XDR/Nano Video Post Production Work Flow Tests & Questions

[Mark Job]

Hi All:
I have been conducting a series of different file conversions from XDR originally recorded files to different file formats using MPEG StreamClip on my iMAC (Because it's way faster than my PC). I need to see which format (s) fast import into my Avid Media Composer PC system and remain uncompressed in that format through export to web encode via Quicktime Reference.

The series of sit down interviews we have done will be posted on our production's website, so I will study in as great a detail as I can, which format provides the greatest quality, speed of import, export and quality web encode via a QT Ref file export to encoder.

Right now, I'm transcoding the CD video file format, which I understand to be the Sony XDCAM HD Codec to the HDV video format for fast import into Avid MC. However, there is a small difficulty. For some annoying reason, there is more than One (1) HDV codec in play with editing systems that only adds confusion to the equasion of converting to HDV - Which HDV codec do I use ?

1. Can someone please confirm the actual technical name and spec of the kind of HDV which is generally recorded onto cassette tape in HDV camcorders ?

* You may wonder why would I ask this ? Well, there is Apple HDV, and there is Quicktime HDV with all kinds of codecs which can be used. In order to fast import into Avid I must use the kind of HDV file format for 1440 x 1080i @ 59.94 MHz which HDV camcorders output to Firestore drives and record onto HDV tape. Great ! So what is it ?

[Rafael Amador]

Hi Mark,
I don't work with PCs neither with HDV, but I think you are complicating your workflow, degrading your footage and wasting a lot of time.
If I'm not wrong the AVID MC works with MXF files. You only need the free QT-to-MXF re-wrapper. No rendering, no quality lost.
Also i don't understand, if you need to transcode, why you choose HDV. Low quality and long-long compression time.
rafael

[Mark Job]

Originally Posted by Rafael Amador

Hi Mark,
I don't work with PCs neither with HDV, but I think you are complicating your workflow, degrading your footage and wasting a lot of time.
If I'm not wrong the AVID MC works with MXF files. You only need the free QT-to-MXF re-wrapper. No rendering, no quality lost.
Also i don't understand, if you need to transcode, why you choose HDV. Low quality and long-long compression time.
rafael

...Hi Rafael. Please allow me to clarify three points.

1, Since I am delivering to web, I'm not overly concerned with the slight degradation of source file quality by going from the XDR's XDCAM HD excellent source quality to the slightly compromised 1440 x 1080 resolution of HDV.

2. * I can certainly go from the original (or converted to MXF with CD's conversion app) into Avid MC as you suggest, but my version of AMC (Ver 3.1.2) will not *fast Import* CD's XDCAM HD native video file format unless I import as an 8 bit or 10 bit 1:1 uncompressed. I conducted a test by doing exactly thus, but this import was not only not a *Fast Import* but it took over 8 hours and one heck of a lot of disc space to keep the CD XDCAM HD file format prestine. It is impractical to wait this kind of time to perform my edit sessions of XDR captured source files, therefore, I need a compromise to save time and disc space.

3. I can Fast Import HDV files in about four minutes versus the 8 hours to do a 1:1 10 bit uncompressed, which leads me to pose another essential question in this process that may allow me to do a fast 1:1 import........

Is the Flash XDR an 8 bit or 10 bit recording device.

EDIT: OK. I made one error in stating that my current version of Avid Media Composer cannot fast import the CD video file XDCAM HD. Avid MC 3.1.2 certainly can import the XDCAM HD CD video files. I will setup a project with this codec setting and try an edit and export.

[Mark Job]

Hi Friends:
OK. The workflow to keep all things from being re-compressed no matter what you cut, or what effects you add, or titles and lower thirds you use, is to set your project to either a 1:1 8 bit or 1:1 10 bit uncompressed. You then set your titles, effects and render settings to the same 1:1 8 or 10 bit and viola !

