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Video playback on RISC OS

By Martin Hansen. Published: 30th Aug 2004, 11:49:29 | Permalink | Printable

What we've got, and looking forward to

Intrigued with digital video playback on RISC OS, Martin Hansen reports on his recent intrepid investigations. It's a messy job, but someone's got to do it.

My daughter, Fran, became a teenager this week although, as I often tell anyone who will listen, she has been acting like one for at least the last couple of years. This manifests itself in many ways but what prompted this article is her emerging passion for rock music played by unsavoury types. A couple of weeks ago, not contented to simply listen to 'The Rasmus' on CD, she began to excitedly wave their CD single at me: track four on the CD, she had noticed, featured a video of the band performing In The Shadows.

I immediately decided not to tell her that her A6 from Stuart Tyrrell could probably play this under WindowsXP or that a DVD player I'd recently seen in Woolworths for around 40 quid claimed to play VCDs (Video CDs), which, I presumed, was what she enthusiastically held too close to my eye-ball to focus on. I had just the machine, I assured her, that was up to the job.

A RISC OS 5 filer windowInto the DVD drive on the Iyonix went the CD and the filer successfully opened the computing component on the CD. As you will see from the screen shot there is quite a lot of clutter but what made me smile was the bright red MPEG icon. I dragged it across to my hard disc, noting that it was almost 50MB of data. These days, 50 'meg' is not a lot and perfectly manageable.

I could remember an announcement in one of the June ANS newsletters that KinoAMP, the MPEG movie player, had been upgraded and so I visited Peter Everett's site to download version 0.32. Similarly minded music video enthusiasts, will also need either AMPlayer or DiskSample as KinoAMP needs one of these to play the sound part of the video track. Do read the installation instructions carefully, as I did, and, hopefully, everything will work right away. I discussed getting AMPlayer working on Iyonix in my recent review on drobe.co.uk of R-Comp's MusicMan, so you may want to re-read that if you have problems.

KinoAmp playing on an IyonixWith the applications software in place, simply double clicking the MPEG icon launches the video. I immediately put The Rasmus on full-screen, much to Fran's delight. The results are excellent and this is the first time that my daughter's rated the Iyonix, "very impressive". MPEGs aspire to display 25 frames per second, but if a system can't cope with that rate, KinoAMP will do the best it can and show, say, 18 of those frames each second. Once the novelty of seeing an MPEG play at all has worn off, dropped frames become, I think, quite noticeable and irritating. The Iyonix didn't drop a single frame.

You can play most music video MPEGs from the CD, or the hard disc, although I later found that, to avoid the occasional "hung machine" problem, from RAM disc is best. I initially discovered this by accident. First, I realised that it is a real faff to have to change CDs all the time, as CD singles typically last under four minutes. Then, having got them on the hard disc, I didn't like to see the drive working as if it were in a Windows machine, constantly pulsed and thrashing. Hence the RAM disc solution. A minor annoyance here is that on the Iyonix this is limited to 131MB, and that's enough room for only two MPEGS at a time. Two RiscPC solutions to the RAM disc limit problem, BigRamDisc and Memphis have not, yet, made the jump to 32bit compatibility.

We still have a lot to discuss regarding the playing of all CD singles with a video track on the Iyonix, mainly because, as I found out over the next few days, 70 percent of singles don't have a straight forward MPEG sitting there, waiting for a RISC OS user to pull it off. First, however, let's take a look at what KinoAMP can do on a StrongARM RiscPC.

When I put one of these enhanced CDs into my Viewfinder fitted Kinetic RiscPC, it froze the machine. I'd known for a while that RISC OS 4 had a problematical CD Filing System but this was the first time I'd been seriously inconvenienced by it, and all the more so when a supposed "bug fix" on the internet didn't work for me. I believe that Warm Silence Software's replacement CDFS will cope, or, alternatively, I could haul the MPEGs in via a network link from Iyonix.

