Roku stripping sides of Comet TV.

Just a note that there is a Roku app for Comet TV.

https://channelstore.roku.com/details/140565/comet-tv

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@Mark12547 wrote:

I have noticed that the Xfinity Beta Stream App on the Roku is cutting off the sides of Comet TV so the Comet TV subchannel of KATU is being cut down from its broadcasted 16:9 aspect ratio to 4:3, so there are unnecessary pillar bars on the side of the part of the image being displayed instead of the full boradcasted image. This happens on the Roku for both on live TV and when playing from the cloud DVR.

 

Comet TV displays correctly (full 16:9 display) on the XG1v4-A connected to a HDTV.

 

This is Comet TV, Channel 301 in the Salem, OR service area, broadcasted from KATU (Portland, OR) on virtual subchannel 2.3.

 

Now much of the content that is broadcasted on Comet TV happens to date back to when TV content was mostly 4:3, but many movies on Comet TV are broadcasted 16:9, so those movies look good on the XG1v4, but when played on the Roku the sides are chopped off and replaced with pillar bars. This was most recently observed about an hour ago watching "Spiders 3D" live on both the XG1v4-A and Roku Xfinity Beta Stream App.

 

Aa an aside, until two weeks ag MeTV (KATU 2.2) had the same problem, but two weeks ago that was fixed and recordings more recent than two weeks ago are correct. Thank you!

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first, SD channels do not broadcast 16:9, they natively broadcast (over the air) in 4:3. However there is a method where the video can be formatted and framed to be displayed as if close to 16:9 (like 14:9) or actual 16:9 using a format called AFD. With AFD there is a text file transmitted in the video stream that says how to display if available in wide screen format. as part of this, edges are 'described' as being ok to not show to stretch the image. The station/broadcaster also has to move/place their channel icons inside of that 'displayed space.  You might look at the same channel on an iPhone device and an Android device. on the iPhone/iPad does the image appear with no black curtains or tiny ones on just left and right side? on the Android device does there appear a curtain on all sides? The X1 set top box passes this information stream to the 'sink' (display device like your HDMI connected TV) and it either is AFD capable or is not. The local broadcaster may not be using the AFD opportunity (yet). usually AFD formatted broadcasts that are displayed without the ability to display see dark curtains all around the video.

While NTSC signals were 4:3, under ATSC 1.0, SD channels can be broadasted 16:9, and Comet TV (an SD channel on KATU 2.3) is indeed broadcasted as 16:9. That is why the XG1v4 can display it as 16:9. However, the Xfinity Beta Stream App on the Roku trims it to 4:3 when displaying it.

Now there are many SD 4:3 channels (such as the SD-only feeds from HBO, Showtime, Screenpix) and those end up letterboxing video content into 4:3 display area, and indeed both the XG1v4 and Xfinity Beta Stream App handle those correctly.

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@Mark12547 wrote:

While NTSC signals were 4:3, under ATSC 1.0, SD channels can be broadasted 16:9, and Comet TV (an SD channel on KATU 2.3) is indeed broadcasted as 16:9. That is why the XG1v4 can display it as 16:9. However, the Xfinity Beta Stream App on the Roku trims it to 4:3 when displaying it.

 

Now there are many SD 4:3 channels (such as the SD-only feeds from HBO, Showtime, Screenpix) and those end up letterboxing video content into 4:3 display area, and indeed both the XG1v4 and Xfinity Beta Stream App handle those correctly.

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All SD (aka non HD channels) are 4:3  and 480p resolution. (https://en.wikipedia.org/wiki/ATSC_standards) 

AFD allows the wider screen capability to sinks (the actual display device like TV/smart phones, etc). when AFD scanned video is not displayed per the properly (if so) coded AFD code then the actual video is displayed since the expanding left to right is not done properly (normally to 14:9). Since the commercials are available in source 16:9 the AFD sent with the commercials are coded for 16:9 so there are no curtains.

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@Rustyben wrote: ... All SD (aka non HD channels) are 4:3  and 480p resolution. (https://en.wikipedia.org/wiki/ATSC_standards) ...

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Don't the tables in that article say that 480 line images can be either 4:3 or 16:9?

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@BruceW wrote:

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@Rustyben wrote: ... All SD (aka non HD channels) are 4:3  and 480p resolution. (https://en.wikipedia.org/wiki/ATSC_standards) ...

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Don't the tables in that article say that 480 line images can be either 4:3 or 16:9?

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no. it is SD.

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@Rustyben wrote:

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@BruceW wrote:

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@Rustyben wrote: ... All SD (aka non HD channels) are 4:3  and 480p resolution. (https://en.wikipedia.org/wiki/ATSC_standards) ...

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Don't the tables in that article say that 480 line images can be either 4:3 or 16:9?

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no. it is SD.

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"No" what? What is "SD"? Your response is unclear.

Could you point out the portion of the article that supports your claim? I cannot find it.

See, for example, the technical information for our local SD Comet affiliate, WXBU: https://en.wikipedia.org/wiki/WXBU#Digital_television, which runs a 16:9 aspect ratio.

Feel free to educate yourself. You might consider giving the stations's Chief Engineer a call.

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@Rustyben wrote: .... broadcast subchannels of other stations (like comet TV) are SD standard definition. ...

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I understand SD just fine, thank you. But you don't seem to understand that, as the OP stated and as the article you yourself posted a link to also states, ATSC SD channels can have aspect ratios of either 4:3 OR 16:9.

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@BruceW wrote:

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@Rustyben wrote:

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@BruceW wrote:

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@Rustyben wrote: ... All SD (aka non HD channels) are 4:3  and 480p resolution. (https://en.wikipedia.org/wiki/ATSC_standards) ...

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Don't the tables in that article say that 480 line images can be either 4:3 or 16:9?

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no. it is SD.

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"No" what? What is "SD"? Your response is unclear.

 

Could you point out the portion of the article that supports your claim? I cannot find it.

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broadcast subchannels of other stations (like comet TV) are SD standard definition. you are welcome to contact the broadcast engineer in your area to discuss AFD/mpeg2 over the air ATSC 1.0 and other topics. wikipedia has an extensive learning library on broadcast TV.

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@BruceW wrote:

See, for example, the technical information for our local SD Comet affiliate, WXBU: https://en.wikipedia.org/wiki/WXBU#Digital_television, which runs a 16:9 aspect ratio.

 

Feel free to educate yourself. You might consider giving the stations's Chief Engineer a call.

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if you contact the engineer he/she will tell you they are transmitting 16 or 14:9 via AFD previously detailed. it is the same 480 format. Back in the 60s they did this with movie presentations using same 35mm movie film but making the image distorted if not projected through a special lense making the image wider. Theaters that the projectionist forgot to change to the special lense saw a distorted narrower picture that was the right height but compressed different amounts left to right depending how far away from the centerline. This concept is very old but fairly new for SD sub channel stations and great care must be exercised in the control room as they change from format size to format size so their station icons and commercials are within the viewing screen. 4:3 tvs get a wide letterbox when the broadcast happens. the issue can currently be seen in Netflix Star Trek Voyager season 1 ep 1 and 2 (didn't test past that episode) as netflix apparently miscoded the AFD and the X1 and Flex overscan it while other devices discard the AFD showing an approximately 1:1 distorted image on the screen. the Flex and X1 Netflix app does try to display it but it overscans (lost detail) on all 4 sides. If you have access to Netflix see that title and epsisode to see AFD in action 'wrong' on a smart phone/tablet/PC.