[mpeg2] Re: KFir MPEG2 Capture Board - Linux Users Experience

[Torsten Howard <torsten@inetw.net>]

On 31 Jul 2002 15:12:30 -0500
"Rett D. Walters" <rettw@rtwnetwork.com> wrote:

> Hello All:
> 
> Before I plunk down my hard-earned money, I am curious as to what the
> overall user experiences are regarding the BMK Kfir Mpeg2 Capture card
> under linux.  I am mainly interested in using it for high-quality PVR
> and Video Capture/editting applications.
> 
> Thanks for any input anyone can provide.
> 

Setup
-------
Here's how the card works.  The module compilation is a little finicky,
and getting the first grab can be a little finicky - there is no feedback
as to what is happening.  If any parameters are wrong, it won't encode
anything.

After you figure out the setup and parameters (very easy to do), and make
the first encode, all works.

To grab the data, all you have to do is this command:
cat /dev/video0 > test.mpg

No Tuner - can be added
-----------------------
As for PVR, there is one problem - no tuner.  You can only grab Composite
video or S-Video.  To add a tuner, you can purchase a Hauppauge card, and
there is a hardware hack (very simple, solder two wires, signal and ground)
to make a video out.  Connect the new video out to the video input of the
bmk mpeg2 card.  Now, tune the Hauppauge tv card (with xawtv, for instance),
and you can record television from the composite video input of the kfir
mpeg2 card.  

You can also tune the channel with a VCR and you don't need a Hauppuage
card, but then you lose a significant part of the PVR functionality.  The
whole idea of letting the machine do the work is gone, because you must
be there to tune the channel, or remember to tune it before leaving.

Advantages
----------
Having two hardware cards, you can watch the video signal and record it at
the same time.  This advantage is mitigated if you have a processor 1Ghz
or greater, because you can do this with a regular TV card.


No Tuner Software
-----------------
There are no current utilities with support this.  I'm taking a look at
freevo, which has a nice interface, but still needs some work.  

Most pvr utilities that currently exist do not allow you to control one
/dev/video while reading from another.   For example
kfir mpeg2 card:  /dev/video0
hauppauge tv card: /dev/video1
You can't tune /dev/video1 while recording from /dev/video0, but this should
be trivial to implement.

It would be simple to add cron jobs to automatically record for a set
period of time every day, week, or month.  Just run the command cat
/dev/video0 > show.mpg - but one caveat, you will have to figure out
how to change the channels of the video-for-linux hauppauge device
(should be simple, but I've never done it).  

No Deinterlacing
-----------------
Also, the video that comes off the mpeg2 card is not deinterlaced.  This
produced some very annoying artifacts, like "feathering," which drives me
nuts!  It is best to post-process video with something like transcode, which
can deinterlace the mpeg.

Can't dynamically change Parameters
-----------------------------------
Once you load the kernel module, you can't change parameters.  For example,
if you tell it to read the composite video port, you can't switch to the
S-Video port.  You must unload the module, and reload.  Same goes for 
switching from PAL to NTSC.

On a side note, the Hauppuage in the US cannot display a PAL signal.  I
wanted to watch the video signal as I record, so I got around this by
using a Composite-->S-Video adapter, which gave me color!  (PAL signal
through an NTSC tuner usually has B&W Picture with messed up sound).

How to use as a PVR
-------------------
So, whereto from here?  As a PVR, you would need to also purchase a Hauppauge
card.  Purchase a composite video port from (Radio Shack), solder two wires
to the video port.  Attach the two coards, install, configure.  Figure out
how to change channels by writing to the /dev/video port, add cron jobs
for recording, and this is the simplest way to get a PVR.  You could also
code a nice GUI app to do all this, but I've been on this list a year and
there is little to no discussion to do anything like this.

The whole process is a little cumbersome.  Part of the problem with current
utilities is they do not expect mpeg2 to come off the /dev/video port, as
most people don't even know there exists an mpeg2 encoder for linux, and most
poeple are not keen to solder wires to make it tune regular Television.

Other Future, Better OPtions
-------------------------------
Even better, there is a new kfir chip, kfir2.  It is on the new Hauppuage
PVR's, and Hauppauge (A German Company - the Germans traditionally are more
in support of Linux) is considering open-sourcing some drivers.  This would
be outstanding, and definitely worth waiting for.

Go to http://www.hauppauge.com and email their sales team, tell them you
are looking for a linux-based PVR and want some drivers.  All the PVR newsgroups
are pushing for this.

Another Option
--------------
If you have an adequate processor, say 1Ghz or greater, than you may want
to wait.  A regular TV card (Hauppuage, ATI, any bt8x8) you can record
and compress in real time, and there are several utilites (and GUI's) that
work with these cards.  With 1Ghz, you should be able to watch the video
and encode simultaneously.  This isn't supported as far as I know, but there
is development going on to create software that can accomplish this.
Especially it is in the plans for freevo
http://freevo.sourceforge.net

Old Hauppuage PVR Development
-----------------------------
Finally, there is some development work for drivers for the old Hauppauge
PVR  http://pvr.sourceforge.net/ but it developement is VERY slow, and I don't
have faith he's making good progress.  He has the video, sound, working, and
it seems the microcode loads, but he is unable to record.

In Conclusion
-------------
I would wait to see if the Hauppauge people release some open-source PVR
drivers, or even just some PVR drivers.  I wouldn't buy their PVR card if
the Linux binaries are closed-source, but I would definitely swap my
current setup if they are open-source. 

If you want to get started right away, and have a good-enough processor, I 
would recommend skipping the bmk mpeg2 card, and going with a cheap Hauppauge
TV-card (or some other TV card).  It is much easier to setup, and you can
record television just as well.

If you have patience, wait for the Hauppauge to release some open-source
drivers for Linux for their PVR cards, or for development to continue at
pvr.sf.net.

Finally, if you can deal with some hassles of setup, or decide you just
want to encode movies from a VCR, the kfir card will do.  The kfir card
should do a better job with high-quality VHS movies, in encoding, than
a bt8x8 chip (i.e. Hauppuage) chip.  The mpeg2 will require post-processing,
though, to deinterlace, and perhaps recompress.

Cool Case
----------
I haven't heard of anyone doing anything with this case, but I want to.
Have a look at this case, I think it is the perfect PVR case.  It takes
an ATX motherboard, PSU.  If anyone has any experience with this case,
please let me know.

http://www.crtcinema.com/cases.html

Torsten