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Local broadcast channels now 720p MPEG4!!

Silver Problem Solver

Local broadcast channels now 720p MPEG4!!

I just noticed that Comcast is starting to convert some local broadcast channels to MPEG4. On my non-X1 DCX-3400, I can tell MPEG4 because the 30-second skip has a bit of a delay, and sometimes the 15-sec rewind doesn't actually go back. I noticed this on a recent recording of "The Tonight Show".

I checked my DTA, which has a nice virtual channel map, and it's true. Here in Chicago, it is showing WGBO, WLS, WMAQ, WTTW and WSNS as MPEG4 (code A in the map) and all on 147MHz. And  yes, they are all downconverted to 720p. As far as I know, broadcast WMAQ (the NBC owned station) should be 1080i.

Expert

Re: Local broadcast channels now 720p MPEG4!!

Evidently Chicago is one of the last areas to change over. It happened here in Minneapolis area about 18 months ago. Local 1080i channels will most likely remain @ (1920 x 1080) / 60i output in MPEG2. With the exception of a handful, all other linear channels with be: (720 x 480) / 60p or lower for SD channels.

 

You might notice a black-screen and short delay when switching from a 1080i channel MPEG2 to a 720p channel in MPEG4, or back. Cable-box has to switch from MPEG2 mode to MPEG4, or the reverse.

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Silver Problem Solver

Re: Local broadcast channels now 720p MPEG4!!

Nope. I am talking about the local broadcast channels being converted to MPEG4 and 720p. WLS (ABC) and WTTW (PBS) are 720p broadcast. WMAQ, WSNS and WGBO are 1080i broadcast. The non-local HD channels converted to MPEG4 nearly 2 years ago.

Expert

Re: Local broadcast channels now 720p MPEG4!!


@andyross wrote:

Nope. I am talking about the local broadcast channels being converted to MPEG4 and 720p. WLS (ABC) and WTTW (PBS) are 720p broadcast. WMAQ, WSNS and WGBO are 1080i broadcast. The non-local HD channels converted to MPEG4 nearly 2 years ago.


I will have to check that out. Our PBS channels were 1080i MPEG2.

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Silver Problem Solver

Re: Local broadcast channels now 720p MPEG4!!

I also found out that WCPX (ion) has also been converted to MPEG4.

Frequent Visitor

Re: Local broadcast channels now 720p MPEG4!!

WLS-DT has always been 720p, but apparently within the past week, they've now gone H.264.
I also think WTTW's also been 720p on their main channel for a while now, but all of their channels have always been MPEG-2, and moderately high bitrate MPEG-2 at that.

They better not touch NBC, CBS or Fox. They have the highest bitrates of all the local stations.

Silver Problem Solver

Re: Local broadcast channels now 720p MPEG4!!

WTTW is actually back broadcasting in 1080i. They have been bouncing between 1080i and 720 over the years.

 

Sorry, but on Comcast, WMAQ is now 720p MPEG4. So far WBBM and WFLD are still passed-through MPEG2 (1080i and 720p respectively).

 

Another nasty side effect of this MPEG4 conversion of local broadcast is that it adds 2-3 seconds of delay. Before, recordings started and ended perfectly on the local statiins. Now I am having issues with the ends cut off on WMAQ and WLS.

Frequent Visitor

Re: Local broadcast channels now 720p MPEG4!!

Yeah, I noticed that. It was like I jinxed myself. I download stuff off of my TiVo, and both “Will and Grace” and “Chicago Fire” were messed up. They must have changed over earlier that day. <br><br>And what’s even worse is that it’s bitrate starved. NBC, Fox and CBS had the highest bitrates of any of the OTA channels.