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Quicktime Codecs
Which Quicktime Version should I use with which DS?


Quicktime Codecs

(added 01.29.2008 courtesy Marianna Montague)

The latest and greatest DNxHD QuickTime codecs are posted on the new Avid Knowledge Base. In this new set, you will find the DNxHD QuickTime codec which now support alpha channel export from a third party application such as Adobe After Effects.

Avid DS Reference codecs (for installing on other workstations) are available for v8.4 here or are available on the DS v10.x installer DVD in both 32 and 64-bit versions.

Note
There is currently a bug in Media Composer that cause imported Quicktime files in a 10bit sequence to generate a 10bit video file and an 8 bit alpha file. Because the video and alpha have a bit depth mismatch these files will cause errors if a project containing these files are conformed in DS.

So if you plan to do the finishing in DS and plan to relink to the media captured in media composer beware of capturing Quicktime movie in a 10 bit MC sequence. This happens regardless of which codec is used in the Quicktime file as long as the codec support alpha and as far as we know this won't happen with other file formats such as AVI.

(This information was added 01.30.2008 per Jean Marc Porchet and will be updated as soon as Avid fixes the problem.)

Note
As of 02.02.2008, Avid has tested the 10bit DNX-HD codec with 10bit alpha when imported in MC it correctly generarte a 10bit alpha in MC so it will conform correctly in DS. Of course this does not solve the problem if the quicktime is for example a plain RGBA 8bit quicktime file.

For clips larger than D1 that need to keep the entire image size use the link file import option. The entire file will be loaded into RAM the first time it appears in a time line. Use to pan/scan big files. This will create D1 media when you process.

NB: For Avid DS 8.4 you can no longer Link to Quicktime files due to an incompatibility in the QuickTime audio stream encoding. This flaw is causing application errors (crashes). All QuickTime files must now be captured in order to be used safely in Avid DS version 8.4. Avid DS version 10 fixes this.


Apple ProRes decoder for Windows (a warning)


Apple ProRes decoder for windows induces a small gamma shift when you import a ProRes Quicktime using Graphics. If you import as Video levels, levels are even more wrong.

Even if you use Quicktime on your DS to export to image sequence, the shift will be there.

This was tested on DS 7.6 Equinox with QT 7.3 and ProRes 1.0.

Exporting an image sequence on a Mac gives the right levels.

(thanks to Annaël Beauchemin)

The "Gamma Shift" occurs all of the time


The Gamma Shift occurs on all YUV codecs, like h264, Blackmagic, Motion-JPEG, Photo-JPEG and also on the ProRes

As a workaround, I've found that these values in for example a "Color Correction Classic" (DS Version 10) restore the gamma shift" close to normal:

h264 = gamma 0.73

M-JPEG, Photo-JPEG = 0.82



Error Selecting Codec


If you do not have the DSComserver appropriately installed, you may get this error. A reinstallation of that server in DS Version 10.1.2 is usually required after you have installed DS in order to get proper exports.


h.264 Quicktime Export issues

So, you are trying to export h.264 from your DS and it fails. One solution is to export without a codec or with a codec that works, then use Quicktime Pro to transcode the file. But that's not elegant.

If you uncheck both boxes relating to frames, it will export.

Multipass encoding and smaller files


DS may not be set up to do multipass encoding, or it may be set up only to do Constant Bit Rate (CBR) encoding, which cannot take advantage of multipass advantages.

In multipass encoding, The video encoder analyzes the video many times from the beginning to the end before the actual encoding process. While scanning the file, the encoder writes information about the original video to its own log file and uses that log to determine the best possible way to fit the video within the bitrate limits user has set for the encoding process.

The best way to understand why this is used is to think of a movie - when there are shots that are totally, absolutely black, like scene changes, normal 1-pass CBR encoding uses the exact same amount of data to that part as it uses for complex action scene. But by using VBR and multi-pass, encoder "knows" that this piece is OK with lower bitrate and that bitrate can be then used for more complex scenes, thus creating better quality for those scenes that require more bitrate.

The end result is a smaller file.

Apple's Quicktime Pro will do multipass encoding.

(Case Study)

This is on a xw8600, running DS10.1.2 and Quicktime 7.4.5.

This was a 20sec spot and the file directly exported from the DS measured 105MB of course then with uncompressed audio.

