[ale] TV in/out - Now getting ALE mail again...

Joseph A. Knapka jknapka at earthlink.net
Wed Dec 6 12:55:35 EST 2000


Egad. So much negativity, man...

OK, well I must admit that all this is very theoretical for
me at this point, because I don't actually have the hardware
available to start playing and I have basically no
experience in this area. But here are my thoughts:

First, requirements:

- Stage 1: get frames off the TV input at a minumum of
24 fps and display them on the TV in real time, with
audio. Build a simple UI for tuning, volume control, etc.
If instead of a TV I need to use a SVGA monitor, that
is not too terrible, but I'd prefer to get TV-out
working.

- Stage 2: record the TV input in MPEG-2 format and
play it back. Once that's done, building a scheduler to
record whatever I want automatically is easy. I'll
have to blow some $ on a giant economy-size ATA66
HD. I'd like to be able to keep 12 hours or so of
recorded material on-line.

If those 2 are all that I can get working, I'll be
happy.

- Stage 3: Display and record simulataneously.

- Stage 4: Record n minutes of the input at all times,
and support freeze-frame, rewind, fast-forward of
the real-time input stream.

Next, plan of attack:

- I'll probably go with an ATI card, because even though
all the features I need are not currently supported, with
ATI's active support they doubtless will be before long.
According to ATI's web page, they are "currently
investigating TV-out support under Linux."

- For MPEG encode/decode, I will either (a) invest in a
badass Athlon motherboard, or (b) blow $400 on an MPEG
codec board (there's a company whose web page escapes
me at the moment that's currently shipping a codec at
about that price, and it's designed with Linux in mind).
About the same cash outlay in either case.

- For option (a) to be feasible, I'll need to find an
encoder/decoder package that handles audio well. Or
write one :--)))) So far I've found a couple of packages
that handle video reasonably on my 400Mhz K6-2, and this
has encouraged me that there ought to be one out there
that does everything I want. Possibly I can hack audio
support into one of the freebies that only supports
video. The MPEG format looks pretty scary, but it's well-
documented, so I can eventually figure it out.

- If necessary, I'll write code to grab frames and audio
from the TV input and feed them straight to the MPEG
encoder. It sounds like going through a separate
input format causes a lot of grief.

It may be that I am hopelessly naive and doomed to fail,
but what the hell. Idle hands are the Devil's plaything,
and all.

-- Joe

> Chris Fowler wrote:
> 
> I've been wrking on this and have given up.  I purchased a Zoran based
> card that I have drivers for in Windows and none in Linux.  I have
> downloaded the Linux drivers.  I want to take a 60 minute tape to
> VCD.  Here are my problems
> 
> 1. 320x200 is the best I can do at 15fps with audio and video.
> 2. at full screen the avi captured looks poor at that resolution.
> 3. The biggest file that I can make on FAT32 file system is around
> 4GB.
> 4. Due to number 3, I can not capture the whole tape.
> 5. MPEG converters cost money.  Too much money.
> 
> For short cuts, the zoran is great.  For real conversion, don't waste
> your time.  I purchased this card because I have a 1.5 hour home video
> that is over 10 years old. It is VHS.  I want tp preserve it as a VCD.
> 
> Chris
> 
> -----Original Message-----
> From: James CE Johnson [mailto:jcej at tragus.org]
> Sent: Wednesday, December 06, 2000 8:56 AM
> To: hirsch at zapmedia.com
> Cc: ale at ale.org
> Subject: Re: [ale] TV in/out - Still not getting ALE mail...
> 
> hirsch at zapmedia.com wrote:
> 
> > Joseph A. Knapka writes:
> >
> >  > Anyway, some time ago someone on the list was
> >  > talking about recording Babylon-5 in MPEG
> >  > format. I'd like to do something similar -
> >  > basically I want to build a TiVo-like system.
> >  > I think I have a handle on getting the TV
> >  > signal into my Linux box and doing the MPEG
> >  > encode/decode, but I haven't been able to find
> >  > any solid data on video cards with TV-out
> >  > supported under Linux. Does anyone have any
> >  > recommendations for that, or for this kind of
> >  > thing in general?
> 
> Have you found a method for capturing and converting to MPEG yet?
> I've been
> trying for a long time and have had, shall we say, "imperfect"
> success...
> 
> Using a Hauupauge card I can capture to AVI.  (Anything over 15fps
> causes the
> audio & video to get out of sync.)  The next step, apparently, is to
> break the
> AVI into a file full of audio frames and another of video frames.
> Those are in
> MPEG format and then get glued back together into a single file.  The
> problem is
> that they're never quite in sync when everything is done.
> 
> The tools I've been using (or investigating) are avi2yuv, mpeg2codec,
> mpegUtil,
> mplex, ulib and vcdtools.  And, of  course, xawtv's record application
> to capture
> an AVI in the first place.
> 
> If you get this thing working or you want someone to test things for
> you, by all
> means let me know.
> 
> As for TV out, I haven't tried that yet.  My VooDoo 3 has an S-Video
> out but I've
> never tried to jack it into the TV.
> 
> Later,
> J
> 
> --
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> message body.

-- Joe Knapka
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