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Barco Image Pro II scaler/switcher question…how does it keep audio/video synced
I’m setting up a new cinema/projection facility. I’m using the new Solaria One + cinema projector for DCP playback. For film festival, i also need to run video source (HDcam, DigiBeta, BluRay, computer with AJA for MOV files)
In this case, all the video sources will go though a Barco scaler/switcher Image Pro II then output of the scaler into the Solaria. Sounds from all machines are plugged into the Dolby CP650.
On the Barco i have it detect the input automatically and output to 1920 x 1080p @ 23.976. So basically, anything in will be rescale and re-cadence to 1920 x 1080 @ 23.76 so the projector will always sees the same signal.
Now, sources with cadence anything but 23.976 will have to go through pull up/down for example (29.97 to 23.976) in this case, how can the image and sound stay in sync since the Barco deal strictly with the image ???
Actually this question is valid for all scaler device out there. Thx
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3 Replies
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It doesn’t. Next question!
You’ll need an audio delay for sure
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[Matt Geiser] “It doesn’t. Next question!
You’ll need an audio delay for sure”
Matt, do you know this for a fact ? Do you use the Barco in a Cinema environment ??
Delays of the Barco is negligible ( less than half a frame). My question above has more to do with playback speed because when you do a 2:3 pull down (24fps to 29.97fps) the audio needs to be slowed down by .01 %
For a quick test i have my AJA IO XT hooked into the SDI input of the Barco. I’m playing a 1080p @ 24 fps file and the output of the Barco is set to 1080p @ 29.97 and into my Dreamcolor. Everything played in sync fine. Hmmm….
Anyways, anyone with experience with the Barco care to chime in ???
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[Anhtu Vu] “Delays of the Barco is negligible ( less than half a frame). My question above has more to do with playback speed because when you do a 2:3 pull down (24fps to 29.97fps) the audio needs to be slowed down by .01 % “
For synchronous output, your delay will be 1 field at best and 2 fields (1 frame) at worst. For asynchronous output, your delay will be 2 fields (1 frame) at best and 3 fields at worst.
You do not need to slow down the audio when running it through it scaler. Think about it: scalers process in real time. They do not have infinite buffers for accommodating time-resampling of content of arbitrary length.
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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