Ender519's profile

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51 Messages

Wednesday, December 7th, 2011 3:07 AM

Confirmed: vip2250 fixes surround sound audio dropouts!

I had a vip1225 hooked up via HDMI to an Onkyo receiver (HT-S8400 to be specific) and I had problems with audio dropouts on surround.  Every few seconds, for a fraction of a second, the audio would drop.  It drove me nuts and I tried everything to fix it.. I tried different (new) HDMI cables, and even a different home theater system!   In the end, I had to keep it on stereo.

 

I went over and over this with UVerse support.  They kept wanting to send me to the paid support line for help configuring my home theater system and out of four techs I spoke to, none ackowledged hearing anything about audio dropouts over HDMI with surround.  In fact, they kept insisting that I plug the HDMI straight to the TV and I kept having to explain my TV is a stereo device, not a surround device so it's not a good test.  They also immediately started jumping on the bandwagen saying surround sound is out of scope.  I saw a couple of posts about the vip2250 fixing this issue but none of the techs would entertain that idea.

 

Finally I pled my case to a very nice agent in billing who had to go WAY out of her way to get me a vip2250.  Hooked it up and sure enough all audio dropout problems are resolved!

Teacher

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15 Messages

11 years ago

With regard to your last question on previous post I have used a Theta Digital TLC optical to SPDIF converter which did do re-clocking of the digital audio from the optical output of a VIP1200 and it worked great. The TLC is not cheap but it does smooth out the digital audio. I would not recommend using the cheap Chinese converters available on Amazon. They do not provide re-clocking of digital audio.

 

Sorry to hear about your video issues with the VIP2250.

Mentor

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40 Messages

11 years ago


@Agent 305 wrote:

With regard to your last question on previous post I have used a Theta Digital TLC optical to SPDIF converter which did do re-clocking of the digital audio from the optical output of a VIP1200 and it worked great. The TLC is not cheap but it does smooth out the digital audio. I would not recommend using the cheap Chinese converters available on Amazon. They do not provide re-clocking of digital audio.

 

Sorry to hear about your video issues with the VIP2250.


Thank you!  Where can I read about one of these?  I must not be good at google I couldn't find it!

Teacher

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15 Messages

11 years ago

Hope this helps

 

Narrative from Theta Digital website...
 
Timebase Linque Conditioner

 

Originally, there was only one method available to connect a CD player / transport to an outboard D to A converter, that being coaxial. The mass-market manufacturers then produced players with the inferior TosLink plastic fiber optic output. AT&T glass fiber optics also became available as a means to interconnect digital equipment. All of these termination methods posed a problem for people trying to buy components that would interface with each other. The Timebase Linque Conditioner was designed to solve these problems. It accepted TosLink and coaxial inputs and output coaxial and optionally AT&T or Theta's Laserlinque. It also contained extensive re-clocking circuitry to combat the deleterious effects of jitter. Poor quality transports still pervaded the market, reducing the effective quality level Theta's D to As could offer. The Timebase Linque Conditioner ameliorated some of the problems. It was even found to improve the sound of our then best combination, the Data III / Generation V.

 

All of the digital-to-analog converters up until that time used integrated circuits (ICs) called op-amps, for the critical current-to-voltage conversion that occurs following the DAC, and for the output buffers. At that time, integrated circuit chips generally were used as cost-efficient compromises, which lowered the quality of components that depended on them, in comparison with equivalent circuits made up of discrete elements on a circuit board. After about a year of research, a new analog section was developed for the Generation III, based entirely on discrete class-A bipolar transistor. This circuitry offered greater processing speed, which produced more detail and a smoother sound.

