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Audio (Dolby AC3) problems on FOX? - Page 2

post #31 of 66
2/1/10 at 3:18pm
Same here. Kenwood is about 6 years old and never had an issue before. AMCHD also has the problem on TWC as well.
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post #32 of 66
2/1/10 at 3:46pm
Quote:
Originally Posted by Ken H View Post

Flaw may be the wrong term. Incompatibility is probably a better way to think about what's happening.

Yep,IMHO, possibly likely due to the new Motorola encoders FOX has been installing.
Have passed this thread on to a few folks.
I had the same issue with some YammyHaw receivers in 1997 with the first HD station I worked on. Turned out to be a bug in the Dolby encoder software, that was quickly fixed once known.
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post #33 of 66
2/2/10 at 6:42am
Thread Starter 
Quote:
Originally Posted by bdfox18doe View Post

Yep,IMHO, possibly likely due to the new Motorola encoders FOX has been installing.
Have passed this thread on to a few folks.
I had the same issue with some YammyHaw receivers in 1997 with the first HD station I worked on. Turned out to be a bug in the Dolby encoder software, that was quickly fixed once known.

Keep us posted on what you hear? If the problem isn't fixed I'd at least like to hear an explanation.

What's funny is I can afford a new receiver; it just goes against principle to buy a new receiver just because the networks are incompetent. Even if some encoder bug only affects 2% of their viewers, they should be willing to fix this. It's been the better part of a year now since this mess started.
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post #34 of 66
2/3/10 at 5:23am
Quote:
Originally Posted by zorinlynx View Post

Keep us posted on what you hear? If the problem isn't fixed I'd at least like to hear an explanation.

... because the networks are incompetent.

Such comments usually don't help your case. Perhaps you would be willling to go and show them what they are doing wrong? I am sure they would welcome the help!
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post #35 of 66
2/3/10 at 5:13pm
Thread Starter 
Quote:
Originally Posted by bdfox18doe View Post

Such comments usually don't help your case. Perhaps you would be willling to go and show them what they are doing wrong? I am sure they would welcome the help!

I'm not basing this only on audio issues. Over the past few years I've seen such things as:

- 4:3 content stretched to 16:9 when upscaled
- 16:9 content letterboxed and pillarboxed (this still happens a lot)
- Switching to pillarboxed low-quality video to show lottery numbers on the screen
- Logo bugs in an awkward 4:3 safe area instead of in the corner where they *used to be* when HD broadcasting first started...

...and other such issues. These things happen often enough that I start to wonder about the people running things. Admittedly they have gotten better in the past few years, though.

While I'm sure you personally are competent, there are still many problems that need fixing.
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post #36 of 66
2/3/10 at 6:13pm
Quote:
Originally Posted by zorinlynx View Post

there are still many problems that need fixing.

Oh, you have no idea..you should deal with HD on a daily basis the way some of us do..sometimes the fixes just aren't that easy!
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post #37 of 66
2/3/10 at 8:37pm
None of the things you mention are caused by incompetence on anyone's part. -
- 4:3 content stretched to 16:9 when upscaled
That's deliberate policy on some channels. derisively called "stretchovision"
- 16:9 content letterboxed and pillarboxed (this still happens a lot)
If the SD version of the channel is transmitting 16:9 material it letterboxes it. If the HD version of the channel is broadcasting the SD version upscaled then it gets pillarboxed. So 16:9 content on the HD channel can easily be letterboxed and pillarboxed.
- Switching to pillarboxed low-quality video to show lottery numbers on the screen
Perfectly normal, if the channel does not have the equipment necessary to deliver this in HD
- Logo bugs in an awkward 4:3 safe area instead of in the corner where they *used to be* when HD broadcasting first started...
Deliberate policy on network channels. They want the logo to be viewable by people with converter boxes delivering a 4:3 picture
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post #38 of 66
2/3/10 at 9:06pm
Quote:
Originally Posted by zorinlynx View Post

I'm not basing this only on audio issues. Over the past few years I've seen such things as:

- 4:3 content stretched to 16:9 when upscaled
- 16:9 content letterboxed and pillarboxed (this still happens a lot)
- Switching to pillarboxed low-quality video to show lottery numbers on the screen
- Logo bugs in an awkward 4:3 safe area instead of in the corner where they *used to be* when HD broadcasting first started...

You have no idea what you are talking about.
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post #39 of 66
2/4/10 at 7:41am
Quote:
Originally Posted by Ken H View Post

You have no idea what you are talking about.

Ken, he knows exactly what he is talking about, just has no idea of the reasons. He has seen those things, as have all of us. It is hard to handle the ignorant questioner. We can hope he gains knowledge.

