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Luis Ortega
Baffling problem
on Jan 17, 2003 at 11:45:23 pm

I edited a 10 minute project on my Avid Xpress DV 3.5 desktop system that used 2 video tracks and 8 audio tracks in a few places, then I did a digital cut (export to tape) to the Sony GVD300 vcr that is connected to my system.
I then digitized the edited tape into my laptop that has Premiere 6.5 using my Sony TRV900 camcorder to do some further work adding titles, some music sound and some sound effects.
Then I exported the final edited project to tape from the laptop to the TRV900.
When I play the final edit from the Premiere timeline it sounds fine, and when I play the tape using the TRV900 to a TV set it also sounds fine. But if I play the tape using the GVD300 I hear sound defects in many places. Some of the dialogue cuts in and out and sounds corrupted. The defects always appear in the same places throughout the tape.
The tape always sounds fine when played from the TRV900 and always has the same sound problems when played from the GVD300.
I have another GVD300 at work and the tape also has exactly the same sound problems on that GVD300 as on the one I use at home.
I have re-exported the final edit several times from Premiere to the TRV900, always blanking the tapes, recording to different parts of the tape, and even using different tapes, and every time the same sound problems appear in the same parts of the project when I play the tape in either GVD300 but never when I play the project using the TRV900. And the project always sounds fine when played from the Premiere timeline. The visuals are always fine in all situations.
I am baffled. Sony is baffled, and the Premiere and Avid people don’t have a clue.
Needless to say, both the GVD300 and the TRV900 seem to work fine in other situations and when playing other tapes, and Premiere and Xpress DV also seem to work fine.
Can anyone figure out what I did wrong or what is happening?
Thanks a lot for any advice.
Luis


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ciabt
Re: Baffling problem
on Jan 18, 2003 at 5:32:43 am

Hi there
I have had the same problem when exporting to my VCR. It plays perfect on the VCR I exported to but I tried playing it on about 15 different VCR's and each time I encountered something different. Some minor issues and on some VCR's some major issues such as sound effects coming in where the weren't put in and sometimes sound not in sync with the video (up to 7 seconds off on some VCR's). I'm really not too sure what to do, I guess hollywood has really expensive mastering decks that seem to be able to make a copy that will play virtually the same on every VCR, but I obviously don't have the kind of money they have and I'm always worried about how its going to play on a clients VCR. I spend all that time working on a project for them and get everything looking perfect, but if for some reason there VCR doesn't play it the way mine does, they'll think I have no clue what I'm doing and never hire me again. I now have a DVD burner (A05) and love it, but unfortunatley some clients still wish to have there videos submitted on VHS. If you find out what to do please let me know, I will be carefully watching this post. Good luck with your video, hope it'll play great in no time.
Later
Brent


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Ron Evans
Re: Baffling problem
on Jan 18, 2003 at 4:58:10 pm

I have experienced a similar problem. I have a Sony DHR1000 as my main editing deck, a Sony PC10, Sony TRV740 ( D8 ) and a Sony TRV50. I rent Pro Panasonic DVC200 for my main camera for bigger events. So I often have a mix from different cameras in my Premiere time line. I had a situation were on one dance concert there was a loud Hip Hop number that would cause the DHR1000 to mute the audio every time it played from the time line or the outputed tape---but this same tape would play back fine from the PC10 or the TRV50!!!! In other words the DHR1000 recorded the data on the tape but would not play it back!!! Eventually I thought about the master reset button the DHR1000, pressed this and it played. I have no idea why but it worked. Since then any time I have doubts about the output from the deck I press the reset button and reset the clock etc. Maybe the data rate is just getting too much and the error correction mutes the output. Different decks have different electronics and reach this point at different times. My guesss is that the reset button empies the buffers and allows the unit to start all over again without some offsset that will cause the problem.. Try and see if pressing the reset works I think most of Sony products have this reset somewhere you just have to search for it a little.

