Los Angeles OTA - ATSC3 launch

Thanks for the info! Didn't get a Flex since I didn't think there would be any PQ improvements until the full ATSC 3.0 rollout.

I got the flex 4k set up and did some test recordings on it with the hvec channels on the channels app they play fine it seems however on the computer using VLC i have no audio and the picture is split into two and the color is purple? has anyone else had this happen?

I just tested with a quick recording from 111.1 KTTV.
It looks and plays fine in Channels DVR, on the webUI as well as Channels app. Of course :slight_smile:

I then opened the same recording on my Mac, using VLC and also IINA. The picture is fine on both, but the audio track isn’t recognized. I typically don't use 3rd party external players with Channels content, so I'm not really sure why there's any difference here. But I do wonder if this discussion has something to do with the issue being discussed: ATSC 3.0 Los Angeles Audio Issue (no audio) on Fox 111.1 - Silicondust

interlaced hevc and lack of AC-4 audio support most likely.

Here's a video player that supports AC-4 decoding, by way of an "experimental version" of FFmpeg, so video and audio play back from these ATSC3 recordings:

It's for Windows, but worked fine for me on my Mac running Parallels. The test recordings I made now include audio on playback.

The FFmpeg project itself has been taking their time to integrate support: #8349 (Dolby AC-4 Support) – FFmpeg
Once it's officially in FFmpeg, then apps like VLC, IINA, Handbrake, Permute and the like should be able to play/convert them too.

Maybe I've missed it, but is there a way to tune the ATSC 3.0 channels (111.1) when going to the standard HD channel 11.1? Mainly trying to get the channels to show up in the guide where the original channel is vs scrolling into the 100's. But also would be helpful to make all recordings use that channel by default as well.

I don't know the answer to that specfically but I'm using customized Channel Collections for all of my browsing and channel surfing, including Favorites (and love that they automatically sync to all my TVs.). With this method it's easy to organize the channels wherever I want them in the guide, in any order I choose. So I just replaced channel 11.1 with the 111.1 one in the Guide. I basically ignore the displayed numbers after that, all of the channel collections are manually sorted in ways that makes better sense to me. In fact I'd love to be able to turn off channel numbers completely.

For forcing recordings to only use a specific channel, you can add that rule, in Advanced Pass editing on the Channels DVR webUI.

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From what I have seen of ATSC3 broadcasts in LA, the quality is the same as before. The bit rate is halved, which benefits the broadcasters (but not really us!) And it looks like some content that used to be 720p is now 1080p. HOWEVER
ATSC3 doesn't just give us a better codec, it also uses a different modulation scheme that's supposedly more robust against the most common causes of poor signals (basically reflections from large buildings interfering with the primary signal). This does seem to work well, in the sense that the quality of signal I get now seems substantially better than before. I don't think I've seen a single dropout on ATSC3 whereas on the same channel (FOX) before this was common.
Of course the channel frequency being used by the ATSC3 signal is also different, so don't take that as gospel...

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" * The major broadcasters may never fully buy-in. They will much prefer you pay for high quality streams."

I'm not sure about this. Sure, in theory they might want this; but I don't believe they are competent enough to actually execute it.
Look at the quality of streaming right now.

  • aTV is nothing but 4K HDR Atmos. Shame it has so little content worth watching.
  • AMZ and Netflix show recent stuff as 4K HDR Atmos and dial it back depending on how old it is. Mostly a good job except Netflix (often) and AMZ (sometimes) screw up the audio channel assignments so that their multi-channel audio sounds like garbage.
  • Paramount+. A few movies in 4K, as far as I know all TV content still in HD.
  • Peacock. Nothing in 4K
  • Spectrum on Demand (ie generic "state of the TV industry"). Apart from the most garbage app available on aTV, everything is 1080p stereo. No HD, no multichannel, no 4K.

So if the mainstream TV industry have some grand plan to charge people for higher quality as streaming, they better damn execute it fast. Because at their current pace, by the time they are ready to offer these higher quality streaming, all the potential customers will already have transitioned to AMZ, Netflix, and Disney+ and will have zero interest in moving back.

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"I just tested with a quick recording from 111.1 KTTV.
It looks and plays fine in Channels DVR, on the webUI as well as Channels app. Of course"

Playback in Channels is not quite perfect :frowning:
I do not see closed captions and (not exactly playback, but playback-adjacent) I can't tell if commercials are being correctly detected. The comskip files all appear to be generated at the correct times (ie half an hour or so after recording finishes), and the comskip .log shows that the content is apparently being understood (somewhat...), but somehow it doesn't get properly integrated.
For example captions do not seem to be detected, likewise volume transitions are not being detected. Even logo's are not being detected (weird!), or black frames.But it's not like comskip just says "unknown codec" and gives up; every frame is apparently decoded, just not "understood".

