Secret to video capture on O2
Khalid Schofield
capture well. I've only recently found the answer to perfect video capture
on O2. There are two problems
1) the main cpu
2) the source time base
3) disk IO
ok the last is a bit of a red herring. Disk IO only means you need 3Mb/sec
xfr to be ok. That is sod all but make sure you aren't running any large
jobs to the same disk while capture is running.
Use dmrecord!
Use dmrecord
oh and did I mention
Use dmrecord!!!!
Mediarecorder is naff. Ian Mapleson and I have spoken VERY ofen about this
and O2 video capture / video processing problems.
Use a constant bit rate is the dmrecord 'brate' option. See man dmrecord
for info. I use 30Mbits/sec brate=30000000
My O2 cpu was an R10,000 225Mhz. I've just upgraded to an R12000 400Mhz
for just over $220. email nel...@comcast.net for a cpu just like mine.
After using my upgraded O2 it feels as fast as my Octane for web browsing.
My R10k 225Mhz cpu used to take a week and a half to open and render
multimap.co.uk now it does it in seconds using Mozilla Firebird :)
The source.....ok thats not so simple. Basicaly I could capture sometimes
on my R10k 225Mhz O2 but only using my analogue out on my DV camera.
On VHS there are time base errors. So the frame rate looks all screwed up
to the O2 video board. I'm using a JVC HR-S9500 S-VHS vcr with s-video in
and out. This has a built in time base corrector. Also having a time base
corrector removes VHS copy protection :)
Editing is now much better too. I'm using Adobe Premiere 4.2 and
moviemaker. To be honest I prefer movie maker but thats just because I
don't understand Premiere 4.2 :)
Also with the R12000 400Mhz O2 cpu installed divx playback is VERY VERY
good. Easily as good as on my Octane which is an R12000 360Mhz with 3Gb of
ram (I'm selling the Octane by the way so feel free to email me about it).
I always capture video at full PAL 30Mbits. Playback is very smooth and I
can output my movies played with mediaplayer or dmplay easily to videoout
and record them to S-VHS tape with no prob's at all.
So looks like the O2 is back processing video and with the added bonus of
the US doller being $1.8 to the pound the 400Mhz CPU's are VERY VERY cheap
for us british people :P
The disk that I'm capturing video to is an external 9.1Gb disk but I do
have an external 550Gb disk pack and a raid that does 74.6Mbytes/sec
sustained transfer rate and is 144Gb is size. My external disk that I
capture to is 20Mb/sec but achieves 17Mbytes/sec which is more than fine
as dmrecord is wanting 3Mbytes/sec.
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
Bjorn Ljungdahl
I'm just thinking of trying out the O2 video capture function and this
gets me well started. I just bough an A/V card so I don't know
much about it. I've read many of you posts regarding video capture
and hopefylly learned something from them.
Are you capturing uncompressed or are you using any of the O2s
capability to compress in real time?
My O2 is only a R5200@300 so I may be in trouble, but I've heard
that the R5X00 series is sometimes better than the (lower) R10k.
/Bjorn
Khalid Schofield
may be ok with that cpu just make sure there are no heavy weight processed
running and you'll be laughing. Capture to a disk other than the system
disk.
I'm always capturing compressed video at 30Mbits/sec using O2 Jpeg
compression.
I'm watching a 22Gb movie file at the moment played back in mediaplayer on
irix on my R12000 400Mhz O2. Very good quality and it's over 2 hours long
:)
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
Lewis Saunders
> Also with the R12000 400Mhz O2 cpu installed divx playback is VERY VERY
> good. Easily as good as on my Octane which is an R12000 360Mhz with 3Gb of
> ram
That sounds very wrong... are you using the recent Neko mplayer tardist? IME
the Octane should be vastly quicker, especially since it's the 360... that's
the one with the jacked up SysAD bus, isn't it?
Khalid Schofield
just as good as Octane for the things I'm doing. Compressed video at
40Mbits/sec is fine :)
I used to do uncompressed work on my Octane with out a problem. I agree
that the O2 would choke is I tried to do the same here. But for general
tasks the faster cpu in the O2 makes things much much better
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
S.Chang
> Yes the Octane should be faster but since the bit rate is low the O2 is
> just as good as Octane for the things I'm doing. Compressed video at
> 40Mbits/sec is fine :)
>
it with Xvid at 23.98 FPS, data rate at 135.3 KBps with screen size of
512x384, and both of R5K and R12K 300MHz O2s are having a hard time
playing back, mplayer complains the CPUs are too slow and advice me to
use -hardframedrop, everyone in the show all have the same skin color as
Barney the purple dinosour, can a 400MHz be that much faster compare to
a 300MHz one?
