Difference in picture quality

ATSC 3.0 Forum
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RonRN18
Posts: 17
Joined: Sun Jan 24, 2016 2:04 pm

Difference in picture quality

Post by RonRN18 »

Our market just went live with ATSC 3.0 on Tuesday. I have been checking all of the different methods of watching my HDHR5-4K. In my house, I have a 75" TCL TV with built-in Roku, a 70" Vizio with the newest generation of Roku Ultra, and two 55" Hisense TVs with built-in Roku. For smaller screens, I have a laptop computer that I have run the HDHomeRun app, and I've downloaded the app for my iPhone 11 Pro MAX phone.

Starting with my 75" TCL television. The HDHomeRun app for Roku on my TCL creates the best picture of all of my televisions. Our lighthouse station has three video streams, one for NBC, CBS, ABC, Fox, MyNetwork, and Univision. Of these three, only CBS is using the AC-4 audio codec, while all of the others are using AC-3 audio. On my TCL, watching all but CBS provides a very stable picture (albeit, upscale softening of video on some content) and great audio. On CBS, I get a good picture but no audio, as apparently the TCL does not do AC-4.

On my 70" Vizio with the newest generation of Roku Ultra, I get great audio on all of the ATSC 3.0 content, but the picture quality isn't all that great. The picture on all of the streams have pixilation occurring all over the screen, especially when there are solid colors at an angle, causing gradations.

For my 55" Hisense televisions, again using the app for Roku, just like the Roku Ultra, I have no audio issues on any channels, including CBS which has AC-4 audio, but the picture is full of pixilation.

On my laptop, I have a very beautiful picture (except see obvious upscaling softening) and have no audio issues when using the HDHomeRun app for Windows. This is on my HP laptop with a 17" 4K display.

Lastly, my iPhone shoes video on each of the ATSC 3.0 streams with a frame rate of a few seconds per frame with no audio issues.

Code: Select all

Virtual Channel	113.1 CBS
Frequency	527.000 MHz
Program Number	3
Modulation Lock	atsc3
Signal Strength	100%
Signal Quality	100%
Symbol Quality	100%
Streaming Rate	4.232 Mbps
With essentially a perfect reception, I don't believe the pixilation issue I'm seeing on all but one of my televisions is due to a poor signal. I know it is not a networking issue. This obviously means that it is a software/hardware playback issue, as evidenced by different results by different devices. There are a few things that surprise me a bit. I would have thought that the newest Roku Ultra should provide the best picture. I know that none of my televisions are high-end devices and essentially brands not known for quality but I find it interesting that my TCL provides such a clear picture with no pixilation like the other Roku devices. It is the same software, just on apparently different hardware. Unfortunately, with the different hardware comes no AC-4 audio support on the TCL. The Roku Ultra and the Hisense TVs with built-in Roku are essentially the same quality. On an interesting side note, I have ripped several 4K/UHD Blu-Rays for my Plex Media Server and the TCL is the ONLY device in the house that is capable of playing some titles that are at a higher bitrate (greater than 100 Mbps); apparently the TCL has a gigabit Ethernet chipset on-board while the Roku Ultra and the Hisense have only 10/100 chipset.

As I mentioned, my laptop, which has a 4K display and has both an Intel and Nvidia GPU chipset, plays all of the video flawlessly and using the HDHomeRun app, I get the AC-4 audio on CBS. I think the picture quality appears slightly better if I stream to VLC but I don't get audio with CBS due to VLC having no support for AC-4.

The part that I find strange is video playback on the iPhone. It is not watchable. Period.

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