I decided to give RISC OS Ltd a call and order the Adjust 4.39 ROMs, which I'd been meaning to do for quite some time, anyway. These came the next day and resolved the CDFS issue for me although another promptly emerged; AMPlayer could no longer seem to access an essential module, the shared C library, correctly. After trying hard to resolve this issue, I decided to switch to using DigitalCD and DiskSample to play the sound part of the MPEGs. Using the link on Peter Everett's KinoAMP website, I downloaded this. I then noticed that one on the files was a bug-fix for earlier versions of Select running DiscSample on Kinetic. As you've probably guessed, this fixed the problem I was having with AMPlayer under the Adjust ROMs on a Kinetic RiscPC.

KinoAmp playing on an IyonixStrongARM catches its breath
KinoAMP does work on a StrongARM machine but you need to help it all you can and, even then, it's not perfect: frames are dropped. For full screen viewing (only) I had to disable Viewfinder with the command *Configure ViewFinderEnable 0, having first hooked up an old AKF60 monitor to the non-Viewfinder video-out. This was just as well, as I then dropped the frequency down to 60Hz which neither my modern CRT or my LCD monitor would have displayed. The MPEG was placed on RAM disc and an acceptable result achieved - one that I would not be embarrassed to show to non-RISC OS users.

I've achieved similar results on other StrongARMs; a 233MHz machine with RISC OS 4 and Select 3i3, and another with RISC OS 3.7. Prior to RISC OS 4, you'll need the BigRamDisc utility rather than Memphis, which is too slow, to create the necessary RAM disc. Incidentally, if you need more RAM for your machine, give APDL a call. I bought an extra 64MB for 22UKP including posting and packaging, which, with a 32MB card already in place, plus 2MB VRAM, has given a friend's machine a cheap boost into the video age.

Some readers may be thinking that this is pouring money into a system that simply can't quite cope. However, the truth of the matter is that KinoAMP, whilst being a substantial step forward for RISC OS, is still not optimised to make the most of the RiscPC's hardware. Other software developments are hovering tantalisingly on the horizon, of which more shortly, and KinoAMP 0.32 is where we have got to at the moment rather than, necessarily, being the final word.

Inspired by the initial successes on both Iyonix and the StrongARMs, I decided to aquire as many CD music videos as I could, and as cheaply as possible. An eBay search using "CD single video" is very effective and a day passed writing out cheques for tiny amounts of money. A local second hand CD shop sold me around forty discs at less than one pound each, and I toured the bargain bins at Woolworths, Virgin and HMV both locally and, as the opportunity arose, further afield. A CD fair in Birmingham was disappointing, unless one was willing to spend at least a fiver a time, and often a lot more, which I was not. I've now got 89 of these discs [89? Give that man a medal - Ed] but, as they came flooding in, I quickly realised that, for RISC OS, there is a problem: only 24 of these had an MPEG on them and, of the other 65, 63 feature something called an AVI file and two remain classified as "seriously weird: investigate later".

More video
KinoAMP can only play MPEGs. As I began to ask around I realised that the world of AVIs is not straight forward, and it took me a while, and with some extraordinarily generous help from some busy programmers, before I felt I was starting to understand what an AVI was, never mind about whether RISC OS could, or was ever likely to, be able to play them. In particular, I had some very profitable email exchanges with Adrian Lees and David McEwan. Adrian is pushing along the CinoDVD project which will make DVDs play on an Iyonix, and maybe, depending on how things pan out, on RiscPCs. David has developed a major application in his spare time called Cineroma. Famously, this is being perfected before being released, in spite of wild enthusiasm about how good it already is from beta testers. It is rumoured to play just about any movie format you care to mention. Release dates for both projects have yet to be announced. Personally, my fingers are crossed for Wakefield 2005, but they are difficult endeavours, and much remains to be done with both of them.

I've enthused about Iyonix-Support in the past and in that forum a useful early posting informed me that an AVI was not a single filetype, in the sense that an MPEG is. Rather it was a Microsoft designed wrapper for packaging all sorts of file-types, primarily intended for unpacking via Microsoft's media player. Armed with this knowledge I was able to ask Adrian and David some slightly more probing questions about what an AVI really was.

Adrian Lees was very specific, "AVI is just a way to interleave a number of audio and visual streams. Just imagine that you have 'n' audio streams and 'm' video streams, and you grab a bit of this audio, then a bit of that video, another bit of this audio, and so on. It's a way to combine multiple streams in a single file."

