Evaluating Digital to Analog Converter Boxes for Users of Captioning - Page 4 - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #91 of 226 Old 03-19-2008, 10:14 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by blacksburg98 View Post

I decided to return RCA DTA800 and bought Insignia. I used to have caption problems on RCA DTA800 on PBS. The problem is gone after I switch to Insignia.

Interesting difference. You had thought the Broadcom processor for the RCA DTA800B might have trouble handling a different kind of background (either transparent or translucent). Have you tried the different backgrounds with the Insignia on that PBS channel?
dmulvany is offline  
Sponsored Links
Advertisement
 
post #92 of 226 Old 03-20-2008, 12:47 AM
Advanced Member
 
Desert Hawk's Avatar
 
Join Date: Oct 2007
Location: Bakersfield California
Posts: 979
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Not about CECBs but related to 608 captions. Bright House of Bakersfield used to carry some Los Angeles stations in clear QAM (now scrambled, analog versions are not). These signals were digital retransmissions of analog broadcast channels. 608 captions were intact, but V-chip ratings were lost. I suppose that the captions, being embedded in the video on line 21, got digitized along with the rest of the video when fed into the MPEG2 encoder/QAM modulator. Why was the rating info not passed along? Also, there were no 708 captions.

How can we say "the digital transition is complete" when thousands of low power stations are still broadcasting in analog?
LOW POWER ANALOG NEEDS TO DIE NOW!!!
Desert Hawk is offline  
post #93 of 226 Old 03-20-2008, 06:34 AM
AVS Special Member
 
jtbell's Avatar
 
Join Date: Oct 2004
Location: Clinton, SC
Posts: 3,822
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 12
Quote:
Originally Posted by dmulvany View Post

ISo at this time in the USA, channel 20 is automatically an analog channel, and 20.1 is automatically a digital channel. After the transition on February 17, 2009, I'd guess that the basic channel number will presumably be used for either the HD digital channel or an SD channel (but I don't know much about that process).

The old channel numbers will technically no longer be valid, that is, in your example, only 20.1 will continue to exist (along with any other subchannels such as 20.2 etc.). However, what happens when you enter "20" at that time will depend on your particular TV or set-top box.

Most digital-only tuners that I've used, including the single CECB I've tried so far (the Zenith) go to 20.1 automatically if you enter simply "20".

My Sony HD DVRs require me to enter "20.1" for the digital channel because they can also receive analog channels. Entering "20" takes me to the analog channel, at which point I can go to 20.1 by hitting the channel-up button. After the analog channels shut down, I expect to get a blank screen ("no signal") when I tune to 20. I suspect most TVs with built-in analog and digital tuners work the same way.
jtbell is offline  
post #94 of 226 Old 03-20-2008, 06:39 AM
AVS Special Member
 
dr1394's Avatar
 
Join Date: May 2002
Location: Mizar 5
Posts: 3,149
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 19
Quote:
Originally Posted by Desert Hawk View Post

I suppose that the captions, being embedded in the video on line 21, got digitized along with the rest of the video when fed into the MPEG2 encoder/QAM modulator. Why was the rating info not passed along?

Line 21 does not get encoded into the MPEG-2 video. Only lines with actual picture information get coded. The typical SD MPEG-2 encoder starts on line 23.

Because CC data is inserted into picture user data, it's the MPEG-2 encoder's job to handle the insertion. For SD encoders, line 21 is captured separately and scanned pixel by pixel to extract the two CC bytes (which are then formated into the picture user data). For HD encoders, it's more complex. Either the CC data comes externally over some link (such as RS-232) or it's extracted from the digital VBI. The specification for this is SMPTE 334M.

Rating info is present in the XDS data that's encoded on line 21 field 2. It's possible that the SD MPEG-2 encoder wasn't bothering with field 2, and that's why the rating info was missing.

Ron

HD MPEG-2 Test Patterns http://www.w6rz.net
dr1394 is offline  
post #95 of 226 Old 03-20-2008, 06:43 AM
AVS Special Member
 
jtbell's Avatar
 
Join Date: Oct 2004
Location: Clinton, SC
Posts: 3,822
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 12
Quote:
Originally Posted by dmulvany View Post

I can see two kinds of 608 captions at once via the CECB (the ones decoded by the CECB and the ones decoded by the TV.) The decoding of the ATSC 608 data by the CECB clearly doesn't prevent the same data from being converted into Line 21 captions and getting decoded by the analog TV.

