New problem arises for HDV editing? at DVinfo.net

Lars Siden · May 27th, 2007, 02:03 AM

Hi guys,

First of all: I'm new to HDV editing :-)

Yesterday I was thinking about the format - m2t - mpeg.

What happens if I have captured some clips and cut them to desired length and thus "cutting away" keyframes? Is the editor smart enough to redo the mpeg "live" on the timeline? Generating the correct number if I's and B's ? Else we will end up with a timeline with incomplete mpeg structures and possible a weird result?

The general question for asking is that I had the chance to play with the release version of PPro 3 for a short while. And there I hade the problems of "not enough frames for transition". But when I pre-rendered it got "fixed" but when I played the timeline(without pre-render) it "stuck" on the last frame on the first clip in the transition. Honestly: I don't don't know the status of his copy of PPro3, I know that he has been a beta tester earlier.

My first project I've shot with my HDV cam - won't end up in HDV, so I can either capture it in SD or convert the m2t -> AVI straight away and avoid any problems. But in the future I guess I'll be doing HD projects.

// Lazze

Lloyd Coleman · May 27th, 2007, 08:32 AM

The problem you describe in Premiere is not from the mpeg stream. It happens even with AVI. When you place a transition between cuts it overlaps the tail of the first clip with the head of the next clip. If it were a disolve transition for instance, it would slowly fade the tail of the first clip while increasing the transparancy of the second clip. It needs these 'tail' and 'head' frames to do this. When you cut a clip and put it next to another clip there are still 'hidden' frames at the end of the cut for the Premiere to use for the transition. If you cut at the end of the clip there are no more 'hidden' frames so Premiere gives the message 'not enough frames for transition' and just re-uses the last frame over and over (giving the stuck look). It you go to the problem transition and trim the clip back a little before the cut it will have a 'tail' to use for the transition.

Lars Siden · May 27th, 2007, 12:35 PM

But the stuck scene went on forever...

And in both Vegas and PP I've seen green or red frames in the start/end of clips... indicating missing mpeg/data

//Lazze

Ervin Farkas · May 29th, 2007, 11:21 AM

The short answer is yes, any decent editor will recreate the groups of pictures (GOP) no matter where you cut. The problems you are experiencing might be due to the limitations of the tryout software.

I've seen green/pixelated frames at the beginning of a clip while using an old, outdated computer setup; it was not able to start the capture fast enough. I am not sure what could cause that at the end of a clip though... it makes no sense.

May 27th, 2007, 02:03 AM	#1
Lars Siden Major Player Join Date: Mar 2003 Location: Sweden, Stockholm Posts: 469	New problem arises for HDV editing? Hi guys, First of all: I'm new to HDV editing :-) Yesterday I was thinking about the format - m2t - mpeg. What happens if I have captured some clips and cut them to desired length and thus "cutting away" keyframes? Is the editor smart enough to redo the mpeg "live" on the timeline? Generating the correct number if I's and B's ? Else we will end up with a timeline with incomplete mpeg structures and possible a weird result? The general question for asking is that I had the chance to play with the release version of PPro 3 for a short while. And there I hade the problems of "not enough frames for transition". But when I pre-rendered it got "fixed" but when I played the timeline(without pre-render) it "stuck" on the last frame on the first clip in the transition. Honestly: I don't don't know the status of his copy of PPro3, I know that he has been a beta tester earlier. My first project I've shot with my HDV cam - won't end up in HDV, so I can either capture it in SD or convert the m2t -> AVI straight away and avoid any problems. But in the future I guess I'll be doing HD projects. // Lazze __________________ Sony HDR-CX130,Canon 5DMKII,i7 930@4.0, 12gb memory, 3x SSD + 2x1Tb(stripe), Geforce 480, Dual 24", Win 7 x64

May 27th, 2007, 12:35 PM	#3
Lars Siden Major Player Join Date: Mar 2003 Location: Sweden, Stockholm Posts: 469	But the stuck scene went on forever... And in both Vegas and PP I've seen green or red frames in the start/end of clips... indicating missing mpeg/data //Lazze __________________ Sony HDR-CX130,Canon 5DMKII,i7 930@4.0, 12gb memory, 3x SSD + 2x1Tb(stripe), Geforce 480, Dual 24", Win 7 x64

May 29th, 2007, 11:21 AM	#4
Ervin Farkas Inner Circle Join Date: Aug 2005 Location: Atlanta/USA Posts: 2,515	The short answer is yes, any decent editor will recreate the groups of pictures (GOP) no matter where you cut. The problems you are experiencing might be due to the limitations of the tryout software. I've seen green/pixelated frames at the beginning of a clip while using an old, outdated computer setup; it was not able to start the capture fast enough. I am not sure what could cause that at the end of a clip though... it makes no sense. __________________ Ervin Farkas www.AtlantaLegalVideo.com

May 27th, 2007, 08:32 AM	#2
Lloyd Coleman Major Player Join Date: Oct 2003 Location: Salt Lake City, UT Posts: 256	The problem you describe in Premiere is not from the mpeg stream. It happens even with AVI. When you place a transition between cuts it overlaps the tail of the first clip with the head of the next clip. If it were a disolve transition for instance, it would slowly fade the tail of the first clip while increasing the transparancy of the second clip. It needs these 'tail' and 'head' frames to do this. When you cut a clip and put it next to another clip there are still 'hidden' frames at the end of the cut for the Premiere to use for the transition. If you cut at the end of the clip there are no more 'hidden' frames so Premiere gives the message 'not enough frames for transition' and just re-uses the last frame over and over (giving the stuck look). It you go to the problem transition and trim the clip back a little before the cut it will have a 'tail' to use for the transition.