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post #1501 of 1519 Unread 09-26-2016, 04:04 PM
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Quote:
Originally Posted by jimv1983 View Post
Just curious, how do you know which channels are on H.264, when then were converted and when more will be converted? You said you are just north of where Ron is. Where is that? I noticed you are in Santa Rosa, CA. I'm about 50 miles south east of Santa Rosa.
I'm in Silicon Valley. Before I retired, I worked in video compression (including cable TV projects like the MPEG-2 encoder in the DCT-6412 P3). I was interested in the MPEG-2 to H.264 conversion, so I kept my MPEG-2 STB so that I could monitor the progress. With an MPEG-2 only STB, all you have to do is scan through the HD channels and see which ones fail to decode the video.

Last week, after the addition of 18 H.264 channels, I hooked up my replacement STB. Now I'll have to check the bitstream from the IEEE1394 port to tell what format the channel is using.

Also, if you have an MPEG-2 only STB on your account, you get an annoying pop-up quite a few times a day informing you to upgrade. So I'm going to return the MPEG-2 only STB pretty soon.

Ron

HD MPEG-2 Test Patterns http://www.w6rz.net
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post #1502 of 1519 Unread 09-26-2016, 04:39 PM
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Quote:
Originally Posted by jimv1983 View Post
Just curious, how do you know which channels are on H.264, when then were converted and when more will be converted? You said you are just north of where Ron is. Where is that? I noticed you are in Santa Rosa, CA. I'm about 50 miles south east of Santa Rosa.
I don't have any Comcast equipment but I do have a couple of TiVos and a Silicon Dust HDHomeRun CableCARD network tuner. With the SD device I can use a browser to access the tuner and can list all the channels being received and on that list any channel that has been converted will have "AVC" noted next to it. See the below image.

With the Tivo you can check in the DVR Diagnostic page(I think, not near the device right now) and it will show the video PID for the channel and whether it is MPEG2 or H.264(AVC).
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post #1503 of 1519 Unread 09-26-2016, 05:27 PM
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Originally Posted by BiggAW View Post
I don't know what to tell you. You've backed yourself into a logical corner with what you're telling us. I also don't believe any TV will have a crystal clear picture on Comcast, but some channels vary system to system and region to region.
And I don't know what to tell you. I know the steps I've taken and I know the results I've gotten. Not sure what else to say about it.

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Yeah, DirecTV costs a lot more, mostly due to Comcast's anti-competitive and illegal bundling practices that they use to force their technically inferior service down people's throats.
Yeah, it's pretty ridiculous and there isn't anything I can do about that. I'm just going to keep pushing Comcast. At some point one of the techs is supposed to come out with ANOTHER TV. It's one of the techs that has already seen and verified the issue but not the one that previously brought the test TV. He also wants to try swapping the box again but since that has already been done I'm not too optimistic about it.

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Originally Posted by dr1394 View Post
I'm in Silicon Valley. Before I retired, I worked in video compression (including cable TV projects like the MPEG-2 encoder in the DCT-6412 P3). I was interested in the MPEG-2 to H.264 conversion, so I kept my MPEG-2 STB so that I could monitor the progress. With an MPEG-2 only STB, all you have to do is scan through the HD channels and see which ones fail to decode the video.

Last week, after the addition of 18 H.264 channels, I hooked up my replacement STB. Now I'll have to check the bitstream from the IEEE1394 port to tell what format the channel is using.

Also, if you have an MPEG-2 only STB on your account, you get an annoying pop-up quite a few times a day informing you to upgrade. So I'm going to return the MPEG-2 only STB pretty soon.

Ron
That's nice. I wish I could get my hands on a MPEG-2 box to try the same thing.
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post #1504 of 1519 Unread Yesterday, 02:19 AM
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Originally Posted by BiggAW View Post
I don't know what to tell you. You've backed yourself into a logical corner with what you're telling us. I also don't believe any TV will have a crystal clear picture on Comcast, but some channels vary system to system and region to region.
So I figured out how to actually take a screenshot from my TV. The attachment titled "Comcast" is a capture of what I get from the X1 box. The attachment titled "Streaming" is what I get from the FOX NOW app. Obviously it isn't the TV itself since the issue shows on the screenshots as well. It was late when I figured out how to do this so it's not from the exact same scene of the show but the same episode. The captures are from the show Gotham on FOX.

