SD DirectTV vs OTA

[frank1492]

I do not have HD DirecTv. I have always been just barely satisfied with the quality of my SD reception when viewed on a HD LCD projector. The S-video is particularly poor. (I know what to expect from other SD sources, so do not feel my expectations are unrealistic.)
Recently I set up an antenna for OTA HD reception. Even non-HD content shows
or stations broadcasting at 480i look appreciably better than anything from satellite. This is even true when the shows are viewed on an old Zenith CRT set with an SD converter box. The difference in luminance and sharpness is striking.
I am aware that OTA is uncompressed while satellite is not, but is this what is accounting for the difference, or is my DirecTv receiver just of poor quality?
Help much appreciated.
Frank

 

[Bob Nielsen]

They are both compressed, but SD via satellite is compressed a lot more.

 

[JosephB]

More importantly DirecTV compresses the OTA signal that is already compressed. It's impossible for DirecTV to transmit a better picture than they are receiving from the station. In fact, it's practically impossible for them to even match it, since re-encoding it to MPEG-4 is going to be lossy, even at bitrates higher than the source.

 

[Bob Nielsen]

The SD channels (with a few recent exceptions) are not re-encoded to MPEG4, but are highly compressed MPEG2. Originally they were encoded to MPEG2 from analog transmissions, but they now (again with some exceptions) pick up the digital OTA signals.

 

[JosephB]

The SD channels (with a few recent exceptions) are not re-encoded to MPEG4, but are highly compressed MPEG2. Originally they were encoded to MPEG2 from analog transmissions, but they now (again with some exceptions) pick up the digital OTA signals.

Right, I missed that this was SD. My point still stands, MPEG-2 or MPEG-4 is lossy..even if they were to re-encode to a higher bitrate than the ATSC they are pulling out of the air.

 

[dancrouse]

If I attach an AM-21 to my HR-22 and install the proper OTA antenna, would I get the uncompressed OTA signals or does the AM-21 do something to water down the picture quality.

 

[raoul5788]

If I attach an AM-21 to my HR-22 and install the proper OTA antenna, would I get the uncompressed OTA signals or does the AM-21 do something to water down the picture quality.

You will be very happy with the picture quality, I am sure. If it is on an hd tv, then so much the better!

 

[JosephB]

If I attach an AM-21 to my HR-22 and install the proper OTA antenna, would I get the uncompressed OTA signals or does the AM-21 do something to water down the picture quality.

You would get the uncompressed OTA signal.

 

[Bob Nielsen]

OTA is compressed, but with a much higher bandwidth than the satellite signal (up to 19 Mbps).

 

[frank1492]

Interesting discussion, but to the second part of my question, are some SD satellite receivers better than others?
And why is it that there is controversy as to whether or not OTA is compressed or not? This is the first I have heard that it undergoes any compression at all.
Thanks, by the way, for all your help up to now.
Frank

 

[Jimbo]

Interesting discussion, but to the second part of my question, are some SD satellite receivers better than others?
And why is it that there is controversy as to whether or not OTA is compressed or not? This is the first I have heard that it undergoes any compression at all.
Thanks, by the way, for all your help up to now.
Frank

Frank,
The typical OTA signal is compressed, just not the same way D* or DISH or cable does it, they have more bandwidth to work with.
OTA signal is run thru MPEG2 technology, D* is currently using MPEG4 on the newer rec's and working towards eliminating all the mpeg2 rec's. and shutting down the mpeg2 signal eventually.

Jimbo