Reducing filesize

[caper]

Hi all. Basically, I want to upload some videos for viewing on the web. They are AVI (divx) and mpegs. I want to reduce the filesize and accept that the quality will be also be reduced. since they are viewed in Flashplayer, that is ok. I normally use virtualdub and tmpgenc plus. Can anyone tell me how to reduce the filesize of the videos? Thanks in advance,
~caper

[Baldrick]

Lower the video bitrate. In virtualdub under Video->Compression->choose the codec and click configuration. In Tmpgenc Plus use the wizard mode and you can set the output file size. Or in the video settings tab lower the video bitrate.

[manono]

I want to reduce the filesize and accept that the quality will be also be reduced. since they are viewed in Flashplayer

If they're AVI they're not going to be viewed in Flashplayer. If they're going to be reencoded by the site anyway, why not just upload them the way they are? The better the quality of the upload, the better the quality of the reencode, and reencoding them yourself adds an extra and unnecessarily degrading intermediate step.

MPEGs might be worth reencoding to 1:1 as sites like YouTube don't take the DAR into account when reencoding and they'll always play with bad AR. Among other ways you can feed them into AutoGK for reencoding to a decent quality AVI.

[caper]

Lower the video bitrate. In virtualdub under Video->Compression->choose the codec and click configuration. In Tmpgenc Plus use the wizard mode and you can set the output file size. Or in the video settings tab lower the video bitrate.

Thanks, but when I choose my video source, then click on "Setting" (near "Load" and "save") everything is greyed out in the video setting window, therefore I am unable to change the bitrate I have "VideoCD NTSC" selected as the template. What am I doing wrong here?

I am also converting AVI to MPG, and when I view the mpg in media player, the actual size of the video is a lot smaller but the video size is still huge. I figured converting a high quality AVI/DIVX to mpeg-1 would have reduced the filesize significantly, but no go.

[caper]

I want to reduce the filesize and accept that the quality will be also be reduced. since they are viewed in Flashplayer

If they're AVI they're not going to be viewed in Flashplayer. If they're going to be reencoded by the site anyway, why not just upload them the way they are? The better the quality of the upload, the better the quality of the reencode, and reencoding them yourself adds an extra and unnecessarily degrading intermediate step.

They are 300MB and don't need to be so huge. the reduction in quality will not be noticeable as much as the reduction in filesize, I hope

[manono]

What am I doing wrong here?

Everything. And converting to MPEG-1 is a dumb idea because, as I mentioned, sites like YouTube don't respect the DAR when reencoding. They expect everything to already be 1:1. Plus the resolution of MPEG-1 is pretty low and has a fixed bitrate which determines the final size. If you feel you absolutely have to reencode (and 300 MB isn't so large and you haven't convinced me), and since you don't know what you're doing, then do as I suggested earlier and use AutoGK for the job. Load the AVI or MPEG, choose a codec (XviD or DivX) and a filesize, and let it go to work on them. A filesharing site like YouTube prefers AVI uploads, and will just screw up any kind of MPEG.

[caper]

Everything. And converting to MPEG-1 is a dumb idea because, as I mentioned, sites like YouTube don't respect the DAR when reencoding. They expect everything to already be 1:1. Plus the resolution of MPEG-1 is pretty low and has a fixed bitrate which determines the final size. If you feel you absolutely have to reencode (and 300 MB isn't so large and you haven't convinced me), and since you don't know what you're doing, then do as I suggested earlier and use AutoGK for the job. Load the AVI or MPEG, choose a codec (XviD or DivX) and a filesize, and let it go to work on them. A filesharing site like YouTube prefers AVI uploads, and will just screw up any kind of MPEG.

It's not youtube. Also, it isn't "DUMB" because DVDlab will not allow *.avi files in the project. I knew I was going to get a lot of "why this" and "why that".

[guns1inger]

When did DVD Lab come into the picture ?

Perhaps you need to give a little more background on exactly what you are trying to do. If you are trying to transfer files for use in a DVD project then you are better off transferring them as AVI files, then encoding on the authoring machine.

Mpeg-1 is allowed in the DVD spec, but only under certain conditions - basically to allow the easy using of VCD material. Therefore the restrictions on it's use means that the quality will be VCD quality - low resolution, low bitrate - and not DVD quality.

If we understand better what it is you are trying to achieve, we will be better able to suggest possible solutions.

