Question regarding multi-channel sound workflow? at DVinfo.net

Graham Hickling · August 12th, 2004, 10:21 AM

Commercial DVHS tapes support multichannel dolby digital audio. For example, to quote from http://www.foxhome.com/dvhs/

"D-Theater also boasts superior audio quality, with its Dolby Digital 5.1 audio streams compressed at 576 kps, which is less compression that DVD (which is compressed at 384-448 kps)."

And NLEs like FCP and PremierePro make it fairly straightforward these days to produce dolby-digital encoded multichannel audio streams (i.e. AC3 files) at a variety of bitrates.

But .... what I have not been able to figure out is whether it is feasible for us to create a valid transport stream, containing multichannel audio, that can be exported back from the computer via firewire to an HDV camcorder or DVHS deck.

Does anyone have any information or experience on whether it is possible to do this?

Thanks in advance!

Steve Crisdale · August 12th, 2004, 05:21 PM

I haven't gone back to tape on either the camera itself or an external deck with m2t edited footage containing Dolby 5.1 encoded audio..... but I have written HD10 clips with Dolby 5.1 audio to MPEG2 and DVD with no problems.

There's no reason I can see, that writing back to cam/deck a Dolby encoded edit wouldn't work, as long as the basic bit rate and sampling depth of the standard stereo stream are retained.

Changing the sampling rate to 44000hz or 96000hz rather than it's 48000hz could potentially cause problems, as would changing bitrate from the 384000bps standard.

Personally, I haven't felt the need to go back to tape with any of the material I've shot or edited - everything goes to DVD for back-up.....but I'm sure you won't irrepairably damage you're camera or deck if you 'sucked it and saw'.....;)

August 12th, 2004, 10:21 AM	#1
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	Question regarding multi-channel sound workflow? Commercial DVHS tapes support multichannel dolby digital audio. For example, to quote from http://www.foxhome.com/dvhs/ "D-Theater also boasts superior audio quality, with its Dolby Digital 5.1 audio streams compressed at 576 kps, which is less compression that DVD (which is compressed at 384-448 kps)." And NLEs like FCP and PremierePro make it fairly straightforward these days to produce dolby-digital encoded multichannel audio streams (i.e. AC3 files) at a variety of bitrates. But .... what I have not been able to figure out is whether it is feasible for us to create a valid transport stream, containing multichannel audio, that can be exported back from the computer via firewire to an HDV camcorder or DVHS deck. Does anyone have any information or experience on whether it is possible to do this? Thanks in advance!

August 12th, 2004, 05:21 PM	#2
Steve Crisdale Major Player Join Date: Jan 2004 Location: Katoomba NSW Australia Posts: 635	I haven't gone back to tape on either the camera itself or an external deck with m2t edited footage containing Dolby 5.1 encoded audio..... but I have written HD10 clips with Dolby 5.1 audio to MPEG2 and DVD with no problems. There's no reason I can see, that writing back to cam/deck a Dolby encoded edit wouldn't work, as long as the basic bit rate and sampling depth of the standard stereo stream are retained. Changing the sampling rate to 44000hz or 96000hz rather than it's 48000hz could potentially cause problems, as would changing bitrate from the 384000bps standard. Personally, I haven't felt the need to go back to tape with any of the material I've shot or edited - everything goes to DVD for back-up.....but I'm sure you won't irrepairably damage you're camera or deck if you 'sucked it and saw'.....;)