SGI: Video

Hi
Someone gave me a stack of VHS tapes for encoding. The VHS player provides good output, but not solid time base corrected output for the O2 not lose a frame after a few minutes.

A little research led to this link, however time has not made availability of 50buck video scaler pro devices easy to find.
http://www.unterzuber.com/TBC.html

Certainly not as cheap as mentioned on ubterzuber, at the 200$ this cbt100 appears to be the OEM for the AVT 8710
http://www.threedoubleyou.com/tbc.htm

http://www.avtoolbox.com/avt8710.shtml

Just wondering what other nekochaners have experienced at the consumer end of the video capture world.

Anyone not have use for their TBC let's PM.

Reply to myself:

The CDM-640 Videolabs Videoscaler Pro does an excellent job.

Not quite the bargain from 2004 but just completed two perfect captures in 2hrs, so that's good enough for me.

Interesting finding: occasionally the O2 will hard lock - but not! Mine has always done on capturing video, switching between an hour or so of captures, even with a different CPU and memory. I've discovered it's not _hard locked_ in the sense I understand it - catatonic, unresponsive X, mouse, and ethernet - basically no interrupt handling. The DMA for audio is still functioning, outputting to the speaker. On a hunch I flicked the input selectors on the VideoPro to attempt to stimulate the AV card video receiver and the O2 came back to life. It wasn't immediate, and took some patience. Ping and mouse came back. After that though, it locked again fairly quickly on a capture, so some kind of state is being corrupted. So a kernel deadlock tied to the video capture, and worse, one that completely inhibits X/mouse/network interrupts. C'mon IRIX. There's nothing worse than a kernel bug and no source.

So want to get into the mavb NetBSD driver for video capture, but we still need a driver for the realtime compression.

That's good to know I've got a stack of VHS tapes I need to convert and I'd dearly love to use my Octane to do it. Here's a question that's possibly worthy of its own thread, does anyone have any experience with the O2 Multiport Video Processor option? Here's a Techpubs link: http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=0650&db=man&fname=/usr/share/catman/p_man/cat3dm/video/mvp.z

that isn't an option, that's the built-in video processor of the O2.
if you want additional video ports, there was a device called the Carbon by a third party.

It's my understanding that the MVP is the option I'm using. MVP being the kernel driver for the A/V or plain audio option cars
There is a completely digital card too and maybe it's the same MVP driver. Moosehead Video Port.

It's the fairly standard audio/video board with the O2cam port. I'm using composite video in and audio stereo in.

You mention Octane: do you have the personal video option? You probably know but you don't get real time compression without the dedicated MPEG compression card. Shame they didn't put ICE in more products but that was probably market positioning for you.

So you guys are saying that's a unique capability of the O2, Octanes don't have it?

There was a whole line of products under the Cosmo Compress banner supporting XS through Impact for Indigo Indy Indigo2 and Octane. So those are all option cards for realtime compression with varying degrees of scarcity and price.
In that regard the O2 is the odd one out.

O2 CPU board contains two CPUs. One is whatever model system R5000 etc. the other is a R3000 derived SIMD which delivers real time image and media functions. It's only presented through the digital media libraries and AFAIK there's no official support to hand code it in MIPS assembler to make it do arbitrary things. What you have in Irix is all you get, see /var/arch/vicetre/.

They called this the ICE or VICE processor for Video Image Compression Engine. This utilised the O2's Unified Memory Architecture leading to the amazing effects not possible on the other platforms. Some say it's also the heart of the Nintendo 64 which may be true given the close ties at the time.

So yes by default it's only something O2 can give you, unless you have the various options.

Personal video on Octane for MJpeg must use the main CPU which was too slow for real time resulting very long post processing and you needed enough raw disk io to perform the uncompressed capture without dropping frames .

So wait, then what the heck are these two doopies for: http://www.nekochan.net/wiki/SGI_O2#O2_Video_System

I remember there was a guy on ebay selling Octane Personal Video Option boards with instructions for getting them to work on Octane2s unfortunately I did not save a copy of the instructions...

The AV1 and AV2 boards act as the analog side of the video I/O subsystem. If you take the covers off them, you find that there's not much inside; audio codec, amplifiers, video switchers and amps, and digital video transceivers. no custom chips.

rooprob wrote:
O2 CPU board contains two CPUs. One is whatever model system R5000 etc. the other is a R3000 derived SIMD which delivers real time image and media functions. It's only presented through the digital media libraries and AFAIK there's no official support to hand code it in MIPS assembler to make it do arbitrary things. What you have in Irix is all you get, see /var/arch/vicetre/.

Actually the VICE is three seperate things: a DMA engine, the bitstream processor which is a a weirdo 16 bit custom MIPS CPU that is designed for Huffman coding/decoding, and the aforementioned R3K which is paired with a SIMD vector coprocessor, AKA the MSP. The MSP can execute a scalar and a vector instruction simultaneously, so really the VICE ought to be thought of as three additional CPUs. openGL, the imaging libraries, and the digital media libraries execute code on the VICE through a library, libvice, in Irix. I have yet to locate any headers for libvice, though. Fun fact: Irix ships with microcode for the VICE for MPEG2 encoding and decoding, but there is no support in the rest of Irix. MPEG2 was one of the major design goals for the VICE, but somehow all we get is MJPEG. Maybe the chip didn't perform as well as desired. I don't know.

