Editing recordings.

B

bernie_pt

Guest
I'm just trying to edit and archive on DVDR for later viewing some TV recordings. I own a Toshiba XS34, and I am having some trouble editing, as some portions that were supposed to be removed (and in the HDD don't show) when dubbed to DVD(R or RW) re-appear. I was told on this forum that it is a common problem with hi-speed dubbing. What I want to know is: Other brands suffer from this problem? If yes, how the other users correct/cope with it? Am I doing something wrong?
Thank you.
 
On the HDD in VR mode, you can get accuracy of editing to a single frame. But then you dub to DVD-Video, it needs to be on a GOP (Group of Pictures) basis. This is per the standards, not specific to the XS34. A GOP is something like 12 frames – e.g. half a second of video.

When you are editing (creating the chapter points), if you select the option to do this in GOP mode, then this can help. It means the edits you do on the HDD will also be in GOP mode – so what you see on the HDD should be the same as on the DVD-Video.

Mark
 
bernie_pt said:
I own a Toshiba XS34, and I am having some trouble editing, as some portions that were supposed to be removed (and in the HDD don't show) when dubbed to DVD(R or RW) re-appear. I was told on this forum that it is a common problem with hi-speed dubbing. What I want to know is: Other brands suffer from this problem? If yes, how the other users correct/cope with it? Am I doing something wrong?
Thank you.

No, you're not doing anything wrong, apart from misunderstanding the strange workings of edits! Don't expect the user manual to make it clear; I found things out that could have added another page of advice to my operating instructions.

I got round this on my Sony HX-900. When you edit on the HDD, some of the frames are "masked off" but not deleted at the A-B edit points. When high speed dubbing takes place, these frames reappear. They didn't reappear when I did real time dubbing.

If you edit a DVD+, the frame edit point "A" jumps to the nearest I-frame at the beginning of a GOP. If there is a change of scene at this point, all well and good, because a new I-frame is inserted when there is a drastic change in the picture content. At the "B" end of the edit, it once again jumps to the nearest I-frame inside the deleted portion of frames. However, you dont know where that frame is.

What gets left behind are the P-frames and B-frames which relate to the preceding I-frame. The majority of my edits are knocking out commercials. There is always a blackout of around 1 second between the ads and the programme content, so I just set the edit points slightly outside the range I need.
 
redsox_mark said:
On the HDD in VR mode, you can get accuracy of editing to a single frame. But then you dub to DVD-Video, it needs to be on a GOP (Group of Pictures) basis. This is per the standards, not specific to the XS34. A GOP is something like 12 frames – e.g. half a second of video.
Mark - certainly not picking on you specifically but just to clarify that the DVD "standard" is 15 frames per GOP, which under PAL is displayed at the rate of 25 per second.
 
I always edit on the PC now. I use either MPEG-VCR or MPEG Video Wizard. Both these programs are excellent and do frame accurate editing. They can accept MPEG, VOB and VRO files for input. No re-encoding is done except to remove/add parts. The new MPEG file can then be put into software such as TMPGEnc DVD Author to create into DVD files.

http://www.womble.com/

http://www.pegasys-inc.com/en/product/tda.html
 
musukebba said:
Mark - certainly not picking on you specifically but just to clarify that the DVD "standard" is 15 frames per GOP, which under PAL is displayed at the rate of 25 per second.

Is a GOP of 15 frames the maximum figure? I have an idea that a new I-frame is inserted when a scene changes, or when there is a lot of fast moving action. Either condition causes a drastic change in picture content.

Unfortunately, the DVD machines don't tell you where those I-frames are, hence the hit and miss accuracy of edits on DVD+. I have never been more than 11 frames adrift after spending a whole afternoon testing the accuracy of the edits. I was beginning to wonder about the life expectancy of the remote control buttons or my fingers!
 
Fifteen isn't the maximum for MPEG2, and currently some terrestrial Digital Video Broadcasts like Freeview use a GOP size of 40. Incidentally this makes for considerable problems when trying to transfer recordings to DVD.

The I-pictures are the only ones directly derived from the original image. The other B- and P-pictures are synthesized with reference to that. The DVD standard says you can only have 15 altogether in one GOP: one I-picture and fourteen B- and P- derivations.

It's not my understanding that an I-picture has to start at a scene change, and may only be achieved by a 2-pass encoder which can store references to such events and thus optimise the whole encoding.

