Apple XDCAM 25P to 23.976 lose 4-channel audio Help!

[Jesus Silva]

I just tried the following, take the XDCAM 25P thru Compressor for ProRess with pass-through audio.
Taking that ProRess file in to Cinema Tool to conform to 23.98, BUT I noticed that the audio change from 48Khz to 46.03Khz, Is this part of the conform?

Kept in mind that the rest of the project is in 48Khz.

“Equations are more important to me, because politics is for the present, but an equation is something for eternity.”
Albert Einstein

[Rafael Amador]

[Jesus Silva] ” I noticed that the audio change from 48Khz to 46.03Khz, Is this part of the conform? “
Right. Now each second are played 23’98 images instead of 25. Also are reading 46.030 audio samples instead of 48.000.
The audio is re-sampled on exporting.
Rafael

http://www.nagavideo.com

[Rafael Amador]

[Jesus Silva] “So, since we are working in XDCAM first it needs to be converted to ProRess 25P and the best way to do this is in FCP? I know we can do it in Compressor but this them will a be a two or three part process and we are dealing with ton of footage. “
As long as there is no re-sizing, changes in pixel aspect, field order neither time-base, you don’t really need Compressor. you can batch transcode with MPGStreamclip.
rafael

http://www.nagavideo.com

[Jeremy Garchow]

[Rafael Amador] “you can batch transcode with MPGStreamclip. “

I wouldn’t trust it. Turn on frame controls in Compressor to ensure a 10 biut transcode. I have no idea what StreamClip does, my guess is 8 bit.

I will test 4 channels through Compressor today.

Jeremy

[Jeremy Garchow]

[Jesus Silva] “I know we can do it in Compressor but this them will a be a two or three part process and we are dealing with ton of footage. “

Why not edit in 25p and then do a final conform to 23.976 at the end?

[Rafael Amador]

Hi Jeremy.
Is possible that MPGStreamclip process the image only in 8b, but that’s no much important because we are not really processing the picture. We are just adding to “0’s’ to the left of the 8b YCbCr to get the 10b YCbCr and writing it in Proress.
There is no resizing, de-interlacing, Chroma filtering, etc. The results should be the same whether processed in 8 or 10b..
Cheers,
rafael

http://www.nagavideo.com

[Jeremy Garchow]

[Rafael Amador] “We are just adding to “0’s’ to the left of the 8b YCbCr to get the 10b YCbCr and writing it in Proress. “

Maybe to the footage, but nothing else.

[Jeremy Garchow]

[Jesus Silva] “Well the main issues is not the actual conversion is the lost of the 4-channel audio after conversion is done. “

I got Compressor to pass through 4 channels of audio. Can you upload a one second 1080p25 full res clip with audio for me? Preferrably something with a sync point…if you can. If not I can make one.

Jeremy

[Rafael Amador]

What I mean is that a plain transcoding in theory should yield the same result in any QT application and whatever the bit depth of the process (more than 8 of course).
You end up with 1024 possible values, but 256 real values per channel.
Nowhere have been created intermediate values that needs to be represented with one or two new bits.
Rafael

http://www.nagavideo.com

[Jesus Silva]

Thanks Jeremy,
The project has already started on 23.976 edit is not possible to go back to 25P edit.

If you do a pass-through converting to 23.976 them you media is of sync.
Them how do you approach that, with compressor.

How can I contact you directly?

Thanks,

“Equations are more important to me, because politics is for the present, but an equation is something for eternity.”
Albert Einstein