transcoding and loss of sync

[Andrew Young]

Hi Paolo,

Sorry for the delay in replying to your generous offer. My ftp site has a 80Mb upload limit and at that size we won't see anything. The clips that show the problem all too well are in the 3 to 5 gig range, so an ftp solution is not going to work from my site. Any ideas? I will send you a disk by mail if there is no other way and you're really up for it. You're on the west coast, right?

[Paolo Ciccone]

Originally Posted by Andrew Young

Hi Paolo,
Sorry for the delay in replying to your generous offer. My ftp site has a 80Mb upload limit and at that size we won't see anything. The clips that show the problem all too well are in the 3 to 5 gig range, so an ftp solution is not going to work from my site. Any ideas? I will send you a disk by mail if there is no other way and you're really up for it. You're on the west coast, right?

Hey Andy.

No solutions for transfers of that kind. Yes, I live in California, if you want to mail a disc I'll send you my address via email. I can't promise I'll find a solution but I'll try my best :)

[Adam Craig]

What ever came of this? I'm having the same problem... All is well in the raw m2t file but quicktime throws it out of sync.
-aj

[Paolo Ciccone]

Originally Posted by Adam Craig

What ever came of this? I'm having the same problem... All is well in the raw m2t file but quicktime throws it out of sync.
-aj

Hi Adam.
Nothing happened, I don't know if Andrew found a fix but in any case, have you tried to trim a few seconds at the beginning of the clip. Basically set the Inpoint in HDVxDV one or two seconds ahead and then export again.

[Adam Craig]

Yeah, I'm trying all kinds of stuff, the support guy(s) at HDVxDV is helping me figure out how to get my footage to an editable state.

MPEG Streamclip just might save my backside.

-aj

[Steve Mullen]

Originally Posted by Andrew Young

I'm going over some workflow options (24p for someone who cant wait for the FCP upgrade and 30p for someone else who has broken timecode that won't capture native) and have run into some snags with the whole transcoding scenario.

Andrew, would you consider Avid Liquid 7.1 for $500? Their capture routine has no Presets. It figures out that the JVC does 29.97 or 59.94 and captures it to disk.

Now you set your Sequence to either 23.98 or 29.97. When a 59.94 clip is droped into a 23.98 Sequence, it's smart enough to SKIP the Repeat Frame Flags. Nothing gets "converted!"

On output, the Repeat Frames Flags are reused. Nothing gets "converted!"

Plus, given Smart GOPS, with cuts-only Sequences -- only 2 GOPS at a cut a re-coded. By the way, runs on an MBP under Bootcamp.

[Paolo Ciccone]

Originally Posted by Steve Mullen

Andrew, would you consider Avid Liquid 7.1 for $500? Their capture routine has no Presets. It figures out that the JVC does 29.97 or 59.94 and captures it to disk.

Steve, at this point I'm so fed up with FCP that *I* would consider it. Do they have a Mac version?

[Andrew Young]

Originally Posted by Steve Mullen

Andrew, would you consider Avid Liquid 7.1 for $500? Their capture routine has no Presets. It figures out that the JVC does 29.97 or 59.94 and captures it to disk.

Now you set your Sequence to either 23.98 or 29.97. When a 59.94 clip is droped into a 23.98 Sequence, it's smart enough to SKIP the Repeat Frame Flags. Nothing gets "converted!"

On output, the Repeat Frames Flags are reused. Nothing gets "converted!"

Plus, given Smart GOPS, with cuts-only Sequences -- only 2 GOPS at a cut a re-coded. By the way, runs on an MBP under Bootcamp.

Hi Steve,

Sounds interesting. Is this a native HDV timeline - no transcoding? Same file size, etc. or have the pulldown frames that get dropped actually been created from the flags? Is it fully compatible with the Avid family of products? Thanks for the info.

Hi Paolo,

Sorry I dropped the ball on that file. I'll try to get back to it.

Andy

[Paolo Ciccone]

Originally Posted by Andrew Young

Hi Paolo,
Sorry I dropped the ball on that file. I'll try to get back to it.

Hey Andy, you're a busy man. I was just replying to the previous post :)

[Steve Mullen]

Originally Posted by Andrew Young

Hi Steve,

Sounds interesting. Is this a native HDV timeline - no transcoding? Same file size, etc. or have the pulldown frames that get dropped actually been created from the flags? Is it fully compatible with the Avid family of products? Thanks for the info.

Fully native! Let me check file sizes and report back.

No real Avid compatibility -- it's a complete standalone application like FCP or Premiere.

[Andrew Young]

OK, I've finally had a chance to experiment with this issue some more and I have worked a few things out. Both MPEG streamclip and HDVxDV continue to make transcodes that have sync drift, but I have learned a thing or two by doing tests with 10, 15 and 25 minute captures that have a slate at each end.

HDVxDV:
-Most of the trouble I had with HDVxDV and 24p material is due to two things: 1) the fact that the program incorrectly times transcoded clips at 24fps rather than 23.98 fps; 2) it is important to place an in point a few secs in from the head of your m2t before doing your transcode (Thanks Paolo for that suggestion). If you just let if fly with no in point it can give you really screwy sync right off the bat. To get around the timing problem you have to do the following:

1-mark your in point and transcode your clip
2-open the transcoded clip in Quicktime player and export the audio as an aif file
3-open the picture clip in cinema tools and retime it to 23.98
4-import both the retimed clip and the aif file into FCP
5-merge the picture clip with the aif clip. Turn off the volume on Trancks 1& 2. Tracks 3 & 4 of the merged clip will have sync that is better than 1 & 2, but not perfect.

Given the supreme hassle of doing all this and the fact that of MPEG streamclip version 1.7 avoids all of this and works better, I can no longer recommend HDVxDV (though it is still fine for capturing the m2t files).

MPEG Streamclip:
-Version 1.7 is much improved in that you can transcode directly to a 23.98 file rather than a 59.95 file, so no transcoded pulldown frames. Setting an in point does not seem to be necessary either. However, using fix timecode breaks does not make all of your sync problems go away.

Both programs were often out by a frame or two at the head. Once put into good sync at the head, both programs were out two frames after 15 minutes on a single takes with no camera start/stops, and 3 frames in a 10 minute clip with multiple stop/starts. When 25 minutes with many start/stops was transcoded, MPEG streamclip was out 6 frames at the end and HDVxDV was out 8 frames (once synched at the head).

So, neither program really does the job right, but MPEG streamclip at least does a slightly less poor job in less steps. I know that all of this seems very arcane, but if your dealing with hours of sync 24p material, these issues are a real pain in the butt.

By the way Paolo, I never sent you a clip to try because it sounded like you were having the same issues. If you really are able to capture up to 30 minutes with either program and have no drift please let me know. Thanks!