Recording VBR vs. CBR

[Steerpike]

I've made dozens of recordings from my WinTV 250 PVR card using both GB-PVR and WinTVCap (I've had to switch to WinTVCap until I can figure out why the pre-show / post-show minutes are not being honored on my recordings).

I've noticed that my WinTVCap recordings are VBR by default. The WinTVCap.ini file allows me to adjust the setting as follows:

BitrateMode = 1 // 0:CBR, 1:VBR

Is there a similar change I can make in GB-PVR? I don't see this in 'direct.ini'. GB-PVR's recordings are CBR by default.

I must say, the quality of the WinTVCap recordings are not as good ... there is something of a 'red tone' which is not there on the GB-PVR recordings. However, I can't trace this to any difference in settings, other than the VBR/CBR one ... and I can't imagine why that would result in a red tone! I searched the forum for "VBR" but got only one hit.

I'm assuming that both WinTVCap and GB-PVR should produce very similar results assuming similar recording settings ... or is that a naive notion ...? Maybe GB-PVR does some nice image equalization or something before writing out the data ...?

I'm going to download the latest version now to see if it fixes the pre-show/post-show minutes issue.

[pancapangrawit]

Steerpike, the most probable reason why you would see better recordings from GB-PVR than from WinTVCap are the rather high standard bitrate settings in GBPVR (which comes at the price of quite high diskspace-consuption, which is relevant if you want to keep a lot of films or want to burn DVDs). If I understand sub correctly, GBPVR doesn't change any of the standard settings defined by the WinTV setup. CBR vs. VBR is discussed quite frequently. VBR (sometimes also calles "constant quality mode&quot is more space efficient and is the standard for DVDs. CBR is seen by some as less errorprone, particularly with the problem video-audio-synch.

I find this an interesting topic. A few posting these days relate to it in the one or other way (e.g. recording volume, prefilter-settings), notably most (all?) enquiries are from Hauppauge-users. WinTVCap allows you to set very many of theses settings via a combination of command-line parameters and ini-file-settings on a per-recording base, thereby overriding - but not changing - the registry settings (via the multiple-profile sections: quality, audio, prefilter, procamp, see amontillados help-file for WinTVCap. Maybe GBPVR could allow for similar settings in the direct.ini? Then interested usesrs could tweak their settings manually. Would be realy cool

[Steerpike]

pancapangrawit - I've done some more testing with this. No matter what I do in the 'WinTVCap.ini' file, I cannot get the color balance of my WinTVCap recordings to match those made in GB-PVR. I've been recording the same show each day, several times a day, and have been comparing the 'intro' piece, which is of course the same (and I've eliminated broadcast variations, having recorded over 40 shows over time now with both programs).

The color balance of GB-PVR is more 'natural' than WinTVCap. But I've set WinTVCap.ini to match (to the best of my abilities) what GB-PVR is using - CBR, 6MBps, etc. All other settings in WinTVCap are defaults and pretty innoccuous - I'm guessing here that GB-PVR is not setting inverse telecine, has closed gop, and so on. I use the WinTV-PVR250 card.

Sadly, I'm still having problems with scheduling with GB-PVR (which I'll cover separately) so have to keep falling back to WinTVCap which handles the scheduling part more reliably at the moment.