HDHomerun official iOS apps now producing much lower video quality

Help and support for HDHomeRun DVR and HDHomeRun software for Windows 10, Mac, Android, XBox, etc.
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csdesigns
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Joined: Thu Jun 20, 2019 2:21 pm

HDHomerun official iOS apps now producing much lower video quality

Post by csdesigns » Thu Jun 20, 2019 2:55 pm

I have noticed for the past few months that the HDHomerun apps on iOS are now producing significantly softer video picture quality in addition to reduced frame rates. This is especially evident when watching sports. I imagine this behavior was done so as to reduce the CPU load on the mobile device and better retain battery life, but I personally don't care about either and would much rather prefer higher picture quality and especially smoother video. I am attaching screenshots to exemplify what I am referring to:
HDHomerun app on iPhone XS Max
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Plex app, using same HDHomerun tuner hw, on iPhone XS Max
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HDHomerun app on iPad Pro 10.5
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Plex app, using same HDHomerun tuner hw, on iPad Pro 10.5
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As should be quite evident, the HDHomerun screenshots are much softer, with lots of aliasing in the lower text crawl and within the logos. And while I know it can't be seen in the screenshots, Plex is transcoding this channel at its native 60p (FOX) and sending to my device 60p video, so everything looks smooth and natural, as sports should. Comparably, the HDHomerun app appears to be delivering at best 30p. I can somewhat understand Silicondust's intentions here (save CPU and battery), but I want the option to be able to view these channels in their native quality, not some half-or-quartered resolution crap. As it stands, this decoding issue makes the native HDHomerun app absolutely useless to me. It's even worse because up until a few months ago, this was not the case and these apps were a great way to quickly watch a channel on these devices!

PLEASE PLEASE PLEASE bring back the ability to watch our channels on our mobile devices at their original quality!!! (Or, at the very least, offer the option to let the user pick which decode profile that they'd prefer.)

{Note, I did find this this other similar experience from another user, but I do not see these same issues on any of my other devices, like Xbox One, Nvidia Shield, or macOS (some wired, some wireless)}
Last edited by csdesigns on Fri Jun 21, 2019 10:40 am, edited 2 times in total.

nickk
Silicondust
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Joined: Tue Jan 13, 2004 9:39 am

Re: HDHomerun official apps now producing much lower video quality

Post by nickk » Thu Jun 20, 2019 4:46 pm

Hi,

If the source content is MPEG2 then it should be displayed at 30fps by the iOS app. This isn't a change - the iOS app has always displayed MPEG2 content at 30fps.

If the source content is h264 then it should be displayed at 60fps using hardware decode unless an error occurs and it drops back to a 30fps decode.

The only thing that comes to mind is if you have a HDHomeRun EXTEND transcoding in Heavy mode - then the HDHomeRun app should be doing 60fps hardware decode.

Is this an ATSC broadcast channel in MPEG2?

Nick

csdesigns
Posts: 5
Joined: Thu Jun 20, 2019 2:21 pm

Re: HDHomerun iOS app producing much lower video quality

Post by csdesigns » Thu Jun 20, 2019 9:33 pm

Hi nickk, thanks for responding so quickly. Sorry for leaving out some critical details as to the setup... These are all OTA ATSC 1.0 MPEG-2 channels, tuned via a HDHomeRun Connect Duo device. I thought I recalled that previous versions of the official iOS HDHomeRun app displayed these channels (ABC, FOX) in 60p, but I may be mistaken or just confused because other apps which can also use the tuner were capable of this (and I'll admit to still being a bit skeptical that this wasn't the case with the official app because I primarily only watch live sporting events through the official app and the lack of native 60p decode would have immediately forced me to go with my Plex setup instead – but then again, I don't recall spending all that much time with the native apps in the past, so it is also entirely possible that I've always just had this issue and only now writing in because of the decrease in PQ).

But I am certainly not mistaken about the sudden and drastic change in picture quality. It truly looks as though the app is applying some sort of low-pass filter or quarter-res base-profile decode process. (A great way to highlight these differences in my provided screenshots is to simply overlay one on top of the other in Photoshop and switch between the layers.) I haven't seen video decode picture quality performance this bad in many years, and I have been tuning into ATSC channels since around 2003-2004 (with an EyeTV 500)!

One big difference I noticed in the decode of the video on the iPad is that Plex looks to be displaying a 1:1 representation of the source with additional letterboxes to fill in the screen. But on the HDHomeRun app, the video is slightly zoomed in and cropped – this upscaling could certainly explain some of the loss in detail, which is much less severe than on the iPhone versions. The iPhone version of the HDHomeRun app actually appears to downscale the video ever so slightly, yet the entire picture is way worse in quality than what Plex is able to offer. Given that Plex is actually live transcoding these channels in my current setup, and that the Connect does not have a native transcoder, this makes little sense to me.

nickk
Silicondust
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Joined: Tue Jan 13, 2004 9:39 am

Re: HDHomerun official apps now producing much lower video quality

Post by nickk » Thu Jun 20, 2019 10:25 pm

When there is a miss-match between the screen aspect ratio and the video aspect ratio the HDHomeRun app will apply a slight overscan to better fill the screen. The maximum is 2.5% on two sides. You can see this in action by using the Mac or Win10 app in window mode and resizing the window.

