Sub Channel Questions

[Stanley Kritzik]

I notice, each time I scan for digital channels, that more are popping up left and right.  4 has 4.1, .2 & .3.  6 has 6.1 and now, .2.  36 has had .1 thru .8 for a while, and some of the newer channels have "futures", too.

So, this is wonderful (maybe) for those of us with antennas, but, as I recall, a very high percentage of viewers use either cable, DirecTV, or Dish, who are not carrying most of the extra sub channels.  This results in two questions -- kind of opposite each other: one is -- with the relatively limited audience for the extra subs, why bother?  The alternative question is -- can and will the likes of TimeWarner and the sat. providers ever carry all those extra subs?

Stan

[John L]

I am begining to think that with Local stations going Digital gives them a much better line to compete with cable.

I know what you mean.... it looks like one almost doesn't need cable and go back to the days of roof antennas and receiving signals direct.

That may and could happen if more locals carry specialty Channels, sports and movies on their sub-channels.

-John L.

[SRW1000]

So, this is wonderful (maybe) for those of us with antennas. . .

It's wonderful, if you don't care about high definition.  Subchannels are great for SD content, but you only have a limited amount of bandwidth.  Their simply isn't enough space to do high-quality HD and subchannels of SD at the same time.

The other problem is that you are starting to see some political pressure to use subchannels as a way to force diversity-driven content on the public.  The type of programming that is perfect for the internet or public access channels.  All at the cost of HD programming.

Scott

[wxndave]

It makes sense for broadcasters to add sub channels.  They now have the ability to sell more ads across all sub channels to offest the cost of transmission.   Plus stations can package ads as a bundle for their clients.

If a station purchases the right encoding equipment, they can still keep quality.  Multi-pass encoders allow a station to add a sub channel at a lower bit-rate.  Plus 720p stations can lower their HD down to 12 mb before you notice problems.

[ArgMeMatey]

If a station purchases the right encoding equipment, they can still keep quality.  Multi-pass encoders allow a station to add a sub channel at a lower bit-rate.  Plus 720p stations can lower their HD down to 12 mb before you notice problems.

Is that fact or opinion?  

I'd like to see a side-by-side comparison.  Is that something they could show me at Best Buy?

[bschlafer]

Correct me if I'm wrong....

Isn't it possible for local channels to carry HD signal on their prime channel, and have enough bandwidth left over for SD on their sub-channels?  

If stations are limited to a certain bandwidth allocation, It seems foolish for the FCC not to allocate enough headroom during the digital conversion for stations to do HD broadcasts effectively.

I thought the whole point of the digital conversion was to allow OTA to grow and thrive?  If broadcasters have to dump HD just to add sub-channels, it pretty much negates any competitive edge they might have over cable/sat services.


*Bill

[SRW1000]

It makes sense for broadcasters to add sub channels.  They now have the ability to sell more ads across all sub channels to offest the cost of transmission.   Plus stations can package ads as a bundle for their clients.

No disagreement there.  I'm only looking at it from the perspective of a viewer who loves and appreciates HD.  I've realized that the dream of high-quality OTA HD is dying as stations seek new revenue streams and as mandates are about to be imposed on them.

If a station purchases the right encoding equipment, they can still keep quality.  Multi-pass encoders allow a station to add a sub channel at a lower bit-rate.  Plus 720p stations can lower their HD down to 12 mb before you notice problems.

Those are some tricky conditions.  It's hard to imagine stations budgeting for new and expensive encoding equipment under today's economic conditions, and there's only a handful of 720p stations in Milwaukee.

Even with higher-quality encoding equipment, there will be some quality loss, but it won't be that apparent unless the content is demanding.  Fast sports action, for example.

Now, if stations would switch from MPEG2 to MPEG4, that would be a different story.

Scott

[SRW1000]

I'd like to see a side-by-side comparison.  Is that something they could show me at Best Buy?

No, it's not something they could demo for you.  Encoding is done at the networks and stations, not with consumer gear.