The pizza place TVs had a picture pretty close to the "Streaming" capture and MUCH better than the "Comcast" capture.
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post #1505 of 1519 Unread Yesterday, 08:07 AM - Thread Starter
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Quote:
Originally Posted by dr1394 View Post
I'm in Silicon Valley. Before I retired, I worked in video compression (including cable TV projects like the MPEG-2 encoder in the DCT-6412 P3). I was interested in the MPEG-2 to H.264 conversion, so I kept my MPEG-2 STB so that I could monitor the progress. With an MPEG-2 only STB, all you have to do is scan through the HD channels and see which ones fail to decode the video.

Last week, after the addition of 18 H.264 channels, I hooked up my replacement STB. Now I'll have to check the bitstream from the IEEE1394 port to tell what format the channel is using.

Also, if you have an MPEG-2 only STB on your account, you get an annoying pop-up quite a few times a day informing you to upgrade. So I'm going to return the MPEG-2 only STB pretty soon.

Ron

An easy way to check which channels are MPEG-4 is with an HD-DTA. If you go into the diagnostic menu by holding down the the "0" numeric key and go to the virtual channel map all the MPEG-4 channels are labeled.
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post #1506 of 1519 Unread Yesterday, 10:28 AM
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Do any of you regularly use the Comcast DVR Manager to program multiple devices? I have effectively used it and now find all has been 'upgraded' to Xfinity and find that once I spend minutes in delayed screens what is presented is worthless. Numerous interactions with customer service has resulted in nothing more than frustration.

Any experience or advice on fixes, alternatives, or course of action?
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post #1507 of 1519 Unread Yesterday, 01:39 PM
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Quote:
Originally Posted by jimv1983 View Post
So I figured out how to actually take a screenshot from my TV. The attachment titled "Comcast" is a capture of what I get from the X1 box. The attachment titled "Streaming" is what I get from the FOX NOW app. Obviously it isn't the TV itself since the issue shows on the screenshots as well. It was late when I figured out how to do this so it's not from the exact same scene of the show but the same episode. The captures are from the show Gotham on FOX.

The pizza place TVs had a picture pretty close to the "Streaming" capture and MUCH better than the "Comcast" capture.
Not sure what you're looking at. I just see normal MPEG-2 artifacts from heavy compression. The TV is still a factor, as it's still decoding and processing the signal before the screenshot is taken.
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post #1508 of 1519 Unread Yesterday, 02:38 PM
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Those low light scenes are going to give the best of displays a workout.
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post #1509 of 1519 Unread Yesterday, 03:01 PM
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Originally Posted by BiggAW View Post
Not sure what you're looking at. I just see normal MPEG-2 artifacts from heavy compression. The TV is still a factor, as it's still decoding and processing the signal before the screenshot is taken.
Not sure what I'm looking at? Seriously? I've never seen compression artifacts look like that. It's usually more pixelation than blurry and dull looking. Sorry but that isn't normal. It's not normal from what I used to get from Comcast(really not that long ago) and it is certainly worse than what the pizza place is getting. Three TVs in my home have shown the same issue as you see in the "Comcast" attachment my main TV (LG OLED), a Samsung 32" (somewhat cheap but not terrible) and the 24" cheap no name brand TV brought by the Comcast tech. So how could that be my TV when all TVs show the same issue? That doesn't make any sense.

And like we talked about before, the local channels and nation wide channels are compressed differently before the signal leaves the head end. Like I said, the Comcast network engineer told me if the issue is on both local and national channels it's very unlikely to be a compression issue.

Plus, didn't you say at one point that I should be getting MPEG-4 anyways? My memory could be wrong on that part.

In a lot of ways you certainly seem to know what you are talking about but some of what you are saying just doesn't add up to explain what I'm seeing with my own eyes. I'm trying to believe you. I really am. Like I said, you seem like a knowledgeable guy. I don't want this to turn into a battle. I'm just pissed off about my problem and your explanations are conflicting with the results I'm getting.

I just want a decent picture like I used to have(and like the pizza place has) and I don't think it's reasonable to have to pay an extra $60 to get the same as I am now.

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Those low light scenes are going to give the best of displays a workout.
Maybe true but I get similar results even from brighter pictures. It was getting late last night so I just did the one comparison.

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post #1510 of 1519 Unread Yesterday, 03:06 PM
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Originally Posted by jimv1983 View Post
Not sure what I'm looking at? Seriously? I've never seen compression artifacts look like that. It's usually more pixelation than blurry and dull looking. Sorry but that isn't normal. It's not normal from what I used to get from Comcast(really not that long ago) and it is certainly worse than what the pizza place is getting. Three TVs in my home have shown the same issue as you see in the "Comcast" attachment my main TV (LG OLED), a Samsung 32" (somewhat cheap but not terrible) and the 24" cheap no name brand TV brought by the Comcast tech. So how could that be my TV when all TVs show the same issue? That doesn't make any sense.

