Non-rendering Editor? (off-topic)

stevefoobar wrote on 1/21/2009, 11:23 PM
There are many times when I have a large video file that contains only a small section of usable video and it would be great to be able to use a simple editor to "cut out" the sections I don't want and re-write the file as a shorter file of just the good sections to save hard drive space. In other words, a program that would just modify the file internally at the file level and then re-write the file, not actually edit the original file in a typical video editor and have to re-render the file to get the new file, since this causes degradation in the output.

Has anyone ever heard of such software that does this? Technically it seems like it should be possible, since it's just a matter of reordering and reconstructing the file bytes in the file structure of the video file.

Thanks.

Steve

Chicago, IL USA

Comments

Chienworks wrote on 1/22/2009, 3:59 AM
If you're dealing with uncompressed, DV, or even MPEG with the newest version of Vegas, then Vegas does what you're asking. Select the portion of the file you want and render with "loop region only" selected. Vegas performs a "smart render" which simply copies the frames bit-for-bit into the new file, no actual re-rendering going on.

Do a search for a program named "womble" which can do this sort of thing too, and handles more formats.
Ivan Lietaert wrote on 1/23/2009, 2:04 AM
When you choose 'save as' for your project, you have the option to 'copy and trim media with project'. Tick it on. This will do exactly what you described. There's no need to render, no need for an external programme.

You basically draw the bits you need to the timeline, cut them as pleased (or: use the trimmer). Then go for 'save as' project, as described above.
discdude wrote on 1/23/2009, 5:21 AM
If you are talking about AVIs, it doesn't get much better than VirtualDub (http://www.virtualdub.org). You can losslessly trim video, change the audio track and more. Also, it is much better at capturing video from analog sources. Best of all, it is free. I use it as a "preprocessor" for files I import into VMS.
stevefoobar wrote on 1/26/2009, 4:54 PM
My goodness, you guys are amazing. I've been using Vegas for some time (obviously not long enough though) and didn't realize it had this capability built in. I'm anxious to try some of this.

I also on my own discovered VirtualDub which is a pretty amazing (albeit sometimes confusing) FREE Open Source program. Here is where you can learn about and download it:

http://www.virtualdub.org/
http://virtualdub.sourceforge.net/

Thanks guys!

stevefoobar wrote on 1/26/2009, 9:42 PM
OK, I've had some time to read the help files very carefully and please correct me if I'm wrong, but it appears that Vegas does something "close" to what I want but not quite and certainly with restrictions that VirtualDub doesn't seem to have.

For example, the help file seems to imply that the smart rendering feature, applies to only DV AVI or MPEG-2 AVI files, neither of which I typically work with (mostly MJPEG AVI). Here is the help file text:

"When you render video to either of the following formats, unedited video frames are passed through without recompression (smart rendering):

DV AVI

MPEG-2 (for files such as those from HDV and DVD camcorders)


HDV support is available only in Vegas Movie Studio Platinum."

Also, the help file states that the "Save As" function with "Create trimmed copies of source media" applied will only "trim" DV video clips. All others it will just copy as-is, which will not do me any good, since as I've stated, I'm mostly using MJPEG AVI files. Here is the help file text:

"If you selected the Copy and trim media with project check box, a dialog is displayed to allow you to specify how you want to copy media files:

Select the Copy source media radio button to copy the entire source media files to your project folder.

Select the Create trimmed copies of source media radio button and enter a value in the Extra head and tail box to reduce the number and size of media files necessary to represent your project.

Your project will be scanned to determine how much of each media file is being used and those regions will be rendered to new media files. The amount of time specified in the Extra head and tail setting will be added before and after the media file to allow subsequent edits. All events are then updated to point to the new files. Finally, inactive takes are removed from the project, and the project is saved.

The newly rendered files will match the source files' properties as closely as possible: audio files will be rendered to the Wave format if under 2 GB (or Wave64 if over 2 GB), and DV files will be rendered as DV AVI files. Because of the lossy nature of other video formats, non-DV video files will not be trimmed, but will simply be copied to the project folder."

Am I missing something obvious? Of course, I can continue to use VirtualDub but I want to make sure first that I really have to, since it's an extra step and another program.

Thanks!
Ivan Lietaert wrote on 1/26/2009, 9:58 PM
You already know more about this than me... my advice: download the manual of Vegas 8 Full from this website: and read about it there:
http://www.sonycreativesoftware.com/download/manuals/vegaspro

Edit: I've taken a deep thought about this (!), and this is my conclusion. Vegas won't 'smart render' your mjpeg files, so my 'save as' trick won't work here.
On the other hand, mjpeg files are already low bitrate files anyhow, so saving them to a file type that has a slightly higher bit rate and resolution will result in only in minimal or no quality loss.

Second, I'm not sure Virtual Dub will do what Vegas won't.

Third, have you considered using the software that came with your camera? I have a gut feeling it will have this functionallity.
stevefoobar wrote on 1/31/2009, 7:25 PM
ivan123, I agree...it appears Vegas won't smart render mjpeg files and yes, they are not as compressed as other formats but it still is not the same as not rendering at all, so there is certainly some noticeable degradation.

I have tested VirtualDub and it does indeed appear to do what Vegas won't, but without anyway to verify the result with software, I'm only judging based on visual examination of the output video. The help files of VirtualDub certainly clearly state it has the abiltiy to output non-rendered video in "most" cases. The help file states "most cases" because apparently some video frames are too complex and to be re-rendered, even if most of the other parts of the video can just be copied to the output video file.

I would highly recommend anyone in a Windows 32-bit platform download and try VirtualDub.
Ivan Lietaert wrote on 1/31/2009, 10:22 PM
Can you sum up a couple of reason to use Virtual Dub next to Vegas? I downloaded it a while ago, and as far as I remember, the only thing I could do with it was cut video into chunks.

EDIT: D...., as I was playing with VirtualDub, I lost time, and got my croissants burned.
discdude wrote on 2/1/2009, 2:59 PM
stevefoobar,

Just out of curiosity, where are you getting your MJPEG files? Does your camera record them?