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

[Torsten Howard <torsten@inetw.net>]

If you have an auto-tuning satellite, you may get very good results
with the bmk board.  Satellites usually have good quality video, 
clean signal.


> 1. How long does the de-interlacing take for say, 1 hour of NTSC full
> frame (~640x480 or something of that nature) at about 5 Mbit/sec
> bitrate? I have a feeling that this post processing may be just as bad
> as MJPEG conversion - 4+ hrs for 1 hour video (at 320x240)...And, on a
> similiar note, do you know where I can find a clip of video captured
> with a Kfir card so I can see how the interlacing looks?

I usually encode to dix simultaneously.  On 1Ghz p3 I get around 14fps.
(about two hours encoding per one hour video).  

I have never tried to deinterlace and write mpeg2.  I would assume it
should be faster.  Maybe even real-time.  I think it's possibel to do
real-time deinterlace from a raw frame v4l device on 500Mhz.  Don't know
for sure.  Resolution is full-NTSC 60fps, I think around 700x400
(It's been awhile since I actually used the board).


> 2. About cron jobs to capture a show: How do you do a "cat" from a
> device for a set amount of time, like 60 minutes

http://www.tldp.org/HOWTO/VCR-HOWTO-3.html#ss3.5


> 3. Do you know if the Kfir2 chip like whats going to be on the Hauppauge
> Card does deinterlacing?

I have no idea.  I would imagine yes, but who knows how to enable the
functionality.  Even the kfir board we have has tons of features that
have hard-coded defaults.  It make is nice and easy to use, but perhaps
it would be nice to enable more control.

I took a look at the visiontech (kfir manufacturer) website, and they
have been bought by motorola, so it is doubtful we will ever see an
encoder like the bmk board again.  The original board was pretty much
a clone of the visiontech reference model but (re)producted by a german
company (BMK Elektronik).

I'm hoping Hauppuage goes open-source for the drivers, it would make
life real nice and easy.

Torsten





> 
> 
> Thanks again,
> 
> Rett Walters
> 
> 
> On Tue, 2002-07-30 at 19:44, Torsten Howard wrote:
> > 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
> 
>