H.264 woes

DOS4EVER

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#41

Post by DOS4EVER » Sun May 21, 2017 9:37 pm

Just connected my media pc after a few months of being offline and I can report that mine mostly works also. I rarely notice any pixel blocking and when I do it's on premium channels and only when there are black bars on the top and bottom of the screen. Otherwise it works great and a big plus is no more 29/59 bug! My htpc specs are in my profile. I do have an Nvidia chipset.

JonDeutsch

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#42

Post by JonDeutsch » Tue May 23, 2017 1:21 am

I am VERY confused about my H.264 issues:

Comcast recently shifted over for me and, like others, once I got stuck on a black screen/audio feed, other, regular channels would also come up black. It's like the H.264 codec gets stuck on.

So, I added an NVidia 730 card, which cleared up the HBO issue nicely on the HTPC. However, Linksys extender still gave me "can't playback video" errors on the same content.

So.... I replaced my Linksys DMA2100 with an XBox360, which improved things a bit on the extender front.

But... it seems like every few days, other, non-H.264 stations like MSNBC start recording black screens w/audio just like HBO used to record back before I got the new Nvidia video card! When I reboot, MSNBC comes back fine. Oddly, when MSNBC is black screened/audio, HBO is still OK to playback/record at the same time.

What the heck is going on with a non-premium station acting like a premium copy-once station??

Thx.
Jon

Space

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#43

Post by Space » Tue May 23, 2017 1:48 am

The problem is that WMC seems to have a problem recording an MPEG2 channel after recording from an h.264 channel, sometimes. I don't think it has anything to do with copy-once or the graphics card you are using. It appears that WMC gets confused and puts the wrong information in the recorded video file so that when you play if back, it does not know how to handle the contents properly. In some cases people have been able to run the video file through a format converter and it played back fine, in other cases it played back, but was still a bit messed up.

I personally think the video itself is fine, but WMC is writing some info to the file that makes WMC interpret the video incorrectly on playback. But this is just supposition until someone with more knowledge on the subject can investigate the "bad" videos.

See the discussion here:
http://www.thegreenbutton.tv/forums/vie ... 8&p=115906

JonDeutsch

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#44

Post by JonDeutsch » Tue May 23, 2017 9:53 pm

Well that's a pretty depressing situation. Looks like a death-of-a-thousand-cuts kind of situation with WMC. After being so reliable for so long, now suddenly it's almost untenable. Will check out the discussion you linked to, thanks.

DOS4EVER

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#45

Post by DOS4EVER » Tue May 30, 2017 7:12 pm

On top of switching compressions to h.264 Comcast also down graded 1080i sources to 720p and I've noticed a considerably grainier look on those channels. Anybody else notice or is it just me?

webminster

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#46

Post by webminster » Tue May 30, 2017 10:40 pm

Everybody has noticed it. There's uncountable numbers of complaints on forums (dlsreports, avsforum, Tivo Community, TGB, and Xfinity's customer forums) about the graininess, soft picture, dithering, macroblocking, etc.

If you complain to Comcast, they'll send you marketing boilerplate about this "Enhanced HD" transition, glowing about the "p" part of the 720p migration, and stressing that they've done extensive engineering studies and customer focus group testing to validate that your picture is actually better - or at least certainly no worse - than before. If it is, it must be your fault.

Under no circumstances will they entertain a suggestion that the pixel density reduction, plus the extra compression (reduced bitrate) they've added to now pack even more channels into each QAM channel, could be problematic for more "discerning" viewers.
-Alan

DOS4EVER

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#47

Post by DOS4EVER » Wed May 31, 2017 4:49 am

Well that just sucks.

sgbroimp

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#48

Post by sgbroimp » Wed May 31, 2017 4:14 pm

Perhaps a long shot for some of you, but you might want to try a signal refresh from Comcast. Takes only a few seconds and helpe me get my non-HD Premiums back up after they were producing sound only, no picture. Won't help the PQ/720 issue of course. ( I am HTPC/Ceton/Core i3/Intel HD2000.)

Ken H

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#49

Post by Ken H » Sun Jun 11, 2017 11:59 pm

Refresh all you want, it will not solve the problem. Neither will changing graphics cards. There is an incompatibility between the new Comcast H.264 signal and WMC.

