No, there is not any wireless link. I have modem/router home hub 5a (gigabit ethernet)-> hub netgear gs605v4 (gigabit ethernet)-> smart TV samsung (fast ethernet) or smart box (fast ethernet).
However, the video quality is good, but it is slow and not in real time e.g. sometimes it blocks for a second.
In order to perform the test, I used DSLreport with 60 seconds (maximum allowed). Do you know a better software or a Web site?
I asked more information to the server provider even if I do not think that it could be the problem since for other neighbourhood it works well.
Then I installed tcpdump, I saved the data via tcpdump -i pppoa-wan -v -U -s0 -w capture.cap and I analysed it via wireshark. With a big surprise for me, I found that the IPTV uses TCP. So it is point-to-point connection instead a more clever multicast connection (RTP over UDP).
The usage of TCP explains the reason for which the video quality is good and slow and as you suggested maybe is related to ACK transmission i.e. in wireshark I saw many duplicated ACKs and many TCP out-of-order segment and reassembled PDU.
How can I setup ack-filter? I found this interesting paper about piece of CAKE and openWRT. They show that ack-filter with aggressive mode produces great benefit. Moreover, the DiffServ4 with BestEffort option achieves a great improvement.
Do you know how to enabled them? I only found this on bufferbloat mailing list
option eqdisc_opts 'nat dual-srchost ack-filter'
and this comprehensive man page.
Finally, I found that during the evening and night when the Internet connection is crowded, the speed is reduced a lot and it could be the source of the problem.
Morning
Evening
or
Note: the evening and night charts for upload have big initial spike at the beginning and at the end of the test.