Are codecs and muxs related to supermarket trolleys?

[ACTCMS]

I'm beginning to suspect that codecs and muxs share a significant amount of DNA with supermarket trolleys - you know the way that trolleys seem to want to do their own thing...

I had everything working fine, then all of a sudden when playing a .mpg video on a machine set up as a GBPVR client:

• GBPVR plays video with no audio
  
• WinAmp plays audio with no video
  
• VideoLan plays both

So some codec or other has suddenly decided to turn left when I really wanted to keep going the way I was heading, or maybe it's a mux - or a graph :confused:.
With a screwdriver and a hammer of the right size I could fix a trolley, but I don't have a clue where to hit a codec.

I know what a codec does and I have some nice tools like GSpot to find out how a file is constructed, but I don't know yet how to figure out what codecs any of my players are using for the same file, or how to control what codecs they are using. I know that there are various config options but they generally rely on the user already knowing which option to chose and so provide little guidance as to the effect of changes (thats why I normally go with the defaults).

Anyway the question is: does anyone know of threads or articles or books through which mastery of the codec could be achieved?

The sorts of thing I want to learn about are:
Installation: what makes a codec available to the OS
Discovery: how do players know which codecs are available
Playback: how do players match a file to codec(s)
Control: how do you change things for the better?

[sub]

Best advice, explicitly select the decoders you want to use in the config app rather than relying on the 'system default' setting - which effectively tells Directshow to pick some random decoder.

[ACTCMS]

Best advice, explicitly select the decoders you want to use in the config app rather than relying on the 'system default' setting - which effectively tells Directshow to pick some random decoder.

I just did what you suggested and by process of elimination I found that by changing my Audio Renderer setting to 'Realtek......' GBPVR now plays video and audio and VideoLan stills works.
I will probably be able to solve my WinAmp problem using the same principle, but I'd still like to find out a bit more about the why...

For instance:

'system default' setting

Something must set these...

[sub]

You can workout which is the system default if you know the rules, but its pretty painful and manual, and I dont have time to explain it. If you want to google on 'directshow merit' you'll find info on the right topic.

[ACTCMS]

And that looks exactly like what I am looking for... TVM

[Ted the Penguin]

however, codecs can be like supermarket trolleys in another way. sometimes the best thing to do is get rid of it and start over.

a good thing to try when codecs are being messed up is to uninstall every codec you have, then reinstall them, one at a time, to see which one is really causing your problem.

[ACTCMS]

however, codecs can be like supermarket trolleys in another way. sometimes the best thing to do is get rid of it and start over.

a good thing to try when codecs are being messed up is to uninstall every codec you have, then reinstall them, one at a time, to see which one is really causing your problem.

and the general principal behind that advice - install only what you need and absolutely nothing else - is so good, it applies to most aspects of running an efficient, reliable and stable system. I've also read several times in the forum that it's better to specify what you want (for codecs/muxs/etc) rather than leave it to 'System Default' (whoever he is) to decide - and that is equally good advice. All advice is very much appreciated...

However, my OP was really asking for a starting point which would allow me find out more about the nature and substance of 'codecs' so that I could follow such advice with a bit of confidence instead of a purely 'Monkeys and Typewriters' approach.

Following sub's advice I googled 'directshow merit', and went to the wikipedia link on directshow. so far I've only had about 30 mins at it, but I'm starting to think that what I have been referring to as a 'codec' might in fact be a 'graph'? I am certainly begining to see how complex the topic is... Already I am seeing how crucial directshow is to any form of multimedia application. Call me old fashioned (in fact, call me anything you like) but I've never been happy relying on technology unless I have at least a basic understanding of it.

Once I do tho', your suggestion is something I will be coming back to.

[Ted the Penguin]

so my understanding is that directshow creates a graph which contains all of the codecs/filters/renderers etc. that will be used to play a file, and you can look at that graph using graphedit, sometimes edit it, but not for GB-PVR. how it picks the stuff to put in that graph, well I know that filters can set them selves as default, and then there are the monkeys... with typewriters

[gEd]

this program enables you to take a good look at the directshow filters and codecs on your system. It also lets you set their merit.

http://www.free-codecs.com/download/RadL...anager.htm

[ACTCMS]

so my understanding is that directshow creates a graph which contains all of the codecs/filters/renderers etc.

That's the sort of understanding I am looking for, but obviously the forum is not designed for posting the volume of info required to explain it all in detail, hence the OP request for pointers...

this program enables you to take a good look at the directshow filters and codecs on your system. It also lets you set their merit.

http://www.free-codecs.com/download/RadL...anager.htm

Just downloaded and installed it on my GBPVR client machine and first impression was - That looks useful and there's not that many codecs in there to do further research on, I'll just look at each one in turn, find out the what, where and why of it - what is in which graph etc etc etc - Then I ran it on my server... there are zillions of them on there :eek:

Client machine is a clean XP install which I regularly wipe, ghost in an image, and start again. Server has been running for about 4 years - started off as 2K - upgraded to XP - must have had a couple of dozen different audio/video/dvd editing programs installed over the years. Amazing difference - there even modem audio codecs on there...

First use brings up a couple of questions (since you're here):
The GBPVR audio problem was solved by changing the audio renderer from 'Mr Default' to 'Realtek HD audio rear output' - there is also a 'Directsound: Realtek HD audio rear output' - what's the difference?
Most of my codecs seem to be merit 0x00000000 - not what I would have expected - I missed something?

Did a bit of research and found this on GDCL - now it's starting to make a bit of sense...