Subject: MBONE "encoding" part II

From: "Forrest W. Christian" <[email-masked]>
Date: Tue, 7 Apr 1998 19:04:29 -0600 (MDT)

The joy of asking a question on a list like this is that sometimes the
main thing that you find out what you should have been asking in the first
place.

Here are some more facts which I didn't even think to include in my
original posting:

1)  The mbone tunnel will need to terminate on the same box.   This
elimiates Microsoft Windows Solutions, as mrouted is (at this poing)
somewhat impossible to port to NT/95.  There are, however, some
interesting commercial Windows products out there....

2)  I'm looking for a vic/vat/wb or vic/vat/wb compatible solution.  (Of
course, I'll need sdr, etc. in addition)

3)  This is for use across the mbone.

4)  The events which this will be used for are usually 2-3 day
conferences, happening at most a few times a year.   Long term reliability
(24x7) is not a big concern as this will be monitored during the event.
However, I want something which can realistically encode a vic/vat stream
for 8-10 hours without needing help.

Based upon the above items and many of the recommendations, I'm leaning
towards a Pentium 200ish FreeBSD box.  I'm familiar with FreeBSD, as it's
my in-house preferred OS.

So, I guess my real questions should be, or should have been:

Has anyone been successful in using a FreeBSD box to encode vic/vat
streams for hours at a time without problems?  (lockups, etc.)

What hardware should I purchase and/or avoid for this use?

(On a semi non-related note)  What frame-rate/bandwidth should I be trying
for when encoding this stuff for the global internet, taking into account
the common links and hardware out there for transport and decoding.

- Forrest W. Christian ([email-masked]) 
----------------------------------------------------------------------
iMach, Ltd., P.O. Box 5749, Helena, MT 59604      http://www.imach.com
Solutions for your high-tech problems.                  (406)-442-6648
----------------------------------------------------------------------

---

From: Bill Fenner <[email-masked]>
Date: Tue, 7 Apr 1998 22:09:13 PDT

>streams for hours at a time without problems?  (lockups, etc.)

I have sent h.261 video from my FreeBSD-2.2.2 box using a Hauppauge
Wincast/TV for a month at a time.  Audio is harder; I'm using a GUS PnP
Pro, which is the card that Mark Handley mentioned is discontinued.
I'd suggest checking out the CARDS file from Luigi's sound driver
(http://www.iet.unipi.it/~luigi/snd980215.tgz) and buying something
supported by it; Luigi's driver is now standard in FreeBSD-2.2.6 and
FreeBSD-current.

>the common links and hardware out there for transport and decoding.

The "standard" for some time has been 128kbps of h.261 video and
~64kbps of PCM or DVI audio.  If you're aiming for lower bandwidth
links, you might want to use lower rates on the video and higher
compression on the audio.  I know there are at least a couple of people
behind 33.6 modem lines connected to the MBone.

  Bill

---

From: Christoph Fleck <[email-masked]>
Date: Wed, 8 Apr 1998 10:03:13 +0200 (MET DST)

> streams for hours at a time without problems?  (lockups, etc.)

We have FreeBSD 2.2.5 with video BT8484 and sound CS4236B.
(sounddriver Luigi Rizzo)
No lookups.
Good Audio. Fast Videograbbing up to 30 fps, 2Mbps (h.261 CIF).
Display 4x Video 15 fps at CIF size. 

Some nags (perhaps there are solutions?):
Audio:  audiodevice is never busy, even if alredy used. That prevents
        audiodevice switching between some VAT from working correct.
System: the shared memory could be a bit larger. Dont know how to do.
        Vic can't display 2x 4Cif with shm (fast).
Video:  sometimes after poweron, once a yaer ;-), there was need to
        run fxtv once before run vic (grabbing makes wrong line order).

> What hardware should I purchase and/or avoid for this use?

Any BT848 based Video-Grabber. Any Crystal CS423x (x=1,2,6,7,8) based
Soundcard.

Christoph Fleck

,------------------------------------------------------------------.
| Referenzzentrum fuer multimediale Teledienste (MMRZ), TU Dresden |
|         Dr. Klaus Koehler, Christoph Fleck, Rainer Kranz         |
| e-mail: [email-masked]             Tel.: 0351 / 463 5653  |
|    WWW: http://www-mm.urz.tu-dresden.de               (GERMANY)  |
`------------------------------------------------------------------'

---

From: Miguel CHAMOCHIN GOMEZ <[email-masked]>
Date: Wed, 08 Apr 1998 10:30:15 +0200

Any experience with portable equipment ?.

  It looks like IBM Smart Capture Card PCMCIA can works on
Linux and FreeBSD with vic.. 

    http://mickey08.mickey.ai.kyutech.ac.jp/~ohashi/scc/

  Regards,

  Miguel.-

---

From: Amancio Hasty <[email-masked]>
Date: Wed, 08 Apr 1998 01:56:32 -0700

The Bt848 driver for FreeBSD is very solid haven't run into a kernel
panic in more than 9 months. The crashes that I have run into  have been due
to hardware defects and the last case a user had a severe mismatch between
his kernel and user application space --- basically he kept upgrading only
the kernel. After doing a complete system build the driver started working 
flawlessly.

The hardware defect category falls mostly in the area of a PCI chipset
either being buggy or not been able to keep up with the video bandwith
and locking up . If a user has a Natoma PCI chipset or Triton PCI chipset
the odds of him crashing the system due to the driver are nearly 0. Our 
FreeBSD multimedia mailing list is very trigger happy to report crashes
and I use my  Bt848 driver (and I am ashame  of it ) every day . Got 
two systems here a P133 and a PPro 200Mhz. 

