some newbe questions (1 Viewer)

[jeanne]

Hi there,

I am dealing with MP for some months now, not getting the tv work properly. There are also some technical questions I don't know anything about. (and I am not even blonde!;0).
So..
1. what is postprocessing en what does it to tv.
2. what is deinterlace?
3. what does the audiomapping do (tvcard properties)
4. Audiorenderer: what does this do? I can choose from several options: Realtek AC97 audio, Default direct sound, default waveout device, directsount nr.0 lineout (emulation), directsound: Realtek AC97 audio, Modemnr. 0 Lineout.

Area: Media Portal Program
MediaPortal Version: 0.2.0.0 RC3 (2006-03-18)
MediaPortal Skin: BlueTwo
Windows Version: Windows XP (SP2)
.NET CLR Version: 2.0.50727
DirectX Version: 4.09.00.0904 (9.0c)
Audio Codec: AVerMedia MPEG-2 Multiplexer
Video Codec: AVerMedia MPEG Video Decoder
CPU Type: Intel Pentium 4 - 3.20GHz
Memory: 511 MB
Motherboard: SiS-661
TV Card Model: AverTV
TV Card Type: AverTV GO 007Plus
TV Card Driver: 2.3.5.36
Video Card Model: Sapphire Radeon 9250 (256 MB)
Video Card Driver: latest
Video Card Resolution: 1024x768
Video Render Type: Overlay
Audio Card Model: Realtek AC'97 Audio
Audio Card Driver: latest
Synopsis::

Can't get the tv work properly. Images are running forward as well as the sound. It all goes too quick.

thanks in advance!
Jeanne

 

[RoChess]

1. what is postprocessing en what does it to tv.

It simply means processing is being done *before* it is displayed/used. For example with the DivX/XviD video codec, it allows the codec to already start calculations on frame 2, when it's still working on frame 1. The benefit is that when B-frames are used, that things will work smoother, and that it allows for certain graphic effects to be applied that can in some cases generate a better picture quality. Hoewever, it comes at a great loss in speed, and on slow computers it is better to disable it.

2. what is deinterlace?

Old TV's (and most TV's fall under this category, even the ones still sold today), buildt up your picture via interlaced mode. What this means is that your TV screen is made up out of horizontal lines. They have 3 color canons in the back of your CRT tube, that litterally blast to the front of the screen and the rays are then bent to go into the right spot by powerfull magnets.

However when the TV has 'drawn' a line, and has to travel back to the left side to start the next line, it is too slow to immediatly start under the line it just drew. So it skips a line.

This means it will draw line 1, 3, 5, 7, etc... and then when it is done, it will go back to the top of the screen and draw line 2, 4, 6, etc. It does this however so fast (50x per second in Europe, and 60x per second in the US) that your eyes see it as a complete picture.

However, computers became faster and where able to eliminate that problem, which introduced 'progressive', as in the image is drawn at once and not in two-parts.

Now the problem comes when you want to 'capture' a TV image, because you have to get the odd lines and then the even lines, merge those together and then take a snapshot of the result. And this can cause weird visual effects sometimes. So deinterlacing can occur in a few ways, one is to simply 'skip' either the odd or even lines and use half of the resolution, and another is to use fancy methods to merge/blurr/etc the odd+even lines into a good result.

3. what does the audiomapping do (tvcard properties)

That I'm not sure on, usually it means that you can select which audio source is linked to the video source, because not every TV-capture card is able to also record the sound. They leave that up to your soundcard, which means mapping has to be done to link the 2 together, so the audio+video doesn't get out of sync... But it can also mean something totally else, depends on the programmer who used it.

4. Audiorenderer: what does this do? I can choose from several options: Realtek AC97 audio, Default direct sound, default waveout device, directsount nr.0 lineout (emulation), directsound: Realtek AC97 audio, Modemnr. 0 Lineout.

That goes back to question #3. You can not only select which audio source is used, but also how it is used. For example windows introduced DirectX for audio (DirectSound) and video (DirectShow), which allows for processing of such things, without interferring too much with the rest of the programs/stuff running. So selecting the DirectX methods is usually best.

In your case you also have a modem card in your system, and eventhough you aren't using it to capture the TV sound, the computer doesn't know that, so it simply gives you the option to select it.

 

[jeanne]

Thank you very much RoChess for your expanded answer! This is really very helpful to me.. I hope this knowledge will help me getting my tv work.

If someone else knows how I can improve the lifetv, it would be very much appreciated!

 

[CHli]

Look at here for the explanation of ffdshow postprocessing :

https://forum.team-mediaportal.com/viewtopic.php?p=80191#80191