Not to even mention the loss of picture quality.....

sgbroimp

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#50

Post by sgbroimp » Mon Jun 12, 2017 2:13 pm

You are right on MPEG4 Premiums of course, but it did fix my no video/sound only on my MPEG2 Premiums recently. Do you have issues on MPEG4 Premiums on Comcast even with a decent video card?

Ken H

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#51

Post by Ken H » Mon Jun 12, 2017 6:24 pm

Yes, I have two Windows 7 PC's, both with AMD Phenom II X4 CPU's and 8GB RAM, and with 'decent' graphics cards; one has an AMD R7 240 graphics card and the other has an nVidia GT 730. One PC is fully updated with Windows and all drivers, the other is a dedicated WMC unit and is no longer being updated because up until now it was rock solid.

I posted this dilemma in the DSL Reports Official Comcast forum, where Comcast representatives address issues directly. Here is their reply:

Do you know if these devices are Mpeg 4 compliant? As we change the way our content is distributed, we are seeing an increase in similar issues where hardware is not mpeg 4 compliant. I had a few cases last week with older Tru 2-Way tvs that had this issue where the TVs themselves that house the cable cards were not mpeg 4 compliant and needed to be updated. I will do some research on my end regarding the devices you're using, but maybe you already know if this is the case? A quick google search shows quite a few people with some of the same components you are using having the same type of issue. I'll report back as I get more data on this and do some more digging.


I don't know if 'these devices' are MPEG4 compliant or not, but I'm guessing not. My best guess at this point is that it would take Microsoft to update WMC and that is probably not happening, or another guess is it's an old hardware issue, or who knows?

I'm not differentiating between premium or non-premium channels for the purpose of this discussion. I sometimes have the problem with them, and other times premium channels work fine; as noted by others it may be the channel you are on before you change to a premium channel or when you change from a premium channel to a non-premium channel.
Last edited by Ken H on Mon Jun 12, 2017 6:35 pm, edited 1 time in total.

sgbroimp

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#52

Post by sgbroimp » Mon Jun 12, 2017 6:34 pm

Well that certainly smells funny. Many others, say those using the Intel integrated Graphics (non-Comcast folks, mostly if not solely) report that a decent, (not always even an expensive) video card fixed the issue for them, so it sounds like Comcast is out of spec somewhere. Not shocking given the history......

Last time I had to call them (recently for that signal refresh), the guy at least asked what type I had and I said "like a Tivo but PC tuner type", he asked if it was a Ceton or Home Run etc. so some progress has been made.

But, hey they gotta fix this and soon.

Ken H

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#53

Post by Ken H » Mon Jun 12, 2017 6:36 pm

sgbroimp wrote:Well that certainly smells funny. Many others, say those using the Intel integrated Graphics (non-Comcast folks, mostly if not solely) report that a decent, (not always even an expensive) video card fixed the issue for them, so it sounds like Comcast is out of spec somewhere. Not shocking given the history......

Last time I had to call them (recently for that signal refresh), the guy at least asked what type I had and I said "like a Tivo but PC tuner type", he asked if it was a Ceton or Home Run etc. so some progress has been made.

But, hey they gotta fix this and soon.
When you say they, I assume you mean Comcast? If so, it may not be their problem if the hardware in question at our ends does not meet MPEG4 standards.

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#54

Post by Ken H » Mon Jun 12, 2017 6:54 pm

So now I'm wondering if anyone here actually knows what it takes in terms of hardware and software to be MPEG4 compliant? Is their a DYI test we could use? (Besides what we already know about losing video).

And I'm also wondering if anyone here knows how to look at Comcast's MPEG4 signal and determine if it's compliant?

sgbroimp

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#55

Post by sgbroimp » Mon Jun 12, 2017 8:06 pm

When you say they, I assume you mean Comcast? If so, it may not be their problem if the hardware in question at our ends does not meet MPEG4 standards.

