Hey Göran,

It seems to me you're dealing with MiniDV video.

If you're encoding a one hour long tape, then it's very likely those 
80mb may be the audio which is not accounted for.  Now, MiniDV cameras 
typically record in 12bits/44khz, or 16bit/32khz.  Either way, if you 
convert down to mono and downsample to 32khz with an audio program, then 
you can use something like 48kbps LAME CBR mp3 encoding, which will 
reduce the amount of space you need to dedicate to the audio.  This 
should sound reasonably well.  If you're inclined to, you may want to 
train a noise reduction filter and run the audio through that first.  If 
all you care is about voice, you can downsample all the way down to 
22khz or even 16khz without much loss of anything.  If you go below 
16khz, then female voices will start suffering.  Less khz, less bitrate 
necessary to encode it, and more bits you can dedicate to video.

Regarding the video, and particularly for presentations, you may want to 
run the raw file through a temporal smoother filter.  VirtualDub has 
one, and I've used it more than once with very nice results (e.g. about 
80 mins of DivX half resolution video in about 200mb, including the 
audio!).  This will eliminate noise while making video look very nice, 
and a side effect is that you get better quality from the video encoder 
since it has less high frequency noise to deal with.  In other words, 
less bitrate dedicated to the grainy mess, and more bitrate dedicated to 
e.g.: making the slides legible :).

Something else that you may want to try is either tell XviD to preserve 
the interlace, or just deinterlace the video altogether.  Deinterlacing 
properly without ruining the resolution is difficult, but done well it 
looks fantastic in progressive monitors.  Essentially you get (assuming 
PAL) 50fps of almost full resolution frames.  The only bad thing about 
this is that it takes more space.  You may get away with it if you run 
the whole thing through a temporal smoother filter first.

Hope this helps,
Andres.


Göran Krampe wrote:
> Hi fellas!
>
> The "raw file" is about 12Gb for 1 hour. :) I am using XviD, 2-pass
> encoding and setting size to 700Mb (though they seem to end up around
> 780). This was a quality level I ended up with when I taped Bryce in
> Brussels - in order to have legible text on the projector.
>
> Someone told me to use a quantizer - perhaps it was Marcus Denker? I
> haven't done that though - should check before encoding the rest of the
> tapes.
>
> I will try to get some more files done later tonight.
>
> regards, Göran
>
>   
>> I think youtube has a limit that is well below the 1h length and 700MB
>> size. Here [1] is a version of the first video on sevenload.
>>
>> Alex
>>
>> [1] http://en.sevenload.com/videos/fLnZ2gj/Squeak-BOF-OOPSLA-2007-1-3
>>
>> Bergel, Alexandre schrieb:
>>     
>>> Thanks Goran,
>>>
>>> This is great!
>>>
>>> Would it be possible to get the raw file? I would like to put it on
>>> youtube
>>>
>>> Cheers,
>>> Alexandre
>>>
>>>
>>> On 25 Oct 2007, at 08:28, goran at krampe.se wrote:
>>>
>>>       
>>>> Hi folks!
>>>>
>>>> Ok, the first tape is up now - second will be up very soon, third
>>>> coming
>>>> in a day or two, read more here:
>>>>
>>>> http://goran.krampe.se/blog/OOPSLA/OOPSLA07-1.rdoc
>>>>
>>>> regards, Göran
>>>>
>>>>         
>>     
>
>
>
>
>