tv tuner with hardware encoder

mrwxyz

Senior member
Feb 7, 2004
334
0
71
I'm planning on getting a tv tuner (the $50 leadtek tv2000xp expert) but i have a question about the onboard encoder. If i get the leadetek without the encoder will it stress the cpu to such an extent that i wont be able to do other things while im watching tv? I dont plan on doing much tv recording, just watching live tv and using the video in to hook up my systems. But while i watch live tv ill probibly be chatting and doing other things together.

Does the encoder only get used when i record tv, or also when i watch live tv?

i currently have a p41.6a with 512 pc100 sdram. I dont plan on doing any upgrading as i'll hopefully be building a new system this winter (and ill carry the tv tuner over to that one). the new comp will be atleast a64 3200+, so if the encoder wont matter at all for that system then i wont bother getting it for my current one.

thanks
 

imported_SolarWind

Junior Member
Aug 15, 2004
9
0
0
On my Athlon Tbird @ 1133, I was able to surf the web just fine while watching TV on the Leadtek TV card.

With the Hauppauge PVR-250 and 350, the encoder gets used when watching live TV, even if you're not recording. With the 250, the CPU has to decode the MPEG2 stream. The 350 has an oboard MPEG2 decoder.

The main advantages of the PVR-250 over the Leadtek are better-quality MPEG2 recording, and the encoding takes less CPU time.

I would guess that while watching TV, the Leadtek has lower CPU utilization than the 250 does since with the 250, the CPU has to decode the MPEG2 stream. However, the 250 should use less PCI bandwidth.
 

Peter

Elite Member
Oct 15, 1999
9,640
1
0
When you're just WATCHING, any card will feed the UNCOMPRESSED stream directly to the graphics card's overlay buffer, no CPU load at all.

TV card onboard hardware compression engines are good fun when you're RECORDING video to disk. PCI bus load as well as CPU load will drastically reduce if the TV card feeds MPEG2 into RAM not the uncompressed stream.
 

imported_SolarWind

Junior Member
Aug 15, 2004
9
0
0
^ My Hauppauge PVR-250 compresses to MPEG-2 even when I'm watching TV live. If you know of a way to get it not to compress the video, please tell me since the artifacts are quite noticeable sometimes.

Hauppague is a bit vague on what the 250 does, but their product description for the 350 is quite clear:
WinTV-PVR-350 contains a highly integrated MPEG-1/2 hardware encoder and hardware MPEG-1/2 decoder. WinTV-PVR-350 uses the hardware MPEG encoder for watching live TV, for pausing live TV and for recording. The encoded MPEG-2 video is sent over the PCI bus, where it is stored on the PCs hard disk (for pause and record) and simultaneously decoded in software for display on the PC screen (in all modes).

While I was correct that the 350 has an on-board hardware MPEG-2 decoder, it turns out that it's only used with the video out.

Also, when just watching TV with the Leadtek with their software or DScaler, there was definitely a hit on my CPU (perhaps due to deinterlacing and resizing). I don't see how DScaler can do what it does unless the live TV video is sent to the memory and manipulated by the CPU.