I think all the external digital tuners that I've used do the same thing: they pass the line 21 data via 480i output to the TV regardless of whether they're decoding the captions themselves. At first glance, it would seem to be logical for them to either pass the line 21 data or decode the captions, but not both at the same time. Maybe the tuner manufacturers don't want to block any other data that line 21 might contain.
jtbell is offline  
post #96 of 226 Old 03-20-2008, 11:09 PM
Newbie
 
blacksburg98's Avatar
 
Join Date: Dec 2007
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by dmulvany View Post

Interesting difference. You had thought the Broadcom processor for the RCA DTA800B might have trouble handling a different kind of background (either transparent or translucent). Have you tried the different backgrounds with the Insignia on that PBS channel?

I set the background to translucent. No problem.
blacksburg98 is offline  
post #97 of 226 Old 03-21-2008, 08:51 AM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
The article at the following URL apparently discusses a new way of recording and encoding closed captions:

http://www.broadcastnewsroom.com/art....jsp?id=337949

This new technology *may* be useful as a solution for fixing current problems that some broadcasters seem to have with the recording and delivery of closed captions. It would also seem to be an update to the document I referenced earlier (and which I've quoted below). The technology's use of timecoding seems promising, and I hope it works well.

BTW, the CECBs with digital closed captioning can be very useful for diagnostic purposes, especially when the analog TV is also decoding the 608 captions in addition to the CECB decoding digital captions. With some syndicated programs, there's a significant lag with one or the other type of captions and this can be seen through the discrepancies between the two captions. WTTG's broadcast of "The Simpsons" at 7 pm, for example, shows very delayed captions for both captions, with the analog captions being slower than the digital captions. For that affiliate or program, the analog captions may be downconverted from the 708 captions instead of the 708 captions being upconverted from the 608 captions, but both types of captions are too delayed to be usable. Try turning off the sound during an animated program with delayed captions and you'll see what I mean. (I sent off an email to WTTG about captioning problems yesterday, but they've never responded to emails from me in the past.)

(Clearly, the extremely delayed captioning process from WTTG doesn't seem to be using timecoding.)

Quote:
Originally Posted by dmulvany View Post

I'd think that syndicated shows would come with at least the native captions that had been generated for the program, and possibly both might be present.

Page 4 of "Implementing Closed Captions" (mentioned earlier) discusses recording DTVCC data. It sounds that it's possible to record and playback DTVCCs by using video servers and separate files for the captions. (However, since I don't have sufficient background in this area, I don't understand the terminology and thus the document fully.)

Has the following question stumped everyone?

Quote:


Here's a question for the engineers on this thread:

The "Law and Order" series were created for one network, NBC, but are frequently syndicated to other networks. "Stargate Atlantis" was produced for the Sci-Fi HD channel but is being shown now on Fox channels. Both seem to have a problem with standard digital captions on my local channels since my Sharp HDTV can't display captions for those reruns on the digital channel, although the CECBs *are* able to display captions. Why would the Sharp HDTV have problems displaying any captions for such programs on the digital channels, while the CECB can display digital captions?

I should add that another person with HD equipment also couldn't see digital captions for "Stargate Atlantis" from two Fox affiliates on his HD equipment, so the problem decoding digital captions is not just with my Sharp HDTV (purchased less than 1 1/2 years ago). I suspect that the Fox stations are broadcasting digital captions in a way that is incompatible with some HD equipment although CECB with newer chips may be able to decode the digital captions. WJLA (local ABC affiliate) and WDCA (myNetworkTV) are also having similar problems.


Dana
dmulvany is offline  
post #98 of 226 Old 03-21-2008, 09:10 AM
AVS Special Member
 
Scooper's Avatar
 
Join Date: Nov 2000
Location: Youngsville, NC USA
Posts: 5,062
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 15
phillips TB100HH9

1. The availability of digital closed captioning features, including enhanced ones such as
changing the alignments, and the number of colors available.
Yes

2. The availability of a CC button on the remote control
NO
3. The usability of the menu activated by the CC button and what the choices are
Not applicable

4. If analog captions can be decoded by the converter box, the ease of reading the font
provided for those analog captions (if present)
The unit provide analog captions that can be decoded by the TV as well as the digital captions

5. The ease of reading the eight different fonts available for digital captions,
particularly the default font
Most of the FONTS are useable - except # 6

6. The availability of a "caption preview" of some kind when changes are made in the settings
for the digital captions, and how well this predicts the largest font style.
Works

7. How large the digital captions are actually capable of becoming (useful for low-vision
viewers or for being able to watch the TV from a significant distance); do the longest lines
of the largest captions fill the entire width of the screen?
didn't test

8. How usable the optional translucent background is in providing sufficient contrast to the
characters used in the captioning

yes

9. Whether there are any bugs associated with captioning, such as a failure to detect analog
captions automatically if there are no digital captions, jerky movements of captions, cut-off
captions, unexpected changes in the background, etc.

