Backing up footage - save as AVI?

[Fred S]

What are the properties of the original captured video file?
And the properties of the rendered file? They should be identical, but what are they?

I right-clicked each from the Library and both look the same - I got the following for both:
File
File Format: Microsoft AVI files --OpenDML
Frame rate: 25.000 frames/sec
Date rate: 3515.63 kbps

Video
Compression: DV Video Encoder -- type 1
Attributes: 24 bits, 720 x 576, 16:9

Audio
Compression: DV Audio -- PAL
Attributes: 32.000 kHz, 12 bit, Stereo

The other weird thing is that if I play the saved AVI in VS10 from the Library it plays fine.

[Fred S]

Just as a further update on this I recorded this edited AVI back to the camcorder, then re-captured, and the newly captured clip plays fine.

So, my last questions; in case I want to re-edit later and in terms of quality, am I losing any quality by doing this (i.e. saving an edited AVI, recording it back to DV tape then re-capturing)? And would I be better doing this rather than just keeping edited MPEGs and re-editing from those?

[etech6355]

The method your using is technically the best method. Editing DV and writing back to the tape. Minimum, if any at all, loss of quality.
Only suggestion I can add is when using Ulead Products capture & edit in DV-Type1 for VS.

[daniel]

When Blue Ray is affordable you could then transfer what you have now saved onto hard drive(s) to those discs and re-use the hard drives for some other purpose.

Not ruling out the solid-state versions of storage (flash cards CF now at 8 GB available/300x speed (Lexar), 16GB in the labs, = 1hour of SD-AVI).
Of course not economically competitive now but think of the ease and speed of access, size of storage box.

[Trevor Andrew]

Hi Fred

Archiving your video files:-
There is no simple answer, If you have important media to save then use several options.
Save to Mini-Dv tape, Dvd, Hard Drive, Bluetooth.

The tape may corrode, the dvd be unreadable in ten years or less, the hard drive may crash. No simple solution.

I have opted in saving my Avi back to camcorder. (Mini dv tape.)
(As etch6355 commented above, there is little or no loss in the transfer of these files.)

In addition I have saved the Mpegs as data files to dvd, including the project clips.
And of course the final movie has been burnt as a dvd.
If I had the capacity I would also save the Avi¡¦s to a hard drive.
How far do I go.!

The other problem you seem to be having is playing the rendered files.
It may be a player problem, or a corrupt Avi file.

I would suspect a player problem. That may be wishful thinking.
But this problem needs sorting, no good archiving corrupt files.

Regards

Trevor

[etech6355]

I capture at 16bit 48khz audio SD DV. This first thing I do with any cam is set the audio to 16bit 48khz.

In VS9 I came across a slight problem with my cam & tapes.
If I started from the absolute beginning of the tape & hit record the dv file was transferred to the harddisk but the properties of the video were wrong.
It was always in the audio section and would say either 32khz 16bit (which is an impossible cam setting) OR 48khz 12Bit, which is also impossible cam setting.
So the header information of the dv file was incorrect.
To prevent this I would always have the cam sync to a few frames (few seconds) then while the tape was playing hit the record icon. Any captures after that within the tape were always good. Even hitting record & letting VS9 control the cam.

Maybe the fault lies in my cam, I don't know. But thought I'd mention this because it can happen, recording a 16bit 48khz dv file and the wrong dv information is written in the header of the file. Only happened when starting from the absolute beginning of the tape. Could also be corrupted data at the beginning of the tape. Would happen to more than one tape though.

Also something new, Panasonic is writing the AVCHD video to a 4gig memory card in their new AVCHD cams. Wouldn't buy one though because of the AVCHD format.
VideoStudio 10 will probably support the Panasonic AVCHD cam format.

[Fred S]

The mention of Blu-ray earlier got me thinking. Does this and HD-DVD use the same MPEG format as for DVDs?

When this sort of thing starts coming through I'd probably be wanting to just make up new discs in the new format with more footage i.e. take (say) 3 hours of footage and make a new disc. Would just taking 3 saved MPEGs and combining into a single disc really result in much loss of quality?

[etech6355]

Fred,
>>>Would just taking 3 saved MPEGs and combining into a single disc really
>>>result in much loss of quality?
That's the thing about editing or working with Mpegs harder.
The DV file video properties are a set standard. Always the same.

It's hard to answer your question. Reason being do all the Mpeg2 files have the same video/audio properties, same construction such as Closed or Open GOP's, GOP Count, P Frame Count, B Frame Count, Compression, video_bit_rate.

Personnally I would keep the videos separate. You could probably smart render them all together into one file IF they all have the same video/audio properties (just don't edit them). If they are smart rendered there will be no loss.
If you try to combine 2 mpegs of different properties, like a 4Mbs VBR & a 8Mbs VBR mpeg2 file only one wil take a hit in quality. That is if you set your encoder properly to match the properities of the better file.

If you choose to archive in the mpeg2 format always try to make the video/audio properties of the mpeg2 file the same.
Many people suggest against editing mpeg files. Main reason is if the files have been saved with different video/audio properties. If you archived mpeg2 videos all at different properties then say want to work on them and they all have different properites on the timeline that can be a problem.

Editing in the DV format doesn't present this problem because it's one set format.