Re: [media-and-entertainment] Use of WebRTC for media content distribution (#1)

@chrisn 

Understood.  Note that my original comment was based on experiences with ATSC 3.0 transport, and I was commenting as to whether QUIC can be used in the context of ATSC's implementation multicast IP for OTA.  I believe the same reasoning would apply to LTE eMBMS and its 5G MBMS.  QUIC cannot be a candidate for ATSC IP Multicast transport in its current form, and the WebRTC WG could look into the issues I have already raised above:

a) Lack of FEC support, which the ATSC has determined is required for the wireless channel conditions that will be encountered by ATSC receivers.  Note that this was raised at the last TPAC WG meetings, and I expect that the issue of FEC support in QUIC will be revisited in the near future.

b) Potential protocol overhead issues.  Obviously based on the back-and-forth above there are differing views on this topic.  I believe "overhead" must include FEC-related overhead such as file repair, protocol headers that allow for identification of the type of media being sent OTA, and necessary protocol support for critical broadcast use cases such as fast channel acquisition.

c) I mentioned EME in my original comment, but to expand on it - any ATSC-compliant transport mechanism must have full support for CENC.  This includes maintaining freshness of the entitlement and supporting all subscription scenarios required by ATSC broadcasters.  This is not just important for ATSC-compliant receivers but also for in-home content redistribution.  Maybe QUIC has a means of supporting EME - I haven't seen it yet.

Note that ATSC requires that all services work regardless of whether ATSC receivers have enabled broadband access or not.  In fact, several broadcasters in markets such as Asia have told us that they have subscribers that do not have any kind of broadband access.  Therefore, QUIC being a suitable replacement for HTTP 1.1 and 2.0 over unicast networks is of limited value in many ATSC deployments.


-- 
GitHub Notification of comment by gmandyam
Please view or discuss this issue at https://github.com/w3c/media-and-entertainment/issues/1#issuecomment-441275265 using your GitHub account

Received on Friday, 23 November 2018 16:00:25 UTC