Which is why it's difficult to edit accurately in a GOP-based mode on a CE single-pass encoder's output.
 
musukebba said:
Fifteen isn't the maximum for MPEG2, and currently some terrestrial Digital Video Broadcasts like Freeview use a GOP size of 40. Incidentally this makes for considerable problems when trying to transfer recordings to DVD.

The I-pictures are the only ones directly derived from the original image. The other B- and P-pictures are synthesized with reference to that. The DVD standard says you can only have 15 altogether in one GOP: one I-picture and fourteen B- and P- derivations.

It's not my understanding that an I-picture has to start at a scene change, and may only be achieved by a 2-pass encoder which can store references to such events and thus optimise the whole encoding.

So... Why is my Sony HX-900 only drifting by an average of 5 or 6 frames after an A-B edit on DVD+? The worst case edit was 11 frames out but that only happened once. Another strange happening is the accuracy at the "B" end of the edit. Unlike the "A" end, it is sometimes only a frame or so adrift from the intended point.

I wonder... Is the Sony capable of inserting a new I-frame in an edit? On the HDD an edit has to be at least 50 frames duration unless it is the very beginning or very end of a title. The only exception is editing over a previous edit where you can knock out just 1 or 2 frames over the "splice" area.
 
Has anyone tried to edit on Sony's HDD and then fast-dub edited material to DVD-RW in VR mode? I'm curious what about frame accuracy in this case?

THX ArtS :hiya:
 
ArtS said:
Has anyone tried to edit on Sony's HDD and then fast-dub edited material to DVD-RW in VR mode? I'm curious what about frame accuracy in this case?

THX ArtS :hiya:

I've done that. The frame accurate dubbing is OK if you do it at real time but the high speed dubbing messes it up. What I suss is this...

1. A small number of frames that you thought were deleted have only been masked off at the A-B edit points. A chapter mark is automatically inserted at an edit point.

2. When playing back, you get a momentary freeze for about half a second at the "splice" but nothing else seems amiss.

3. When high speed dubbing takes place, the masking off is lost. The frames reappear.

4. If real time dubbing is executed, the masking, as far as I recall, is unaffected but the frame freeze from the HDD becomes several unfrozen frames on the DVD. (5 or 6 frames, I think.)

The biggest hit and miss operation is A-B editing on DVD+ which I mentioned in an earlier post. A bit like being on the rifle range, aiming for a target with a dodgy sight, and shooting the one next to it.

All the fun of the fair!
 
nwgarratt said:
I always edit on the PC now. I use either MPEG-VCR or MPEG Video Wizard. Both these programs are excellent and do frame accurate editing. They can accept MPEG, VOB and VRO files for input. No re-encoding is done except to remove/add parts. The new MPEG file can then be put into software such as TMPGEnc DVD Author to create into DVD files.

http://www.womble.com/

http://www.pegasys-inc.com/en/product/tda.html

I am looking for a HDD recorder that is capable of transfering it's data, VOB or MPEG, to the PC for editing.
Can you please tell me what hardware you use?

Thx in advance,
Mahi
 
Mahimahi said:
I am looking for a HDD recorder that is capable of transfering it's data, VOB or MPEG, to the PC for editing.
Can you please tell me what hardware you use?

Thx in advance,
Mahi

All HDD recorders can dub its recording to DVD (either as a DVD VOB files in DVD Video format or DVD RAM fomat as VRO files).

Then you just need a DVD drive in the PC to read the discs. In my case I needed a DVD RAM DVD drive as I have Panasonic. I use a old LG 4040 and now have a Pioneer 109.
 
Thx for the reply nwgarratt :)
But what I'm realy looking for is a recorder with an Harddisk that can connect to the PC through 1394, USB or LAN.
I know the KISS can do it but I prefer something more relyable.
 
But what I'm realy looking for is a recorder with an Harddisk that can connect to the PC through 1394, USB or LAN.

I don't know any that can do. Most that have firewire have it as a input not a output.
 
Mahimahi said:
But what I'm realy looking for is a recorder with an Harddisk that can connect to the PC through 1394, USB or LAN.
AFAIK there aren't any DVDRs that do this.

Depending on your intentions, you might consider the Topfield TF5800, which is a Freeview-only HDD PVR (ie without intrinsic DVD writing capability) that has a USB connection for downloading recordings to PC or Mac for editing/burning. You will need to be prepared to play with installing one or more application modules to accomplish this and other features, but there's an active support group here and a dedicated thread over on Digital Spy.
 

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