Removing Video Frames Damaged by Flash Photography

[SCDVD]

When shooting a video when people are nearby taking flash photographs, the brightness of the flash causes a frame in a video being shot at the same time to be overexposed. With a CCD camcorder, the whole screen in this frame is overexposed. With a CMOS camera, the effect is more noticeable (ugly) because only part of the frame is overexposed. This rolling shutter effect tends to make the flash more noticeable and look worse.

I'm looking for an easy way to delete the affected frame(s) and replace it with an adjacent frame. This needs to be done before rendering to prevent the encoder from spreading it to adjacent frames due to the blending effect of intraframe compression. I want to replace the frame rather than just delete it because if this is done on a number of frames in a video, the missing frames would cause the audio to go out of sync with the video so it's important to not change the video length. If a frame were replaced with an adjacent unaffected frame, the duplicate frame would be virtually undetectable even is a high action shot.

What is a good tool to snip and copy/paste frames in a DV video stream? Since HDV is already MPEG from the camera, has interframe compression already spread the effect from the flash to adjacent frames? If so, I assume this is a more difficult problem to deal with.

[gadgetguy]

Use the FreezeFrame filter in AviSynth. It was designed with your specific needs in mind.

[SCDVD]

Is there an in-editor way to do this on the time line? I use Vegas Pro 8.

[manono]

The Debugmode FrameServer perhaps? I don't use Vegas, so I don't really know. Or you could do it in a script, save it as lossless, and import that into Vegas for further work.

http://avisynth.org/mediawiki/FreezeFrame

[Alex_ander]

In case of single frame it is also possible to use AviSynth plugin BadFrames (blend adjacent frames or just repeat previous) and MFlowInter function of mvtools2 plugin (interpolation from 2 adjacent frames).

[GT Music]

You can use Vegas to do exactly what your asking. With your project open zoom in on the timeline to see the frames one at a time, At the begining of the first flash, place your cursor/line at that point and press the S key which will split or slice the project at that location. Then move your cursor/line to the right at the end of the flash and once again press the S key to split it. At this point click on the section between the split points to highlight it and delete it, If you have the ripple feature enabled, the project will close the gap automaticaly when you delete. Do this with each (frame set)that is effected. Hope this helps.

[SCDVD]

Thanks GT Music. It's funny but your suggestion prompted my attention to what I was doing wrong. I had ripple edit on which was screwing up what I wanted to do. I turned it off and it does what I want now. I need to remove the frame and replace it with a copy of the adjacent frame. If ripple edit is on, the automatic gap closing was screwing me up. Although one (or a few) deleted frames in a video wouldn't be noticeable, deleting too many would cause a detectable loss of sync with the audio. I ungrouped the audio and video so that the audio track is untouched when I delete a video frame. By replacing the deleted frame with a copy of the adjacent frame, the audio and video sync is not affected. If the audio and video aren't ungrouped, deleting the audio along with the video frame can cause an audio blip or pop that can be heard in some cases. I can't see any visible impact on the video. The replaced frame doesn't create any visible change except what I want - the flash is gone. The is very useful on footage from a CMOS camera and its rolling shutter that can create some ugly frames if nearby flashes are going off while shooting.

[harley2ride]

SCDVD- I'm not sure what you mean about the video getting out of sync by cutting too many frames. In Vegas 5, I edited out hundreds of frames of video of my ex and her brats, and my encoded video is in sync and looks great. In some places you can tell that a lot of frames were cut out, by how the audio changes from what it was, into something else, rather quickly. But I could fix that with some fades/transitions if I really wanted to.

As long as your audio and video are locked on the timeline, the audio should not get out of sync with the video.

[SCDVD]

harley2ride, you aren't understanding my point. If you have the audio and video locked on the timeline and snip out frames, you are snipping out pieces of the audio as well. When you have a video of someone speaking or singing for example, you don't want to take out snippets of the audio because you will hear the missing pieces. The result is that it looks like some amateur shot a video of their ex and her brats and it looks like an amateur hack job.

The technique that I described is to unlock the video and audio so that the process leaves the audio intact. If you then remove damaged video frames, you leave a hole in the video stream. If ripple edit is on. the video frames will slip to fill in the holes which will cause the frames to slip with respect to the audio. If ripple edit is off and you copy the adjacent frame into the spot where you removed a frame, the relationship between the audio and video isn't shifted. The duplicate frame is virtually undetectable when the video is played. Grandmother might not care if "In some places you can tell that a lot of frames were cut out, by how the audio changes from what it was" but a pro doesn't have that option when he turns over the DVD of the wedding ceremony for example.