GOP, Sync Issues, Compression Markers in FCP?
by Tim Green
on
Aug 23, 2008 at 8:17:26 am
[Edit: sorry for the double post. I thought I missed the button the first time so I clicked it twice. Moderators, can you delete one of them?]
I know this issue is all over the web, but I haven't been able to find an answer after many hours of looking.
I'm editing a rather large project in Final Cut Studio 2. It's a sports training DVD for basketball coaches by Bob Hurley, the winningest high school basketball coach ever (and a great guy too).
Anyway, we have a natsound track and a commentary track for all the drills he runs in practice -- two audio streams for each video stream. So I'm exporting video only, then the two audio tracks via "Audio to AIF" export option. Hence, the files don't have exactly the same root name structure as if I had exported audio and video together, so DVDSP doesn't bring the audio in automatically. That's no big deal, but I'm having the dreaded "AC3 files are different lengths than the m2v files" issue, even though they are exported from the same sequence with the same in and out points.
I think I realize that this has something to do with GOP, and chapter markers needing to be on an I-frame. (BTW, I shot and am editing in HDV, using ProRes in render options). Do I need to add compression markers at the end off all my sequences to force an I-Frame?
Should I just put all my assets on separate tracks in DVDSP so they stay in sync? I don't mind the playback lag for this project.
Am I missing something?
I'm not nearly as good in DVDSP as I am in FCP or in the audio world... I have always found DVDSP a bit confusing, but I imagine it has more to do with the DVD spec than any conscious decisions made by Apple.
Is there a book I should buy? Should I get Apple certified?
I know this is a lot of questions, but I just missed the deadline for this project today, and I'm pretty bummed out about it, although the client is being cool. It's for Reebok and could really help my career. The project is going well -- I'm just stuck now with a lot of great material and I'm having trouble getting it onto a DVD. A common problem, I'm sure.
So, I'm drinking many cocktails and listening to house music into the wee hours to try to regroup and have at it again tomorrow afternoon. Booze and beats are the only thing that calm me down, except for my beloved Klonopin. :-)
Anyway, I digress. Any help or guidance much appreciated!
Re: GOP, Sync Issues, Compression Markers in FCP? by Michael Sacci on Aug 23, 2008 at 10:18:39 pm
[Tim Green]"Should I just put all my assets on separate tracks in DVDSP so they stay in sync? I don't mind the playback lag for this project. " Not sure I understand what you are asking here.
[Tim Green]"Is there a book I should buy? Should I get Apple certified? " The Apple Pro Training books are a great way to learn the ins and outs of any of the Apple apps, I highly recommend them if you like to read and do (This is my preferred way to learn a new app) This book gives you exactly want Certification classes do without some added insight from the instructor.
As for syncing audio.
1st are you sure the In and Out are set at the same place for when you export the movie and the audio?
But the way I recommend encoding HDV is to use - Export to Compressor. Before you do this turn off one set of audio. Encode video to m2v and the first audio to ac3, this will give you the best quality video and hopefully will lock audio and video together. It will take longer to encode but the time is worth it. Try CBR at 6-6.5Mbps if you can, it will speed things up and once again give you better results.
Try this and let me know if it helps. I don't use HDV so this is stuff that simplifies the process, gives better quality and hopefully will solve your problem.
Re: GOP, Sync Issues, Compression Markers in FCP? by Tim Green on Aug 23, 2008 at 11:18:15 pm
Michael,
Thanks so much for the reply. I just called my local Borders Books and I am on my way to pick up the book: Apple Pro Training Series: DVD Studio Pro 4 (2nd Edition). I do like to read books, and since the only manual for DVDSP is a PDF, I haven't read it like I would want to. There's nothing like a book -- reading on a computer is tedious, and you can't dog-ear the important pages....
Yes, my In and Out Points were definitely the same -- I made sure of that :-)
I've read that exporting directly to Compressor gives better results, but you lose FCP during the process, and it doesn't give a time estimate, so I usually make Reference movies and run them through Compressor. How much better is the quality when doing it the way you suggested? It's curious to me that it's better that way; I thought that was what reference movies were for. Since they are not self-contained, they just reference the original clips. I believe you of course -- just wondering why.
Re: GOP, Sync Issues, Compression Markers in FCP? by Michael Sacci on Aug 24, 2008 at 12:30:09 am
Quality comes from the fact that is is standing a full uncompressed frame to compressor, no effect or filter goes through the timeline's codec. Things like graphics especially benefit but a short test I saw a long time ago showed an unbelievable difference between rolling flames shoot in HDV that was sent from within FCP vs. the movie imported into Compressor. I always try to have the longer encoding time built into my schedule and have been really happy with the results I get.
Hope you enjoy the book, since it is hands on it is much better than the manual.
Re: GOP, Sync Issues, Compression Markers in FCP? by Alexander Kallas on Aug 24, 2008 at 12:11:49 am
[Tim Green]"Hence, the files don't have exactly the same root name structure as if I had exported audio and video together, so DVDSP doesn't bring the audio in automatically" ??? DVDSP ls an authoring tool, with limited editing capabilities.
[Tim Green]"I'm having the dreaded "AC3 files are different lengths than the m2v files" issue," If your audio is not exactly the same length as the video this is true. Add an audio slug in FCP and trim your audio exactly to your video before exporting and transcoding
Re: GOP, Sync Issues, Compression Markers in FCP? by Tim Green on Aug 24, 2008 at 1:22:12 am
"If your audio is not exactly the same length as the video this is true. Add an audio slug in FCP and trim your audio exactly to your video before exporting and transcoding "
Duh! Why didn't I think of that? My audio tracks are not quite as long as my video tracks in FCP. I'm re-exporting the audio with slugs that extend to the out point right now.