720p MPEG2 content on MacOS and iOS should be identical in image quality, with 60fps on MacOS and 30fps on iOS.

1080i MPEG2 content is more complex due to deinterlacing.

Are you seeing the difference only on 1080i channels?

Nick
[edited]

nickk
Silicondust
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Joined: Tue Jan 13, 2004 9:39 am

Re: HDHomerun official apps now producing much lower video quality

Post by nickk » Thu Jun 20, 2019 10:46 pm

BTW - I edited the thread title as the problem you are seeing is specific to iOS.

The HDHomeRun apps are custom for each platform, making use the hardware video decode features and/or GPU acceleration features specific to each platform. For example, platforms like Nvidia Shield and XBox One support all formats of video decode 100% in hardware - the HDHomeRun app is not involved in the picture quality.

Nick

csdesigns
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Joined: Thu Jun 20, 2019 2:21 pm

Re: HDHomerun official apps now producing much lower video quality

Post by csdesigns » Fri Jun 21, 2019 8:02 am

720p MPEG2 content on MacOS and iOS should be identical in image quality, with 60fps on MacOS and 30fps on iOS.

1080i MPEG2 content is more complex due to deinterlacing.

Are you seeing the difference only on 1080i channels?
Here's exactly the rub... The channel I provided the screenshots from yesterday is FOX, which is broadcast in native 720p60 in the States. So there is no deinterlacing involved as there would be with 1080i channels. I am not certain if this issue extends to 1080i native channels (CBS/NBC/PBS) as I don't often try to watch those channels live in the HD Homerun app because they don't broadcast many sporting events that I care about.

Unfortunately, the programs being broadcasted right now (~10am EST) on both of the main 720p channels (ABC/FOX) are talk shows, which have little motion and detail, so I can't really do a 1:1 comparison between the iPhone/iPad/macOS apps, as the source content doesn't lead itself well to such comparisons. But I will try again later during the Women's World Cup as this is excellent content for showcasing this issue.

Regarding the whole 60p vs 30p playback thing on iOS – is that something we can fix for a future version of the app? I know that for the majority of content out there, 30p is more than sufficient, but for sports it is a huge let down; especially considering Plex can deliver 60p with the same content as does the native iOS sports-centric channel apps such as ESPN, MLB.TV, and FOX Sports (in fact, if it weren't for the Plex integration, streaming the game with the FOX Sports app would have also been a far superior option to the HDHomeRun app).

csdesigns
Posts: 5
Joined: Thu Jun 20, 2019 2:21 pm

Re: HDHomerun official apps now producing much lower video quality

Post by csdesigns » Fri Jun 21, 2019 9:10 am

So while the content being broadcasted right now may not be the most detailed, it is still decent enough (especially in the banner text overlay) that you should be able to see some key differences. Instead of comparing against Plex however, I will now use the 'Channels' iOS app in these screenshots, as 'Channels' does not rely upon server-side transcode to H.264 (similar to the HDHomeRun app), thus this being a more like-for-like comparison:

HDHomeRun native iPhone Xs Max
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'Channels' iOS app Default decode settings (High Quality 60fps) ATSC 1280x720 MPEG-2
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'Channels' iOS app High Quality 60fps ATSC 1280x720 MPEG-2 decode
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'Channels' iOS app High Quality 30fps ATSC 1280x720 MPEG-2 decode
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'Channels' iOS app Low Quality 60fps ATSC 1280x720 MPEG-2 decode
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'Channels' iOS app Low Quality 30fps ATSC 1280x720 MPEG-2 decode
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Image

Image

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I am curious if SiliconDust is using the same SDK for the player as 'Channels'? Because the performance I am seeing in Channels is nearly identical to what I recall I used to see with the HDHomeRun native app on iOS when it launched not too long ago on the App Store. But it seems that the SiliconDust devs have made a recent change whereby the default settings for the decode performance have been set to something much lower, which is about on par with what I get in the Channels app when I lower the decode settings in that app (Low Quality 30p mode). Major difference of course being that in the Channels app I can manually set the decode performance to my preference, whereas I have no such capability in the official HDHomeRun app.

Hard to believe, especially now after these screenshots, that there is not something wrong, or at least something that could be fixed if desired, with the HDHomeRun native app. It is not a good thing that this issue can be so clearly seen from just simple small screenshots of talking heads video content.

nickk
Silicondust
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Joined: Tue Jan 13, 2004 9:39 am

Re: HDHomerun official apps now producing much lower video quality

Post by nickk » Fri Jun 21, 2019 10:40 am

It looks like a different color space is being used creating brighter colors.

We recently upgraded the YUV to RGB conversion to use GPU shaders on iOS.

Will review.

csdesigns
Posts: 5
Joined: Thu Jun 20, 2019 2:21 pm

Re: HDHomerun official iOS apps now producing much lower video quality

Post by csdesigns » Fri Jun 21, 2019 10:43 am

Yes, the color is certainly more muted on the HDHomeRun app than either Plex or Channels. Color is of much less concern, to me at least, than actual picture detail or motion quality however. I doubt I would be in the minority here.

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