Doesn't seem to be

10. Whether the remote control has an SAP or audio button to switch to a second audio channel
(for descriptive video services), a raised dot on the 5 button, and raised dots on the Power
button or other buttons (useful for low vision or blind users).

Yes on the audio button - no on any raised dots for low vision users - this makes the remote rather unfriendly for low- or no - vision users

11. How well the user manual explains the different digital closed caption settings,
including whether it advises choosing Service 1.

Clearly explained on 2 pages

12. Whether the CECB has crashed and what the circumstances were.
no crashes - I got a "long term" test going right now.

You CAN put antennas on your owned and/or controlled property...
http://www.fcc.gov/mb/facts/otard.html

Being A Beacon of Knowledge in the darkness of FUD
Scooper is offline  
post #99 of 226 Old 03-21-2008, 11:12 AM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Scooper View Post

phillips TB100HH9

Thanks for reviewing this, Scooper. I hope if you get more information, you'll update your review by editing the existing one.

(The Title area may show up when you edit the posting; strangely it's not visible when doing a Quick Reply.)

The product is called the Philco TB100HH9 on the box, isn't it?

Quote:


1. The availability of digital closed captioning features, including enhanced ones such as changing the alignments, and the number of colors available.
Yes

FYI, most CECBs may not provide the ability to change the alignment of the captions. Could you clarify whether this CECB does? For example, neither the Zenith nor the Insignia offer the ability to change the alignment, though my HDTV does. There are times when the captioning keeps covering up important information, so it would be nice to be able to change the alignment. I think that's an optional feature for CECBs, however, though mandatory for HDTVs.

The number of colors available may also vary among the CECBs. (Just realized I need to update my own review with this information.) My HDTV offers 35 colors, while the CECBs I've tested offer only eight, which I'll list in the review. (I much prefer the greater number of colors available with the HDTV.)

Quote:


4. If analog captions can be decoded by the converter box, the ease of reading the font
provided for those analog captions (if present)
The unit provide analog captions that can be decoded by the TV as well as the digital captions

How usable are the analog captions decoded by the converter box? (They can't be changed by the user, so if they're not good, that's important.)

Quote:


6. The availability of a "caption preview" of some kind when changes are made in the settings
for the digital captions, and how well this predicts the largest font style.

Works

Just to clarify for everyone else----I would guess you didn't test how well the caption preview predicts the largest font style (since you didn't test the fonts for #7 below).

Quote:


7. How large the digital captions are actually capable of becoming (useful for low-vision
viewers or for being able to watch the TV from a significant distance); do the longest lines
of the largest captions fill the entire width of the screen?
didn't test

If you can test this later, that would be very useful. I should change this question to ask how much of the width of the screen the longest lines of the largest captions take up.

Quote:


10. Whether the remote control has an SAP or audio button to switch to a second audio channel
(for descriptive video services), a raised dot on the 5 button, and raised dots on the Power
button or other buttons (useful for low vision or blind users).

Yes on the audio button - no on any raised dots for low vision users

Doesn't sound very blind-friendly compared to other remote controls.

Quote:


12. Whether the CECB has crashed and what the circumstances were.
no crashes

I should probably change this question to be answered primarily by people who use captioning all the time to watch a variety of channels. (The Insignia didn't crash for quite a while until it was on a channel receiving problematic digital captions; other people probably haven't noticed problems with it because they don't use digital closed captions often enough.)

This CECB has pass-through of analog channels, but the MaxMedia CECB is supposed to have this feature as well. I don't know if the MaxMedia will have a CC button on the remote, however.
dmulvany is offline  
post #100 of 226 Old 03-21-2008, 11:10 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Note: Ron's evaluation of the Samsung DTB-H260F was accidentally delayed by the AVS Forum due to being held up in a queue for moderation. He posted this several days ago but it did not show up until Friday evening. New members' posts are apparently moderated automatically. (I myself am not a moderator on this forum, and this policy was established by the AVS Forum, not me.)

