Just out of curiosity: Differences between BT848 and 878?

[MrMungus]

TIA

[FulciLives]

Ask trevlac ... he will bore you with all the gritty details (just kidding my friend!)

- John "FulciLives" Coleman

[MrMungus]

Ask trevlac ... he will bore you with all the gritty details (just kidding my friend!)

- John "FulciLives" Coleman

Well, I don't need *gritty* details...

[lordsmurf]

The mean/cranky answer: same shit, different age. Supposedly the older 848 is lesser of evils, but I don't really know firsthand.

[FOO]

I think the 878 might have audio capture while the 848 does not.
Maybe - not sure .
Why you wanna know ?
There are data sheets in PDF on the Conexant site for those

[MrMungus]

Thanks for the answers. One thing I did find out is that 848 is limited to 4:3 aspect ratio and 878 is not. I've found some other references; just thought asking here might be faster. Thanks!

[trevlac]

Thanks for the answers. One thing I did find out is that 848 is limited to 4:3 aspect ratio and 878 is not. I've found some other references; just thought asking here might be faster. Thanks!

I'm not sure what you mean by aspect ratio....looking at the 878 spec it is clear it was intended for broadcast and there is no wide NTSC broadcast. PAL+ maybe. So, no aspect ratio is not a difference.



I'd have to go with Foo on this. May be more differences, but sound seems to be the big one. Also, from my limited experience, there is a big difference from card to card even with the same chip. So comparing chips may not get you the results/info you want. I've been very happy with my AverTV. $29 if I recall.

http://www.conexant.com/servlets/DownloadServlet/100119a.pdf?FileId=542

The Bt878/879 has all the video capture features of Bt848A, plus integrated BTSC stereo decode, and FM radio capture data processing. The DMA capability is enhanced to allow for low latency, digitized audio stream transport. The chip enables dbx-compliment stereo, TV, FM radio, and base-band video and audio as input sources. In addition, the chip simplifies the computer/broadcast signal interface down to a single PCI connection.

[FOO]

Looks like it's mainly audio , with some more flexible video
settings available also.
I don't see how different cards with these chips could be much different
except for drivers and tuner since they essentially do everything including the PCI interface.

[SLK001]

The 848 is video only.
The 878 is video (RE: 848) plus mono audio.
The 879 is video (re: 848) plus TV stereo capability.

[trevlac]

I don't see how different cards with these chips could be much different except for drivers and tuner since they essentially do everything including the PCI interface.

What about the analog filters before the chip even gets the signal? Can't the quality of the input jacks make a difference?

In this thread, some pics from a scope are posted. They measure the signal just before it gets to the chip. Different chips, so maybe this is not valid for what I said? Regardless, the signal is quite different before it gets to the chip.

However, I work at a bank. What do I know about electronics? I bow to your knowledge. Heck, all BT8x8 cards are probably made in the same factory in China.

[MrMungus]

I'm not sure what you mean by aspect ratio....looking at the 878 spec it is clear it was intended for broadcast and there is no wide NTSC broadcast. PAL+ maybe. So, no aspect ratio is not a difference.

I mean the ability to choose an aspect ratio that is not 4:3.

[trevlac]

I'm not sure what you mean by aspect ratio....looking at the 878 spec it is clear it was intended for broadcast and there is no wide NTSC broadcast. PAL+ maybe. So, no aspect ratio is not a difference.

I mean the ability to choose an aspect ratio that is not 4:3.

Frame size is up to the driver. I don't have a BT848 card, but it looks like you can use the BTwincap driver on a BT848.


BTW: For some reason, AR is a messy/confusing subject. In a nutshell, assume the source is 4:3. The card (based on what the driver says), crops the source. Then, based upon what you tell it, the card resizes. If you did not tell it the same as what was cropped, your AR is no longer 4:3.

For example: NTSC Bcast is 711x486. Btwincap crops this to 712x480. If you ask for anything other than 712x480 you are changing the AR.

This of course is in DVD type pixels (13.5MHz). If you want PC/SVCD/VCD pixels, the numbers are different, but the story is the same.

I've been known to go on and on about this. But it's a bit off topic.