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Audio/Video Synch Problems + Much Much More
I’ve just started using After Effects CS3 and these forums have been unbelievable valuable. But for the life of me I cannot figure out what’s happening to me…
I have a 6 min clip that needs to be chroma keyed, then edited with other media in Sony Vegas 8.1. The source file is an AVCHD file (720p, 1280x720x12, 23.976 fps, 48,000 Hz stereo audio). I use the comp settings for HDC/HDTV 720 25 on full resolution. I chroma key with Keylight, then send the comp to render cue.
In the render cue I change the render settings to “Best Settings”, output module to “Lossless with Alpha” and I turn the audio on.
After rendering I throw the new file into Sony Vegas and discover that the video is out of synch with realtime. The audio is unaffected, but the video is slower.
Upon further testing I find that the video is ALWAYS out of sync in AE. Even when I RAM preview. But the exact same file plays correctly in Sony Vegas.
Trying to figure where this problem started I go back and start from scratch. Only now, in the project window, the source clip has a completely different fps (19.98fps instead of 23.976fps). This only happens after I’ve brought the clip into AE and tried to render. “Virgin” clips’ details show up properly.
Question 1: What am I doing here that is making the video go out of sync (how can I prevent this)?
Question 2: Why is AE “reading” my source clip incorrectly and/or changing the fps?
Thanks in advance,
Cuitla
After Effects CS3 ver8.0.0.298 -
4 Replies
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[Cuitla Huezo] “The source file is an AVCHD file (720p, 1280x720x12, 23.976 fps, 48,000 Hz stereo audio). I use the comp settings for HDC/HDTV 720 25 on full resolution.”
Instead of manually setting the comp settings, try letting After Effects create the comp for you by dragging the source clip into the “Create a New Composition” icon at the bottom of the project window. See if that fixes it for you, since you appear to have set your comp settings incorrectly.
You might also need to right click on the clip, go to interpret footage, and make sure all those settings match your footage (interlacing, etc.).
Jon Geddes
Providing the Best Motion Menu Templates Available for Video Production
http://www.precomposed.com -
first, do what dave says… use vegas to export the footage to a codec that does not use temporal compression.
quicktime’s lossless animation or uncompressed avi are good choices, as they will avoid further loss of data due to compression, however the files will be very large.
if you can’t afford the drive space for either of those, quicktime’s photo-jpeg is quite good, avid’s dnxhd (free download from avid, it’s a quicktime codec and should work with vegas) is good and dvcprohd would work too if you have it.
once you’ve done that, do what jon describes in ae and drag the footage to the comp icon to have the comp take on all the attributes of the footage…. the comp setting you mentioned sounded like it was 25 fps, so that may have been causing some issues with your 23.976 fps footage. you can double check how ae is interpreting the footage by selecting it in the project window and choosing file>interpret footage>main, you can double check (or correct) the frame rate, field settings, etc…
you’ll also want to render from ae using one of the above codecs (probably the same one you imported into ae) — ae won’t render to mpeg-4 very well either — then let vegas convert it when you import it back in, if needed.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
All good suggestions there for you. But perhaps a simpler solution, since you’ve already done the keying is to ensure that your footage is interpreted as 23.976 and that the comp is also 23.976.
And youshouldn’t need to render the entire 6 minutes. A one-minute test should be sufficient to see if the drift still occurs.
HTH
RoRKbroadcastGEMs – AEPro Volume 02 (Professional Adobe After Effects Project Files – Now Available).
Adobe After Effects Training in South East Asia.
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Okay I tried Jon’s and Roland’s suggestions first and it worked. AE choked through the render and eventually gave me what I wanted. But I will heed Dave’s warning about the freaky file formats in AE and try to avoid them in the future.
I do have the drive space right now, so I’m going to give Kevin’s suggestion a shot and convert my AVCHD files to one of the lossless formats first (in Vegas), then do the keying in AE, then render into the same file format.
Thanks again. You guys are the best!
Cuitla
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