Encoder Quality Issues - Anyone Have Sample Recordings?

[mike1961]

I am wondering if anyone has perhaps 15-30 seconds of video I could download from an ftp site (perhaps anywhere from 10-30 megs). I'm starting to believe that the quality problems I'm having is not with my decoders but my WinTV 500 capture settings or cards or something in the encoding process. I just converted some old videos from my Tivo with VideoRedo and the quality looks better on my computer when I play it with my media player than my Sage Recordings. The Tivo records at 352x480 at 2600 kbps and continues to look better. I'm starting to think the problem is with the encoding process and not so much Sage or my decoders.

Thanks,
Mike

[Opus4]

Is it a DirecTivo? If so, doesn't that just record the digital stream instead of doing any encoding on its own?

- Andy

[Kirby]

Originally Posted by Opus4

Is it a DirecTivo? If so, doesn't that just record the digital stream instead of doing any encoding on its own?

- Andy

Not sure what he has, but yes, DirecTivo's and HD Tivo's only record the MPEG2 stream. No encoder chip onboard, no need for it.

[mike1961]

No - it's the Tivo Series 2 and I'm pretty sure it's not a direct stream because we do not have hi def. The format is 352x480 at 2600 kbps.

Thanks,
Mike

[stanger89]

Have you Calibrated your capture card?

[hechacker1]

I am currently uploading samples to here:

http://ordorica.org/moviez

just the .avi files. they are just random clips i found with your size specs, and a few even larger if you have the bandwidth.

My settings:
PVR-250MCE
Sage TV 5

Brightness: 158
Contrast: 155
Saturation: 150
Sharpness: 205
Hue: 129

6.5 vbr Mbps, varies from 4mbps - 11 mpbs.. although it mostly stays where you tell it.

And notice that this is configured for Nvidia hardware (6800gt) and nvidia decoders with Overlay and Hardware accel..

if I use VMR9 i lose hardware accel (nvidia specific). And the colors and brightness change drastically from overlay to VMR9.

[mike1961]

How can I tell it's configured for overlay? I thought VMR9 was always a better choice to use. I downloaded two of your samples (ferris bueller and a sports center video). To tell you the truth, I didn't think they were that much different from mine. One problem I'm noticing is when I make it full screen on my 1024x768 monitor, that's when it starts to look "grainy."

Any ideas?

Oh - once again - I didn't notice much if any difference between VMR9 and overlay but I can try it on my other computers.

Thanks,
Mike

[mike1961]

Originally Posted by stanger89

Have you Calibrated your capture card?

I'm currently using the defaults but I have played around with the brightness and contrast settings. It seems that these settings may actually be adjusted either before or after the capture. Also, I believe I can adjust the brightness and contrast directly in Sage (and probably should since I would think it would override and settings to the tuner).

Also - it seems like many of the settings in your link is for the ffdshow decoder.

Thanks,
Mike

[blade]

Originally Posted by mike1961

I'm currently using the defaults but I have played around with the brightness and contrast settings. It seems that these settings may actually be adjusted either before or after the capture. Also, I believe I can adjust the brightness and contrast directly in Sage (and probably should since I would think it would override and settings to the tuner).

Also - it seems like many of the settings in your link is for the ffdshow decoder.

I don't know what you mean by adjusted before or after. If you've already captured the video then adjusting the settings isn't going to change what has already been captured.

If you read the guide you'll see that it tells you to adjust the settings from within Sage. Also you need FFDshow and Dscaler in order to run the histogram, which is why there are directions for using it in the guide.

If the capture cards aren't calibrated correctly colors can bleed together and you can also lose detail from whites being too bright or darks being too dark.

[stanger89]

Originally Posted by blade

If the capture cards aren't calibrated correctly...

The biggest thing I've noticed is that having the brightness too high (as it usually is) accentuates the noise in the signal making it look worse than it should.

And yes, changes to the capture settings only apply to recordings made during/after the change. Pre-existing captures will be unaffected.

[hechacker1]

right.. it encodes the files with those settings.

i have noticed that i do generally get better image quality with a darker setting, and less sharpness, but all that really does is mask the grain and make the encoder ignore a lot of the dynamic range.

since then I have applied brighter settings to get more detail out of the picture, but the noise has gone way up on bad channels. I guess they aren't "digitally clear" but for analogue channels, the grain actually creates an illusion of detail.

To me, those video files playing through SageTV using the nvidia decoder are really nice. I mean, for sdtv, and having bad cable quality, i really can't ask for more.

but yeah, my files will probably look weird to you considering our different setups. Different decoders and VMR vs Overlay. Nvidia decoder definately makes the video look at least 2 twice as good as anything else, it just does such a good job with deinterlacing and motion detection.

On VMR my video files are actually encoded at a way darker setting because VMR for me makes the video playback very bright. Also, VMR is done in software and overlay is sent through my hardware.

[mike1961]

In general, what is a better setting Overlay or VMR?

Edited: by the way, out of curiousity, what do you like to set the brightness, contrast, sharpness and other Sage settings to? I'm assuming if I do this in Sage, I don't need to set that with the hauppauge tweaker because Sage overrides those defaults.

Thanks,
Mike

[mike1961]

I will also try the calibration link that stanger recommended. I'm thinking maybe that will make a big difference. But, I'm wondering if I'm supposed to install the ffdshow decoder as well and keep it installed and also I'm assuming these calibrations have to be done on each tuner.

Thanks again,
Mike

[blade]

Originally Posted by mike1961

I will also try the calibration link that stanger recommended. I'm thinking maybe that will make a big difference. But, I'm wondering if I'm supposed to install the ffdshow decoder as well and keep it installed and also I'm assuming these calibrations have to be done on each tuner.

Thanks again,
Mike

You only need FFDshow while doing the calibration and each capture card will need to be set.

[stanger89]

Originally Posted by hechacker1

i have noticed that i do generally get better image quality with a darker setting, and less sharpness, but all that really does is mask the grain and make the encoder ignore a lot of the dynamic range.

Don't get me wrong, I'm not saying to make it darker to hide noise. What I'm saying is that properly calibrated, so that the "black" and "white" points in the picture fall at the correct location (that being 16 and 235 respectively), that noise will be much less visible. By default it always seems that black is somewhat above 16 and white is often blown out into clipping.

At the same time, by doing that you're encoding the maximum dynamic range in the signal, encoding as close to the original levels as possible, and making encodes which will match the levels in other sources (namely DVD and HDTV) so that one display calibration works for all your sources.

[stanger89]

Originally Posted by mike1961

In general, what is a better setting Overlay or VMR?

Both have plusses and minuses from a practical/subjective perspective (Overlay is less resource intensive but VMR9 provides transparency, Overlay can appear "sharper", but VMR9 is smoother).

From an objective perspective, VMR9 is more accurate than Overlay, providing correct video levels, and not messing with the source.

Edited: by the way, out of curiousity, what do you like to set the brightness, contrast, sharpness and other Sage settings to?

It's really hard to say, it seems each tuner is a bit different, and more importantly each cable system/source is different.

I'm assuming if I do this in Sage, I don't need to set that with the hauppauge tweaker because Sage overrides those defaults.

Correct, for those values, though if you want to get into the Noise Reduction settings Sage doesn't override them by default.

Oh, and ffdshow is just a tool, you don't need to keep it enabled after you're done. Think of it like a multimeter or spectrum analyzer for this purpose.