David McEwen was careful to point out that the AVI wasn't just a wrapper to get off and throw away, "The actual container [the AVI wrapper] of a movie file is very important as it contains pertinent information about how to play the movie, tell you the codecs used [of which MPEG is but one] and, for example, the timings for each frame.

I was intrigued by all of this; inside some of these AVI files could simply be an MPEG, but I couldn't manually just remove the wrapper by hand, as I had, perhaps naively, initially hoped.

Adrian again: "Normally, an AVI is used to wrap a single audio stream and a single video stream. In the case of an MPEG, it wraps a single MPEG stream, which is already audio and video into a single AVI stream."

So, where does this leave RISC OS in the mighty quest I'd given it, namely, to play CD pop-music singles with video ? Both Adrian Lees and David McEwen, were up-beat about the future. Soon, you will not have to abandon RISC OS in order to play an AVI.

Adrian Lees thought that Cino should play some AVIs and do so well. He commented, "The fact is that whilst the Iyonix's hardware is not equal in performance to the PCs built in the last three years, our software is greatly under-using what we do have as, indeed, WindowsXP does with what is available to it. Decoding and rendering under RISC OS could be many times faster."

And David had this to add, "Cineroma will not need anything done to the majority of AVI files you are looking at to be able to play them. Like with an MPEG in KinoAMP or a Replay file, you just double click on a file and it will play."

In the meantime, we do, thank's to Peter Everett's efforts, have the new version of KinoAMP; and it's free. If you've got some enhanced CD singles in your collection, do try them out. RISC OS is not fully modern multimedia compliant yet, but further progress seems to be on the way.


KinoAmp VCD compatibility list
AVI overview MPEG overview

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Interesting article. I was surprised when there was actually an MPEG file on the CD, and that it was suggested these discs will play on a VCD player; Enhanced CDs are very rarely VCDs. What you normally find is a Macromedia Flash file (and player for Windows) on the disc with embedded video, of some kind. On top of that, there are also the fancy graphics and links to hidden parts of websites. As to whether this works on !Flash, I have no idea. I seriously doubt the video would play though!

Something RISC OS should latch onto before it's out of date again is MPEG4 - this goes further than previous MPEG versions. Instead of being a codec, it's become a set of recommendations about how to write a codec. Such codecs are DivX, Xvid, DV, Window Media 9, RealVideo and QuickTime. These codecs have their own pros and cons, butin general they provide better compression to quality ratios than MPEG2 (what DVDs and VCDs use). On the PC, these files normally have an AVI extension, however it is rare to find MPEG2 with an AVI extension (it's normally MPG, MPEG or MP2).

 is a RISC OS UserSmiler on 30/8/04 1:16PM
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Please note: MPEG2 is DVD and SVCD (Super Video CD). VCD (Video CD) is MPEG1 CBR.

 is a RISC OS Userbernie on 30/8/04 2:34PM
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and windows media 9 isn't mpeg4 aiui, although quicktime and realplayer are more mpeg4ish, apparently the mpeg4 fileformat is based on quicktime.

I don't think they'll be a DVD player for RiscPCs, but it was mentioned that DVDFS might be converted so owners could read data off DVDs. Anyway, DVD standalone players are as cheap as 25ukps now.

 is a RISC OS Usermavhc on 30/8/04 5:50PM
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mavhc> DVDFS will definitely be available on the RiscPC. Whether we make DVD playback available for Kinetic RPCs will depend upon whether it's fast enough to be viewable at DVD resolutions. It could, in any case, be useful at VCD resolution.

 is a RISC OS Useradrianl on 30/8/04 7:12PM
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Very interesting. The difference with the quality/timing of putting an mpeg movie file in a RAM disc being played on a RiscPC with KinoAmp is impressive. Logical now when I think of it ! Its a shame that more cd singles dont use mpeg files.

 is a RISC OS UserFuzzie on 30/8/04 9:20PM
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Another well writen article.