Ron's evaluation is at:

http://www.avsforum.com/avs-vb/showt...3#post13411173

Quote:
Originally Posted by Ron V. View Post

I also have a Samsung DTB-H260F, which is not a CECB. It is billed as a terrestrial HDTV receiver and “by-the-way” it receives clear QAM. It has HDMI, component, two sets of composite, digital audio, S-Video and RF out. The RF out appears to be a copy of the RF in, unaltered by the box. The signal level of RF out is reduced when the box is turned off.

Interestingly, it does not provide CC data on the composite and S-Video outputs, neither as graphics overlaid on the video image, nor as data in line 21 of the VBI. It also does not support the menu function nor the OSD on the composite and S-Video outputs. I wonder why Samsung even bothered to include those outputs since they are so limited in function.

I would guess that Samsung thought the typical user would need to be able to record TV programs using the composite or S-video outputs, but they didn't think about deaf and hard of hearing people needing to record Line 21 caption data also. That tuner probably doesn't translate the ATSC 608 caption data to NTSC 608 caption data as the CECBs are required to do. (Possibly the FCC did not address this issue with tuners.)

Therefore a CECB could come in handy as a way to provide closed captioned recordings of digital television programming.

Quote:
The lack of caption data and/or caption graphics on the composite and S-Video interfaces means that recording to a DVD or VCR would not produce open or closed captions. No captions at all!

It's a shame that the ability to decode captions was removed from the S-video and composite cables; it would have been easy to leave that feature in.

Quote:
If the box were connected to a DVD recorder with the component or HDMI interfaces, then open captions could be recorded. The result would be a DVD with captions that are always there and the caption settings can not be changed. This would be the same if you were using a cable or dish STB connected to a “tuner-less” DVD recorder with component or HDMI cables. I do not yet have a DVD recorder with component or HDMI inputs, so I can’t test this paragraph, but it seems logical to predict what would happen.

I suppose the Blu-ray DVD recorders might need HDMI or component video.


Thanks for sharing this evaluation, Ron!
dmulvany is offline  
post #101 of 226 Old 03-22-2008, 02:43 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10

I've reported problems earlier about the Insignia CECB crashing five times while using digital closed captioning. Those crashes happened only on channels with problematic digital closed captioning. ("Problematic" closed captioning means that the station isn't providing full digital captioning on either my HDTV or the CECB or both.)

I picked up a Zenith DTT900 on March 10th. It crashed Friday night, 3/21/08 (or early am 3/22/08) for the first time. The Zenith crashed on a commercial broadcast by the local myNetworkTV affiliate, my20 (WDCA). So far, getting digital closed captioning from that particular station seems to have caused four out of six crashes on the two CECBs I've tried out.

The variables involved seem to be:

* Digital closed captioning activated
* Problematic closed captioning from the station
* Using a CECB
* Possibly a transition between pre-recorded captions for a program and a different kind of caption from a commercial (since commercials are visible during several of the crashes and in one case, there was a black screen.) Another possibility is that "paint on" captions used by some commercials might clash somehow. (I'm not expert in this kind of issue, however, and would welcome other ideas.)


My Sharp HDTV does not crash like the CECBs do (with the computer code showing up on the screen), although it does freeze from time to time. (I don't know why the Sharp freezes, but one cause may be using the remote to change channels quickly. Other times it has frozen without me doing anything at all. The HDTV does not freeze often; the CECBs are crashing more often than it does. In both cases, I have to unplug the device to get it working again.)

The other stations in my area with problematic captions are WJLA (ABC), WTTG (FOX), and WETA (PBS). I think the other crashes of the Insignia CECB happened when the CECB was tuned to WJLA and WETA (with the black screen occurring on an SD channel from WETA).
dmulvany is offline  
post #102 of 226 Old 03-22-2008, 07:41 PM
Advanced Member
 
Konrad2's Avatar
 
Join Date: Apr 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 10
> Line 21 does not get encoded into the MPEG-2 video.
> Only lines with actual picture information get coded.
> The typical SD MPEG-2 encoder starts on line 23.

So what is the garbage in the top few scan lines
if it isn't the captions? Visible (and rather annoying)
when you letterbox 720p or 1080i channels, or on a display
that does not overscan. Not always present, it comes and
goes.
Konrad2 is offline  
post #103 of 226 Old 03-22-2008, 09:21 PM
AVS Special Member
 
dr1394's Avatar
 
Join Date: May 2002
Location: Mizar 5
Posts: 3,149
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 19
Quote:
Originally Posted by Konrad2 View Post

> Line 21 does not get encoded into the MPEG-2 video.
> Only lines with actual picture information get coded.
> The typical SD MPEG-2 encoder starts on line 23.