 

Theta TLC Reviews...

http://www.audioreview.com/cat/digital-sources/dacs/theta-digital/tlc/prd_123794_2738crx.aspx#reviews

 

 

Theta TLC Images...

http://www.google.com/search?q=Theta+Digital+TLC&hl=en&rls=com.microsoft:en-us:IE-SearchBox&prmd=imvnsfd&tbm=isch&tbo=u&source=univ&sa=X&ei=bA9_UIOnAae9iwKCl4DwDg&ved=0CGYQsAQ&biw=1024&bih=581

 

On ebay....current
 

 

 

Audiogon Ad Expired...

http://app.audiogon.com/listings/theta-digital-timebase-linque-conditioner-cleans-any-di

 

 

ebay ad sold...

http://www.ebay.com/itm/Super-Rare-TLC-Timebase-Linque-Conditioner-by-Theta-Digital-ORG-BOX-CHARGER-/130767402367

 

Expert

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9.4K Messages

11 years ago

My TV is a Sony KDS-55A3000, a 2007 model LCoS which was a great TV for its time. I still think it produces a superior picture to most LCD TVs, but your VT50 would probably outperform it.

However, on my TV, there is an HDMI settings option that controls how the TV negotiates with an HDMI source to control the color space. My TV has this setting as "Auto", "RGB", or "YCbCr", meaning that it can ask the HDMI source to send the picture data as the preferred output of the source, force the selection of RGB (making the source perform the YCbCr->RGB conversion), or force the selection of YCbCr (allowing the TV to do the YCbCr->RGB conversion).

See if your TV has a similar setting. Because the problems you're seeing are primarily grayscale issues as well as off-colors, I wonder if the YCbCr 4:2:0 -> RGB 4:4:4 chroma upsampling algorithm is part of the problem. Forcing your TV to negotiate YCbCr over HDMI transfers the chroma upsampling responsibility to your TV rather than the STB.

Furthermore, different chroma upsampling algorithms are supposed to be used for HD (Rec.709) and SD (Rec.601). You might repeat your testing with the STB output set to 480i vice 1080i and see if the chroma anomalies disappear.

Mentor

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40 Messages

11 years ago


@Agent 305 wrote:

Hope this helps

 

Narrative from Theta Digital website...
 ...


Thank you for taking the time to do this!   I must have been fat fingering something in my searches.

 

 

Mentor

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40 Messages

11 years ago


@SomeJoe7777 wrote:
My TV is a Sony KDS-55A3000, a 2007 model LCoS which was a great TV for its time. I still think it produces a superior picture to most LCD TVs, but your VT50 would probably outperform it.

However, on my TV, there is an HDMI settings option that controls how the TV negotiates with an HDMI source to control the color space. My TV has this setting as "Auto", "RGB", or "YCbCr", meaning that it can ask the HDMI source to send the picture data as the preferred output of the source, force the selection of RGB (making the source perform the YCbCr->RGB conversion), or force the selection of YCbCr (allowing the TV to do the YCbCr->RGB conversion).

See if your TV has a similar setting. Because the problems you're seeing are primarily grayscale issues as well as off-colors, I wonder if the YCbCr 4:2:0 -> RGB 4:4:4 chroma upsampling algorithm is part of the problem. Forcing your TV to negotiate YCbCr over HDMI transfers the chroma upsampling responsibility to your TV rather than the STB.

Furthermore, different chroma upsampling algorithms are supposed to be used for HD (Rec.709) and SD (Rec.601). You might repeat your testing with the STB output set to 480i vice 1080i and see if the chroma anomalies disappear.

Interesting, I didn't think the Uvere STB's were even capable of outputting YCbCr (at any level) I thought it was only RGB 4:4:4.  Too bad there isn't a way to force the STB to use YCbCr by default, I believe that's what it should be doing by default.