The news that DVDFS will come to the RISC PC is good news indeed.

 is a RISC OS UserRevin Kevin on 30/8/04 9:26PM
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Mephis is 32bit, but does not seem to be very stable. You may also find that as it uses the Sprite area, it is more limiting than the RAM disc - sprite area tops out at 16Mb.

 is a RISC OS Useropelfruitcase on 30/8/04 9:27PM
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Someone want to highlight the differences between DVDFS and CDROMFS ?

 is a RISC OS Userimj on 30/8/04 9:45PM
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DVDFS supports the extra commands required for streaming and decrypting video, as well as hopefully later adding support for DVD-RAM (ie. a fully writeable FS). It should also give better performance through use of DMA, prefetching and cacheing, although some of these will be unavailable on the RiscPC oweing to hardware limitations.

 is a RISC OS Useradrianl on 30/8/04 10:41PM
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If Memphis doesn't support using a separate DA then it'd be useful to have something that does. Then the disc can grow to the size of the machine's RAM. I had a feeling that it did though.

 is a RISC OS Userjohn on 31/8/04 12:02AM
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The minimum a DVD player on an RPC would have to do for me to be interested would be to play sound smoothly and leave the desktop responsive while playing in a window. The main use would be having music videos playing while doing something else. I would only put movies in to check what's on them. Dropped frames would not be an issue for these uses.

 is a RISC OS Userjess on 31/8/04 9:16AM
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More disks that have mpegs that work on KinoAmp. Sugababes - freak like me. Gary Numan - Rip, (2 versions, only 1 has a video) Crazier (3 versions with different videos), Hives - main offender, The lost brothers - cry little sister (this one had to run from ram disk on an RPC, the others are OK from hard disk)

 is a RISC OS Userjess on 31/8/04 9:27AM
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BigRamDisc for RISC OS 3.5 to 3.7 is at;


Another Rasmus CD - Guilty - contains an MPEG.

 is a RISC OS Usermartin on 31/8/04 11:05AM
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PS. Most of the tracks I listed would qualify as Rock music played by unsavoury types. The Numan ones both having been Number 1 on Kerrang channel for example.

 is a RISC OS Userjess on 31/8/04 12:08PM
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adrianl wrote: DVDFS will definitely be available on the RiscPC. Whether we make DVD playback available for Kinetic RPCs ...

I only have a 200MHz RPC and I asked a PC owning friend to give me a few shorts de-protected extracts of the DVDs like XMen-2. A quick test of them with KinoAmp+DiskSample+AC3 decoder shows that if I view them from HD (not enough mem to put them on RAM disc) at 50% in grey mode I have just enough power left to not break the sound (some in 2.0 and one extract in 5.1) and to get about 2fps.

HD activity alone (RapIDE) grabs 50% of the CPU so even if Cino is faster than KinoAmp for decoding the video (maybe?) and the sound (I haven't much optimised the AC3 codecI, it has the same speed as decoding MP3s) I would replace Kinetic RPC by Omega in your statement.

 is a RISC OS Userandretim on 31/8/04 3:31PM
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Thanks for the info. Cino is just over twice as fast as KinoAMP on the Iyonix, and that's playing AC3 audio too, HD access on a Kinetic RPC could be a problem, but non-blocking PIO should improve things quite a bit (time spent waiting for the data, rather than transferring it, is obviously time wasted).

I think it's a possibility, but time will tell. BTW, I believe KinoAMP would benefit from calling OS_GBPB directly rather than using the CLib routines; IIRC Cino showed a marked improvement when I made that change; presumably because of CLib's buffering.

 is a RISC OS Useradrianl on 31/8/04 5:15PM
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Changed to OS_GBPB, file reading is divided by around 2.65 here, you gain at least 1fps for VCD. Tested XMen-2 extract (with AC3 5.1): 32K, no sound: 3.22 fps -> 4.37 fps 32K monochrome, no sound 3.31 > 4.49 32K monochrome, 50%, sound: 1.59 -> 3.21 32K, sound: x -> 3.21 16M sound: x ->2.18

 is a RISC OS Userandretim on 31/8/04 8:27PM
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 is a RISC OS Userandretim on 31/8/04 8:29PM
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Sorry for the mess I was trying to post the comments with Netsurf. 32K, sound: x -> 2.57 (not 3.21)

 is a RISC OS Userandretim on 31/8/04 8:34PM
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