* A strange setup indeed, is how AMC works if you setup an XDCAM HD Project. AMC will automatiocally transcode your video files upon import to the DNxHD 145 codec - *Read Recompression.* I think I will have to upgrade to the new resolution independent AMC ver 4.x

In the newer version of AMC, when you setup a project as an XDCAM HD one, your imported files are kept in their original state and only a recopying process takes place. You do not have to set your project up as a 1:1 uncompressed.

Now let's see what the workflow is in FCP 7.0 to keep the CD recorded files in their prestine condition, if any ? I suspect the same setting might have to be used for projects- that is the HD Uncompressed project setting, but we will see.

[Rafael Amador]

With FC you can edit native CD files whatever the size, data-rate, etc.
You can cut and export without re-compression.
Only the GOPs in the cuts are rebuild as per the sequence codec.
About the question if XDR records 8 or 10b, MPEG-2 do not supports 10b.
rafael

[David Issko]

Originally Posted by Mark Job

Is the Flash XDR an 8 bit or 10 bit recording device.

Both the XDR & nano are 8 bit recorders. There has been much discussion about 8 bit vs 10 bit recently on this forum. Check it out.

[Mark Job]

Originally Posted by David Issko

Both the XDR & nano are 8 bit recorders. There has been much discussion about 8 bit vs 10 bit recently on this forum. Check it out.

....The reason for asking this question is I can set Avid MC for 8 or 10 bit uncompressed, and I wanted to make sure I matched the settings properly to avoid any chance of AMC trancoding something because it was in one format of video (In this case 8 bit files) instead of what I had set the project to (10 bit uncompressed)

[Rafael Amador]

Hi Mark,
Converting the 8b of the NANO to any 10b codec makes sense in a workflow were you introduce some Luma/Chroma filtering. You get more than 255 values of Y', Cb and Cr that they should be sampled in 10b.
This happens when you capture your 8b stuff with an AJA or so. There is also software that helps when going from 420 to 422 or 444 and from 8b to 10b.
If you are purely transcoding 8 to 10b, the only thing you do is to add two more "0's" to any Y'CbCr value. You get 25% bigger files with the same picture information.
In need of transcoding the NANO files the best option would be a 8b Uncompress codec.
An 8b compressed solution makes no much sense coming from 8b MPEG-2.
IMHO editing native is the best option, and if you are compelled to transcode, think that if you capture through a good IO card you are adding value to your picture. No only adding more bits.

[Dan Keaton]

Dear Mark,

For 10 bit capture to be useful, one needs a 10-bit camera.

All HD-SDI is 10-bit, but many, in fact quite a few cameras, are 8-bit somewhere in the signal chain, so all one gets is 8-bits, embedded in a 10-bit word.

Note that true 8-bit offers over 16 million colors, not 256 colors as some like to say.

[Mark Job]

Originally Posted by Rafael Amador

Hi Mark,
Converting the 8b of the NANO to any 10b codec makes sense in a workflow were you introduce some Luma/Chroma filtering. You get more than 255 values of Y', Cb and Cr that they should be sampled in 10b.

...Yes, I agree. I always add color correction, image and density correction (Only where needed), and lower thirds, so 10 bit uncompressed it is.

Originally Posted by Rafael Amador

IMHO editing native is the best option, and if you are compelled to transcode, think that if you capture through a good IO card you are adding value to your picture. No only adding more bits.

...I agree again. The only reason I am not editing native in Avid MC, is much to my great surprise, this earlier version of AMC (3.1.2) does *not* allow one to import the XDCAM HD codec based files Convergent Design is using *natively* into an XDCAM Project. (???) AMC *Transcodes* this automatically to DNxHD 145 Mbps codec !! Ughhhhgghhh ! This is the dreaded recompression, which must be avoided at all costs ! The only solution left open to me is to import the CD video files into an 8 bit or 10 bit uncompressed project which leaves the XDR files in their original integrity. I just want to have a post workflow which preserves the original quality of the source files.

...........Now it's onto looking closely at FCP 7.0 on my iMAC and see if there is way to do native post in this app.