file exports

[sicilian]

okay i'm kind of a noob, so take it easy on me
i just exported an edited video for the first time. the original files were avi files. i then went to create video file and selected same as project settings
when the file finished encoding (or rendering) it ended up being about 52 GB!
the original avi file was only about 200MB. i didnt even do much editing. mostly just changed the chapters around. it was only 20 minutes total.

thanks for any help

[Ken Berry]

Unfortunately, we are going to need more information. At first blush, it sounds to me as though you started out with one of the highly compressed formats like DivX or XVid which use .avi as their extension, but then converted it to raw, uncompressed AVI which is (as you have found) huge... around 65 GB per hour of video.

But we need to confirm a few things. First, right click on the original .avi file within Video Studio, when the file is either in the timeline or in the library pane, and copy down all its properties here please.

Next we need to know exactly what your project properties were -- all of them.

Do you have the DivX or XVid codecs on your computer?

What version of Video Studio are you using? What are your computer specifications? What operating system does it use?

[sicilian]

thank you for the quick reply
upon reading i am pretty sure that must be the problem - the video is umcompressed. i just did not think that an avi format would end up being larger than the original vob format.

here are the properties
orignal file:

format: microsoft avi - open dml
file size: 169,133 KB
frame rate: 23.976 fps
duration: 891.808 secs
data rate: 188.49 Kbps
compression: VFAPI reader codec
24bits, 720x480
AUDIO
48000 KHz, 16 bit stereo

project properties:

NTSC non-drop frame
microsoft avi file
24 bits, 720x480, 30 fps
lower first field
uncompressed
48000 KHz, 16 bit stereo


computer specs: pentium 4 2.4 GHz, 512 RAM, 7200 RPM harddrive

* i dont know if you are familiar with the video codec, but is from a program of the same name. i was informed that it was a way to put the vob into a 'dummy' avi file to be edited, but also saving on time and space.

so. i guess my new question is how do i export an edited clip with good quality, but at a reasonable size?

[sjj1805]

thank you for the quick reply
upon reading i am pretty sure that must be the problem - the video is uncompressed. i just did not think that an avi format would end up being larger than the original vob format.

here are the properties
original file:

format: Microsoft avi - open dml
file size: 169,133 KB
frame rate: 23.976 fps
duration: 891.808 secs
data rate: 188.49 Kbps
compression: VFAPI reader codec
24bits, 720x480
AUDIO
48000 KHz, 16 bit stereo

project properties:

NTSC non-drop frame
microsoft avi file
24 bits, 720x480, 30 fps
lower first field
uncompressed
48000 KHz, 16 bit stereo


computer specs: Pentium 4 2.4 GHz, 512 RAM, 7200 RPM hard drive

* i don't know if you are familiar with the video codec, but is from a program of the same name. i was informed that it was a way to put the vob into a 'dummy' avi file to be edited, but also saving on time and space.

so. i guess my new question is how do i export an edited clip with good quality, but at a reasonable size?

You've answered your own question if you look at the items I highlighted in red for you.

Please view this link
Brief explanation of file formats and compression

[DVDDoug]

so. i guess my new question is how do i export an edited clip with good quality, but at a reasonable size?

To some extent, that depends on what you are going to do with the clip, watch it on your computer?, Make a DVD?, upload it to YouTube?, etc.


If you keep the same format and enable SmartRender, the file will only be re-rendered where required. So, if you just cut-out some parts, the quality won't be affected at all. If you splice two clips together with a crossfade transition, the video will have to be re-rendered during the crossfade. On the other hand, if you apply color or contrast correction to the entire video, then the whole thing will have to be re-rendered.

And, to some extent it won't matter. The current bitrate (data rate) of 188.49 kbps is very low for video (low bitrate = low quality). Since your'e not starting-out with a high-quality video, you don't have to worry as much.

If you do need to change the format, keep the bitrate the same or higher. A higher bitrate is required for less efficient compression schemes like MPEG-2... I assume your current file is something like MPEG-4 or some other more-effecient scheme. Don't change the resolution (720x480) or the framerate (29.97 FPS) unless the target format requires it.

With lossy compression, the bitrate determines the file size and the quality:

Higher bitrate = higher quality = bigger file size = lower compression = less playing time.

Lower bitrate = lower quality = smaller file size = higher compression = more playing time.

Just to give you some ideas:
AVI/DV is nearly as good as uncompressed AVI. It requires 13GB per hour.

Commercial DVDs are MPEG-2. Bitrates are typically around 6000 kbps, which works-out to about 3GB per hour, depending on the audio format.

