Okay I got some answers from the rental house regarding XD Direct. Seems it is a refinement of a product called or from NL Tek. Start at the bottom and move up to see the chronology of the thread we've had:
Hi John,
Responses below in RED.
What is the data size of the proxys XD direct creates relative to our typical 10:1 SD resolution we use for offline?
The proxies are created in-camera and are similar to the highly compressed Avid JFIF bitrates at about 1.5Mb/s, which equals about 675MB per hour.
Are the proxies XD direct creates true HD files for an Avid HD project.
No, the proxies are SD files that match the audio, visual and meta-data of the higher res files. The raster is SIF 352x240.
The main reason we have traditionally used an Avid SD project is for the 10:1 or 10:1m resolution space savings over something like DNX 36.
Agreed.
There are advantages to keeping the offline completely in an HD project and it would be great to avoid SD transcodes assuming the proxy files are similar in size to what we are use to with 10:1 media.
May need some help with this one, as I am not clear of the benefits of keeping the OFFLINE process, which is comprised solely of SD material, in an HD project. Media Composer will be forced to work very hard to playback multi-cam groups and all renders would then be in HD (like DNx36) which would consume much more space than 10:1m, 15:1s or 14:1 (in a 24p project) and goes against the intention of the previous point.
I am aware as of Avid version 7, and perhaps earlier verisons, Avid came out with an H.264 resolution for offline.
Partly true- Media Composer can edit what is known as "Interplay Proxy" which only comes from particular sources, such as Airspeeds and interplay transcodes. It cannot, however, render in it, so we are back to JFIF rendering in SD. We are discussing including what it would take to add interplay proxy transcoding to the XD / AI Direct software for non-XD sources that do not natively have proxy, but that is all future stuff with no clear timeline.
Is XD Direct creating proxys that are like the Avid H.264 media choice.
No, they are not h.264 bur rather MPEG-4 Part-2, unlike what Interplay creates.
My understanding is that some but not all of Avid's current H.264 media choices will work going back as far as Avid 5.5.5.
This is likely true- Interplay support is the key hook for associating h.264 proxy playback.
Can you shed some light on the nature of the XD Direct proxy media?
XD Direct does not create or generate any media, rather it is a transfer tool to "shovel" data off the disc, take the high-res camera native audio and marry it to the proxy vide, apply some intelligent metadata changes, the write to local or shared storage. The imported results will be proxy video material that is standard XDCam Proxy and the audio is whatever the camera was set to record in high quality.
XD / AI Direct "fixes" the many holes in the Sony / Avid media relationship by bringing in the HQ audio with LQ video, applying tape and source names that carry through to tape batch digitize or disc batch ingest while overall making life better.
In my experience transcoding Avid media doesn't lose necessary metadata but your workflow may be different. In fact consolidating or transcoding media in Avid usually makes the metadata more robust because it bakes it into the actual .mxf file unlike the "soft" metadata that happens when you just change something in a bin.
XD / AI Direct helps to "bake" in metadata. A way to test is to, instead of dragging the AAF "clips" out of Direct and into a composer bin, use the Media Tool and drag the ingested media to the bin, the explore the column data. That will be a read-out of what was in the MXF essence vs what came in via AAF.
When you say the links will be lost with a transcode to SD is that when using the tape name addition work flow or is that universal.
A second gen transcode of an imported source may lose the "source ID" from the XDCam disc. This may have been fixed in a version of MC, not sure which one.
I know adding tape names will remove the file path metadata on a particular clip in typical Avid workflows is this what you are concerned about? Does the same thing happen when using the batch import workflow where XD Direct doesn't add tape names?
XD / AI Direct adds source names, so as long the XDCam tape UMID services the transcode, it will be batch importable.
Or is there the old issue of Avid assuming that any tape named source came from a 30 tape with pull down added in a typical telecine workflow before we had decks that could record and playback 24/23.976? That issue has bitten us in the past.
Not that I am aware of- If the XDCam camera was physical set to record true 24p at 23.98, both the high res and low res will be true 24 with no cadence interpolation.
Thanks for all the info. Looking forward to learning more about the XD Direct workflow.
Sure thing. From very early on we have worked with the original developer, a company called NL Tek, to adapt their local ingest product to work with Unity (or any) shared storage WITHOUT interplay, and in a way the Media Composer will like. We licensed the core software and leveraged it under our brand of XD Direct (at the time Wexler Video was the company) and put it out on nearly every reality show that shot on XD Cam since around 2008. It works well and is a lifesaver.
John Moore Barking Trout Productions Studio City, CA bigfish@pacbell.net
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Howdy!
The discs will (and should be) write locked as soon as they come out of the camera. XD-Direct does not write any data back to the disc. It uses the discs original UMID and links it to the Avid source name you as the user set during ingest, then includes that data into the Avid MXF media that it writes to storage.
Think of it like: Read from Disc -> Fix Metadata -> Write w/ new metadata to storage
That being said, to your previous point- TRANSCODES of this material WILL BREAK the relationships established by XD Direct, as Avid effectively "forgets" the UMID and MOBID data that XD Direct was so careful to associate. Those transcodes will relink back to their source material just fine, but that source material was SD proxy… Said another way- Second generation transcodes will not share the genetics required to complete the high-res batch import part of the workflow.
The workflow would need to be: Name & Ingest Proxy, Copy clips (AAFs) to SD Project, Group, Multicam Edit, Render, Lock, Migrate HD Project, Batch Import.
Also know that Same as Source exports are not possible with Long GOP (proxy and high res) so QuickTime outputs will be renders / transcodes.
Regarding 23.98- No issues there as long as the camera is truly set to 23.98 progressive and not "24 over 30" which is 24p look with interlaced cadence remapped to 30fps.
