicolas George <nicolas.george@normalesup.org>
Date: Wed, 16 Feb 2011 14:44:31 +0100
Subject: [PATCH] ffserver: set the sample aspect ratio.

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
(cherry picked from commit 6741f7c9be4913e084ad067571f3f29853ec5d5a)