To give a flavor of the output:

Distribution of Volume        cutting:  87 positive and  84 negative, ratio is 1.0357
Confidence of Volume        cutting:  84 negative without good logo is too much
Confidence of Volume        cutting:   0 out of   0 are strict, too low
Black Frame List
---------------------------
Black Frame Count = 1
nr 	frame	pts	bright	uniform	volume		cause	dimcount  bright   type
  0	114944	1917.616	     0	     0	     0	           br	     0	     0	B
Combining CC Blocks...
CC's detected on the following frames - 1 total blocks
--------------------------------------
 0 - CC start -      0	end - 114944	type - NONE	length - 0:31:57.61

Caption sums
---------------------------
Pop on captions:        0: 0.00 - 0:00:00.00
Roll up captions:       0: 0.00 - 0:00:00.00
Paint on captions:      0: 0.00 - 0:00:00.00
No captions:       114945:100.00 - 0:31:57.66
The NONE type of closed captions were determined to be the most common.
Start -      1	End - 114944	CCF -  1	CCL -  0	Type - NONE

Fuzzy scoring of the blocks
---------------------------
Block 0 has twice excess length.
Block 0 score:	Before - 1.00	After - 0.00
Dictionary not processed successfully
Threshold used - 1.0500	After rounding - 1.0500


	---------------------
	Initial Commercial List
	---------------------
No change

Logo fraction:              0.0000      Logo disabled
Maximum volume found:         7618
Average volume:                540
Sound threshold:               500
Silence threshold:             100
Minimum volume found:            0
Average frames with silence:    45
Black threshold:                19
Minimum brightness found:       28
Minimum bright pixels found:     0
Minimum dim level found:         0
Average brightness:            318
Uniformity level:              700
Average non uniformity:        161
Maximum gap between logo's:     -1
Suggested logo_threshold:   0.7750
Suggested shrink_logo:	    0.00
Max commercial size found:      -1
Dominant aspect ratio:      1.7800
Score threshold:            1.0500
Framerate:                  59.940
Average framerate:          59.941
Total commercial length:    0:00:00.00
Cut codes:
  F: scene	 c: change
  A: aspect	 t: cutscene
  E: exceeds	 l: logo
  L: logo	 v: volume
  B: bright	 s: scene_change
  C: combined	 a: aspect_ratio
  N: nonstrict	 u: uniform_frame
  S: strict	 b: black_frame
  		 r: resolution
----------------------------------------------------
Block list after weighing
----------------------------------------------------
  #     sbf  bs  be     fs     fe        ts        te       len     sc   scr cmb   ar                   cut    bri logo   vol sil   corr stdev   cc
  0:+     0   0   0      1 114944     0.00s  1917.62s  1917.62s   0.00  0.05   0 1.78  7      {  E         br  3180 0.00  5400 450  0.000    31 NONE      

114944 Frames Processed

BTW is anyone using all this fancy neural network hardware we will have in all our Apple Silicon Macs going forward to detect commercials? That seems like a natural fit, likely to work a lot better than the rigid techniques of comskip, and a nice little project for some youngster wanting to make a name for themselves and to get started with modern SW development...

Commercial detection on ATSC3 requires a newer DVR prerelease

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As of a few days ago, this lineup has changed in Los Angeles.

The 3 ATSC 3.0 channels are now on KCOP's RF 13 signal instead.

KTTV's RF 11 signal now has the following in ATSC 1.0:
11.1 KTTV-DT
11.2 FOX-WX (Replacing the backup KTTV)
11.3 TheGrio
11.4 Decades
13.2 BUZZR
13.3 MOVIES!
13.4 HEROES

13.1 KCOP-DT is now on KTLA's RF 35 signal

I haven't changed any of my hardware or positioning of my antenna... and for the first time in the many years since I've had an antenna set up in this location, I just discovered, I'm now picking up a very usable signal for KABC for the first time. Makes me wonder, did KABC boost or change anything recently? Has anyone else experienced this? I'm in mid-city, still using this indoor antenna. Regardless of why, I'm happy about this development.

I think they may have. I've noticed the opposite effect sadly. KABC has had periods, mostly in the evenings, lately that signal quality drops below 50 and tanks symbol quality. Haven't moved the attic antenna in years and it seems to only happen with 7.1 and its subchannels. I haven't seen anything on RabbitEars that shows a change.

Animation

An older problem has resurfaced, there's once again no sound coming from KTLA 105.1 (ATSC3) channel, via Channels DVR or the HDHomeRun app. I've reverted back to KTLA 5.1 (ATSC1) for now.

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Per discussion in this thread, I reported the issue to KTLA. This morning I received a personalized email reply from Wayne Manous, KTLA's Engineering Operations Coordinator, sharing all of his contact information, and sure enough, 105.1 has sound again!

It is fixed now. If this occurs again, just switch to 5.1 ATSC 1.0 instead of 3.0 and of course send me a note :blush:

I now notice another difference I've not seen before. This time with the FOX broadcast on ATSC 3 channel (111.1.) There is a black border that doesn't show on the ATSC1 channel (11.1)

I tried the Channels settings under Playback > Advanced > "Stretch Video to Fit" and "Overscan" and neither had any effect. So I've gone back to the ATSC1 broadcast for now. The TVE stream is fine too.

Good news, I reported the above to [email protected] and quickly received this reply from [email protected]:

Hi,
Thank you for reaching out. I just heard the following from our Engineering department, so you should see this improve at some point this morning:

Yep valid issue. Has to do with a configuration change we made earlier today. Will fix asap.

Thank you for watching :blush:

:slight_smile: :+1:t3:

Eventually San Diego will go ATSC3...Or not...

This is now fixed.

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