So what is the garbage in the top few scan lines
if it isn't the captions? Visible (and rather annoying)
when you letterbox 720p or 1080i channels, or on a display
that does not overscan. Not always present, it comes and
goes.

It's not caption data. The line 21 caption format only exists for 480i. Basically, it's a mistake. Some encoder or decoder along the transmission path is starting on the wrong line.

Correct starting line numbers:

480i = line 23
720p = line 26
1080i = line 21
1080p = line 42

Ron

HD MPEG-2 Test Patterns http://www.w6rz.net
dr1394 is offline  
post #104 of 226 Old 03-22-2008, 09:32 PM
AVS Club Gold
 
deeann's Avatar
 
Join Date: Mar 2002
Posts: 2,979
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Konrad2, are you using a flat panel display?
deeann is offline  
post #105 of 226 Old 03-22-2008, 10:01 PM
Advanced Member
 
Konrad2's Avatar
 
Join Date: Apr 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 10
dr1394> The line 21 caption format only exists for 480i.
dr1394> Basically, it's a mistake. Some encoder or decoder
dr1394> along the transmission path is starting on the wrong
dr1394> line.

A lot of material on 720p and 1080i is upscaled from SD.
So it is caption data that got shifted down by mistake?
It happens quite a bit, on multiple stations.

deeann> Konrad2, are you using a flat panel display?

No, a direct view CRT. I don't normally see the garbage
on 480i since it is hidden by overscan.
Konrad2 is offline  
post #106 of 226 Old 03-22-2008, 11:42 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I've added a photo of the crash to the initial posting about the crash of the Zenith CECB and also modified the posting.
dmulvany is offline  
post #107 of 226 Old 03-24-2008, 03:19 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
This afternoon, I had the HD broadcast of "Emma" from WETA (a local PBS affiliate) displaying on my HDTV along with the converted display from the Zenith CECB on my analog TV.

I'm hard of hearing and lipread, and became aware I could no longer use hearing and lipreading together to understand what was being said through the CECB. I doublechecked by watching and hearing the HDTV, and the audio and video were synchronized there.

The CECB, however, was delaying the audio significantly.

I turned off the CECB briefly, and that was successful in re-synchronizing the audio and video.

(The audio is set to mono, fwiw.)

Not being an audiovideo professional, I'm not sure what the CECB's inability to keep synchronizing the audio with the video means, but it sounds like a problem that would increase the longer the box was on, which would be particularly bad if one was using the box for recording purposes. Doesn't sound good in general.

(I had noticed a problem with synchronization with the Insignia when I had that box, but hadn't thought to turn off the CECB to see if that would correct and isolate the problem. This is a problem that probably won't show up for a few hours.)

Thoughts? The digital closed captioning was turned on at the same time. (The CECB's digital captions were also slightly out of step with the TV's analog captions.)
dmulvany is offline  
post #108 of 226 Old 03-24-2008, 04:32 PM
AVS Club Gold
 
deeann's Avatar
 
Join Date: Mar 2002
Posts: 2,979
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Konrad2, It doesn't sound like the same thing I get on my display when the V position is moved down (it looks like an end of image boundary, but might be a sync line, I used to know what it really was but don't remember right now).

Dana, one think I'm wondering about is how warm is the Zenith getting when the a/v slipping happens and are there any hot spots in certain areas besides around the top vents? I saw internal pictures from another thread and didn't see any heatsinks (at least ones that are apparent) and it looks to be a pretty small box.
deeann is offline  
post #109 of 226 Old 03-24-2008, 08:19 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by deeann View Post

Dana, one think I'm wondering about is how warm is the Zenith getting when the a/v slipping happens and are there any hot spots in certain areas besides around the top vents? I saw internal pictures from another thread and didn't see any heatsinks (at least ones that are apparent) and it looks to be a pretty small box.

The CECB hadn't been on a terribly long time, and has a lot of ventilation on top on the right hand side. It doesn't seem to feel very warm even when it's been on a long time, but I can only feel the outside of the box.

What would cause the problem to be fixed by turning the CECB off momentarily?
dmulvany is offline  
post #110 of 226 Old 03-24-2008, 08:53 PM
AVS Club Gold
 
deeann's Avatar
 
Join Date: Mar 2002
Posts: 2,979
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Yeah- in a lot of cases of looking for overheating you shouldn't need to pop it open, there would be a hot spot you should feel somewhere on the chassis (sometimes it's on the bottom if there are no vent holes there) or where the coax plugs in.

