I've just started having to deal with some music videos that are encoded in Real Media format. I have to state that even though the compression is great it is such a pain having such a closed propriatary format!

I would like to convert it to some more open format so that I can use some of the free editing tools. I don't mind if it is converted into avi or mpg.

Now I am really not knowledgable about converting video, so here are some questions I hope someone can answer.
I do know that doing any format conversion (ie RM to avi,mpg degrades quality)

I have used a few programs to do some test conversions (RM to DixX) and the resulting file is huge! 3MB RM -> 60MB avi (default settings in the program). I know I can cut down on the bitrate to reduce the size but how does one determine the decrease in quality? are there any programs like encspot which can determine the decrease in quality when converting? Is there any correlation between the size of the original file and the size of the converted file to determine quality?

I did some extensive googling to try and find information about converting and most are very basic on how to do the conversion but I couldn't find any that talk about the details like quality, which codecs are better to use and at what settings, etc Does anyone know any sites that I might read up on this?

I guess that should be enough for now

Hi, the easiest way to convert your real video files is to install gabest's real media directshow splitter. You can get it here http://sourceforge.net/projects/guliverkli/ Also, you will need to have the real player installed to actually play the video. You will also need to have avisynth 2.5 installed, http://sourceforge.net/projects/avisynth2/ then you need to make a script like this one:
loadplugin("c:\path\directshowsource.dll")
directshowsource("c:\path\movie.rm")
#then do crop and resize if you need to do them
Then you can open this in virtualdubmod and encode to divx or xvid. As for the resulting quality of the encode, it probably will not be great. There is no program that will tell you how much it has degraded. There are measures such as PSNR which will tell you how much the resulting file differed from the original. But they are all mathematical and do not model how the human eye judges quality. So using them to judge the quality of the encode is questionable at best. As for which codec you should use, there are many out there that are very good. Personally I use XviD, I would try the default settings and see if it meets your expectations. XviD 1.0 binaries can be found here http://www.roeder.goe.net/~koepi/

Thanks Bonzi

I did some more searching and I'm really suprised that I can't find really any information about video conversion and quality differences. Now I realise it is perhaps very subjective but not one webpage seems to have information on it without just saying not good to do.

Do you think there is a difference in quality between using using a program like Boilsoft RM converter and using VirtualDub? I tend to think not since they are essentially doing the same thing?

Do you know any video forum that would be the equivalent to HA for video related information?

Hi, I have never even heard of Boilsoft RM so I cannot tell you if there will be any quality difference compared to virtualdubmod. But if the conversion is done correctly there should not be any. Personally, I would strongly suggest doing the conversion with directshow, avisynth, and virtualdubmod since this is sort of the "tried and tested" method. I would also strongly agree with you when you say that video quality is very subjective. Anyhow, as for another video board you can head over to http://www.doom9.org that is pretty much where all the video gurus hang out.

Always seem to lose the post when I write the longest posts

Boilsoft makes some 1-click software for converting all sorts of formats.
I put a lot of merit in tried & tested methods but what kind of quality differences do you think might appear between the 2?

Also do you know of any tools to check/fix problems in video files?