Author Topic: Quality of TV tuners?  (Read 2764 times)

Monkgs

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Quality of TV tuners?
« on: August 26, 2008, 10:29:23 pm »
I remember way way way back in the day playing with an All in Wonder as a TV tuner. Unfortunately the quality of said device was brutal and was quickly placed on the shelf. Have TV tuners made much improvement lately? Should I go buy the PVR150 expecting decent results? My source will be the analogue output of my digital cable box. On my 50" LCD the standard def source looks pretty good, will this change (much) through the TV tuner?

jondecker76

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Re: Quality of TV tuners?
« Reply #1 on: August 27, 2008, 06:14:05 pm »
I have a PVR-500 Hauppauge card

In 0704 the quality for me was absolutely horrible. I remember asking myself why anyone in thier right mind would even use MythTV if this was the quality they would be watching it in - so I never used MythTV in 0704 (I'd never used MythTV before this)
. When I reinstalled with 0710, I figured that I would check the liveTV again. I'm not sure what changed (or if there was some other tuning I could have done under 0704) - but capturing via s-video now has beautiful picture quality. It would take a pretty good eye to spot the degradation from the original. Its so good, that I even record movies and Pay-Per-View movies for permanent inclusion into my media library.

grepico

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Re: Quality of TV tuners?
« Reply #2 on: August 28, 2008, 09:00:41 pm »
I have a PVR-500 Hauppauge card

In 0704 the quality for me was absolutely horrible. I remember asking myself why anyone in thier right mind would even use MythTV if this was the quality they would be watching it in - so I never used MythTV in 0704 (I'd never used MythTV before this)
. When I reinstalled with 0710, I figured that I would check the liveTV again. I'm not sure what changed (or if there was some other tuning I could have done under 0704) - but capturing via s-video now has beautiful picture quality. It would take a pretty good eye to spot the degradation from the original. Its so good, that I even record movies and Pay-Per-View movies for permanent inclusion into my media library.

How are you getting Pay-Per-View to record? 

I've tried with a Comcast box as well as a DirecTV box and in both cases I can only view ppv by switching to the box (not going through MythTV).  i.e. On my Comcast box on-demand is channel 1, when I tell MythTV to tune to Ch1 I get nothing.


skeptic

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Re: Quality of TV tuners?
« Reply #3 on: August 28, 2008, 09:14:45 pm »
The cable box s-video output shows whatever is on the cable box.  Use the s-video input on the PVR-150 and there you go, record whatever the cable box is tuned to.  Myth isn't going to "know" when to start/stop the recording, nor will it have the movie name/info, but once the video is captured you can edit, transcode, rename, etc. the video then use the web admin Amazon lookup to fill in the rest.  I haven't recorded ppv stuff, but I use s-video to capture all the non-basic cable TV stuff I record.

Without starting a technical debate, in my experiences the PVR-150 s-video capture quality is roughly the same as watching TV via direct STB s-video to TV.  In fact, I'd say it's a tad better than the PVR-150 TV-Tuner because the STB plays from a digital signal but the tuner is stuck with the analog cable source.  It's still SD, so it sucks compared to a true HD picture.


skatingn330

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Re: Quality of TV tuners?
« Reply #4 on: August 30, 2008, 05:44:14 am »
I'd go with the HDhomerun, it seems pretty legit.
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colinjones

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Re: Quality of TV tuners?
« Reply #5 on: August 30, 2008, 09:48:02 am »
With capturing analogue there's always the potential to screw the picture by it not syncing very well and other weird analogue effects. Can be v good can be unwatchable. If you have the option decode DVB/ATSC directly on the LMCE machine and the picture will always be great (as good as the original, anyway). Just needs to be unencrypted or your provider allow you to decrypt on your own hardware.

JRoque

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Re: Quality of TV tuners?
« Reply #6 on: August 31, 2008, 07:21:22 am »
Hi. Note that, while the HDHomeRun is an excellent tuner, it only receives digital signals; no analog.

JR

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Re: Quality of TV tuners?
« Reply #7 on: September 04, 2008, 01:52:43 pm »
I have the Hauppauge Nova-T-500, and generally, I have to say that it is very good. However, I have noticed some slight blurring, namely when credits are scrolling across the screen at the end of a program, and you can't quite read them. With a bog-standard £15 digibox, this doesn't happen - is there any reason why the Hauppauge card might be doing this? I'm using an Nvidia 7100GS graphics card.
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colinjones

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Re: Quality of TV tuners?
« Reply #8 on: September 05, 2008, 12:27:19 am »
I have the Hauppauge Nova-T-500, and generally, I have to say that it is very good. However, I have noticed some slight blurring, namely when credits are scrolling across the screen at the end of a program, and you can't quite read them. With a bog-standard £15 digibox, this doesn't happen - is there any reason why the Hauppauge card might be doing this? I'm using an Nvidia 7100GS graphics card.

Its probably the Nova T... There are so many options, it can be hard to troubleshoot this, but it not uncommon! Are you using deinterlacing? If so, what settings as I found that the suggested tvtime ones cause this, and changing one setting can get rid of a lot of the stutter.

