how do I avoid large file sizes with virtualdub?

[maureensullivan]

I have been converting avi files with dvcodec into avi files with divx codec. I use virtualdub. I have noticed though that the divx file sizes I get after conversion with virtualdub are larger than the dvcodec files I started out with. Sometimes over twice as large. Am I doing something wrong? I open the file in Virtualdub and select fast recompress in the video menu, then select divx in the compression menu there. I select full processing in the audio menu and mpeg layer 3 in the compression menu there.

[maureensullivan]

Here is a screen shot of the properties of the dvcodec file I started with which was 711,816 KB in size

[maureensullivan]

Here is a screen shot of the properties of the divx codec file that I created with virtualdub which is now 1,582,082 KB large

Notice that even though I chose mpeg layer 3 compression in the audio compression menu its saying the audio format is "PCM". Ihave no idea how that happened either.

[Baldrick]

Are you using same video bitrate in virtualdub? 121kbps. It is a very low bitrate for video....

[maureensullivan]

I really do not know. I am not that sophisticated yet.

[Baldrick]

Select Video->Compression, choose the DivX, click on Configure and under Rate Control Mode set the Bitrate.

[jagabo]

Regardless of what Windows is telling you, the source files are not DV codec. DV only supports 720x480 NTSC, or 720x576 PAL. And it only supports one video bitrate 3600 kbps, not 121 kbps.

The reason your files are growing is because your output bitrate is higher than your source, both the audio and video.

[maureensullivan]

Thanks. So, ...
a) what are the files I have?
b) how do I set the output so that it is the same as my starting file?

for the file in my example how would I change the audio output to be the same as the source file? Use "direct stream copy" or use full processing and select the mpeg layer 3 under the compression menu? And if I do that which of the many formats in there should I choose.
and how do I change the video settings? go into the divx settings, and then select 121kps in the rate control box?

[maureensullivan]

PS I am converting these files to divx because divx files will play on my D-Link wireless media server. The original "dvcodec" files will not play. Picture, and even sound quality is not that important to me at this time. I am trying to save precious space in my hard drive, so I want to convert all the files that won't play, into a version that will play, so I can delete the originals. I want as small a file size as is possible so I can store as many of them as possible on my hard drive.

[jagabo]

a) what are the files I have?

VirtualDub should be able to tell you via File -> File Information. Or you can use AVICodec or GSpot.

b) how do I set the output so that it is the same as my starting file?

Use the same audio and video bitrates.

for the file in my example how would I change the audio output to be the same as the source file? Use "direct stream copy"

Direct Stream Copy would be best. That would simply copy the compressed audio from the input file to the output file. But it doesn't work in all cases.

or use full processing and select the mpeg layer 3 under the compression menu? And if I do that which of the many formats in there should I choose.

You should probably keep it as MP3 since you have some hardware requirements. Decompressing 128 kbps MP3 and recompressing it back to that bitrate will cause some quality loss.

and how do I change the video settings? go into the divx settings, and then select 121kps in the rate control box?

Yes, but you probably want to use a 2-pass encode for best quality. Set Divx to Multipass First Pass, Save as AVI, then set Divx to Multipass Nth Pass and Save as AVI again. During the first pass Divx is only examining the video. During the second pass it uses the information from the first pass to compress the video as best it can for the given bitrate.

[maureensullivan]

So which is better for the audio (as in which will be the smaller file) using direct stream, or using the mp3 compression?

and how do I set the bitrate in the audio settings, I do not see a box like in the video setting to select the audio bitrate

[maureensullivan]

I do not understand your advice about the multipass. So I save the same file twice??

[jagabo]

I do not understand your advice about the multipass. So I save the same file twice??

Yes. Some frames require more bitrate than others to deliver the same quality. During the first pass Divx examines the video and keeps a log of the complexity of each frame. During the second pass it uses what it learned from the first pass to decide how much bitrate each frame should be given in order to maintain the best image quality for the specified average bitrate.

[kschang]

Yes, exactly like he described.

The first time you save, the program will spit out an output file, then a "profile" of the output to be used in the 2nd pass.

The 2nd time you save, after setting it to 2nd pass, it'll then give you the final output.

Depending on your CPU power, each pass can take several hours.

[maureensullivan]

OK I downloaded avicodec and used it to id the avi files I downloaded.