That tale on levels of knowledge, incomplete:

Those who don't know and don't know that they don't know, teach them

Those who don't know and know that they don't know, teach them

Those who don't know and think that they know, run from them

Those who know and know that they know, learn from them
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post #40 of 66
2/4/10 at 12:22pm
Thread Starter 
Quote:
Originally Posted by texasbrit View Post

None of the things you mention are caused by incompetence on anyone's part. -
- 4:3 content stretched to 16:9 when upscaled
That's deliberate policy on some channels. derisively called "stretchovision"
- 16:9 content letterboxed and pillarboxed (this still happens a lot)
If the SD version of the channel is transmitting 16:9 material it letterboxes it. If the HD version of the channel is broadcasting the SD version upscaled then it gets pillarboxed. So 16:9 content on the HD channel can easily be letterboxed and pillarboxed.
- Switching to pillarboxed low-quality video to show lottery numbers on the screen
Perfectly normal, if the channel does not have the equipment necessary to deliver this in HD
- Logo bugs in an awkward 4:3 safe area instead of in the corner where they *used to be* when HD broadcasting first started...
Deliberate policy on network channels. They want the logo to be viewable by people with converter boxes delivering a 4:3 picture


Thanks for clearing up the reasons behind a lot of these issues. It makes more sense now, even if I think some of the practices are still annoying. They could easily show us the lottery numbers during the next break, for instance.

I guess it's not as bad as it used to be; I remember when UPN would occasionally show entire episodes of "Enterprise" at low resolution, letterboxed and pillarboxed. It was maddening; I haven't seen screwups on that level in a long time, though.

But back to being on topic, I hope this audio issue can be fixed.
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post #41 of 66
2/4/10 at 4:06pm
Quote:
Originally Posted by zorinlynx View Post

I hope this audio issue can be fixed.

Oh, I'm fairly confident that at some point the cause will be found.
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post #42 of 66
2/8/10 at 5:14pm
They may have found the problem in Cleveland. As of tonight (Feb. 8) WJW Fox's DD sounds great from DirecTV. Yesterday it was stuttering like crazy.

Strike that --- 30 minutes into House it started up again. Probably when they went to local spots.

So close!
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post #43 of 66
2/9/10 at 8:02pm
I emailed a tech at Kenwood about this and he said:

"We believe the surround signal is being sent at 192kHz (not a valid copyrighted Dolby signal)."
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post #44 of 66
2/10/10 at 8:12am
Quote:
Originally Posted by tfelmly View Post

I emailed a tech at Kenwood about this and he said:

"We believe the surround signal is being sent at 192kHz (not a valid copyrighted Dolby signal)."

Then he probably needs to read up on the Dolby specs.
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post #45 of 66
2/10/10 at 1:41pm
Just as a little more info., most networks distribute their audio either discrete 5.1 or via Dolby E, which is VERY stable. Once that signal gets to your local affiliate, they decode the Dolby E stream, hopefully keeping all attached metadata, and add LOCAL audio. At that point, before it leaves their house, it's converted to Dolby Digital AC3.

If there were problems with the network feed, the local would certainly hear it as they MUST decode the Dolby E stream in their facility prior to re-encoding to AC3.
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post #46 of 66
2/10/10 at 4:45pm
Quote:
Originally Posted by Eric Seaberg View Post

Just as a little more info., most networks distribute their audio either discrete 5.1 or via Dolby E, which is VERY stable. Once that signal gets to your local affiliate, they decode the Dolby E stream, hopefully keeping all attached metadata, and add LOCAL audio. At that point, before it leaves their house, it's converted to Dolby Digital AC3.

If there were problems with the network feed, the local would certainly hear it as they MUST decode the Dolby E stream in their facility prior to re-encoding to AC3.

Not at FOX. The encoded AC3 stream is sent from the network and passed through at the local level.
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post #47 of 66
2/10/10 at 5:45pm
Quote:
Originally Posted by Eric Seaberg View Post

Just as a little more info., most networks distribute their audio either discrete 5.1 or via Dolby E, 3.

CBS uses Dolby E for 5.1 and PCM for stereo. ABC and NBC use phase aligned discrete pairs for 5.1, and PCM for stereo. FOX uses bit stream splicing with the network audio being pre-encoded 5.1 @ 448k.
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post #48 of 66
2/11/10 at 4:40pm
Quote:
Originally Posted by spwace View Post

Not at FOX. The encoded AC3 stream is sent from the network and passed through at the local level.

Are you serious? Then how do they insert local audio? You can't unpack/repack AC3 without terrible artifacts!!
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post #49 of 66
2/11/10 at 4:47pm
Quote:
Originally Posted by Eric Seaberg View Post

Are you serious? Then how do they insert local audio? You can't unpack/repack AC3 without terrible artifacts!!

We don't do anything to the network audio. We only splice back and forth between the local and network streams at the appropriate times.
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post #50 of 66
2/11/10 at 5:01pm
Quote:
Originally Posted by spwace View Post

We don't do anything to the network audio. We only splice back and forth between the local and network streams at the appropriate times.

So you splice in another AC3 stream? It's certainly random, isn't it, since you're not locked to video frames as Dolby E. That does explain a lot.

