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slice1900 said:

FWIW, my understanding is that when Directv's LRF (local receive facility) is co-located on premises with a station, typically they are getting the MPEG2 stream that is sent to the station's encoder, which means they get the same thing as if they picked it up OTA. That would be delivered to them via ASI. Whether OTA is better depends on how much extra compression they may do when they convert it to MPEG4 (i.e. how many other HD channels they have to carry on the same transponder depending on the needs of the market)

However, in some cases I've heard they get the raw uncompressed HD-SDI feed into their encoder, which means they can get better quality than OTA. Whether they actually do have better quality again depends on how many other channels share the same transponder.

The same applies for cable, if they get the raw HD-SDI feed they may have better quality than OTA, but some systems that really compress it (like Comcast's MPEG4 headends making everything 3 Mbps!) they may be worse.

Where I live the local Fox and CBS stations had no subchannels for a long time, and OTA was vastly superior to Directv's feed. Now all the local stations have three subchannels, and the quality is pretty much the same between cable, OTA and Directv. Unfortunately nothing compared to what it was with a pristine 19 Mbps MPEG2 HD via OTA!

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videojanitor said:

Where I work, DirecTV has a fiber feed and uses OTA as a backup. Comparing the two signals, I don't see any difference, and wouldn't expect to as they are both the same ~14 Mbps feed from the encoder. The subchannels on the OTA signal also affect what is sent through the fiber.

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HoTat2 said:

But the ASI fiber feeds to the MVPDs have those same sub-channels added in as well since it comes from the same station encoder output which feeds the ATSC broadcast transmitter.

So even though the MVPDs may demultiplex the local station's transport stream to separate out the channels they wish to broadcast and place them on separate channels of their systems. The individual streams have still been originally compressed to the same amount by the local station as the streams in the OTA broadcast signal.

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K9SAT said:

I can speak from experience and give direct incite. DirecTV gets the majority (I say 75 percent) of its local affiliate signals via OTA 8VSB like you do at home. The only time DirecTV sees an ASI feed or fiber feed is when the Local Collection Faculty (NOT LRF LIKE E* calls them) is co-located at a TV station and that TV station usually hands off an ASI signal to them with OTA used as a backup. Outside of that, unless a TV station delivers that type of signal (ASI) to the LCF by running and paying for a fiber line or microwave link (Not usual) it's all OTA. This is becoming less common sense ATT took over as most of the LCF's in ATT territories have moved to ATT properties to save cash on renting space at local TV stations. This is good as it allows ATT to keep expenses down.


Some areas have moved to locations co located with Uverse where Uverse gets an ASI feed it's shared with DirecTV. Uverse also used a mix of ASI and OTA. Some providers are willing to provide an ASI link and handoff to ATT, whereas others don't want that expense and are ok with OTA being the primary delivery mechanism. It all boils down to what the provider agrees with ATT and what's available to them at the LCF site.


Generally, the ASI feed is the same feed that is going to the transmitter with sub channels included. Very useful for those markets where the TV station is a dual affiliate IE CBS/FOX, etc. That is not always the case though and there are times where DirecTV does get a better signal from the local affiliate that's better than the OTA. Generally when there is an ASI signal available, DirecTV takes that signal first, and uses OTA as a backup. It's all dependent upon what's contractually written though with the affiliate. DirecTV does not get a raw HDSDI feed.


DirecTV takes that affiliate signal and recompresses into both MPEG4 HD and MPEG2 SD and then that signal is sent to the regional uplink facility where it's multiplexed, the video signal is then encrypted and ancillary data is added for ad insertion / guide data, etc., (made DirecTV's signal) and uplinked to your home.

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HoTat2 said:

Generally speaking though ...

Do you know if the local TV feeds collected at an LCF which are destined for final uplink through a regional uplink facility go directly to that regional facility for format conversion, encryption, ad insertion, etc., then uplink? And DIRECTV monitors and controls the various processes along the signal chain through remote links back to the main broadcast centers at the LABC and CRBC?

Or are all the locally collected feeds first sent to either of the two main broadcast centers the LABC or CRBC, for monitoring and processing and then back out to the RCFs for uplink (except for those locals uplinked from the broadcast centers themselves of course)?

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Jimbo said:

In my case, its the Fox that has been out for all this time, they are ran by the local CBS here, CBS has stayed on, either their contract wasn't up or they resolved it witbout taking them off the air.

When I checked late last night, FOX was still off the air.

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