Here is the tech specs for avi files for my media player:
Supported Video Formats:
• MPEG 1 (up to 8Mbps)
• MPEG 2 (up to 8Mbps)
• MPEG 4 (ASP - Advanced Simple Profile)
• XVID (with MP3 and PCM)
• AVI (MPEG4 layer only, does not support uncompressed AVI)

The avi files I downloaded do not play in my media player. But when I use virtualdub to convert them to divx they do play.

here is what avicodec said about the 2 files I have been mentioning:
original file (does not play in media player)
File : 695 MB (695 MB), duration: 1:37:23, type: AVI, 1 audio stream(s), quality: 51 %
Video : 605 MB, 869 Kbps, 29.969 fps, 480*360 (4:3), MP42 = MS MPEG4 V2, Supported
Audio : 89 MB, 128 Kbps, 44100 Hz, 2 channels, 0x55 = MPEG Layer-3, Supported

divx file I made with virtual dub (does play in media player)
File : 1.50 GB (1.50 GB), duration: 1:37:23, type: AVI, 1 audio stream(s), quality: 74 %
Video : 562 MB, 806 Kbps, 29.969 fps, 720*480 (4:3), DX50 = DivXNetworks Divx v5, Supported
Audio : 982 MB, 1411 Kbps, 44100 Hz, 2 channels, 0x1 = PCM, Supported

It looks like the original file is MPEG version 4, so I wonder why it won't play.
Anyway since I know divx will play, I want to use virtual dub to create the smallest file size that will still ply in my plaer.

any insights?

[kush]

Or give Gordian Knot, with autoGK (which in turn controls VDub and other progs) as the front-end program to do the conversion for you. Load the video in question, and in AGK, set the fps you want (likely unchanged), resolution (probably stay auto or fixed 640), audio bitrate (there is an 'original' tickbox suggest you prob use that), target size (completed file)..Then preview to see if it will look right for you, then add job -> Start.

I suggest using AGK for the simplicity - for me even running conversions manually, with some good guides here I wasn't able to hit a proper two-pass target size for some reason..Found AGK way back when, and don't need to even worry about that anymore.

A few more things:
a) I believe it defaults to two pass encoding, so no changing there
b) Some of the stuff I mentioned above are in a 'hidden' settings menu (Ctrl-F9 combo iirc), but I suggest you *not* fiddle with those unless either know what you're doing and/or are willing to experiment (and waste some encode time)..For example, I have to use the hidden settings auto-crop tuning needs to fiddle with some HDTV capture conversions.
c) I know it's been mentioned before, but the Windoze properties panel (in my experience) it terribly inaccurate in it's file info..I personally use GSpot for that purpose...As mentioned VDub will tell you, but for me, importing 2-4+ GB .TS HD streams take too darn long in VDub.
d) I ramble a bit too much when I've just woken up not long ago and haven't had enough coffee yet ...All this to pretty much say ause AGK, it's a nifty little program..

[edit] MS MPEG4 v2 - it my memory hazy or is that that crappy old pre-Divx/Xvid hacked M$ codec?..Anyway, to get a the same size, in whatever program(s) you end up using for the deal, try setting the same bitrates as Avicodec gave you..To shrink a bit more, you could try dropping the audio to 96k - although I wuoldn't suggest it..128k is the lowest I'd EVER go, below that it starts to sound really tinny in my experience..You could lower the video bitrate some, but I wouldn't do that unless you're either willing to take a quality hit, or resize down some to compensate (ie: down to 512x384 or something - keeps the same 4:3 ratio).

[Nelson37]

You have an old, MPG4 file.

You are upsizing the video to 720x480.

You are getting completely uncompressed, PCM audio. This is causing your file size issue. Just look at the video and audio filesizes.

Your problem would have been prevented by a more complete understanding of the process. Correct procedures for this conversion are available in multiple Guides. There is no substitute for doing the basic reading which will give you a more complete knowledge of what you are attempting to do.

More complex procedures, even with complete, step-by-step instructions, will be much more difficult without an understanding of the basics of video.

[jagabo]

VirtualDub:

File -> Open Video File
Audio -> Direct Stream Copy (the default anyway)
Video -> Fast Recompress
Video -> Compression -> Divx (multipass first pass)
File -> Save as AVI
Video -> Compression -> Divx (multipass nth pass, set bitrate)
File -> Save as AVI.

