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Advise needed regarding file naming, AMA transcoding and finaly upgrading quality

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Anna Wysocka
Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 15, 2012 at 9:09:33 pm

Probably its easy but I habe just started working properly on Avid MC 5.5 and I do not want to make a mistake at very begining and then suffer.

I am working curenly on not so long feautre film which was shot on Canon 7D. I have Avid MC 5.5 on PC. Because I haven't been before working on such a big project I am not sure if my computer will handle it despite i think that it should be pretty good. (Double Xeon 5620 2.39GHz - 27GB RAM - 3 x 1TB HDD - 2GB nVidia Quadro 4000 graphic card) I was told long time ago to edit on lower quality and than upgrade it but I am not sure how exacly to do it.

This is my current idea what I think what to do- tell me what i should change in it

1. Us AMA to link files with MC
2. rename files (can i do it?)
3. transcode files to DNxHD codec (but which? DNxHD36 or DNxHD145?)
4. sync with sound
4. edit
5. and here is a problem how to upgrade files should i delete associated media and then somehow reconnect with files after I will transcode renamed earlier AMA files at higher DNxHD?)

sorry if those questions are to trivial


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Michael Kammes
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 15, 2012 at 11:13:11 pm

1. Yes, AMA link to h.264 Canon files is great. It's easy, but performance will suffer unless you transcode to a DNXHD codec.

2. You can rename in the bin, but it will not change the file name at the OS level.

3. DNX36 is meant for offline use. I don't know what frame rate/size you shot at, but DNX145 is generally considered to be the baseline for broadcast quality.

4. Yes. You may want to look into Plural Eyes and it's use within Media Compsoer (http://www.singularsoftware.com/help/pluraleyes_mc/howto_pluraleyes_mc.html) as it will change this entire workflow.....but it will semi automate your sync process. Make sure to note Plural Eyes usage with AMA vs Avid clips.

5. Refer to #3. If you do DNX145, you don't have to do an offline / online workflow. If you DO want to do an offline / online workflow, Avid has a RELINK option which can match by file names, reel number, etc...so you can relink to the high res media.

My suggestions:

Investigate Plural Eyes. Using this software (and, which version of it - one works with AMA media, one doesn't) app will change your proposed workflow completely.

Also, consider transcoding to DNX145 (via AMA, then transcode, or, just do an "import") and using that all the way through. If you have the drive space, your machine shouldn't have much of a problem editing with it.

Good Luck.

~Michael



.: michael kammes mpse
.: senior technology & workflow consultant
.: audio specialist . act fcp . acsr
.: michaelkammes.com
.: twitter: @michaelkammes
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Anna Wysocka
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 16, 2012 at 2:32:24 am

Thank you very much for your advise. I have checked plural eyes webpage and it seems amazing. I have already put it on my to buy list in better financial climate. I have spend all my money on computer and avid I will have to do some manual labour work on sync for some time.

Clips size is 1920x1080 at 25fps

I was experimenting a bit on possible workflow and this is what seemed to work. I would like to emphasize on "seemed" as on various forums it was told that AMA files should not be renamed in canon 7d footage as there might be some problems with relinking later on... In my wee test everything was ok but perhaps there would be some glitches on larger sequence.

here it is - my master plan A

1 Import clips via AMA
2 change name add scene numbers, takes and all notes
3 transcode do DNxHD36
4 sync
5 edit
6 go back to AMA files
7 transcode to DNxHD120 or 185 (I have actually checked and there was no option for DNxHD145 just 120 and then 185 - this bit I have to still research why)
8 highlight my beautiful edited final sequence
9 relink
10 export

If I am utterly wrong feel free to call me blond and highlight where was my error.


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Michael Kammes
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 16, 2012 at 3:16:02 am

DNX followed by a number signifies the data rate of the media in mb/s. This varies depending on frame size and frame rate. Avid confuses this by lumping similar date rates into families, although the exact data rate may not match the number...exactly.

So, anyway, at 1080p and 25fps, DNX145 quality is equal to DNX120.

