Video Studio 9 - Lossless DV Handling

[stindlpeter]

When I load a DV file into Video Studio 9 (type 1 AVI) and write it back to the disk the file size is different. The frames and all the other information seems to be the same. So where does this change in file size come from? I want to have a lossless data handling.

By the way. I could not find any way to save a DVD file without creating the DVD folders for audio and video. At least not if I want to use my own settings for DVD encoding. Did I overlook anything?

And last - How can I avoid ANY quality losses when handling DV files - editing and writing back the project to hard disk. I want to keep them as they were recorded.

Thank you for reading this and many more thanks for any advice.

[stindlpeter]

Sorry - had a wrong audio setting as default in the DV export definition. Now the files are the same in size. But I still do not not understand what the non-square pixel rendering does when I write back the clip to a DV file again.

[2Dogs]

Sorry - had a wrong audio setting as default in the DV export definition. Now the files are the same in size. But I still do not not understand what the non-square pixel rendering does when I write back the clip to a DV file again.

I'm no great authority on this, and I'm sure others will hop in and correct me if I'm wrong, but my understanding of non-square pixel rendering is that it enables you to achieve the regular 4:3 aspect ratio.

For example, with NTSC sytems, the resolution is commonly 720x480. Square pixels would then suggest an aspect ratio of 1.5:1

[stindlpeter]

Thank you for the pixel info. But if the capture is lossless than it should not make any difference.

I was wrong again. Whenever I "capture" a DV video and write it back to the harddisk the file size is not the same. At least when I do this the first time. When I reload the changed file and save it back the file size does not change.

So I am back to the first square. Lossless would mean no change at all in the file data. And the difference in the file size between the original and the altered file is significant. I compared all the file data of the two files. Frames, etc. everything the same. But something is missing - the new file size is smaller than the old one. And if I write the data simply back on tape I will not get the same.

[2Dogs]

Thank you for the pixel info. But if the capture is lossless than it should not make any difference.

Dear Peter,

this may not be directly relevant but may be of some interest.

A year or two ago, when I was trying to evaluate different video editing programs, I tried capturing DV type 1 from my MiniDV camcorder and writing it back to the camcorder.

I then repeated this process with the re-recorded clip 10 times, to see what if any loss in quality resulted.

Using Intervideo WinDVD Creator 2, there was a significant, and to my mind unnacceptable drop in quality by the 10th generation.

With the Ulead 7 trial, there was only a barely perceptible drop - less for example, than the drop associated with transcoding at even the highest quality settings to MPEG2. (the only problem, and a VS7 bug I believe, was that there was no audio on the DV type 1 clips recorded back to the camcorder!)

All of the tests were entirely subjective, of course. I did not make use of resolution charts, but simply scrutinised the clips and looked in particular at critical areas where shortcomings would likely appear first.

I did not look at file sizes, however.

For my own practical purposes at least, and I am fairly anal retentive about such things, I would say that DV type 1 capture with VS is lossless.

[stindlpeter]

Thank you a lot for your response. I use the freeware WinDV and not a fancy software for capturing my videos. The size of WinDV is 92 KB - what helps to avoid skipped frames too. Thank you for the hint that Intervideo does not provide the solution for my worries. But after more than 30 years in the IT business I am a bit disappointed what the marked offers in respect of video handling and edditing. It is a very simple task not to alter any information when you write back data...and one of the MOST BASIC requirements of ANY software. Imagine you copy a file with your OS and the size of the new file is different...

WinDV I just use for capture because I am tired of losing all the features my camera loses when you take the tape out - what you have to do when you use Video Studio 9. I do not write back data to a DV tape - when the camera breaks you have lost as long as you do not buy a new one. Better to put them on a computer medium. But I am aware of the fact that burned DVDs are not without problems too. So better you have a copy or two...

In respect of capture quality I could not find a difference between Ulead and WinDV. Since the data on the DV tape are digital already it should not be more than a digital copy anyway. But I need a software to edit and write back. Ulead only changes the file size the first time when you save - I still do not know why. If you reload the changed file and write it back it has the same file size as the first changed file.

I am not the video freak spending endless hours in front of the editor. I want to make sure that I can keep the data as long as possible and in the original form. But as you say it is hard to tell if there are minor changes in quality. In any case - DV is a very lossy format and DVD does it make not better. DVD somehow looks better because it reduces the amount of (wrong) information. Great job of the industry to sell less for more...