When you turn it back on it resets and queries all available streams, timecode and possibly guide data (unless it pre-fetches and saves guides to cache memory at certain intervals) if it's similar to other digital receivers. I should pick one of these up soon to try out myself.

Can you recreate the a/v sync slip after running it for a while with captions off?

Edit- and I wonder what happens if it slips and you change channels.
deeann is offline  
post #111 of 226 Old 03-24-2008, 11:43 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by deeann View Post

Yeah- in a lot of cases of looking for overheating you shouldn't need to pop it open, there would be a hot spot you should feel somewhere on the chassis (sometimes it's on the bottom if there are no vent holes there) or where the coax plugs in.

Can you recreate the a/v sync slip after running it for a while with captions off?

Edit- and I wonder what happens if it slips and you change channels.

Even when it's on a long time, I still don't feel any hot spots.

I can't understand TV without captions, and this problem took a long time to show up, so I'll continue to use digital captions to see if the sync problem shows up again---and will change the captions to see if that re-syncs it.

Hmmm...I had left it on WETA HD a long time before seeing the slip. Might be necessary to leave it on one channel a long time for the problem to show up.

Dana
dmulvany is offline  
post #112 of 226 Old 03-25-2008, 08:27 AM
tc1
Advanced Member
 
tc1's Avatar
 
Join Date: Mar 2006
Location: North of Goose Creek, SC
Posts: 559
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Processor not strong enough to keep up? Turn it off, or change channel, and cache memory is cleared and start over at 0?

HTPC With OTA only, HD with Surround is so AWESOME!
tc1 is offline  
post #113 of 226 Old 03-26-2008, 09:30 AM
Newbie
 
Ron V.'s Avatar
 
Join Date: Feb 2008
Location: Georgia
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Failure in lip-sync is a very serious problem. I watched an old movie - "Singing in the Rain" which is (partly) about the transition from silent movies to talkies, and the early attempts at lip-sync sometimes didn't work out. The movie industry finally got it right. It's no problem on analog TV since the audio is sent at the same time as the video and both are received and displayed instantly. With digital though, we have buffers and the box has to have some means of pointers to know where real time is in the buffers. It sounds like Dana's CECB lost it's pointers. Maybe it is one defective box or a design bug that will impact lots of them.
Ron V. is offline  
post #114 of 226 Old 03-26-2008, 09:48 AM
Newbie
 
Ron V.'s Avatar
 
Join Date: Feb 2008
Location: Georgia
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
In my evaluation of the Samsung DTB-H260F, I wrote that I did not have a DVD recorder with component (or HDMI) inputs. My thought was that I could record "open captions" by connecting the tuner to a DVD recorder. I checked a few stores and I did not see *any* DVD recorder with component input! They have component output, but not in. I assume their thinking is an ordinary DVD recorder can only record standard definition, so why have component in? Well, if HDTV tuners only have captions on component out, like mine does, then that is a good reason to have component in on recorders. Maybe a Blu-Ray DVD recorder has component in. That would be over-kill just to get captions!
Ron V. is offline  
post #115 of 226 Old 03-26-2008, 10:11 AM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Ron V. View Post

Failure in lip-sync is a very serious problem. I watched an old movie - "Singing in the Rain" which is (partly) about the transition from silent movies to talkies, and the early attempts at lip-sync sometimes didn't work out. The movie industry finally got it right. It's no problem on analog TV since the audio is sent at the same time as the video and both are received and displayed instantly. With digital though, we have buffers and the box has to have some means of pointers to know where real time is in the buffers. It sounds like Dana's CECB lost its pointers. Maybe it is one defective box or a design bug that will impact lots of them.

I had noticed a slip with the audio/video on the Insignia CECB earlier but hadn't thought to check it against the HDTV at the time, and had thought the sync problem might have originated from the transmitting station.

I wonder if the digital closed captions are somehow overloading the available cache memory/buffers and causing the crashes I saw with the Insignia and Zenith (no one has reported a problem with crashes if they're not using digital closed captions). There might also be a related problem with time code information not getting through, which contributes to the synchronization problem.

I think this is probably a problem with all the LG chips used in the Insignia and Zenith boxes.

I don't know how serious this is, though. Do crashes and sync slippage problems take a toll on the CECB, and will they wear out faster because of the crashes? I imagine if they were left on in a frozen position due to a crash, they wouldn't turn off, and that might be bad for the CECB. Could they be a fire hazard if they heat up because of being stuck in a crash? (Consider that we'll want to leave them on for a long time if we want to record something from the CECB.)
dmulvany is offline  
post #116 of 226 Old 03-29-2008, 11:12 AM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
As a result of setting up my TiVo to watch the output from any CECB that I'm evaluating, I was able to look back at what led up to the second crash the Zenith CECB had early this morning.