I'm not really sure about MPEG-4/DivX/Xvid, but I think you can get "DVD quality" at about 2500kbps, which works-out to something in the ballpark of 1.2GB per hour. (I think most DivX movies actually use lower bitrates.)

YouTube (and most similar websites) has bitrate and file size limits that prevent you from uploading "DVD quality" videos.

[sicilian]

thanks for all the help guys.
i am sure this type of question has been answered time and time again, so thanks for taking the time.

i am still new at this compression thing. i had the idea that avi's were high compression. this idea probably originated after i had seen an entire DVD movie on a single 700MB CD. i am not sure which codec was used, but the quality seemed pretty good - at least on a 19" LCD monitor.

so, this all started when i wanted back up my home movies - which i copied from a miniDV camcorder to a standalone DVD recorder - to a smaller format, and then edit them from there.

any ideas on the proper codec to get DVD5 to 700MB CD - seems outrageous, but i have seen it, as mentioned earlier.

also i am not sure how i got the bit rate at 188 kbps. that is extremely low! perhaps it has something to do with the VFAPI codec.

anyway, thanks for the help.

[Ken Berry]

Yes it is absolutely normal. As I said, it is done with the DivX or XVid codecs (or indeed other highly compressed mpeg-4 codecs). Those two codecs use high compression (and thus low bitrates) and produce good quality. To get them, you have to have the codec -- which is why I asked if you had either on your computer. Both are capably of compressing a 90 minute movie onto a CD, and several movies onto one DVD.

The only problem is that, apart from anything else, those CDs and DVDs are only going to be able to be played on a computer which has those codecs, unless you happen to have a stand-alone DVD player which is rated to play DivX movies. You burn them to disc just as if they were data files. But the player can see the format and will play them. But only a smallish (but growing) number of DVD players can do that to date. So you can't really distribute such discs to friends unless you know your friends either have a computer with the relevant codec, or else a DVD player which will play DivX discs...

[sicilian]

DivX or XVid codecs (or indeed other highly compressed mpeg-4 codecs). Those two codecs use high compression (and thus low bitrates) and produce good quality. To get them, you have to have the codec -- which is why I asked if you had either on your computer.

yes. sorry Ken. forgot to include that in my reply. i have since aquired both codecs. still, i have not been able to specify a specific size for the output avi file with the encoding program that i'm using. so, the avi's have come out to roughly 1/4 the size of the original DVD5. but, i'll get there.

also, how does Ulead handle/ like the DivX or Xvid codecs?

The only problem is that, apart from anything else, those CDs and DVDs are only going to be able to be played on a computer which has those codecs, unless you happen to have a stand-alone DVD player which is rated to play DivX movies.

i would just like to back these files up in a compressed format, and then edit them from there. i have another program which can convert the avi's back to VOB's, if needed.

thanks for the help again guys! top notch support on a great product!

[Ken Berry]

I am not sure that you can actually specify an output size, just as you can't with the other less compressed formats like mpeg-2 or DV. You need to adjust internal factors like bitrate to do that, but you also need to experiment to see if the final quality matches your needs. The lower the bitrate in any given format, the lower the quality, and this also applies to DivX. Conversely, the lower the bitrate, the more video you can fit on a CD or DVD. But that quality vs. size ratio always depends on the needs of the user, if you see what I mean. Using the Home Theater settings in DivX would be the usual place to start, but you can configure the internal settings with one of the buttons on the DivX control panel.

Which brings me to your second point. If your intention is merely to back-up the video, but then later convert it back to mpeg-2/vob (the same thing), and edit it, then I would only advise against such a workflow. Going from a less compressed format to a highly compressed format like DivX is one level of loss of quality. The observable quality of DivX/XVid is high, yes, when it is played back on your computer or a TV. But high compression inevitably means that a lot of digital information is thrown away in the process. That is what compression is all about. The technology of DivX/XVid, and thus its main selling point, is that it is highly selective about what information it throws away and what it retains, and it results in high quality viewing.

But when you convert back, that is another conversion step, and conversion from one format to another inevitably results in loss of quality. Moreover, when you think about it, going from highly compressed to less compressed does not mean that you get back any of the digital information thrown away in the original conversion to DivX. That is gone forever, and your conversion program has to invent data to pad out the video to its less compressed state. It does so essentially by duplicating or borrowing from the information which has remained after the original conversion. So the end result is not wonderful.

No, if you want to keep your original video archived for later use, I am afraid I can only recommend that you either burn it to many more DVDs as archived files in the original format; or else buy a big external (or internal) hard disk and store it all there, again in its original format.