S.Chang
Khalid Schofield
Erm please say how you made the divx :) I'd love to be able to divx my
movie's I've made from capturing on my O2 :)
I'm now watching the simpsons and have been watching loads of movies
encoded in divx
I'm using:
MPlayer 1.0pre5 - MIPSpro Compilers: Version 7.4.2m (C) 2000-2004 MPlayer Team
I also set a copy of 'The Passion' playing that I captured on the O2
yesterday. The file was 38Gb's and I was outputing to video and recording
on S-VHS. No frames dropped. I'm using a disk that irix seems to get about
40Mb/sec out of
Check your disk speed using this
diskperf -W -D -r 1296k /disk_under_test/benchmark
/disk_under_test is the mount point of the test disk and "benchmark" is
the output file that diskperf writes it's bits too so it can test disk
performance with.
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
S.Chang
up-to-date version later on, never thought this could be a problem
though, I am still using 0.93 on my Sun.
> Erm please say how you made the divx :) I'd love to be able to divx my
> movie's I've made from capturing on my O2 :)
>
I use MEncoder, never try it on my SGIs, I know it will take too long to
encode 1 hr of Stargate SG-1...
you could also try ffmpeg, I use this on my Sun and ffmpegX on Mac, the
quality is better than using DivX Pro in my opinion.
> diskperf -W -D -r 1296k /disk_under_test/benchmark
>
> /disk_under_test is the mount point of the test disk and "benchmark" is
> the output file that diskperf writes it's bits too so it can test disk
> performance with.
>
That's the first thing I did, disk I/O seems to be normal.
S.Chang
S.Chang
Got the 1.0pre5 installed, and staring with
mplayer -vo sdl -ao sdl -framedrop video_file
without mplayer.conf
still very slow, the sound and the video are not synchronized.
The strangest thing is I just did a diskperf -W -D /test on the R5K O2,
and it's reaching 40MB/s whereas the R12K O2 is struggling to get to
30MB/s, both systems have new Seagate 10K RPM 73GB disks, the only
difference is the R5K is runs 6.5.25 and the R12K is still running
6.5.15 from Ian's original setup.
S.Chang
Khalid Schofield
So are you capturing using dvgrab on your SGI then divx'ing your files?
What format are your movies when you feed them into mencoder?
What command are you running to make your divx?
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
On Thu, 7 Oct 2004, S.Chang wrote:
Khalid Schofield
my seagate 7200rpm disk. When I installed my 72Gb seagate 10k rpm disk I
got 40Mb/sec :) When I capture I nail the processes that are not needed
(like all those httpd's esphttp stuff and the ns-httpd, do you know what
chkconfig I have to switch off in order to never get any of the httpd's
running by the way? webface is off).
I'm just running mplayer with the defaults from
/opt/mplayer/etc/mplayer.conf as they are well optimised for CRM graphics
:)
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
On Thu, 7 Oct 2004, S.Chang wrote:
S.Chang
> mencoder :) yay
>
> So are you capturing using dvgrab on your SGI then divx'ing your files?
> What format are your movies when you feed them into mencoder?
>
> What command are you running to make your divx?
>
mencoder video_you_want_to_encode.mpeg -oac lavc -ovc lavc -o movie.avi
-lavcopts vcodec=mpeg4:autoaspect -vf crop=716:572:2:2,scale=640:480
This is what I use to convert.
Here is the page for using MEncoder to encode
http://www.mplayerhq.hu/DOCS/HTML/en/mencoder.html
S.Chang
Khalid Schofield
how are you moving the SGI video format to mpeg2? Or are you just
capturing on your PeeCee and not using the sgi?
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
S.Chang
> Neat
>
> how are you moving the SGI video format to mpeg2? Or are you just
> capturing on your PeeCee and not using the sgi?
>
SGI, and they would take too long to convert the files.
mencoder should also be able to convert SGI video file to divx.
S.Chang
Khalid Schofield
the goal I set out with :)
Wonder if anyone has done it. I've never amanged to get my irix captured
video files to play back on a PC :(
*********************
Khalid Schofield
System Administrator / EM Technician
Dept. Of Materials
University Of Oxford
Parks Road
Oxford
OX1 3PH
Email: khalid.s...@materials.ox.ac.uk
Tel: 01865 273785
Fax: 01865 283333
Web: http://www-em.materials.ox.ac.uk/people/schofield/index.html
On Fri, 8 Oct 2004, S.Chang wrote:
Lewis Saunders
> Got the 1.0pre5 installed, and staring with
> mplayer -vo sdl -ao sdl -framedrop video_file
> without mplayer.conf
> still very slow, the sound and the video are not synchronized.
Bad bad bad... if you got the new magic special version from nekochan.net,
you should use -vo -sgi -ao sgi, or just let it use its defaults. Should be
a huge lot faster than the SDL output plugins.
S.Chang
S.Chang