zambelli
16th November 2020, 03:28
I'm restoring an old 480i video that was originally shot, edited and exported/archived in MiniDV (DV25 480i30 4:1:1), and I'm running into a really odd artifact that I'm hoping someone might be able to help me remove/undo.
I typically use QTGMC for deinterlacing SD videos because QTGMC does such a great job producing smooth edges without jaggies, so I was surprised when I encountered very noticeable jaggies in many scenes of the video (see attached image DV_problem_QTGMC.png for example).
My first thought was that maybe it's a chroma displacement issue caused by improper 4:1:1 conversions, but the raw interlaced footage looked pretty clean too (attachment DV_problem_480i.png).
Next I separated the fields to inspect them individually - and was very surprised to find jaggies present in the individual fields too (attachments DV_problem_field1.png and DV_problem_field2.png) - which means the jaggies in the output are not caused by QTGMC or any part of the Avisynth processing chain but are definitely present in the source itself.
I've encountered similar looking artifacts in the past that were caused by interlaced video being incorrectly treated as progressive somewhere in the editing/transcoding chain, but in this particular case I know for a fact that the video was shot on MiniDV (single camcorder), edited in Premiere Pro as a 480i DV project, and exported out directly to MiniDV tape. So if the artifact was introduced by Premiere, it's very strange that it was only introduced for certain scenes and not others.
Any ideas what may have caused this, and if/how it could be fixed/undone?
The attached screenshots represent just a small portion of the full frame, and they have been enlarged by 2x (nearest neighbor resize) to better highlight the jaggies. If anyone's interested in inspecting the video itself, I've shared a 10 sec DV25 clip here (https://www.dropbox.com/s/7b1azq5l9fjn42a/RTT_DV_clip.avi?dl=0)).
I typically use QTGMC for deinterlacing SD videos because QTGMC does such a great job producing smooth edges without jaggies, so I was surprised when I encountered very noticeable jaggies in many scenes of the video (see attached image DV_problem_QTGMC.png for example).
My first thought was that maybe it's a chroma displacement issue caused by improper 4:1:1 conversions, but the raw interlaced footage looked pretty clean too (attachment DV_problem_480i.png).
Next I separated the fields to inspect them individually - and was very surprised to find jaggies present in the individual fields too (attachments DV_problem_field1.png and DV_problem_field2.png) - which means the jaggies in the output are not caused by QTGMC or any part of the Avisynth processing chain but are definitely present in the source itself.
I've encountered similar looking artifacts in the past that were caused by interlaced video being incorrectly treated as progressive somewhere in the editing/transcoding chain, but in this particular case I know for a fact that the video was shot on MiniDV (single camcorder), edited in Premiere Pro as a 480i DV project, and exported out directly to MiniDV tape. So if the artifact was introduced by Premiere, it's very strange that it was only introduced for certain scenes and not others.
Any ideas what may have caused this, and if/how it could be fixed/undone?
The attached screenshots represent just a small portion of the full frame, and they have been enlarged by 2x (nearest neighbor resize) to better highlight the jaggies. If anyone's interested in inspecting the video itself, I've shared a 10 sec DV25 clip here (https://www.dropbox.com/s/7b1azq5l9fjn42a/RTT_DV_clip.avi?dl=0)).