Thanks you guys are a veritable font of information!

jodys wrote: Actually the VICE is three seperate things: a DMA engine, the bitstream processor which is a a weirdo 16 bit custom MIPS CPU that is designed for Huffman coding/decoding, and the aforementioned R3K which is paired with a SIMD vector coprocessor, AKA the MSP. The MSP can execute a scalar and a vector instruction simultaneously, so really the VICE ought to be thought of as three additional CPUs. openGL, the imaging libraries, and the digital media libraries execute code on the VICE through a library, libvice, in Irix. I have yet to locate any headers for libvice, though. Fun fact: Irix ships with microcode for the VICE for MPEG2 encoding and decoding, but there is no support in the rest of Irix. MPEG2 was one of the major design goals for the VICE, but somehow all we get is MJPEG. Maybe the chip didn't perform as well as desired. I don't know.

Hmmmm, that's interesting, so none of that intended functionality made it into the O2+ version either? And then they left it all out for the Octane, Fuel and Tezro?

@jodys Cool. Good knowledge. I did know about the BSP and MSP but only from the old Linux source.i believe crime can also take over the from the main CPU. Any idea what the various file types are all about in the var arch vice directory.


To Vishnu comment not that the demise of sgi isn't already well covered I believe the SGI descendant of the O2 was the Visual Workstation. The O2+ was a pretty cynical relaunch of the original with minimal engineering effort.

rooprob wrote: To Vishnu comment not that the demise of sgi isn't already well covered I believe the SGI descendant of the O2 was the Visual Workstation. The O2+ was a pretty cynical relaunch of the original with minimal engineering effort.

Oh well but at least the O2+ had the R12000 400MHz version, which people must still find to be pretty useful because you sure don't see them for sale anywhere...

rooprob wrote: @jodys Cool. Good knowledge. I did know about the BSP and MSP but only from the old Linux source.i believe crime can also take over the from the main CPU. Any idea what the various file types are all about in the var arch vice directory.

the Crime chip (CRM) is like the "northbridge" of the O2. it accepts requests from the CPU and the other I/O chips and buffers them to the memory. It also contains the OpenGL accelerator component, unimaginatively called the "Rendering Engine", which is like the Indy's XL graphics (no geometry engine).
the VICE chip sits on the same bus as the CPU (SysAD bus), which limits its usefulness somewhat, since they both share the same path to main memory. Furthermore, they are not cache-coherent with one another.

vishnu wrote: I remember there was a guy on ebay selling Octane Personal Video Option boards with instructions for getting them to work on Octane2s ...

I thought the Personal Video only worked on Mardi Gras graphics ? I know it has those three ribbon cable connections to the MXE, which don't exist on VPro ... the Octane Compression card supposedly does work with VPro, tho. Have one but never installed it so I can't say from personal experience ...

robespierre wrote: the Crime chip (CRM) is like the "northbridge" of the O2. it accepts requests from the CPU and the other I/O chips and buffers them to the memory. It also contains the OpenGL accelerator component, unimaginatively called the "Rendering Engine", which is like the Indy's XL graphics (no geometry engine).
the VICE chip sits on the same bus as the CPU (SysAD bus), which limits its usefulness somewhat, since they both share the same path to main memory. Furthermore, they are not cache-coherent with one another.

I wouldn't class the O2 graphics as just another XL. Clearly it doesn't have a fully accelerated 3D pipeline, but there are compelling differences from the XL. MRE being able to do color space conversions is one of them. The VICE is available to perform some pretty substantial imaging calculations is another. I think that really the O2 is a memory controller with some coprocessors, just look at the diagram in the technical report. This is great when you are using VICE or fully utilizing the rendering engine, but not so great when you want maximum CPU speed. Hence the well documented underperformance of the R10/12k in the O2.

The VICE and the CPU are not cache coherent but I don't think that is really necessary for their purposes. If your MSP is processing GBs of data sequentially do you really want to keep a cache coherent?

I think what limits the VICE is not a shared bus but the sheer complexity of making it work. A driver and library would already handle loading ucode and allocating buffers, but you'd be writing two different bits of assembly, both of which need to be less than 4k and both of which are different dialects of MIPS. Furthermore, each chip has loads of quirks and probably bugs.

I agree the VICE is neat, but it is also quite slow (I think that both versions use a 66MHz clock). And accommodating the VICE makes the R12k's interface to the system slow as well.
One thing that is intriguing about the O2 architecture is its similarity to the Ultra64 and its RCP. I wouldn't be shocked if there was unexplored potential there for graphical (or audio) emulation.

hamei wrote:

vishnu wrote: I remember there was a guy on ebay selling Octane Personal Video Option boards with instructions for getting them to work on Octane2s ...

I thought the Personal Video only worked on Mardi Gras graphics ? I know it has those three ribbon cable connections to the MXE, which don't exist on VPro ... the Octane Compression card supposedly does work with VPro, tho. Have one but never installed it so I can't say from personal experience ...

Yeah I remember the instructions for getting those ribbon cables to talk to the VPro were decidely non-trivial.