Nero Video Grabber vs Hauppauge WinTV-USBlive2 vs August VGB300

[Alwyn]

While it is relative simple and reliable to discover duplicates by means of a script

Do you have a script for spotting dupes I could try?

[Sharc]

While it is relative simple and reliable to discover duplicates by means of a script

Do you have a script for spotting dupes I could try?

The DeDup avisynth plugin comes to my mind:
http://avisynth.nl/index.php/DeDup

The first pass 'DupMC' will create a log.
A very low difference (~0%) between 2 frames indicate a duplicate. The log can be evaluated in Excel for example, or evaluated and processed in pass2 ('DeDup') for removing the duplicates.

[jagabo]

AviSource("filename.avi"
WriteFileIf("Dups.txt", "YDifferenceFromPrevious<0.5", "current_frame", flush=true)

Open the AVS file in VirtualDub then use File -> Run Video Analysis Pass. When it's done you will have a file called Dups.txt that has a list of the duplicate frames. You can change the threshold to reduce false positives or false negatives. Also note that it only compares the Y channel (not U and V).

[Alwyn]

Thanks guys, I finally got DupMC working after seeing Jagabo's comment re running the video analysis pass. That isn't mentioned in the wiki or readme that I can see.

@Jagabo, I'm still experimenting with your script. I haven't worked out how the "difference" parameter affects things yet.

[jagabo]

YDifferenceFromPrevious is the average difference of the Y value of each pixel of the current frame and the previous frame. If the current frame and the previous frame are identical (as far as the Y values are concerned) the calculated value will be zero. It will be non-zero if any of the Y values is different.

Note that compression artifacts (when using lossy compression) or other noise may cause originally identical frames to no longer be identical. That's why a non-zero value is used in the sample code. It is no longer possible to detect for certain which frames were identical before the lossy compression.

[Alwyn]

Thanks, I'm working with analogue AVI captures.

I've set the "Diff from Prev" to 0.0 but am getting just a list of numbers (I assume the frame numbers, looks like very frame) with no other details, as per the attached.

The DupMC report does show the % difference between each frame.

[jagabo]

I've set the "Diff from Prev" to 0.0 but am getting just a list of numbers

Yes, that's all it shows, the frame number of frames that are duplicates of the frame before them. Oh, it also always shows frame zero as a duplicate, a false positive (as there's nothing to compare that frame to). It shouldn't show every frame is a duplicate.