With respect to audio , I just got back on track to finish writing an
audio driver for a PCI soundcard . No word yet on completion time till
I am fully satisfied that the card will serve the FreeBSD requirements : like
being able to run for weeks at time, smooth full duplex operation, etc..

	Amancio

---

From: Hugh LaMaster <[email-masked]>
Date: Wed, 8 Apr 1998 10:15:59 -0700 (PDT)

[1-2]&
> 3)  This is for use across the mbone.

Much clearer requirements.  Thanks.

> my in-house preferred OS.

It sounds like you have answered the first question for yourself: FreeBSD.

I don't own a single share of Intel stock, and it is correct, and,
fashionable, to point out how much you can do with a low-end 
system on *BSD.  Even a 386 (remember those?) can run a BSD 
Unix well.  Nevertheless, for video encoding, I would recommend
a new P II (or PPro200, although they are rapidly disappearing new).
For a few hundred dollars extra, you can get a P II 266 on a 440LX
chipset with 128 MB ECC SDRAM.  For video apps, you can always
use the extra memory and cache bandwidth.  For example, sometimes
it is nice to actually display what others see while you are 
broadcasting - but, this eats up a lot of the CPU.  Audio has always
been more costly than one would think, and if you want to experiment
with, e.g., gsm, even more so.  A Pentium classic system won't have the 
headroom to experiment while doing a broadcast.  And, if you plan to run
wb, you will need more memory.  Also, XFree86 isn't as fast/efficient 
as a commercial X Window System should be, so extra CPU horsepower helps.
Another factor is network garbage (ie ICMP unreachables, etc.) and the 
ability to ignore the garbage without dropping packets - this is also 
helped by having a faster system.

This is one of the few cases where I would recommend a faster CPU/more
memory over a fast SCSI disk.  A minimal (SCSI) disk will work fine here-
if your mbone apps start paging, forget it.  You can always add a Seagate 
Cheetah later if you need it.

Get a motherboard with five PCI slots so you have room for
a PCI audio card when someone gets a driver working for one 
of them.  Or, a motherboard with a built-in SCSI and 4 PCI 
slots.  Or, one AGP slot if you want to try it.  But, you 
should have Ethernet, video capture, and (future) audio on PCI.  
You can build an (almost) pure PCI (no ISA cards) system 
quite reasonably today.

> So, I guess my real questions should be, or should have been:
:
[reliability:] I've had a few problems with XFree86 reliability
and performance, none with FreeBSD itself.

> What hardware should I purchase and/or avoid for this use?

One of the Bt848 cards [e.g. Hauppauge WinTV] is indicated for video.
For audio, Luigi Rizzo, who did the recent audio drivers, was suggesting 
the Aopen or similar CS-whatever based card - very inexpensive - for an 
ISA card, (until PCI cards are supported).

> the common links and hardware out there for transport and decoding.

Mbone custom dictates a maximum of 128 Kbits/sec video and pcm/2 
audio, with lower bandwidths appreciated, for a general viewership,
unscoped mbone presentation.  Personally, I think some of the lower
bandwidth combinations, e.g., of 64 Kbits/sec video and DVI/4 works 
nicely, and goes over ISDN with 2 B-channels, which the standard 
broadcast does not.  Some material works fine with even lower 
bandwidths, e.g. <30 Kbits/sec video and GSM audio - some
experimentation/tweaking might get it to work over 56 Kbits/sec
ISDN, frame-relay, and V.(whatever) modems.  There is a fairly
large potential audience out there stuck behind one of these.
I'm surprised that more people don't try to work with lower-bandwidth
formats when doing talking-heads-with-slides, because the lower 
bandwidth can work well and increase the potential audience.

On the other end of the spectrum, if any in-house use is planned,
it is now feasible to use 400-800 Kbps video in house, behind
an admin-scoped address boundary, provided you are using fast
systems.  Unfortunately, the Bt848 doesn't do M-JPEG, because
it works well in low-loss ~1 Mbits/sec "intranet" situations.

As always, additions/deletions/corrections welcome.

--
 Hugh LaMaster, M/S 233-21,    ASCII Email: [email-masked]
 NASA Ames Research Center     Or:          [email-masked]
 Moffett Field, CA 94035-1000  No Junkmail: USC 18 section 2701
 Phone: 650/604-1056           Disclaimer:  Unofficial, personal *opinion*.

---

From: Christoph Fleck <[email-masked]>
Date: Wed, 8 Apr 1998 20:19:31 +0200 (MET DST)

> Also, XFree86 isn't as fast/efficient 

I have done some tests with vic on different Hardware on X86 and other X.
The results are in german language present:
http://www-mm.urz.tu-dresden.de/pc-hardware/vic_anzeigeleistung.html
Short try with translate at alta vista (no corrections) you could see at:
http://www-mm.urz.tu-dresden.de/pc-hardware/vic_anzeigeleistung_eng.html
It takes 1 min and the result is not that much bad ;-).

Christoph

---

From: Mark Handley <[email-masked]>
Date: Tue, 14 Apr 1998 12:31:16 -0400

>supported by it; Luigi's driver is now standard in FreeBSD-2.2.6 and

If you want a particular recommendation, I've just got an A/Open
AW35Pro, which is supported by Luigi's driver, works well, and only
cost $40.  My only reservation is that in my machine the mic input is
too noisy to use, but the line input works fine, and a cheap Radio
Shack microphone mixer works fine to boost the mic level to line
level.  I talked to Brad Karp who also has this card, and his doesn't
suffer from this, so perhaps it's something peculiar to my
motherboard.  You'll also need to build a vat with the modified
audio-voxware.cc from Luigi's web page.

I had a minor problem with the Wincast/TV card producing image
corruption when the capture frame rate is being limited via the
driver, but the fix is trivial.  If you see the problem, let me know.

Cheers,
	Mark