Ron Evans


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Luis Ortega
Re: Baffling problem
on Jan 18, 2003 at 5:39:36 pm

Thanks for your advice, guys.
I investigated a bit more and discovered that all of the projects that I have exported to tape recently using the TRV900 as the recording device (but from different computers) have similar sound defects when played on any of the GVD300s but sound fine when played on the TRV900.
These projects were shot on various cameras and edited on different computers by my students and are fairly simple projects using two video and two audio tracks with a few titles.
I started checking the menu settings on the TRV900 and noticed that the audio mix had been set to st1 during these operations and the manuals recommend setting this between st1 and st2. The other audio related settings seemed set ok (hifi sound set to stereo, audio mode set to 16 bit).
Today I did a quickie edit experiment using the Avid xpress dv and this time I exported the timeline to the TRV900, making sure that the audio mix was set between st1 and st2 and hifi was set to stereo and audio mode set to 16 bit. Then I played the exported tape in the GVD300 and this time all of the sound is fine when played. It also sounds fine when the TRV900 is used for playback.
Now I have to try re-exporting my students' projects again next Monday at school and see if this time the tape will play back OK on the GVD300s.
Thanks again for the advice. Do you think that having the audio mix setting to one extreme while doing the export to tape would also be able to cause these peoblems?
Is there a correct way to set audio mix, audio mode and hifi sound if a project has been filmed in 16 bit and then edited with some added sound tracks in an editor? Is 16 bit the correct setting to use on a DV camera if the material will be edited later and other sound tracks added in the editor? I just assumed that everything should always be shot using 16 bit, but I am confused as to what that means in relation to later editing and further sound mixing. I read the manuals for the GVD300 and the TRV900 but I am still unclear as to what to do.
Thanks again.
Luis


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Ron Evans
Re: Baffling problem
on Jan 18, 2003 at 7:36:35 pm

DV has two audio modes. 12bit 32khz and 16bit 48khz. As long as you are consistant with you definition to your NLE all will be well. For instance if you tell Premiere that the source is 32khz but you want the output to be 48khz it will reencode the output for you. At the 12 bit 32khz the camcorders or decks can add another track of stereo audio ( 4 tracks or two stereo tracks in total) this is what the mix controls are for on the output of some of the decks and camcorders that have the ability to do an audio dub. They allow you to select which tracks to hear. IF you select ST1 and ST2 you will get a mix of all 4 tracks. When recording at 48khz there is only one stereo track and no audio dubbing is then possible. OF course if you select ST2 when you have recorded on ST1 you will hear nothing!!! a lot of the early DV camcorders only recorded on ST1 in 32khz ( just like my Sony PC10 and I am not sure about the TRV900 ) Most of the Canon's give you a choice and for the XL-1 allow you to record on all 4 tracks at once.
IF you are going to always edit in the computer then use 16 bit if your camcorder allows. IT is more important for you to know what the audio was recorded at since the NLE will sort it all out if you tell it to. IF you output to tape from an NLE the camcorder will essentially just copy the DV data so you will get what the NLE created NOT what you think you have set up on the camcorder( recording speed is about your only real choice). If you told the NLE to create a 48khz 16bit output then you will get one stereo audio track in the DV data. By default your TRV900 will play this back correctly. I believe that the audio settings on your TRV900 will only effect playback from the TRV900 or recordings made by the camera NOT DV input from the NLE.


Glad you found the problem

Ron Evans


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Luis Ortega
Re: Baffling problem-solved at last
on Jan 29, 2003 at 4:44:53 pm

Hi Ron,
I finally discovered what the real problem was, and it had nothing to do with the settings or the decks.
The projects that were having sound problems turned out to have sound clips that had been overdone in gain and the waveforms were clipped a lot.
I had to open the sound mixer in the editing software and bring down the sliders for the tracks to about -6 db, in some cases even -12 db before the exported to tape material stopped causing audio defects when played on different machines. The tests I had done just throwing some clips together and exporting them did not have the problem because their sound was OK, but the problem kept re-occuring whenever I tried to re-export the problem projects, regardless of the settings on the trv900 or the gvd300s.
Just wanted to share that bit of infor with anyone who may be havig a similar problem.
Thanks for your help.
Luis


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