DSWiki - H

H


Contents

Working with h.264 files
HAL Errors
Tips for working with HD
Working with the HDV video format





h.264 Files (the easy way)

(Added 10-23-2007 thanks to Bill Admans MH)

Buy one of these two USB devices that make h.264 files out of Quicktime reference files:

ADC Tech's Instant Video To-Go for PC costs around $65 at Best Buy.
Elgato's Turbo.264 for Apple and costs around $100 at the Apple Store, usually less elsewhere.

  1. Create a Quicktime reference file of the sequence or clip you want to encode.
  2. Bounce out of the editing application and open the encoding software that comes with the USB device.
  3. Make sure your settings are correct and let it render.

OR

Send it to another workstation that's connected to your shared storage. The other workstation does not have to be something fancy. It could even be a cheap PC from Frys or a little Apple Macintosh Mini.

So long as you have a fairly new workstation with multiple core CPUs, you can go back to editing with little to no impact on performance because all the hard work is happening on the USB device.

NB: Avid does not support the use of these USB devices on a DS but certain persons we know of may have tried this successfully.


HAL Errors

No, this is not 2001: A Space Odyssey, and you are not Dave (unless you are).

From the DS perpective, an HAL error is the general catch point where anything that have gone wrong in the player/Hardware path is caught and told to the user. There are no specific action that triggers this, but rather a pretty large number of bad things could trigger this. Sometimes the HAL Error have additional information in the message, sometimes it does not.

Many things could have gone wrong, from bad media to buffer allocation issue, codec errors, hardware error, weird SW hiccup and many other things that could happen. Which is why when you get some "HAL Errors" it's important to describe the situation as much as possible, the format you where using, what media, compressed or not, with Fx or not, on playback or just scrubing, what you were doing at the time it happens etc etc etc.

As a side note, there is always an HAL present, it's not a hardware-specific thing, even the software version has one.

(Thanks to Nicolas Courtemanche)

We do use a start up procedure that ensures all indexers are running before launching DS, keep the drives de-fragged regularly, and stop the slp before exiting windoze... all the standard "keep the DS happy, and it will keep you happy" stuff.

(Thanks to Dermot Shane and Sean Stall)

If you are operating a Nitris BoB, you can usually clear a HAL error by exiting the DS application and rebooting your BoB. This is, unless you have indexer problems or other problems associated with your media or your sequence or your project, as Nik described above.


HD Tips


ENSURE FRAME ACCURACY BETWEEN OFFLINE AND ONLINE.

  1. When you down-rez your HDCam (1080psf@23.98) to SD make sure that 2:3 (not 3:2) pulldown is applied with the "A" frame hitting at a :00 frame.
  2. Important - since you cannot always trust dubbers, check your down-converts to make sure 2:3 cadence is correct. Also make sure that there is no offset. (Anything on the HDCAM at a second frame i.e. :00 will match the SD at a :00 frame).
  3. Set up your Media Composer project at 24p (since hardly anyone has media comp's supporting 23.98 yet (MC v11.8+).
  4. Just like doing a 24fps film based project, digitize your down-converted media into the AVID MC starting at a :00 frame. This way the pulldown frames will be properly extracted and frame accuracy will be maintained between 24-30-24.
  5. (If you follow steps 1,2,3 - the frame accuracy between rates will always be perfect) (Note - If you digitize in Media Composer in a 23.98P sequence, you will be able to digitize your audio in Digital mode and the OMF¹ will translate perfectly into Pro-Tools.
  6. When your offline is done, create a new bin and duplicate your sequence into that bin. Delete any un-necessary tracks (e.g.: audio, offline reference etc) Decompose with 0 frame handles to create new master clip references within the sequence. You can delete the de-comped clips. DS will make its own from the reference clips later. (If I have time, I usually pull a 24fps EDL at this stage using ED: manager v11.1+, otherwise a 30 EDL can be converted to 24fps via Delmar.)
  7. Open MediaLog V11.1 or above. Start a new project. Move the bin with the sequence into your project in MediaLog.
  8. Save the MediaLog project as an AFE. (Use v11.5 downloadable from the DS www site)
  9. Start a new 1080psf@23.98 project in DS.
  10. Open the AFE in your project. Select "force create new clips" and set up a folder for the new clips to be directed to.
  11. Drag the sequence to your time-line. DS will take a while to translate.

You should now have a frame accurate sequence that reflects your offline.

Notes:
¹If you have file based audio in a sequence and want to create an OMF your first step should be to generate a new clip using the "Timeline to Clip" function. You can then drop that new clip into a sequence and successfully output file based audio to OMF (but it must be in chunks smaller than 2GB).



CONFORMING AUDIO FROM MEDIA COMPOSER 24p
When MC digitizes with the pulldown switch, audio is re-sampled at 47.952K, and sped up to 48K within the software to match true 24fps speed. For film, this is ideal, because everything eventually resolves to 24fps. But for video -- that OMF is being exported at true 48K, and being imported to DS at true 48K. But DS is playing video at 23.976p, and that audio is never slowed back down, so it is off. To get accurate sync audio for online, you have to redig audio from the offline master, or from sources. Also -- if redigitizing audio from the offline, make sure that 23.976p output speed is set on the MC side.

Basically, MC speeds up the audio on import, but never slows it back down on digital export.

A dicey, but proven workaround:

  1. 23.976p HD masters
  2. Downconvert to NTSC
  3. Offline at 24fps.
  4. Convert to AFE, import to DS, conform and online, etc.
  5. audio...

Have MC generate an OMF, then Audio Timewarp in DS by .001%, or use the Audio Suite Pitch Shift effect in MC before export and change audio by .001%. Depending on length of program, this might be quicker.


