There is a one frame processing time for any encode or decode process. Usually, we will put encoded E stream on tape one frame early in relation to master, always with sync pop so when it is decoded, it will be in sync. This is common practice, so we expect that any tapes we receive with E streams will be one frame early. When you decode, it comes out in sync - with a sync pop you can easily tell what you've captured is in sync in relation to captured TC and/or captured non-stream audio.
On Tue, Nov 12, 2013 at 11:05 AM, johnrobmoore <bigfish@pacbell.net> wrote:
Is there any kind of delay that requires and offset after capture. I've read the dolby E is generally offset 2 or so frames to accommodate the decode time. Does that come into play in your workflow?
--- In Avid-L2@yahoogroups.com, Mark Spano <cutandcover@...> wrote:
>
> What Pat said.
>
> I use a Tek AMM768 (http://www.tek.com/audio-monitors/amm768) which is an
> audio monitor that has SDI inputs and AES outputs and a Dolby E decoder
> built in. I send the SDI signal from tape through the AMM and decode the E
> into its parts, and capture the channels over AES into a Nitris DX at
> 24-bit / 48 kHz (PCM/MXF). Then, for E encode, I use the Minnetonka SurCode
> for Dolby E encoder (
> http://minnetonkaaudio.com/index.php?option=com_content&view=article&id=83&Itemid=99)
> to do an offline encode at the new frame rate.
>
>> On Tue, Nov 12, 2013 at 5:11 AM, Pat Horridge <pat@...> wrote:> > *VET*
>
> >
> >
> > Dolby E is just a data stream created with guardbands around the video
> > frame boundaries.
> >
> > So it's PCM uncompressed data.
> >
> > If you capture as PCM (MXF is fine) at 24 bit you will capture a data
> > stream. You can't play it back and hear audio but you can, in theory cut it
> > on video frame boundaries and lay back to tape.
> >
> > It's imperative that it retains sync with the video frames of course.
> >
> > There are plugins that let you decode the data stream to discreet audio
> > channels either in software or in hardware externally.
> >
> > The safest way is to decode the Dolby E on the way in to your Avid and
> > capture 5.1 audio (it could be 8 channels in all)
> >
> > Then frmae rate convert and the re-encode back to Dolby E. that can all be
> > done in software but make a mistake anywhere and you can corrupt the stream.
> >
> >
> >
> > Pat Horridge
> > Technical Director, Trainer, Avid Certified Instructor
> >
> > *Production Editing Digital Media Design DVD**T* +44 (0)20
> > 7505 4701 | *F* +44 (0)20 7505 4800 | *E* pat@... |
> > *www.vet.co.uk <http://www.vet.co.uk>* | Lux Building 2-4 Hoxton Square
> > London N1 6US
> >
> >
> >
> >
> >
>
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