And like we talked about before, the local channels and nation wide channels are compressed differently before the signal leaves the head end. Like I said, the Comcast network engineer told me if the issue is on both local and national channels it's very unlikely to be a compression issue.

Plus, didn't you say at one point that I should be getting MPEG-4 anyways? My memory could be wrong on that part.

In a lot of ways you certainly seem to know what you are talking about but some of what you are saying just doesn't add up to explain what I'm seeing with my own eyes. I'm trying to believe you. I really am. Like I said, you seem like a knowledgeable guy. I don't want this to turn into a battle. I'm just pissed off about my problem and your explanations are conflicting with the results I'm getting.

I just want a decent picture like I used to have(and like the pizza place has)



Maybe true but I get similar results even from brighter pictures. It was getting late last night so I just did the one comparison.
Can you upload a short clip of where you're seeing the problem? It's impossible to see anything definite with cell phone images.

Can you be specific on exactly what areas in those images are bad?
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post #1511 of 1519 Unread Yesterday, 03:22 PM
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Can you upload a short clip of where you're seeing the problem? It's impossible to see anything definite with cell phone images.

Can you be specific on exactly what areas in those images are bad?
The last pictures I uploaded were not taken with a cellphone. They weren't taken with any camera at all. My TV has a feature that allows me to take a screenshot of whatever is on the screen. Notice the "LG" logo in the lower right corner. The feature doesn't allow me to take a video and like you said the cell phone camera doesn't really show the issue.


If you look at the images I attached the quality issue is very obvious. The attachment named "Comcast" clearly shows blurriness and a dull picture. Especially in the face. The other image(named "Streaming") is obviously much better.

I'm on a break at work right now so I can't do anything but when I get home I'll do some screen captures of some other content.
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post #1512 of 1519 Unread Yesterday, 06:39 PM
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Here's a bit-rate graph of my first HD H.264 capture from Comcast. It's animation content, so it's pretty easy to encode. I'll have some movie content soon.



Ron

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post #1513 of 1519 Unread Yesterday, 07:43 PM
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While I was dissecting that bit-stream, I found some textual user data. This was at a local ad insertion splice point. The bit-stream is a little different, so I don't think that the network portion of the bit-stream is from an Elemental encoder.



Ron

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Average bit-rate is around 3 Mbps.



Ron

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Thanks for those images Ron.
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Average bit-rate is around 3 Mbps.

Ron
In your personal opinion how was the picture quality? At an average bit-rate of 3Mbps were you pleased with what you saw?
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post #1517 of 1519 Unread Today, 01:47 PM
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This site may be of interest. It maps a lot of European SD and HD digital TV OTA and cable muxes and satellite transponders :

http://en.digitalbitrate.com/dtv.php...ng=en&mux=BBCB

This should show you the UK main national HDTV multiplex. This is a 40.25Mbs DVB-T2 mux (in an 8MHz RF channel) that carries :

BBC One HD 1080i
BBC Two HD 1080i
ITV HD 1080i
C4 HD 1080i
C5 HD 1080i
CBBC HD 1080i (This is a part-time kids channel that now runs a very compressible graphics loop 2100-0700 which will help statmuxing)
Film Four+1 576i (It's incorrectly reported as 1080i in the grid)

As you can see - most HD 1080i channels peak at 17Mbs, but average around 4.8Mbs. (The joy of statmux!)

Also - ignore the 'scantype' report on this mux. UK OTA HD encoding flips dynamically between 1080p25 and 1080i25 at the encoder level based on whether the source content is detected as interlaced or progressive.

BBC One/BBC Two/ITV/C4/C5 are the 5 main terrestrial networks. They share a single mux in HD. (Kind of like ABC, CBS, NBC, Fox and PBS all in 1080i in a single channel in the US - though we have 8MHz not 6MHz channels, and are heavily networked with no real affiliates)
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post #1518 of 1519 Unread Today, 05:32 PM
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Quote:
Originally Posted by jimv1983 View Post
In your personal opinion how was the picture quality? At an average bit-rate of 3Mbps were you pleased with what you saw?
I thought it looked pretty good. I don't have a large TV that shows every fault, but I did watch it on my computer monitor from about 24 inches away. However, at these low bit-rates there's not a lot of leeway for difficult to encode scenes. If you single step frame by frame, you can always find some hideousness.

























Ron

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post #1519 of 1519 Unread Today, 07:06 PM
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Not sure what I'm looking at? Seriously? I've never seen compression artifacts look like that. It's usually more pixelation than blurry and dull looking. Sorry but that isn't normal.
It is the new normal on Comcast. I've seen much worse.
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