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GH2 to 5DtoRGB audio video sync drift after transcoding to Prores
Hello everyone, I just bought 5gtoRGB batch and used it to transcode footage shot on a GH2 stock FW at 24H of a 1.5 hour lecture, and I encountered a very strange problem with sync drift… Wondering if anyone has any insight?
Basically in some of my longer clips (2 out of 3) which are each approx 25:38 long the video drifts out of sync from the audio in my transcoded footage (I’ve checked the original .mts files and they are properly synced). I know that it’s the video drifting out of sync and not the audio because I also recorded audio on an external recorder (at 48k) and the camera audio + external never go out of sync. The drift is very slight, only about 4 frames in one and 7 frames in the other, and I’m able to resolve it by changing speed slightly in FCP. However it does make me a bit nervous about being able to rely on 5DtoRGB in the future…
Some other info
Until I used 5DtoRGB (was using FCP 7 log and transfer before) I had no idea that .mts files were broken up into different files after a certain length, but it seems like they are divided at around 25:38 though the precise length varies (25:39:04 in one, 25:38:13 in another, 25:37:09 in another). Additionally it seems that there are about 2 frames missing from spanning files… Never seen that before when doing log & transfer.
As I mentioned, only two out of my three 25 minute clips have this drifting problem, but all 3 seem to have the same properties (23.976, 48k) post transcode. There are a number of shorter clips, but I can’t tell if they have or don’t have drift as I don’t think they last long enough for it to show up.
I’ve tried exporting in 5DtoRGB with output format at both ‘source’, ‘23.976’ and ’24’–source and 23.976 had the same drifting sync issue, 24 exported without audio (and was way further out of sync when I tried repairing it with an audio track)
Any help would be appreciated, would be great to figure out if i’m doing something wrong or there’s a bug with the software…
Ben
Ben
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