Question about MPEGS

[elmer166]

Ok, I looked through the web site and cannot find what I am looking for. I am not even sure what it is called. This is what I want to do. I am a Firefighter and take video of fires. I then convert them on my computer to MPEGS to be put on a web site for people to download. The files are quite large. I would like to make them smaller by taking out frames? I am not sure what this is called or if it is even the correct term. Could somebody point me to the right tutorial or the correct term for this? I hope I explained myself correctly.

Thanks

[andkiich]

If size of the videos are an issue, but you want to keep the quality high, you might want to consider maybe using DIVX or Quicktime. You can get the DIVX codec for free and the Quicktime codec will probably cost you, and am unsure of the price.

The reason I bring these other options up is that they will probably be easier to convert the files to one of these formats then it will trying to take out frames and having to worry about a/v sync issues and such.

This didn't exactly addres the question you were asking but thought it to be usefull none the less.

[Vejita-sama]

I would recommend going with DivX too. The 'problem' is that most PC do not have the DivX codec installed on them. But you can provide a link on your website for people to d/load it (it's freeware and small, so you can either host it or just give a direct link).

If you don't like that you can use either qt or microsofts ASF format. Most people do not have these codecs installed either. However, windows internet explorer will automatically connect and d/load these codecs (or direct you to where to d/load them).

With that said. MPEG files tend to be rather large. What you want to do is lower the framerate (which will affect the quaility). I would encode at 15fps at a low resolution. Neither framerate nor resolution affect size, however when framerate goes down you want the resolution to decrease or the picture will look like crap. Similarly, you can lower the bitrate because there's less video to actually encode.

In the end it's the bitrate and runtime that affect the size of your MEPG file. This is a point of confusion for a lot of people, but think about it. If the bitrate = 1000kbit/s and I have a 10sec video I'll get a 10,000kbit movie. The resolution, quaility of the source, size of the source, framerate, etc. really have nothing to do with it.

Lowering the framerate and resolution, will just make the lower bitrate movie not look quite as bad. Again thou, DivX is the best way to go for this.

[mats.hogberg]

Just keep in mind, that DivX is free for personal use only - not commercially. XviD is on the other hand completely free to use for any purpose.

/Mats

[dcsos]

Having done a lot of this first we need to know WHAT EDITING PLATFORM are you using?

Here's suggestions if you're not yet...

PREMIERE 6.5 by Adobe the standard in video editing for corporate or super-home video, but now surpassed by
VEGAS VIDEO 4.0 avail now

If you're doing MPEG, stick to MPEG-1, as playback of DVD streams or MPEG-2 requires some users to install playback capabilities if they don't have a DVD drive native to their system..
MPEG-1 on the other hand is small enough for WEB USE if you follow a
VIDEO CD or similar template
(VIDEO 352x240 from 720x480 capture or 320x240 from a 640x480 capture)
(audio 22KHZ 16 bit or Microsofts RADIO QUALITY is adequate if you do stereo for non-music fare)
YOU COULD USE MPEG-4 (DIVX)
but again many userers will need an INSTALL FILE to see your stuff

MPEG-1 on the other hand, while not as efficiently compressed,
is UNIVERSAL...
YOU CAN PLAY IT on MAC OS 7.5 and UP to OSX
hWile WINDOWS 95 VERSION B and HIGHER can play it with no additional software..
THEN YOU COULD GO QUICKTIME
I also recomend the codec thats free called CINEPAK
that is built in to WINDOWS and plays in WINDOWS MEDIA PLAYER without installing QUICKTIME..
Its not as good as the sorenson codec used by media companies for trails, but its almost as good and despite being a little fatter in file size, the resulta with CINEPAK are good if you again follow a standard template

...WITH CINEPAK QUICKTIME MOVIES you can go to a 1000KPS LIMIT per second and a halving of the frame rate 12 if your a PAL and 15 if youre an NTSC
too make a smaller downloadable file

Does this help?

[elmer166]

Yes, it helps. Thanks for all the replys. I will try your ideas tonight.


Scott

[dcsos]

You can even make MPEG-1 at VIDEO CD rates (CBR of 1150kbps)
have half the frame rate and it will play in most of the software players.
I use a plug in by PANASONIC the panasonic mpeg-1 plugin at 15frames a second and it can almost halve the file size.

I almost never use the proprietary solutions many corporations want you to use LIKE REAL MEDIA(.rm) or WINDOWS MEDIA (.wmv)..
I don't want to force formats that aren't there already!
and wmv only plays properly on windows no matter what they tell you at MICROSOFT.