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#1
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Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
I was asked today if the 5.1 sound on a DVD can be ripped into 6 discrete channels as the distributor requires HD cam SR. A distribution company I am working with is re-issuing and older film and all they have is the sound of the film as it exists in the original release of the film on DVD in surround 5.1 (they don't have the master 5.1 sound prior to the AC3 encode or the master PT sessions).
BTW, this is all 100% legit, the distributor/producers have all the rights to the film (it is their film) it is not like they are trying to illegally rip off a feature film. |
#2
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Re: Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
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#3
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Re: Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
Yes, I agree, this is exactly what I suspected. I don't know why they do not have the originals, I am told that hey do have the M&Es and the LTRT but not the master 5.1...strange!
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#4
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Re: Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
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I would say while it is possible to do this it is not good practice. The expectation when requesting/receiving audio discrete on a HDcamSR is that the material is 'un compressed full bandwidth' This material will have had data reduction to 448kbps as part of initial Ac3 encode and so could not be considered 'un compressed full bandwidth'. My understanding of Ac3 is that it was not designed for several encode/decode passes -like Dolby E -but as a final delivery codec ie encode once, decode once. Anyway I guess best to inform your client -get them to check delivery specs, and let them decided what they want to do. Probably be worth having a listen to the material after it has been re-encoded to Ac3 again -to see what the result is. All the best Bruno |
#5
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Re: Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
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maybe even keep only the C for dialogue and mix with the other five M&E channels... just an idea...
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MacPro 7.1 8c 3.5 GHz, 48GB RAM, HD native PT 2021.12.0, 10.15.7 www.imdb.com/name/nm0501611/ |
#6
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Re: Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
Thanks for the suggestions. The producers will decide on what is best but given what they have it may be easier to re-mix from the very original OMF and create brand new sound track.
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#7
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Wow. Easier to remix from original omf?!
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#8
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Re: Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
Use the LtRt and M&Es to recreate....
an AC3 encoded, decoded, encoded and decoded once again is going to sound like crap.. That's why they have DOLBY E, so you can encode and decode as many times as you want. cheers geo
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georgia hilton CAS MPSE MPE Hilton Media Management Film Doctors http://www.filmdoctors.com Me... http://georgiahilton.webs.com/ Stage 32 http://www.stage32.com/profile/6569/georgia-hilton My Production Company http://www.hiltonmm.com CREDITS (partial) http://www.imdb.com/name/nm0385255/resume MEMBER: IATSE LOCAL 700 |
#9
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Re: Is the quality of a "ripped" AC3 good enough to lay back to HD Cam
Another vote against AC3. Be careful when combining LtRt and other stems. Make sure that phase alignment is spot on and check stereo & mono down mixes.
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