I have laid back my pictures to a HDCAM SR and everthing is fine but I have another tape with Dolby E on it which I have to insert on to my master. I know how to insert on to HDCAM SR using the non audio menu but I only have one machine.

Is it ok to capture the audio in to Symphony Nitris then lay back to tape ? Does it do anything to the dolby e in the way of making it unusable or altering it in anyway.

I've got to deliver this on Monday so any help or advice would not only be appreciated but would also literally save my life/marriage/job. Sadly as I write this and realise I'm not actually being over dramatic.

Many thanks for any adive in advance.

We've done this successfully several times. The key is to remember to turn on "data mode" on the deck audio channels when you lay back.

Thanks Terence. I'm fine doing VTR to VTR but was too scared of using the Symphony Nitris in case Avid had some kind of processing in the Audio I didin't know of that changed it. My project was 24 bit matching the pro tools session so I should have been more confident but I didn't want to ruin the tape.

Out of interest the guys in sound put in a frame delay when laying back does that count with Avid laybacks ? Would you pullup the Dolby E by a frame compared to the other tracks ?

Thanks very much for your advice.

I've only done "straight in and straight out" Dolby audio and never had any sync issues.

Thanks Terence that's really useful to know.

Hi all,

I have some info which may or may not be useful.  First, I am intrigued that Terry seems to have  had success capturing and playing back Dolby E in a SN.  Reading his post I am not quite sure that is what he is saying.

Terry?

The reason I bring this up is that the party line from Avid is that you can not do this.  That the capture into Avid "breaks" the Dolby E stream.  So we never even tried.  Guess I have to experiment now ...

As to delay, the Dolby E boxes - encoder and decoder - each take 1 video frame of time to do their work.  So if you want to have the Dolby E track play in sync with the AES track after they are decoded, you must advance it on tape by 1 frame.

Terry is correct about making sure "data" mode is on.  But I will alslo say that various deck models work differently.  For example, a good old DVW A500 (digibeta) has no Data mode.  And it records Dolby E just fine.  So crack open the manuals to whatever deck you are useing.

And without Dolby E encoders / decoders to test, test, test, I would be nervous to do anything.  I find that it is a finicky format at best.  Our audio guys have a love/hate relationship with it.

Just my 2 cents ...

Jef

Good thing I didn't know it wasn't supported when I tried it. ;-)

There is no frame delay added as you aren't coding / decoding, just copying a data stream.

We monitored the progress through our Tektronix scope which has the Dolby option in it.

I was using an SRW 5500 with menu #305 fild edit mode 1-2. # 317 in cut mode#809 muted to cope with the the jog issues. #831 switched to non audio. #831 continuous.  

It worked fine but I was worried in case there we any artefacts I was unaware of so in the end the sound mixer did a lay back.

Our sound mixers have a few issues with Dolby & HD. It's all my fault......apparently.

 

jef:

As to delay, the Dolby E boxes - encoder and decoder - each take 1 video frame of time to do their work.  So if you want to have the Dolby E track play in sync with the AES track after they are decoded, you must advance it on tape by 1 frame.

I don't think this is universal.  Here in the UK the BBC specs state :

"5.3. Multi-channel (5.1) timing on tape
o The Dolby E encoded signal should be in sync with the stereo signal ON
TAPE. This positioning allows further processing to be done to the final
tape if required. The DolbyE signal will be advanced by 1 frame in the
play-out chain to compensate for the Dolby decoder delay"

Yet another thing to think about, especially when doing multiple deliveries . . .

regards

Brian

Hi,

You are correct.  Not every network does it the same way.  You have to find out from each.

Jef

Hi Terry,

Does the Tek scope actually decode the audio to multi channels for you to hear or just give some evaluation?

Jef

Well I just tested it here and it failed.

Panasonic D5 1080i 59.94 into SN ver 1.7.2 via HD-SDI and back to same machine via the same path. 

Using Dolby Decoder to decode the new recording.  I get error lights and no sound.

So what did you do differently Terry?

Jef

EDIT:  We poked around in the SN and changed some settings and it now seems to work.

Important settings 24bit audio, convert sample rate when playing - Never, sample rate conversion - Never. 

What settings did you have your deck set to ?

Panasonic HD D5 have no special settings for data.  Just make sure the "Rate Convert" button in the audio menu is off.

Jef

I don't have a HD D5 , which is a shame because I had one at my previous job and I loved it.