As a 'program provider', I sure wish all the networks would figure out a consistent delivery method that would insure me, as a paying customer, the same quality output as what I put on the tape. We are supplying program with PCM stereo on 1/2 and Dolby E in 6-channel mode on 3/4 on HDCam. We do 6-channel because we also deliver XDCam to some stations and since it can only do 16-bit audio, we step-down the Dolbys.
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post #51 of 66
2/11/10 at 5:28pm
Quote:
Originally Posted by Eric Seaberg View Post

So you splice in another AC3 stream? It's certainly random, isn't it, since you're not locked to video frames as Dolby E. That does explain a lot..

The splice is done at the MPEG level using the ASI stream. Basically, in simplistic terms..it's a 'transport stream" clean (kinda) switch.

Kinda dated, but here are two good explanations:

http://www.mpeg.org/MPEG/splicing-FAQ.html

http://broadcastengineering.com/infr...splicing_mpeg/
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post #52 of 66
2/11/10 at 7:24pm
Thanks Bob and spwace... it just doesn't seem as clean to me as what Dolby E is spec'd to do. I'm just surprised that since the technology exists with Dolby to make it easy for everyone, especially with metadata and dialnorm, why is it taking so long to implement?

I, at least, do applaud ABC and NBC for keeping it discrete, but that means any dialnorm info I add is totally lost, and there are a LOT more places for my 5.1 mix to shift heavy Ls or C or whatever. If CBS does use Dolby E, do they retain the originator's metadata? I had heard at a 5.1 symposium at NAB that one of them, could be CBS, strips all metadata and sets dialnorm for -31.

Why have all these great tools for post-production and delivery if the networks don't read it or care about it?

(Interesting articles, Bob. Thanks, but it certainly seems like there's potential to lose sync between audio and video by splicing, yes? At least an audio frame.)
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post #53 of 66
2/11/10 at 11:13pm
Splicing effectively gives them 100% HD+5.1 coverage, discounting the markets where Fox is only available on an analog LP or digital subchannel. There are plenty of ABC, CBS, and NBC affiliates not doing HD, and far more who can't do DD5.1. If the station can somehow manage to put 720p into the local side of the splicer, they can get perfect Fox network HD and 5.1 out to their viewers, even if their local stuff looks like a 20 year old VHS tape.
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post #54 of 66
2/12/10 at 10:42am
Quote:
Originally Posted by Eric Seaberg View Post

Why have all these great tools for post-production and delivery if the networks don't read it or care about it?

There is at least one aspect to FOX's delivery method that is quite appealing to me -- the local station cannot alter the network audio. There are several affiliates of "other" networks in my area that are unlistenable due to the HEAVY amount of compression they are applying. Dynamic range is reduced to zero, and all background sound is sucked up the same level as dialog. Unlistenable. With FOX's method, the affiliate is out of the loop, providing the untouched network audio to the home. I like that.
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post #55 of 66
2/14/10 at 3:47pm
I'm about ready to drop more money and replace my Kenwood AVR to fix this problem.

Are new AVR receivers immune to this issue? I'm looking at an Onkyo SR607 FWIW.
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post #56 of 66
2/14/10 at 5:52pm
i am having the problem on my SR607. i watched the Nascar race today on Foxand the problem kept happening. I have been watching the Olympics since then on NBC without the problem happening.
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post #57 of 66
2/14/10 at 6:28pm
I watched parts of the NASCAR race but didn't have any audio problems. I'm on DirecTV FWIW. I think you posted over on Afterdawn.com too.
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post #58 of 66
2/14/10 at 6:31pm
Thread Starter 
I wonder if they changed anything at FOX? I've been watching FOX Sunday night without any glitches or problems tonight.

Anyone else?
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post #59 of 66
2/14/10 at 6:44pm
I just went to check out FOX during American Dad and yes the sound is clear.

Hope they fixed it!

BTW - I posted a MP3 clip with a sample of the sound I am getting from Fox and other HD networks.

Can you take a listen here:

http://www.dbstalk.com/showthread.ph...02#post2357102

Is the same thing you are hearing?
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post #60 of 66
2/14/10 at 7:17pm
Thread Starter 
Quote:
Originally Posted by tfelmly View Post

I just went to check out FOX during American Dad and yes the sound is clear.

Hope they fixed it!

BTW - I posted a MP3 clip with a sample of the sound I am getting from Fox and other HD networks.

Can you take a listen here:

http://www.dbstalk.com/showthread.ph...02#post2357102

Is the same thing you are hearing?

Nope, my problem sounds different. The audio mutes for a few seconds at a time. In fact, it's mostly muted, with only occasional blips of sound coming through. If I hold my ear next to the speaker, I can hear the sound playing normally at an extremely low volume when it's muted. This means the receiver is correctly decoding, just muting because it thinks there's a problem with the bitstream.

It seemed clear tonight, but only time will tell. I hope to watch "24" tomorrow in real 5.1 for the first time since the season started!

I'm starting to wonder if the problem is due to flakey firmware in some piece of equipment deployed by several networks. It seems to have started with FOX and has now spread to several other networks. The bad stream seems to be messing up with DBS networks' equipment as well. It's pervasive and I hope they can find the issue soon.
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