VIEWING AN OFFLINE SD SEQUENCE WITH A DIFFERENT FRAME RATE

THAN AN ONLINE HD SEQUENCE.

If you have, say, an HD online at 23.98 and a SD offline at 29.97. You need to continually reference the offline cut. Instead of having to jump back and forth between sequences, do the following:

  1. Export your 29.97 offline as an AVI reference movie
  2. Open your HD online sequence.
  3. Double click on your AVI reference to launch Windows Media Player.
  4. Under "Tools - Options" choose "Display on top when in skin mode."
  5. Under "Skin Chooser" on the main interface choose a skin.
  6. You now have a floating window to play your offline in.


HOW TO GET ACCESS TO ENTIRE HD FRAME IN SD TIMELINE (DSlist_tqj - 12/07/06)

Capture the HD footage in a native timeline (ie the same format as the HD)Drag the HD clip onto the SD timeline and you will be able to pan/scan with the DVE. In 7.5, if the frame rates are different you won't be able to drag onto the SD timeline, in which case make an HD Ref Movie of the HD clip and link to it in the SD sequence.


How to output a 1080psf / 23.98 seq to 1080i / 59.94 HDCAM tape

(added 04.14.2008)
Three Methods:
Method 1:
  1. Crash record the HDCam deck and output directly from the Nitris BoB using the 1080i 59.94 stream (real time 3.2 insertion).
  2. Do a machine to machine dub to have the program start at the correct time code.

If there are cadence issues, Chuck Crews says he'd blame them on Avid. Besides, you will always have your 23.98 master to fall back on.

Method 2:
  1. Output directly to a 23.98 tape, full program.
  2. do a machine to machine dub using the 59.94 output from the deck (again real time 3.2 insertion).

Method 3:
  1. Using the output tool, output an .AVI reference file from your 23.98 sequence.
  2. Open a brand new sequence at 1080i.
  3. Capture the .AVI reference file, be sure your capture settings are in order, specifically do NOT change the frame rate at this time. Also, don't link to the file.
  4. Add a 3:2 expand onto the clip, process and you should be able to insert directly to any tape at 1080i 59.94.

The 3.2 insertion is almost always available in real time from modern editing applications and decks and is your best friend for conversions both ways between 24f and 30f.

(Special thanks to Chuck Crews.)


How to output a file from HD to NTSC


If you are looking for a letterboxed 4X3 QT:
  1. Choose 720X486 as your size.
  2. Go to custom and set your source region as 1920X1080 with no offset and destination to 720X366 with a y offset of 60.

If you want to deal with square pixels:
  1. Choose 720X540 as your size.
  2. Go to custom and set your source region as 1920X1080 with no offset and destination to 720X407 with a y offset of 66.5.

(Special thanks to Brandon Bussinger)


Downconverting HD Progressive tapes for SD offline

Case Study:

Source Tapes: HDCAM-SR 1080 23.987 PsF. Offline Down Converts: DBC 29.97 frame rate. AFE Conform & Finishing: HDCAM-SR 1080 23.976 PsF.

  1. Offline downconverts of 23.987 should be NDF.
  2. Always make Non Drop frame down-converts, otherwise you cannot easily predict 2:3 cadence.
  3. Make sure that the 2:3 cadence conforms to the normal standard of A = :00, :05; 10; :15, 20; 25
  4. Check the down-converts for accuracy because its easy to mess them up and make tapes that are out of sync to the HD version.

Downconvert the HD source tapes to SD (standard-definition) tapes, using the 16:9 anamorphic aspect ratio. If they are shooting time of day TC, they need to do a dailies session and make a tape with new, unbroken TC, otherwise you are most likely screwed.

There is a guide that may be downloaded and given to clients here.

(Thanks to Spencer, Jef Huey, Jay Hunt Bill Admans and Gus)


How to open an HD sequence in an SD sequence in DS version 7.6 and below


(Case Study)

DS Nitris V7.6

An HD sequence is opened in an SD sequence. Not even changed or edited, just opened in the source viewer while an SD sequence is in the main viewer. If that HD sequence is then opened agian, all of the projects geometry values in any geometry-based effects are all messed-up. DVE values, positions, crops, graphics objects, etc. Any non-geometry-based effects, like blurs and color-corrections, are OK.

If the HD sequence is brought into the SD sequence as a reference clip (holding ALT while dragging the sequence in) then there are no problems.

The weird thing is that the HD sequence was just VIEWED inside the SD sequence and nothing was saved.

Check User Preferences in the Editing tab and see if "Always update clips in source viewer" is deselected and this will not happen.

This is a known bug, or “Feature” In 7.6 and lower, if you load a sequence into the source side, it applies the sequence preferences for conversion mode to the sequence (all media and presets). If you drag directly into the sequence, you don’t get this. But always make a duplicate of your sequence before for safety sake.

This bug was fixed in Version 8 and above.

(Thanks to Ed Fraticelli, Jef Huey, Tom Phillips, Tony Jover and Sean Stall)



HDV

(added 08.01.2007 from the List MH)

To work with HDV in the DS, You either need a Miranda HDV Bridge to get from HDV to SDI or you need to bump everything HDV to another format to use. There have been mixed reviews of the Miranda Bridge workflow. For some it works well and for others...they continue to curse HDV as a format.

You can also get the Sony HVR-1500 with HD-SDI out and RS-422 control and you're supposedly all set. (This needs to be tested) But if your client is shooting with a JVC GYHD250 which, unlike Sony's 15 GOP, works at 6 GOP. The JVC also has an odd pulldown that FCP can deal with but almost nobody else works with it. Avids particularly do not like JVC's 720 24p.

Revised: Nov 24, 2009 7:46 am