 

My receiver shows RGB in and it's sending RGB back out.  (no conversion, it's on bypass for these tests as well... I tried a cable direct to the TV)

 

I don't believe I have a way to force the negotiation.  Thus far whatever TV I have connected the 2250 has exhibited the same issues, clipping grayscale 16-18.   Red tint in the lower grays.  The gamma is for sure lower on the 2250 than the other STB I have.  The difference is easily seen (especilly as the compression artifcats rear their up on the 2250), I have my main input calibrated to BT.1886 gamma with a 2.22 power law in one ISF mode and a sRGB gamma on the other  mode (I was cross comparing).  It's very apparant the 2250 lowers the gamma when it's connected vs the other box.  The non -DVR looks really good, the 2250 just looks like it has white crush, missing shadow detail and the overall gamma is too low.  To my eyes it appears to be around 1.8 - 1.9 which is kind scary to me since my BT.1886 gamma starts at around 2.2 at a 10% stimulous  and goes to 2.3 at 90%.

 

I really appreciate the suggestions!  I hope someone from AT&T reads this and gets on it.  I'm thinking this does explain why most people think the 2250 seems to show more compression artifcats, the lower gamma will do that for sure.  The image is very good on my other non DVR box with the BT1886 gamma, outstanding at times to be honest especially when I add just a hair of noise reduction and edge enhancement in my receiver  (Onkyo NR818).

 

I'll let ya know how 480i goes.  I'll snap some photos of the black clipping and white clipping slides on both DVRs with same input/settings.  So you can see what I am.

 

 

Mentor

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40 Messages

11 years ago


@Agent 305 wrote:

Hope this helps

 

Narrative from Theta Digital website...
 
Timebase Linque Conditioner

 

....


I forgot to ask you.  I wanted to clarify something.  Does this unit help when the STB digital output is in surround sound mode?   My issues (like most) are on HD channels with 2 channel DD audio.   Does it pass everything through as 5.1 and 2.0 but simply correct jitter?

 

thanks again!

 

Teacher

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15 Messages

11 years ago

The Theta Digital TLC does not change the audio format coming into it. If you send it Dolby Digital 5.1in it will output Dolby Digital 5.1. If you send it Dolby Digital Stereo in it will output Dolby Digital Stereo. (the digital audio output settings are made in the STB)

 

What it does do is allow you to use the Toslink output form your STB and then use a Coax SPDIF cord to your processor or receiver. It will take the digital audio coming into it and reduce the jitter and re-clock it. My results were smoother and much more detailed digital audio with the Theta in the loop and no audio dropouts.

 

I used the Theta TLC with the Toslink output on my VIP1225 as a work around for the audio dropout problem I was having using the HDMI audio out on the VIP1225. 

 

When I got the VIP2250 STB my HDMI audio dropout problem was corrected so I sold the Theta TLC to a friend as I no longer used the Toslink audio out on the new  STB box. 

Mentor

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40 Messages

11 years ago


SomeJoe7777 wrote:
You might repeat your testing with the STB output set to 480i vice 1080i and see if the chroma anomalies disappear.


In regards to 480i  the chromra anomalies are better as well the grayscale clipping is gone.  I can now see down to 17  (16 should be black).

 

I do hope someone who has some degree of influcence reads thee issues and addresses them.  Getting the video right will help peoples impressions of the service.  I bet most people do notice the side effects of the gamma being lower and clipped blacks (most probably haven't a clue what gamma is though).  Since it's coming out of black so fast compression artifcats show up more.  They should want to fix this...   too bad wants and will's aren't always the same 🙂

 

I hope the problem resides in software and not the hardware...

 

I wonder when the next update is due an I wonder if this can even be considered for it.  Hopefully it's already on the plate.

Mentor

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40 Messages

11 years ago

Just before anyone else tries, the Theta Timebase Linque didn't help the drop outs to my Onkyo NR818.  I just got mine today and it's still popping/dropping frequently.  Doesn't seem like there is much difference, perhaps some improvement but it's certainly not a fix.

 

I might have to switch back to the 2250 and suffer a bit with the gamma/red tinted dark grays.

 

Now I have an antique Theta audio device...  I guess I'll put it back up on ebay... sigh.  

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