Digitizing Hi-8 tapes - audio issues

[Arnoscopy]

I need some advice.
I'm using firewire to digitize Hi-8 tapes into FCPX. The video and audio signal come in just fine but, curiously, the audio begins to drift.
This does not happen with S-Video or RCA and does not happen with the same set up and DVCAM. It is uniquely 8mm. Any ideas what
causes this and how i can fix it while still importing via firewire? Thanks!

 

[ColdCase]

All tapes or just some? All recorded with the same camera?

 

[R S K]

but, curiously, the audio begins to drift.

One can only assume it's the classic discrepancy between the project sample rate and the clip sample rate. E.g. project set to 48KHz and the clips have 44KHz… or the other way around. Adjust the one or other accordingly. Optimizing could help, too.

 

[Arnoscopy]

One can only assume it's the classic discrepancy between the project sample rate and the clip sample rate. E.g. project set to 48KHz and the clips have 44KHz… or the other way around. Adjust the one or other accordingly. Optimizing could help, too.

no, i tried adjusting sample rate. my first thought was clocking issue or sampling rate. i'm pretty sure i tried optimizing too.

 

[Arnoscopy]

All tapes or just some? All recorded with the same camera?

good point. i do have alignment issues with the video and i have been working exclusively with one source. i'm testing a differently sourced tape now and trying to acquire the original camcorder for playback as that might be the solution

 

[ColdCase]

I've seen this sometimes when editing OTA broadcasts where video frames are dropped for one reason or another, but there is no associated gap in the audio. So, during capture, the video gets ahead of the audio (there is more audio than video). I haven't worked with Hi-8 for maybe a decade, so my memory is unreliable. If I recall correctly, the video and audio tracks are not time code synced on the tape. Something you would not notice playing back via a player as the tracks are physically held in sync. But converting to digital not so much, as I think the video and audio are captured separately.

My OTA capture software provides access to parameters I can tweak to minimize the affect. I believe I used to capture troublesome Hi-8 tape in short segments/clips, short enough that the drift is not noticeable, and then piece the clips together during editing.

 

[hwojtek]

Recorded va captured FPS?

 

[rajs]

Instead of capturing via FCPx did you try doing a capture via ffmpeg ? Was the video and audio still out of sync (drifting ) ?

i.e.

ffmpeg -f avfoundation -capture_raw_data true -i "DCR-TRV103" -c copy -map 0 -f rawvideo aa_tape_1_capture_video.dv

replace "DCR-TRV103" in above with your devices name, which can be found via this command:
ffmpeg -f avfoundation -list_devices true -i ""

 

[Arnoscopy]

Instead of capturing via FCPx did you try doing a capture via ffmpeg ? Was the video and audio still out of sync (drifting ) ?

i.e.

ffmpeg -f avfoundation -capture_raw_data true -i "DCR-TRV103" -c copy -map 0 -f rawvideo aa_tape_1_capture_video.dv

replace "DCR-TRV103" in above with your devices name, which can be found via this command:
ffmpeg -f avfoundation -list_devices true -i ""

ok, I need help with this. I only know of FCPx to capture and it was suggested to me that FCPx is outdated for this kind of application. I was not aware of this at all. How do I ffmpeg?

 

[rajs]

Go to thread linked below (you've posted on it in the past) and follow the instructions in the 1st post. All of it is detailed there.

ffmpeg video and audio capture instructions