[Cornucopia]

Since your player supports mp3, you should leave the audio alone (aka DirectStreamCopy). For video, Xvid looks like a good choice.

The "old MPEG4 v2" isn't a standard ISO MPEG4, it's Microsoft's very non-standard variant of it (they jumped the gun) which they tinkered with on the road to coming up with WMV (also non-standard MP4). So, it's gonna have to get changed.

Choice is to upsize or not? Depends on how your player plays it. It could automatically blow the 480x360 up to full screen, or not. If it does, your job is easier, just change the codec and the bitrate. Unfortunately, your original BR is a probably a little too low for great quality. You don't want to lose more, so you'll want the BR to be a little bit higher. I'd go ~1.2Mbps, which will give you a 38% increase in the size of the video stream (audio being the same). Make sure PAR is 1:1.

If your player DOESN'T support auto-blowing up smaller sizes, you should resize to 720x480, with NTSC PAR (0.9090909:1) and accordingly give it a slightly larger bitrate (say ~1.65Mbps).

All other encode choices (GOP, Q-matrix, etc) should be whatever you player supports best.

That's a good starting point, but you decide what works for you.

Scott

[Scorpion King]

File : 695 MB (695 MB), duration: 1:37:23, type: AVI, 1 audio stream(s), quality: 51 %
Video : 605 MB, 869 Kbps, 29.969 fps, 480*360 (4:3), MP42 = MS MPEG4 V2, Supported
Audio : 89 MB, 128 Kbps, 44100 Hz, 2 channels, 0x55 = MPEG Layer-3, Supported

you know, trying to explain how to do a conversion process to someone new to video is tough. There are so many variables and so much to explain I too think it best to read the guides. You will learn a lot and what you learn you will remember.

This file you have looks like it is already converted, you just need to get it playing on your computer. It might be with an old mpeg4 codec but a conversion to divx isn't going to make the file that much smaller if you retain the quality the file has now. Yea I know it will be a little smaller, and it might look just as good (or bad) as it does now, but to go through all this conversion process for a few MB? Not me, Im toooo lazy. lol

I have never worked with MS MPEG4 V2 before (that I know of) so I just now created one. In VirtualDub I used ffdshow for compression then from inside ffdshow the MS MPEG4 V2 codec. The file plays fine in WMP and Media Player Classic.

Looking at the microsoft site I found this: http://support.microsoft.com/kb/899113
It appears I got MS MPEG4 V2 support in XP-SP2. Thanks Bill.


Wouldnt it easier to get the file to play? Who knows, might be fine as is.

Best of luck.

[jagabo]

This file you have looks like it is already converted, you just need to get it playing on your computer.

You seem to have missed this:

PS I am converting these files to divx because divx files will play on my D-Link wireless media server.

[Scorpion King]

The avi files I downloaded do not play in my media player. But when I use virtualdub to convert them to divx they do play.

In my post I was assuming the "files won't play" on his D-Link because he can't get them to play on his computer. I am also assuming the data rate of 869Kbps isn't the problem for his server since a conversion to Divx isn't going to lower the data rate that much unless he really is willing to take a quality hit. I don't remember the throughput off hand of IEEE 802.11 but I assume it is plenty high enough for either file. My wireless Linksys router says "rate: 36Mbps".

The original file is 695MB and 1:37:23. That looks like 7.15MB per minute. 2 cans and a string should work for that much.

And I guess I am also assuming that since the original files were encoded using MS Mpeg-4 V2 that the quality level is low (by todays standards) even at 869Kbps making it probably necessary to clean up the video, something that I feel is/might be difficult for someone new to video.

And I am assuming that in the real world a file that is 695MB just isn't that big anymore.

Good luck all.

edit: I am also assuming that for compatibilities sake ffdshow will always be around.

[jagabo]

In my post I was assuming the "files won't play" on his D-Link because he can't get them to play on his computer.

I know, but I think the OP was talking about this:

http://www.dlink.com/products/?pid=318

And inadvertently referred to it as a server, not a player.

[Scorpion King]

Ok Thanks jagabo.

I still think the 2 cans and a string would work.

I'm gone.