It turns out that the Zenith crashed in response to a commercial featuring "Children's Benadryl Perfect Measure," which appears to be like the same one that caused the first crash of the Zenith CECB. The actors were clearly the same, but there might have been a shorter version of this commercial as I couldn't find an exact duplicate of the first picture in the commercial.

Here's the first crash of the Zenith:



Here's a photo from the commercial this morning that led to the second crash that shows the same actors from the first crash:



Here's the second crash of the Zenith:



(The actress with short black hair on the right side in the first crash is the same one on the left side in the second crash.)

Moreover, as I look at the pictures of the other crashes for the Insignia, two featured commercials that seem to be related to medicine or medically-based cosmetics of some kind, so I'm wondering if the same outfit is producing and captioning the commercials that were on at the time of the crashes.

I've taken pictures of 5 out of the 7 crashes; 3 of the 5 crashes experienced by the Insignia CECB and 2 of the 2 by the Zenith. (One crash from the Insignia happened on an SD channel from WETA, a PBS affiliate, and the picture was black.) In all cases, the digital captioning had been activated.

I've uploaded pictures of the crashes at:

http://picasaweb.google.com/dana.mulvany/CECBCrashes

You can see larger versions of the pictures above at that URL.

My hypothesis is that there's something about the 708 captioning from some commercials that is overloading the components within the CECB that handles the digital captioning. So far, no other user of the Zenith or Insignia CECB on the AVS Forum appears to be using digital closed captioning all the time, so they're not experiencing these crashes.

This could be a problem for other CECBs that have digital closed captioning. If more people would try out different CECBs with digital closed captioning for a long time, we'd have a better idea whether this is a problem for all CECBs.

(Most of the crashes have happened on the local myNetworkTV affiliate channel, so that might be a good channel to check out.)
dmulvany is offline  
post #117 of 226 Old 03-29-2008, 11:53 AM
Advanced Member
 
Malouff's Avatar
 
Join Date: Mar 2008
Posts: 819
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
dmulvany,

Thank you for grouping together all of your crash pictures.

Either there is a general error message or a problem with the cc Parse
I suspect that their is a invalid or unprintable ASCII code.

Did you contact your Station with the problem?
If you did then the 45 days is coming close and you should file a FCC Complaint.
http://www.fcc.gov/cgb/dro/tips_on_f...complaint.html
Malouff is offline  
post #118 of 226 Old 03-29-2008, 01:26 PM - Thread Starter
Senior Member
 
dmulvany's Avatar
 
Join Date: Dec 2003
Location: Rockville, Maryland and Sausalito, CA
Posts: 419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Malouff View Post

dmulvany,

Thank you for grouping together all of your crash pictures.

Either there is a general error message or a problem with the cc Parse
I suspect that their is a invalid or unprintable ASCII code.

Did you contact your Station with the problem?
If you did then the 45 days is coming close and you should file a FCC Complaint.
http://www.fcc.gov/cgb/dro/tips_on_f...complaint.html

I've emailed several stations about the captioning problems, though not about the crashes since that seemed like a hardware problem with the CECB. Have only heard back from WTTG/WDCA, and that engineering department thinks they're transmitting the captions fine and seems to be thinking there's something wrong with my fairly new HDTV (even though other HD equipment also has similar problems not getting digital captioning from those channels, and even though I can get captions fine from digital channels of other stations).

I'm a bit concerned that some stations and cable companies are rather quick to ascribe problems to causes other than their own equipment (I've heard of many consumers getting this kind of response). I do plan to write formal complaints documenting numerous problems. My understanding is that it's especially important to document problems before the end of this quarter, and then I'll have some time to write up the letters to each station. I would have to follow up with a complaint to the FCC within 30 days after getting a formal response from the station if I'm not satisfied with that response (or 45 days after I send in my letter if I never get a formal response). If I waited to document problems until April 1st, however, the station would technically have until July 15th to respond.

Anyone know if we can find out how the FCC has responded to previous complaints about digital closed captioning?

Dana
dmulvany is offline  
post #119 of 226 Old 03-29-2008, 01:43 PM
Advanced Member
 
Avio's Avatar
 
Join Date: Mar 2007
Location: ABQ: NM
Posts: 826
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by dmulvany View Post

... Anyone know if we can find out how the FCC has responded to previous complaints about digital closed captioning? ...