Exporting a ref form the DS and opening that in QT 7.4.5. and doing a h264 from Quicktime Pro resulted in a file that was 36MB. A huge difference and the
uncompressed audio can maybe be responsible for 4-5MB of that difference, but not more.

And I can't see any particular quality differences when looking at the final files.

Both encodings used the "Best" setting.

(Thanks to Mike)

(Thanks to Tom D. Shannon Dunn and M Badertscher)



Importing more than two tracks of audio


Just tried to link/capture a QT with 4 tracks of audio. Video captures just fine, audio fails. Movie inspector shows *2 x 24-bit integer (Little Endian), Stereo, 48.000 kHz* for audio tracks (four channels of audio). DS Version 7.6 can capture this but Version 10 cannot.

Linking the QT-file/files on the other hand, seem to bring in audio, at least from some files. But gives peculiar results.

Linking a Motion JPEG-A QT-file with 4 separate mono-tracks (which definitely contains audio) looks right when you check the DS file properties, but when it’s sent down to the timeline, it creates 16, yes SIXTEEN mono tracks, but/and all are silent.

Another example file, this time an HD ProRes file containing ONE stereo-soundtrack and TWO mono-soundtracks also looks okey when it comes to file properties, but when sent down the timeline creates THREE stereotracks and 2 x THREE mono.tracks., ie, NINE audio tracks all in all.

This time all the audio tracks contain audio, but it looks like it’s the FIRST soundtracks stereo-pair that’s been distributed to all the nine audiotracks. The two mono-tracks should have contained separate dialogue and. narration but the linked file audio only contains mixed audio.

So it looks like when linking a file, the number of audiotracks created in the timeline is

“Number of DS Audiotracks” = “Actual QT file soundtracks” x “Actual QT file soundtracks”




Which version can I use?


For Avid DS v10.3, you can use Quicktime v7.6 or greater. To capture and link to any QuickTime files, you must have QuickTime v7.6 or greater. Other QuickTime enhancements include:


For Avid DS 10.0, Apple QuickTime 7.4.5 can be used (7.5+ is not yet qualified). You need this version of Quicktime to extract RED audio files correctly.

To guarantee proper import and export in Avid DS, open the Apple QuickTime Player. Under Edit > Preferences > QuickTime Preferences...


In the Avid DS Output Tool, the QuickTime export options dialog may open behind the Avid DS interface. When this happens, it appears as if the application is no longer responding. Select the QuickTime export options dialog in the Windows Task bar to raise it above the Avid DS application. This is a 64-bit limitation only.

You can now export Quicktime Reference files, but only in DS 10.1.1 in 64-bit. If you must have Quicktime Reference files, you have to use 32-bit Avid DS software from versions 8.0 through 10.1.0.

For Avid DS 8.4, Apple QuickTime 7.1.x can be used except that you can no longer Link to these files due to an incompatibility in the QuickTime audio stream encoding. This flaw is causing application errors (crashes). All QuickTime files must now be imported in order to be used safely in Avid DS.

For Avid DS 8.0, Avid recommends QuickTime 7.0.4 up to QFE 2a. Since the QFE 3 release, Apple QuickTime 7.1.x is now qualified. Due to the above QuickTime audio issue, Avid recommends you import QuickTime files instead of linking.

For Avid DS 7.6 and all releases prior to 7.x, Avid recommends QuickTime 6.5.2 only. Don't use Apple Quicktime 7.2 for any version of DS.

So if you have Avid DS version 5.x, 4, 2, 1 and 7.1, use Quicktime 6.5.2.

Tip: Create a subfolder with in the project folder called Linked Files. This folder will then be archived with the rest of the project. (Archived to Disk) Note: This can cause issues, particularly truncated AVI captures. It's a pain that it causes issues because it's a convenient workflow. Philippe's clever Archive Backup tool can also copy all linked file sources, so a convenient workflow can therefore be to put your source files anywhere you like, use Archive Backup to back them up when the project's finished with, then delete the original folder.

Quicktime issue it's all about where the file resides.

Do not place Quicktime files in your project folder. If you do, you will get the following error:

Quicktime_Error.jpg

No Quicktime file should be in an indexed folder otherwise it may prevent its capture in DS. Place your Quicktime files elsewhere.

For more information about Quicktime, please see our information on file capture

Revised: Aug 23, 2010 9:17 am