Yes, Comcast is what I have. What makes me wonder about them is that others on various forums have stated their equipment works on Cox (MPEG4 Copy once) and some other non-Comcast carriers. Some I think with straight Intel Grahics with no additional video card, but a number of others using a simple card. I was, in fact, going to get a card, but being on Comcast and reading your posts and those of others, I am not going to do so as it sounds like a 50/50 deal at best as to whether I will get the Copy Once Premiums in MPEG4. (By the way it is only those, ESPN using MPEG4 comes in fine.) Net is not MPEG4 alone but the MPEG4 with Copy Once encoding (Premiums) seems to be the stumbling block.

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#56

Post by Ken H » Mon Jun 12, 2017 9:27 pm

sgbroimp wrote:
Yes, Comcast is what I have. What makes me wonder about them is that others on various forums have stated their equipment works on Cox (MPEG4 Copy once) and some other non-Comcast carriers. Some I think with straight Intel Grahics with no additional video card, but a number of others using a simple card. I was, in fact, going to get a card, but being on Comcast and reading your posts and those of others, I am not going to do so as it sounds like a 50/50 deal at best as to whether I will get the Copy Once Premiums in MPEG4. (By the way it is only those, ESPN using MPEG4 comes in fine.) Net is not MPEG4 alone but the MPEG4 with Copy Once encoding (Premiums) seems to be the stumbling block.
It would be huge to confirm that other cable providers are using MPEG4 and those like us with Windows and CableCards are having no, or solvable by hardware upgrades, problems. That way we could go back to Comcast and put the ball in their court.

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#57

Post by stuartm » Mon Jun 12, 2017 10:16 pm

I am on Comcast and they have switched my HD to MPEG4, I have only a couple of copy-protected channels in my subscription. They work fine except if the GPU is Intel GPU. I long ago added lower end Nvidia cards to my HTPC's to make sure I could play copy-protected MPEG4. I know of no verified case where a WMC user with Intel GPU can view MPEG4 copy-protected content with WMC. Since other graphics cards work with copy protected h.264 this is a problem in the Intel drivers/hardware. I see no evidence that Comcast is putting out "bad" h.264 streams. There is an additional WMC bug where switching a tuner to a some MPEG2 channels from an MPEG4 channel causes WMC to not properly detect the stream has changed from h264 to MPEG2. On my system these are the lower resolution Encore channels. I can easily verify this on my HTPC using 411-Info. This makes the MPEG2 channel play only audio but fail to play video. Again, no indication that Comcast has done anything wrong in its h.264 stream. (Except the crappy quality and reduced resolution :( ). This doesn't impact me too much since I rarely watch the non-HD channels. The only fix I think Comcast could provide would be to switch to all MPEG4 then the confusion that hits WMC on stream format change would not happen. Since the problems all seem to be in WMC I don't think any change in video card (except to cure the Intel problem) will fix anything. nor will any hits from Comcast to the cable card change anything.

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#58

Post by DaveInPa » Tue Jun 13, 2017 12:49 pm

I have Comcast cable. I watch a mixture of HD and SD channels. I'm using a computer I built in 2013 with AMD A6-5400 CPU with Radeon HD7540 integrated graphics.

Comcast made the switch to h.264 a few months back.

The only issue I have with the Mpeg4 / H.264 is when I rewind/fast forward/skip back/skip ahead. Sometimes it hangs (when I push a lot of buttons fast).

I have no issues changing channels between SD/HD/H.264/Mpeg2. I have 2 couple premium channels. All channels play fine, both audio and video.

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#59

Post by sgbroimp » Tue Jun 13, 2017 2:28 pm

I agree with you, Ken. We need some folks, preferably using WMC/ Intel's GPU Graphics, on Non-Comcast Cable networks to weigh in and tell us they get MPEG4 copy protected channels just fine. If not, at least some who moved over to a new video card and solved their issues. At least a couple of Comcast folks have weighed in. A mystery why you are having issues with a decent video card. Only thing I can think of is for you to run your WINSAT, then the Digital Cable Advisor again, get Comcast refresh, reboot and then run the signal set up again. Will all that work? 50/50 at best perhaps, but won't cost you much to try.

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#60

Post by JonB65 » Wed Jul 05, 2017 2:32 am

Would installing a codec pack help with any of these issues? Would it allow the H.264 to be processed/understood? I haven't tried yet, but am tempted, because nothing else seems to work. I got the NVidia GT730 and still have the same issues with black screen but sound playing.

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