You could try contacting the FCC Consumer Center and asking:

FCC Consumer Center

www.fcc.gov/cgb
E-mail: fccinfo@fcc.gov

Contact Us Toll Free
Federal Communications Commission
Consumer & Governmental
Affairs Bureau
445 12th Street, SW
Washington, D.C. 20554

1-888-CALL-FCC (1-888-225-5322)

TTY: 1-888-Tell-FCC (1-888-835-5322)

Fax: 1-866-418-0232

Avio
Avio is offline  
post #120 of 226 Old 03-29-2008, 01:49 PM
Member
 
dingo99's Avatar
 
Join Date: Oct 2001
Posts: 65
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 13
Review of the Channel Master CM-7000 captioning capabilities:

1. The availability of digital closed captioning features:

Yes. The CM offers the following features for customizing digital captions:
Size, Font, Text Color, Text Opacity, Background Color, Background Opacity, Edge. Seven fonts and eight colors are available.

2. The availability of a CC button on the remote control:

Yes (marked as Subtitle)

3. The usability of the menu activated by the CC button:

The first push of the button shows the current setting at the bottom of the screen. Each push steps through Digital-1 through Digital-6, then through CC1, CC2, Off. It thus takes nine pushes of the Subtitle button to go from Digital-1 to the OFF position, and there is no way to go back one step if you've gone too far.

4. The ease of reading the font provided for analog captions decoded through the converter box:

Poor. The box uses its default font and size, which is very narrow. A full line of text spans less than half the width of the screen. You are better off using the TV's analog captions, if available.

5. The ease of reading the seven different fonts available for digital captions:

Style options are Default, Font-1,2,3,4, Casual, Cursive, Caps
Font-1,2,Caps are serif fonts
Font-3,4,Casual are sans-serif fonts
Cursive is a script font - difficult to read

6. The availability of a "caption preview" when changes are made in the settings for the digital captions:

Yes, and it is a fairly good indication of the actual caption size.

7. How large the digital captions are actually capable of becoming (useful for low-vision viewers):

Not large enough. Size options are Default, Small, Standard, Large
The size option changes only the text width. All three sizes are too narrow. Even at the Large setting, a full line of text spans only about half the width of the screen.

8. How well the optional translucent background provides a contrast to the characters used in the captioning:

Default contrast is inadequate. Edge effects can be added to improve visibility. For me, the most usable combination is Font-4, Large, Raised or Uniform Edge.

9. Whether there are any bugs associated with captioning, such as a failure to detect analog captions if there are no digital captions, jerky movements, cut-off captions, unexpected changes in the background, etc.:

The CM does not switch to analog captions automatically when there are no digital captions. You must manually switch the CM-7000 to CC1 for analog captions, or turn on TV's captions in order to see the analog captions.

The CM sometimes exhibits an issue with displaying certain digital caption programming (the kind that pops up rather than types out word-by-word). Some captions that would normally be aligned along the bottom of the screen appear near the middle of the screen, yet captions aligned to the top of the screen display properly. The alignment problems are not present for analog captions decoded by the CM.

10. Whether the remote control has an SAP button, a raised dot on the 5 button, and dots on the Power button (useful for low vision or blind users):

The control has an SAP button (labeled Audio), and the power button is red. There are no raised dots on the remote.

11. How well the user manual explains the different digital closed caption settings.

The manual does little more than show a picture of the OSD menu.

12. Whether the CECB has crashed and what the circumstances were.

None yet.

Overall opinion:

In general, the captions are simply too small - the CM's digital captions (large size and widest font options) are about 2/3 height and 1/2 width of my TV's built-in analog captions.

The CM-7000 is one of the few CECB's with S-Video output. Compared to composite video, the benefit of S-video is the absence of dot-crawl artifacts. Captions via composite video may have a shimmering or flickering effect, most pronounced when using caption colors other than white. These artifacts are not present when using S-video. However, this added clarity may not make up for the CM-7000's very small caption text size.

The attached photo shows both the CM-7000 digital captions (large size, Font-4, using S-Video) and my TV's built-in analog captions. The CM-7000's digital captions (top) are quite small, but S-video helps make them clear and reasonably usable if you have good vision and/or a large-screen TV. Unfortunately, the CM-7000 has no larger fonts, so these captions can be challenging to read from across a room. My TV's built-in analog captions (bottom) take up a lot of screen space but are very easy to read from a distance.
LL
dingo99 is offline  
Reply Coupon Eligible Converter Box (CECB)

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off