Also, be aware of you refresh rates - display vs the TV standard. Guessing you are in the UK, so 50Hz for your TV, if your display is set to 60Hz, then there is the potential for strobing effects that would appear like this as well.

jondecker76

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Re: Quality of TV tuners?
« Reply #9 on: September 05, 2008, 01:13:45 pm »
I did a more in-depth comparison last night.

My satellite box is connected to my tv by standard rca composite cable, and to my pvr-500 tuner 1 via s-video.
The recorded video is of much better quality than composite straight to the tv.
Comparing an s-video feed straight to the tv to a recorded s-video feed, I could see no difference in quality. The only difference I could see was that the recordings were a couple of pixels short (horizontally) from filling up the screen.

purps

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Re: Quality of TV tuners?
« Reply #10 on: September 05, 2008, 02:37:37 pm »
I have the Hauppauge Nova-T-500, and generally, I have to say that it is very good. However, I have noticed some slight blurring, namely when credits are scrolling across the screen at the end of a program, and you can't quite read them. With a bog-standard £15 digibox, this doesn't happen - is there any reason why the Hauppauge card might be doing this? I'm using an Nvidia 7100GS graphics card.

Its probably the Nova T... There are so many options, it can be hard to troubleshoot this, but it not uncommon! Are you using deinterlacing? If so, what settings as I found that the suggested tvtime ones cause this, and changing one setting can get rid of a lot of the stutter.

Also, be aware of you refresh rates - display vs the TV standard. Guessing you are in the UK, so 50Hz for your TV, if your display is set to 60Hz, then there is the potential for strobing effects that would appear like this as well.

Thanks for your reply.

I had really bad jerkiness to begin with, using the "Bob" deinterlacing, but after disabling deinterlacing completely, it looked much better (I'm using PAL-I with a CRT TV via S-Video). Maybe it would be worth experimenting with other deinterlacing options.

The blurring that I mentioned really isn't THAT bad, but it can be quite noticeable when the credits are scrolling across or up the screen. I never thought of changing the refresh rate, I will try this. I understand PAL-I (which is what I chose in the LinuxMCE setup screen) gives rise to a 50Hz refresh rate - am I changing the TV setup itself to match this, or should I be changing the refresh rate in LinuxMCE to match the TV?
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colinjones

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Re: Quality of TV tuners?
« Reply #11 on: September 05, 2008, 10:33:32 pm »
Your probably right that that chooses 50Hz for you but its worth checking - the vast majority of the world uses 50Hz, but there is still a preference for 60Hz :) and PAL really refers to the colour system rather than refresh rates (there are perfectly valid 60Hz PAL systems used out there). Basically, the TV will be driven by whatever signal is coming out of the core as long as it is in range of what the TV is capable. Take a look at your xorg.conf or xorg.0.log files to determine the refresh rate.

 Below is the usual recommendation I have seen, except I changed "cheap_mode" to 0 from 1. This fixed up the judder that deinterlacing introduced for me,

method=Linear,cheap_mode=0,pulldown=none,framerate_mode=full,judder_correction=1,use_progressive_frame_flag=1,chroma_filter=0,enabled=1

totallymaxed

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Re: Quality of TV tuners?
« Reply #12 on: September 07, 2008, 09:58:29 am »
I have the Hauppauge Nova-T-500, and generally, I have to say that it is very good. However, I have noticed some slight blurring, namely when credits are scrolling across the screen at the end of a program, and you can't quite read them. With a bog-standard £15 digibox, this doesn't happen - is there any reason why the Hauppauge card might be doing this? I'm using an Nvidia 7100GS graphics card.

That 'blurring' you refer to has nothing to do with the T-500 at all. Its caused by the video card & driver and the setup of those elements in your system when you play back a live stream from the T-500 or a recorded stream from a hard drive.

A £15 Freeview Digibox has dedicated MPEG2 hardware to cope with these issues... unfortunately currently much of the special hardware in your video card is not exploited as well as it could be because the manufacturers closed source drivers do implement it. Intel interestingly have the least capable GPU hardware (compared to nVidia/ATI) but in our assessment currently have the best MPEG2 hardware support in their drivers...so MPEG2 playback performance is often measurably better on their GPU's.

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Monkgs

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Re: Quality of TV tuners?
« Reply #13 on: September 07, 2008, 10:13:53 am »
I did a more in-depth comparison last night.

My satellite box is connected to my tv by standard rca composite cable, and to my pvr-500 tuner 1 via s-video.
The recorded video is of much better quality than composite straight to the tv.
Comparing an s-video feed straight to the tv to a recorded s-video feed, I could see no difference in quality. The only difference I could see was that the recordings were a couple of pixels short (horizontally) from filling up the screen.

Excellent. This is what I was hoping to hear. Thanks!

zug

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Re: Quality of TV tuners?
« Reply #14 on: September 08, 2008, 03:59:25 pm »
I had a PVR-500 and it was awful. Completely unwatchable.
I now have a Nova T 500 and although it's vastly better than the PVR-500, it really stuggles with motion, especially Football matches.
I am going to try some of the tweaks mentioned above to see if it improves.
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