Compressing files

[KitKat]

I think this should be a fairly easy question to answer, for those of you who know about this kind of stuff, and I've gone on google and tried to resolve this myself, but then I just got confused.

I have a video file that I took with my microscope camera at work, and the filesize is huge. To give you an idea, the video is a minute and a half long, and it comes out to about 2.5 gigs. I think that the obese file size is causing it to play back slowly, because my work computer just can't keep up with all the information, and it looks a bit jerky in some spots when it plays. So, what is the best way to bring this file down to a manageable size? Is there a certain program I should be using? I want to do this at work, so pirating a program is out. I have to either use a free program or convince my supervisor to buy one. Any suggestions?

[Buffalobiian]

What's the filetype or the file extension to that file?

Being a large (yet uncompressed) file doesn't usually cause slow playback to my knowledge. It's usually the highly compressed ones that cause issues (regardless of size) because it requires the CPU to decompress it at a faster rate.

But yeah, what's the filetype?

If you're eager to get a name though, I've got a program called Ripbot264 (http://www.afterdawn.com/software/video_software/video_encoders/ripbot264.cfm) (freeware) that converts a variety of video formats to mp4/mkv with a few clicks. It's pretty simple to use too.

[KitKat]

Thanks for the info, Bill.

It's just a regular .avi file. If the filesize isn't interfering with my playback, that means I need to look elsewhere for what's causing my video to be so jerky. Maybe it's the fault of the camera that recorded it?

[Buffalobiian]

Thanks for the info, Bill.

It's just a regular .avi file. If the filesize isn't interfering with my playback, that means I need to look elsewhere for what's causing my video to be so jerky. Maybe it's the fault of the camera that recorded it?


Hmm. Well from what you said before, I was sort of expecting the file to be something like an uncompressed stream. That avi file ridiculously huge though.. even for uncomrpessed streams.

If you've got time while you wait for someone better to jump on this thread, you can try processing through Ripbot to see it changes anything.

Other troubleshooting would include playing normal vids (eg anime), then HD, and maybe another sample vid recorded from that camera to see where this jerking lies.

[darkshadow]

The filesize is screwing with the playback, since you hdd simply can't keep up with the data that is being streamed.

Just load up a copy of virtualdubmod, select the xvid codec as your compression, and save the new file. I would suggest putting the bitrate on 2k-5k ( when configuring the xvid codec).
This can ofcourse be done much better with 2 passes and vbr settings. etc.. But just using the settings I mentioned above should give you a MUCH smaller filesize in the end.

[Buffalobiian]

The filesize is screwing with the playback, since you hdd simply can't keep up with the data that is being streamed.
Just load up a copy of virtualdubmod, select the xvid codec as your compression, and save the new file. I would suggest putting the bitrate on 2k-5k ( when configuring the xvid codec).
This can ofcourse be done much better with 2 passes and vbr settings. etc.. But just using the settings I mentioned above should give you a MUCH smaller filesize in the end.

I was thinking this too initially, but 2500MB @ 90sec = ~28MB/sec of read speed, which should be way below the read-speed of modern HDDs, and many non-relic HDDs.

[Kraco]

Regardless, they cause problems. Might be a fundamental problem with the avi format, fragmentation, or whatever, but huge uncompressed avi videos surely cause playback problems. I've witnessed it enough times myself.

[David75]

I would try mpc-hc for playback, freeware program in the opensource community.

I would also search for mediainfo (freeware too) and ideally give a copy of the data so that we can assist you on that problem

[KitKat]

Thanks for all the suggestions! Ripbot didn't quite work, I must not have had it on the right settings, but virtualdubmod worked like a charm. The filesize is down to 31MB which is way better. The playback is very smooth now. There's still one place in the video where it's discontinuous, and things seem to suddenly jump forward, but I can live with that. Probably a glitch due to the computer doing the recording needing so much processing power to store such a volume of information.

David, I tried the playback in mpc as well as regular Windows Media Player to begin with and both had trouble with the file when it was huge. Ordinarily, I'd love to supply you guys with the file to play around with, but at the moment this is unpublished research data, so I can't really circulate it in case my supervisor wants to publish it in a journal. Maybe I can take another video with the microscope camera and see if it has any discontinuous points in the recording. I'll let you know if I have a file for you to look at.

[David75]

Mediainfo is just a tool providing with data and stats regarding the file, and nothing about its contents at all provided the name of the file doesn't give too much information of course ;)
It gives the codecs used, formats and all kinds of information that is precious to help someone with their file.

mpc-hc can sometimes help if the video card is compatible with DXVA and you're lucky with the file.


regarding the glitch, it probably is coming from the time it was recorded as you pointed out, so there's probably nothing to do about it. VirtualDubMod can repair the index of files, so if it didn"t do it, the problem is elsewhere. There are some repair tools, but its more like hit and miss... and sometimes be very lucky.
Best choice would be to cut the part, probably