I have a chart on my website: http://michaelkammes.com/wp-content/uploads/2010/11/codec-chart.gif

But lets examine your workflow. Why do you want to edit low res, then relink to high res? Are you short on drive space? If you edit low res and then relink to hi res you'll have:

Canon 7D files
DNX36 files
a smaller batch of DNX120 files.

Why not JUST create DNX120 files and use that as as your edit and master? It's broadcast quality. DNX120 is 15Mb/s, so 900MB/minute. Determine how much footage you have and see if you have enough storage for that.

Do a test with a few files and see if you can relink after changing the file names INSIDE Media Composer. You'll see in the relink dialog box there are many ways to relink footage - NOT just file name.

~Michael



.: michael kammes mpse
.: senior technology & workflow consultant
.: audio specialist . act fcp . acsr
.: michaelkammes.com
.: twitter: @michaelkammes
.: facebook: /mkammes

Hear me pontificate: Speaking Schedule .


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Hans Sieber
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 16, 2012 at 10:14:47 am

I would as Michael suggested just do a straight import using some form of Online DNXHD codec without going the offline/online workflow. Relinking in Avid can become VERY troublesome. Sometimes it works other times where everything seems to be the same it doesn`t. Relinkg made me loose a lot of what once was on my had called hair.
Just one little hint from my side. Using AMA with H264 files results in a gamma shift. Its not a false remapping using RGB or 709. It`s a gamma shift by the value of 0.18. It´s not too obvious to get noticed right away but it crushes you blacks very heavily if you got some low light footage. Straight import works fine.
Avids AMA is still not what it should/could be. But time will tell.

Hans


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Anna Wysocka
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 16, 2012 at 3:34:10 pm

Thanks again for all the information.
Michael you are right I will better work online and transcode to DNx120 instead of relinking everything later with a fear that something might go wrong.
I can just add that I was doing small tests yesterday with all possible combinations of relinking with different orders in workflow to see if there would be some problems and everything was relinking smoothly - that’s why after reading on different forums what problems other editor encountered - I just knew that there might be some hidden problem that I just don't see right now.

Hans - my footage is very good lighted - no night scenes etc. so I am lucky in that aspect. I was reading in some posts about changes in gamma. Do you then recommend just importing files than link through AMA when I will end up with editing low exposed clips?

Thanks again


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enrico bartolacci
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 16, 2012 at 4:42:56 pm

Anna, problems arise when you're near the end of the work, never on tests :D

and, you're looking not to a relink, but to a batch import.
If you link to ama and then transcode to - say - dnxhd120 (or 185, i usually use 185 with 7d) you don't have other media to relink.

If you transcode a 120 to 185 and then relink, you are only going to have higher space occupied in the drives, as the "starting media" for the transcode is the 120, not the original ama linked media.

So, you have 2 options: relink to the original media (a pain, in fact, often you'll have headaches for it) or batch import (right click on sequence -> batch import). This way, the media will be created from the original ama files.


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Hans Sieber
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 16, 2012 at 9:58:29 pm

Dear Anna,

I only use AMA with certain codecs. Avids AMA works pretty fine with DNxHD, Animation, and Camera Files like XDCAM. Prores files have their own problems. I NEVER use AMA for H264 files. The gamma change to the files is irreversible (as far crushed blacks are concerned) and dabbling in CC with heavily compressed files like H264 is a delicate thing in itself. Therefore I recommend a straight import of such files. Do it in the online Codec of your choice. DNxHD 120 seems quite enough for H264 files. Larger codecs don`t improve waht is not there in the first place.
I hope that Avid will fix this problem. It´s been there from the start of AMA. But no avid rep I talked to so far, has ever heard of it. I always get told to check my import settings...

As always time will tell.

Hans


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Anna Wysocka
Re: Advise needed regarding file naming, AMA transcoding and finaly upgrading quality
on Feb 17, 2012 at 6:02:42 pm

I was researching this subject a bit - I have found that post on avid forum http://community.avid.com/forums/p/87056/493545.aspx#493545 - user blafarm performed some tests and described differences in various imports/exports/re-imports settings. I think I am convinced that just straight import with File Pixel to Video Mapping set to "Computer RGB (0-255)" seems to be the best option to keep contrast more or less intact when dealing with canon 5/7d footage.

I would like to again thank everyone for help on that issue.


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