No known issues related to switching between SD and HD media, as long as the high res material was recorded in true 23.98. Honestly that sounds more like a Media Composer bug and we can offer no assurances that the issue will not occur with any media, not just XD Cam proxies, in the version you will be using. When in doubt, test.
Motion effects- As long as the proxies are 23.98 and match the HQ frame for frame, timecode and all, any effect application issues sounds like Media Composer bugs and should be evaluated ahead of time.
It is always recommended, with very rare exception, that media be ingested and edited in a project format that matches the source media. Project settings do many back-end things in composer that allows the best possible playback. Cutting SD proxy in and HD project will force MC to up-res the raster of everything to 1920x1080 prior to doing what you asked it to- an unnecessary resource drain for sure. Exceptions might include- only having SD sources to mix in HD projects, A/B cuts to ensure frame accuracy, etc. If it is a SD offline, keep the project raster SD and framerate in sync with the HD material.
Hope this helps,
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Thank you for your response! That does put my mind at ease. I've looped in my co-AE, Supervisor, and Online editor so they can read our comments and be on the same page. Am I right in assuming we should be sure the discs are not write-locked so that the XD-Direct can apply the disc name? Also is there any difference in workflow if we shoot in 23.98? I've found that Avid often gets confused when switching between HD and SD project modes when dealing with 23.98 and that can cause timecode problems and the Avid often treats SD 23.98 as if it were 30i. We've also had problems applying motion effects like speed ramps when edited in SD (for example 14:1) to HD when conforming 23.98 clips in the past. Would the 23.98 proxies be SD and also require ingesting in SD mode or would an all-HD workflow work better for 23.98?
Thank you for bearing with me on this, as it's a new format for me.
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Here are some notes to help alleviate your concerns. Yes, this software has been used on shows with 1-2000 discs per season, over multiple seasons. This is isn't just an "ingest station" as the software bridges the gaps where Avid misses the mark on the workflow, allowing the clips to maintain relvence over time.
One note- To be on the safe side we should switch the "workflow" back to "batch ingest" even though you won't see the Avid "Tape ID" in the column it is making the relevant links for batch ingest conform. I am going to see if we can play a trick and set the Tape Name anyway for peace of mind, though again it should show in the Disc ID column.
To get bit more technical…
XD Direct was designed to allow metadata refinement to avoid those concerns using file based workflows. By changing the clipnames with XD Direct confusion is avoided as to what the clipnames actually are. Not having fifty C0005 clipnames is very important to being organized within the editor. Same for Tape names.
With regard to Batch import or Batch capture workflows. The editor references back to unique MOBIDs not clipnames and it uses a similar UMID for disk names. These numeric strings are used to define XDCAM disks and clips shot by the camera. So the editor will always find the correct assets, However without XD-Direct it may ask for disk "987249847" not "TapeName-061915" again as long as you can find the disk that it references, the editor will work fine. Without the better naming capability of XD Direct it can get confusing quickly. XD Direct makes asset names more meaningful and operators (AEz, Editors, etc) are more efficient with less errors.
The issue is defining user friendly asset names (which are used as aliases to the clip MOBID & disc UMID)
If you use a batch digitize approach this is avoided, because Avid forces you to select a meaningful TAPENAME and CLIPNAMES. This is the old school way from the early 90's, it works and is well known, but it's analog and you lose a generation digitizing also all digital relationships to the original media are lost (no batch import available).
Using filebased workflows with XD Direct allows you to define good names for clips and XDCAM DISCS. If you did not do this the operator can get confused with many clips with the same name and dealing with raw disk UMIDs instead of meaningful tape names.
I hope this answers his questions. With XD Direct it is not a requirement to name disks and clips in the camera. They can if they like, but its much easier to do this at ingest time. Using XD Direct they can conform using batch import or batch capture (once we pick the workflow upfront).
Hope this helps!
Thanks again for the demo the other day. It looks like the workflow we're going with should be fine based on what we saw, but I just wanted to run something by you to be sure we're doing this right. I've had some AE friends of mine who don't work here at Irwin strongly encouraging me to be sure the camera operators set the cameras to give unique disk and tape names while they're shooting. They say this is necessary even for workflows that include an ingest station because they tell me the naming method in the station doesn't change the basic names of the MXF files that end up in the Avid media folders, that they still all begin with "C001.. C002.. etc" and that this can cause issues down the line like relinking issues, or clip names in Avid reverting to those generic names in the episode sequence and not maintaining the ones we gave them in the ingest software, and that when it comes time to uprez, the disc will still be seen as "untitled" when inserted into the U2 we'll be using for Batch Import and could cause difficulty on that end. Is there anything to this concern? In our experience, it's best not to rely on the 15-20 camera operators to consistently implement something like that and our Supervisor is not in favor of adding that to their plate.
They are also telling me that Batch Import may not be the best choice for a project as large and with as many discs as ours. They stress that it's safer to use the tape names and Batch Capture with an F1600 for conforming. I'm hoping that isn't the case because I was able to convince Irwin to rent an ingest station by promising they wouldn't have to rent one of those decks later. Have you seen shows with LOTS of disks (we'll have anywhere between 500-1000 total) have success with the Batch Import method of conforming, especially without making their camera people name the clips in-camera?
I'll be at work after 2PM tomorrow (Wednesday) and would be happy to talk about all this, if that would work best for you. I'm hoping these are just concerns by AE's that simply aren't familiar with your particular software, but any light you can shed on why I'm getting these dire warnings from other AE's would be hugely appreciated.
Thanks!
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Posted by: bigfish@pacbell.net
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this is the Avid-L2
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