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unable to get realtime play back when previewing HDV 1080i50
Hi
I am unable to play back real time video when previewing through my black magic decklink HD card.
I have a quad core intel mac with 9 gig of ram and am running OS 10.5.6 and after effects CS3.
I have some footage which is HDV 1080i50 and it wont play in real time.
Ironically I have tried it with full HD 1920 x 1080 which has H.264 compression and that works and plays in real time for around 200 frames at a time.
I can also get full HD motion graphics to work (1920 x 1080)
But if I use the HDV 1080i50 footage I dont get real time play back.
Can anyone advise me on this plus maximising the memory and processing power that I have?
I have render multiple frames enabled and disc cache enabled.
Please can someone advise me?
thanks
Dan and Neil
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4 Replies
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in addition to what dave says, to get better play back thru your decklink card, you may need to use a comp that matches a standard that you decklink card uses…
i have an sd decklink card, and it often won’t preview sd in realtime if the comp is not a standard d1 comp. you should be able to see the standard that the decklink card is set to output in preferences>video preview, under the ‘output mode’ it should give you the frame size. make a comp that matches that frame size, drag your footage in and try a ram preview.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Hi Dave and Kevin
Thanks for the link, im pretty familiar with previewing and certainly dont use the space bar to do so.
Ive been using after effects in SD for a number of years and now upgrading to HD.
Thanks for the info about H.264, the reason I mentioned that is because I just so happened to have a 1920×1200 quicktime to try although it is compressed in this way, I would never use H.264 as a working file in After Effects.
It did work though, for some reason I managed to watch it through my 1920×1200 monitor and card.
I also tried re compressing the file in question to uncompressed quicktime, this did not work either.
Could you advise me on a codec to use?
I have just received an updated video clip to use.
the file is 1440 x 1080 (1.33) seperated upper DVCPRO HD 1080i50
The thing is that I am adding graphics to this file so I need it to preview.
the pixel aspect ratio of the file is not square, its (1.33). Could this have anything to do with it?
After effects recognises it as 1440 x 1080 with none square pixels. Quick time recognises it as 1920 x 1080
So presumably the best way to create a comp from this file is to drag into onto the new comp button.
which is the way that I normally work.
The HD presets in video preview dont have an option for 1080i50. Could this be the reason.
Does this new file and information help solve the problem?
thanks for your reply so far.
Please could you advise me further.
Best Wishes,
Dan and Neil
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what are the output modes for decklink card?
and, if you choose one that is as close to 1080i50 as you have, what is the frame size displayed under the output mode?
if there is any selection for pal 1080, it should give you a frame size that it works with. assuming that the hd card is similar to my sd card, that fame size will be the frame size that you should try for your comp to try and get realtime playback of ram previews. if you have a setting for output quality (in video preview) you might try setting that to faster, rather than more accurate (at least that’s a setting in the sd card).
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Hi the frame size in the output mode is 1920 x 1080.
there is no selection for PAL 1080
The output modes go as high as 1080 i 30hz-RGB
and 1080p 24hz – RGB
I will try faster rather than more accurate and get back to you.
neil
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