[opendtv] Re: Software updates for DTV sets
- From: "Albert Manfredi" <bert22306@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Wed, 24 May 2006 21:10:14 -0400
Richard Hollandsworth wrote:
>1. The latest press release says that this is supposed to occur
>without any knowledge or intervention by the user. So will
>the set manufacturers's assume that everyone can receive
>and actually watch their local PBS station when the
>"upcoming download announcement" is periodically broadcast
>(Q: how often?). Or will the set automatically come on in
>the middle of the night to look for the announcement and
>then come on at the scheduled time to tune to the digital
>PBS station and receive the download.
My STBs, when in standby mode, appear te receive the time updates from
whatever station I was tuned to when the STB was turned to "standby." I'd
expect the same sort of thing for software updates, where the receiver
either scans channels in standby mode to see if any carousel is offering
anything of interest, or just goes to a pre-set PBS frequency and waits
there for the carousel. Much like VCRs do in NTSC, for time and date.
>2. So what happens if the rugrats are watching MUSTARD
>PANCAKES--will it wait until the next schedued download
>period???)
That would be my guess, unless the set has more than one receiver.
>And since the ATSC A/90 and A/97 specs don't indicate any
>FEC other than MPEG2, how many times will a download
>need to occur before it is succcessful???
A combination of a block FEC code in the data frames and carousel should
take care of that. And, of course, there's always the 2/3 viterbi
convolutional code at work in the 8-VSB demod. There are clever codes out
there for this type of application. What this does is minimize the need to
wait for another pass of the carousel. And no reason whatever to standardize
the block FEC, either. Any manufacturer can do his own thing.
>3. How long will it take for the carousel to cycle through
>every software update (days? weeks? months?)
If you dedicate, say, 1 Mb/s to these downloads, it might not take all that
long for any given manufacturer. Like, minutes if all works the first time,
maybe hours if you need more attempts? Of course, this could get much worse
if software becomes as bloated as what PCs seem to require.
>4. Since the downloads are encrypted, will a CableCard (both
>one-way and two-way?) be required to decrypt the download---or
>will it work without a CableCard decryptor, just like ATSC???
If they want to encrypt, why not use a one-way scheme? But maybe much of the
time this code doesn't need encyption? Does it have intrinsic worth except
to the owners of that receiver?
>6. With software update being standard on cable, SAT and PC
>systems for many years now, why did it take so freeking long
>for this to be implemented for DTVs??? A/97 date is Nov 2004
>and A/90 is Jul 2000 (defines the "data carousel").
A/90, written in 1999 and published in 2000, had what any software designer
would need. For that matter, any software person reading A/53 could have
figured out that this was a doable do. A/97 doesn't add much to A/90 that
wasn't obvous from the start, I don't think. I never considered this a
technical problem at all. Just one of designers accepting that DTT in the US
maybe does exist, and maybe it's time to make it work well. You know, ditto
for AVC and all the rest that people go on saying can't be done.
>7. Although I understand the desire of ATSC to do it the
>"ATSC-WAY", why didn't the set manufacturers simply
>implement either a phone line modem and/or an Ethernet
>connection for updates--after all most of the circuitry is already
>there for CableCard.
They definitely should, if for no other reason than as a last resort. But
FWIW, my STBs both have an RS-232 connector in the back for exactly this
purpose. Presumably, I should be able to go to a web site and download the
update, then connect the STB to my PC and transfer the files.
All you need is a web site to check once in awhile, if you want to go this
route. My Philips DVDR has this already. Download the files, burn a CD-ROM,
and play the CD ROM in the DVDR. Works fine.
Bert
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