If you search around long enough, you should be able to find some screenshot comparisons of the same programs from different markets, some that multicast against some that don't.

Scott

[SRW1000]

Correct me if I'm wrong....

Isn't it possible for local channels to carry HD signal on their prime channel, and have enough bandwidth left over for SD on their sub-channels?  

If stations are limited to a certain bandwidth allocation, It seems foolish for the FCC not to allocate enough headroom during the digital conversion for stations to do HD broadcasts effectively.

I thought the whole point of the digital conversion was to allow OTA to grow and thrive?  If broadcasters have to dump HD just to add sub-channels, it pretty much negates any competitive edge they might have over cable/sat services.


*Bill

Stations are allocated a maximum bitrate of 19.38Mbs.  It's up to them how they divide that bandwidth.

The original goal and intent was for stations to be able to broadcast either a single HD program or up to four SD channels within that bandwidth.  The general thinking at the time was that stations would multicast during the daytime and switch to HD network programming during prime time and for sports.

None of this was mandated, and stations are free to do whatever they want.  So, yes, they can broadcast their main programming in HD, and allocate some of their bandwidth to SD subchannels, but quality on all subchannels  will likely suffer, especially during demanding scenes.

Again, this can be somewhat mitigated with higher-quality and more sophisticated encoders, but that costs stations money.  There would also be the option of switching to MPEG4, but that's not realistic.

Scott

[Will]

Again, this can be somewhat mitigated with higher-quality and more sophisticated encoders, but that costs stations money.  There would also be the option of switching to MPEG4, but that's not realistic.

I've wondered about this.  Could they really do MPEG4?  I guessed that MPEG2 was part of the ATSC (8VSB?) standard, and that MPEG4 would require a new standard altogether.  Would an old ATSC tuner be compatible with MPEG4 should a station broadcast it?

Will

[brewtownska]

Will,

I almost asked the same question you did, but after a little searching, it looks like they added MPEG-4 as part of the ATSC standard back in July 2008 (referencing http://en.wikipedia.org/wiki/Atsc)

But like you said, that means any devices created BEFORE that time probably can't support that codec.  So the chances of the locals broadcasting in MPEG-4 is slim as they might alienate some of their viewing audience.

Mike

[WITI6fan]

It makes sense for broadcasters to add sub channels.  They now have the ability to sell more ads across all sub channels to offest the cost of transmission.   Plus stations can package ads as a bundle for their clients.

If a station purchases the right encoding equipment, they can still keep quality.  Multi-pass encoders allow a station to add a sub channel at a lower bit-rate.  Plus 720p stations can lower their HD down to 12 mb before you notice problems.

Some ABC O&O's are doing this with the "Live Well HD" network.

From what I hear, let's hope it doesn't spread anymore...

[InsulinJunkie]

Some ABC O&O's are doing this with the "Live Well HD" network.

That's even worse because that's multiple HD streams, and not just HD + several SD streams.

It looked pretty bad on WLS (before they switched back to 7, and started broadcasting a whopping 4.75kW, and like countless others, I lost them - despite always being able to get analog 7 for years and years).

Chicago is far worse for subchannel cramming than Milwaukee, IMO.  It seems like everyone there is moving towards cramming everything like WDJT is up here.  For bitrate concerns, WBBM is the one Chicago station that would preferred over its Milwaukee counterpart, because they have no subchannels yet.

[LoadStar]

Stations are allocated a maximum bitrate of 19.38Mbs.  It's up to them how they divide that bandwidth.

That 19.38 Mb/s rate - that's on the OTA channel, right?

Is there anything that says that they couldn't offer a higher bitrate version on the fiber feed they provide to the cable/satellite/IPTV providers?

[SRW1000]

But like you said, that means any devices created BEFORE that time probably can't support that codec.  So the chances of the locals broadcasting in MPEG-4 is slim as they might alienate some of their viewing audience.

Mike

Yeah, which is part of the reason that it's unlikely.  After all the hoopla over the recent conversion, who's going to sell the public on the idea of buying yet another converter box to see HD?

Scott