[caper]

It is just like I asked in my initial post. I want to take both AVI and MPEG files, and reduce the filesize, accepting quality reductions. How much quality loss will be decided by me. Manano suggested AutoGK, but won't that be AVI? I prefer working with mpg files. Some of the files will be used in DVD lab and some will be uploaded to the net. The uploading tool is embedded in flash and thus, I get a lot of adobe alerts like "there is a script running which may cause your computer to become unresponsive". The larger the file, the longer it takes to upload, and the more of these errors. therefore I need to reduce u/l time by reducing filesize. Thanks.

[guns1inger]

You have two different targets for the file, so you should be looking at two different solutions. For DVD, if your source is worth it, you should stick with mpeg-2 at full-d1 if quality is important.

For uploading you need to consider what the target resolution will be, and what formats they accept. For there you can work out which format is best for quality versus size. Mpeg-1 is not a very good compression scheme, and while mpeg-2 is better, neither are very good at low bitrates. Xvid, Divx or even H264 are generally far more appropriate for online use because they have a superior quality versus compression outcome.

[caper]

Guys, we are getting off topic here. The question at hand is how to reduce filesize of a video, of both mpeg and avi. Thanks. I can make another thread later on choosing best format for dvd-lab another time. Cheers.

[guns1inger]

The answer, already given, is simple - you re-encode at a lower bitrate using an efficient codec, and potentially at a lower resolution.

There is nothing else to it. Easy.

All you need to do is choose the most appropriate resolution, bitrate and codec based on the target needs, which you seem to think are not relevent, or identical in all cases (and they aren't)

[caper]

ok thanks, but the problem is that in tmpgenc, those options are 'greyed' out and cannot be changed. Frustrating.

[guns1inger]

Then use a better tool, or don't use the preset templates in tempgenc

[caper]

Hmmm. I chose "New project" which gets rid of templates, and chose a bitrate of 750 instead of 1150 or whatever is there as a default, and the filesize came out the exact same. good grief.

[manono]

Still trying to get MPEG-1 out of it? Still a dumb idea. And, as I said earlier, MPEG-1 has a fixed bitrate which just happens to be ... 1150. You can set the bitrate for whatever you like and it'll still revert to 1150 if making MPEG-1. And it's CBR also, not a good way to encode when trying to shrink the size while trying to retain quality. Perhaps if you had taken gunsl1nger's advice you wouldn't be wrestling with the same problem 10 days later.

[caper]

ok, so mpeg 2 then? Basically I will accept a lower filesize(mpeg or avi) by whatever means. I was only choosing mpeg 1 because it was what worked in the past and was stable.

[poisondeathray]

Hi caper, it's already been mentioned, but all you have to do is lower the bitrate for your re-encoded video

Filesize = bitrate x running time

This is an immutable law (unless you live in some parallel universe )

For example if your current video had a combined audio & video bitrate of 2000kb/s and was "x" filesize, if you lowered that total average bitrate to 1000kb/s it would be "1/2x" filesize.

If you need help figuring out the exact steps, just shout and list what program you are using

[caper]

Thanks poisondeathray. Cool handle btw. Well I have had no success with TmpgEnc. i opened the file (an mpeg 1 already converted from avi) and chose "Settings". Then I changed the bitrate from 1150 to whatever but the filesize always comes out the same. I also selected mpeg 2 as the type. I tried different bitrate modes (CBR VBR, etc etc) This is my first time messing with bitrates so thanks for helping. What do you suggest for software for doing this?

[poisondeathray]

manono already explained why you got those results with MPEG1

Are you using tmpgenc (the original) or tmpgenc express?

Personally I would upload h264/aac/.mp4 as this would be the smallest filesize / best quality combination.

It also depends on what application you are using to host the files, and if it accepts this format natively or re-encodes it. This format has worked with for Adobe Flash player ever since 9.3. Easy to use GUIs would be Ripbot264, XviD4PSP, maybe even staxrip. The negatives are that it takes a lot more CPU power to encode to h264 (i.e. slower)

If you were set on using MPEG2 (bad choice IMO, because of poor compression and lack of deblocking; and your goal was to reduce the filesize), you could use avidemux or avanti to encode to MPEG2.

Give Ripbot264 a shot; it's really easy to use, and if you get stuck, someone will help you out. Enter the bitrate that you need for a certain filesize as explained above (using 2pass mode)