Privoxy proxychains problem

Hello,

I use xupnpd2 (http://xupnpd.org/xupnpd2_en.html) on my MIPS-based 
router to restream some HLS-streams from the internet to my TV. This app 
doesn't support https. The author doesn't want to provide a newer 
version of xupnpd2.

I try to restream webcams from Skyline-webcams (e.g. 
http://www.skylinewebcams.com/de/webcam/czech-republic/prague/prague/old-town-bridge-tower.html), 
which uses https. But it's possible to receive the m3u8-file (the URL 
including query-string is in old-town-bridge-tower.html) in http. The 
m3u8-file contains https URLs (ts-video-files, which also can downloaded 
in http).

My idea is to use a filter proxy to replace the https URLs in the 
m3u8-file by http URLs. I installed Privoxy 3.0.24 in Ubuntu 16 with 
these filter:

/etc/privoxy/user.filter:
FILTER: test
s@https@http@g

/etc/privoxy/user.action:
{+filter{test} +force-text-mode}
/.*m3u8

A first test worked (URLs were replaced):
http_proxy=127.0.0.1:8118 wget 
http://hddn01.skylinewebcams.com/live.m3u8?a=sfvhd515q59ag2lp08o76bdme7

But with proxychains it doesn't work:
proxychains wget 
http://hddn01.skylinewebcams.com/live.m3u8?a=sfvhd515q59ag2lp08o76bdme7

I also contacted the author of proxychains. He replied, I should use 
sniffing, but I have no sniffing experience.

Maybe someone in the Privoxy mailing-list could help me?

Best regards,
Thomas