Editing .mpg vs Editing .avi

skinned_knee wrote on 3/20/2007, 12:42 PM
I have been using VMS at home for quite a while, and I love it - 95% of the time it's straight firewire captures from my camcorder, 5% of the time it's Tivo a/v through camcorder into VMS via firewire.

I am now starting a job (full time job change) that will be heavily weighted toward capturing/editing videos for a website. Work has purchased VMS and a Canopus ADVC110 on my recommendation (source video is cable TV via a DVR) This of course allows me to capture DV-AVI and all is well... Work also supplied me with a WinTV USB2 device that will capture video, but I have only been able to make it capture .mpg.

I'm trying to determine which is the better way to go here. the WinTV USB will schedule recordings so that the .mpg is already on the hard drive when I'm ready to start editing, so that is a plus - compared to having to capture from the DVR after I get here. There are a couple of other usability issues that make deciding on a method difficult.

My question for yall is this --- am I asking for any kind of trouble using .mpg as my source video instead of starting with DV-AVI? I have done some side by side tests, and to be honest, I can't tell any difference in the final product, which 99% of the time is 320x240 .wmv.

I really thought the DVR - Canopus setup was the way to go for this, but I'll be darned if I don't think the WinTV USB is working out just as well.

Take a look at

http://www.thewyatts.net/test/comparison3.wmv

- the first 10 seconds was done with one source, the last 10 seconds with the other - they do look different, but I can't declare one better than the other - can you? Ignore the audio levels - that issue is being addressed.

Please convice me that I'm not making a mistake committing to the .mpg capture system...

Comments

4eyes wrote on 3/20/2007, 1:06 PM
If you plan to edit the mpegs (cut out material) then VMS can be somewhat tricky because it doesn't allow you to customize the mpeg2 video-bit-rate when rendering to a separate file.
Haven't edited mpegs to much using VMS but when you right-click on the video in the timeline there are choices such as do smart mode re-encode, do not re-encode, and always re-encode.

If it's for work I would use Womble or VideoRedo to perform any editing of mpeg video.
They are dedicated to strictly doing just that, mpeg editing. Especially if you get a corrupted mpeg2 file which eventually happens to all of us
when the usb device or capture device decides to hiccup..
skinned_knee wrote on 3/20/2007, 1:31 PM
Is that "Smart Resample", "Force Resample", "Disable Resample"?

What is that acutally doing? it appears that the default is "Smart Resample"
rustier wrote on 3/20/2007, 3:44 PM
If you are capturing from a dvr you are converting the source to mpeg back to anolog - the through your canopus to DV-avi - so your capture method gives you a third generation video to work with in VMS.

Capturing through your usb device I assume you use directly and not through the pvr so you are getting a second generation video in mpeg.

Canopus is by far the better way to capture especially if you plan to edit. You will get more data and depending on the model, a cleaner signal and you will not have audio sync issues- which you will run into editing some mpegs.

The best way to capture would be to fire up your VMS capture program and capture directly from the source - your cable - into DVavi. Also keep in mind re-encoding mpeg to mpeg will lose some data and give you a lower quality video. Womble may be a better choice for editing mpegs.

One more thing to consider - rebroadcasting video on the internet without permission is an infringement of their copyrights. You see it all the time on youtube - but they are currently being sued for it. You may want to reconsider - as the legal system may take note.
Denver Dave wrote on 3/20/2007, 4:23 PM
Is your ultimate presentation format going to be .mpg, wmv or .FLV ? .mpg might be the best for editing, but I've found that for the same file size I get better quality with .wmv and .flv as well as being to have better control over the embedded player on the web page.
Chienworks wrote on 3/20/2007, 4:47 PM
If you're looking for "programmed recording" with your Canopus box, i wrote a program that controls SONY's VidCap.exe program just like the timer in a VCR, except that it can't change channels.

http://www.chienworks.com/software/vidcaptimer/

It's free. It works, mostly. I've found that it helps a lot to set VidCap's priority to above normal and make sure VidCap is the active window.
skinned_knee wrote on 3/21/2007, 10:49 AM
Final product will be .wmv - I don't care what format the source is - that is why I was asking if there is a problem editing .mpg with VMS.

I actually work for the television station in question, repurposeing some of our content for the web) so there is no legality problem. I do appreciate you pointing out the legal side of this, as I am sure many people aren't aware.

I will look into the timer thing - that sounds pretty cool.

I had not thought about the fact that taking pre-recorded video from a DVR had already gone through a level of compression - good point.

It sounds like any problems with editing .mpg would be evident during the editing process - so there are no long term problems with doing it - if it works, go for it, eh?
4eyes wrote on 3/21/2007, 11:31 AM
>>>Final product will be .wmv - I don't care what format the source is -
>>>that is why I was asking if there is a problem editing .mpg with VMS.
There is a problem editing mpeg's in all programs. That's why I said IF you are forced to then I would have a handy program set aside to use in case you do have to work with the mpeg's. A program designed for mpeg editing.

Going by my experience these hardware mpeg capturing devices don't produce editable mpeg's. I wouldn't trust your usb capture device's mpeg videos it produces. After editing them the wmv file can easily have audio sync issues.
That's not VMS, there's mpeg video and then there's editable mpeg video.
Even editable mpegs blow.

Best choice is always frame accurate DV editing / conversion.


jdachik wrote on 3/21/2007, 1:27 PM
Before getting a DV cam, and Firewire card, I used to capture MPEG-2 files with a Pinnacle Moviebox USB device. And I edited many of those MPEG videos with Vegas with no problems what so ever. The speed of loading and moving the clips around was slightly slower than AVI, but the only really compelling reason I see for importing and editing AVI instead of MPEG is for quality sake - i.e. when trying to output a nice quality DVD. If your final output is a small file for the web, the difference in quality will be minimal, as you have observed. So, IMO, you should be just fine with MPEG.