Directshow Filter issue

[shumisha]

Hello there!

I am having trouble with playing some mpeg2 files. Here is the story : I have done a Powerpoint front-end to a small number of mpeg2 video files. When using this powerpoint front-end on my own PC, everything is OK, videos play just fine. When moved to other PCs, it does not work : the film is not displayed, it looks like the video player jumps directly to the end of the file, even though the film duration is correctly displayed.
I tried on a dozen PCs, it has worked about 50% of the times. These PCs have various config. : 2000, XP, XP SP2, graphic boards nvidia, ATI, various versions of directx, various mpeg2 filters (nero, pinnacle, Powerdvd). I could not find any relationship between "it works" and a specific configuration. Even older PC works where some very recent don't make it.
Let's also mention that in all cases, Windows Media Player or PowerDVD or WinDVD read all files perfectly. It's only when using Media Player (not Windows Media Player) that I have the problem, whether directly (running mplay32.exe) or when the mpeg2 file is embedded in Powerpoint.

Using Gspot, Filmerit and Graphedit, I could find a difference between a "good" PC and a "bad" one, related to the MPEG 2 Splitter (mpg2splt.ax).
- on a PC where the mpeg2 files can be read with mplay32.exe, this filter appears as MPEG2-Splitter, and it Pin 0 output type is set to Video
- on a PC where this does not work, the filter appears as MPEG2-Demultiplexer. Output type for Pin 0 is Mpeg 1, which I think is the problem.
Both PC in this case are Win XP SP2 under directX 9.0c.

Now the question is : why is this, and how do I fix it ???

I already tried, with little hope, to copy mpg2splt.ax from one PC to the other, to no avail. Any lead to a possible solution will be very much welcomed!

Thanks for any help

[celtic_druid]

For use with PowerPoint, I would stick with MPEG-1.

[shumisha]

Thanks for your reply. However,

a/ from my past experience, mpeg1 quality is too low, especially when presentation is displayed on 42" screen ! DivX could be an alternative, I have not tried yet.
b/ it works on many PCs and fails on some others, so this is really "just" a matter of a proper configuration
I'd rather not give away so easily !

Regards

[jimmalenko]

Thanks for your reply. However,

a/ from my past experience, mpeg1 quality is too low, especially when presentation is displayed on 42" screen ! DivX could be an alternative, I have not tried yet.
b/ it works on many PCs and fails on some others, so this is really "just" a matter of a proper configuration
I'd rather not give away so easily !

You realise that all versions of Windows Media Player will play MPEG-1 natively, and that you could make a 1440 x 960 MPEG-1 file if you really wanted to ?

The point being that every single PC ever with Windows on it should play MPEG-1. MPEG-2 requires something "added", such as PowerDVD or other MPEG2-capable player/codec. Also, as this is only for computer playback, you are not bound by any resolution restrictions apart from those that your video card can display on the screen, so display on a 42" screen should not be an issue. And as for quality, bitrate can be as high or as low as it needs to be too.

[shumisha]

I see your point. However, let's not forget about size. The seven clips I am including in my presentations total up approx. 2 GB when mpeg2-compressed. I have also another 500 MB of PPT files and viewer. When I talked about quality, I was not talking about resolution, which is not the main point in the matter. The main difference between Mpeg1 and mpeg2, as far as I know, is compression ratio. My clips compressed using a decent resolution will be way too large to fit on a DVD, hence making it difficult to transfer to other PC. I have not run any test on this, that's what I assumed beforehand.
Additionnally, my experience of recent PC is that they all come with DVD drive, and almost always bundled with the corresponding software, so finding an mpeg2 codec is not a problem. At least it was not on the (now) 15 PCs I tested.
Then being all mpeg2 has other advantages. I have used the same edited clips to produce a Video-DVD that can play on standalone players for example.
And last but not least, this is supposed to work easily, and it works fine on 9 PCs out of 15. I would like to understand what's going on...

[shumisha]

In addition to my previous post, please remember that this is not a Powerpoint-related issue. Playing mpeg2 does not work using MediaPlayer, even though it works using Windows Media Player. It means it will not work for mpeg2 video embedded in any other application (though I have not verified this). This is why I am willing to understand what's happening.

[jimmalenko]

Well, not to argue, but compression ratio / size of files is totally dependant on bitrate and running time, and is no different if you use MPEG-1 or MPEG-2. The exact same file encoded at the exact same specs with the only difference being MPEG-1 or MPEG-2 will come out at exactly the same file size (allowing for rounding errors, of course ).


Good luck, anyways

[shumisha]

Agreed on size = bitrate x running time, but I thought it was another difference between MPEG1 and 2 that MPEG 1 was limited in bitrate (5mbit/s ?), thus its limitation in quality when resolution was going up ? Otherwise why not use Mpeg1 instead of mpeg2 (besides other other things like VBR) ?

[jimmalenko]

Agreed on size = bitrate x running time, but I thought it was another difference between MPEG1 and 2 that MPEG 1 was limited in bitrate (5mbit/s ?), thus its limitation in quality when resolution was going up ? Otherwise why not use Mpeg1 instead of mpeg2 (besides other other things like VBR) ?

MPEG-1 is limited to 1856kbps to remain compliant with the DVD standard (@ 352 x 288), but in terms of PC-only playback, the sky is the limit in terms of how high you can push the bitrate.

I just did a sample MPEG-1 720 x 576 encode in TMPGEnc @ 12,000kbps with no hassles:

[shumisha]

But correct me if I am wrong, mpeg 2, at the same 1856kbps which is DVD standard, will deliver 720x576 display (with fairly good colors and so on) while mpeg1 is limited to 352x288. Thus Mpeg 2 must compress more that is within the same bitrate, MPEG will fit more information. Therefore using MPEG 2 I can use for instance 8000 kpbs instead of 12000 or more for the same visual quality using mpeg1 ? or not ?

[jimmalenko]

Sort-of. Not exactly right, but not entirely wrong either

Once we start talking about DVD standards and why MPEG-2 is used over MPEG-1, we're sorta getting off the track from the problem at hand, aren't we ?

(meaning I'm not sure exactly how to answer your question )


Bear in mind that I'm just advocating a way of getting around the codec issue you're facing, and saying that it could be done in MPEG-1 for PC-only playback if required ...

[mgh]

Use something like the Radlight Filter Manager to adjust relative merits.On my PC both the splitter and the demultiplexer use the same .ax file!

[shumisha]

Jimmalenko : right on, we are drifting away. It will be difficult for me to switch back to mpeg 1 as I have lost some time ago the original AVI (or actually the Studio 9 edit files). Re-compressing from the mpegs 2 into mpegs 1 will not yield very good results I believe.
I have also tried inserting a Windows Media Player object in Powerpoint, or using VLC as my default mpeg player, to no avail (Powerpoint still uses WMP, even if VLC is set as default player). Nothing I could think of works reliably....

mgh : I already tried this using Filmerit. Both are also in mpg2splt.ax on all machines I have used. But then I found a strange situation: on a machine that works (ie uses Splitter), splitter has a LOWER merit than demuxer. On machines that do not work, demultiplexer is used whatever the relative merit I set !? Any clue ?

[mgh]

Try setting demultiplexer to 20000000-i have radlight filter manager-as per them with that merit value or below-windows will not use it-as per my experience, it is true-note down original value in case you need to change back.