100Mbs Long GOP in Avid generates errors

[John Mitchell]

I consistently get a *random* error when trying to AMA link to 100Mbs long GOP media (MXF) in Avid (* Exception: Failed to get the sample temporal offset from the AMA Plug-in). I don't get this error on 35Mbs media.

After some investigation I suspect the following: Something in the XML data within the MXF structure the Nano generates is upsetting the AMA plug in. For example:

I link to a bunch of files - the AMA plug in comes up with no error (in the console) but files appear to be missing in the numerical sequence eg . xxx1001, xxx2001, xxx4001 (xxx3001 will appear to be missing). When I go back and try to AMA those individual files they turn up in the Avid bin with a different label to the clip name and these are always the files with the errors. Within the bin these clips have no end point as if the plug in can not find or calculate the correct end frame for the clip and in doing so also mucks up the label. These clips will playback OK within the XDCam viewer Sony provides.

I get frustrated when trying to isolate whether a problem is generated by the plug in or the Nano - all I know is it doesn't work and it makes for an impossible work flow. This is a chroma key job so it would be really nice to get it working correctly. The files generated by my JVC camera in SonyEX format link via AMA perfectly (of course they are only 4:2:0).

In summary I really wish that CD had gone down a properly structured XDCam directory as both Sony and JVC did when utilising this codec instead of random MXF files. There is no utility as far as I'm aware that will do this either.

[Dan Keaton]

Dear John,

I will alert our support team about this problem.

Could you please help us by provide which specific version of Avid you are using?

[John Mitchell]

Hi Dan

I can confirm this happens with both Avid 5.5.3 and 6.0.1.1. It is an updated AMA MXF plug in 6 so it is happening with 2 different versions of the AMA plug (I'm guessing one is 64bit and the older one is 32bit but they are probably similar). Ican also confirm the same error whether on a Mac or a PC and the exact same files affected. I'm thinking it is between 25% and 30% of the files that are affected.

The other interesting thing to note is that although the camera was set 1080P25 the files are all flagged 1080i50. I'm sure this isn't much of an issue as the de-interlace makes them progressive but i thought the Nano was supposed to detect the correct stream from the camera> (JVC HM700 in this case). i can't recall on the day whether I checked it so unfortunately I can't say what the Nano was reporting while recording. There is no menu in the HM700 to set the SDI output to anything different apart from downconvert.

In the meantime I'm converting all the files to DnxHD 185 8bit to get around the problem but would love it if we could track down a solution either at Avid or CD. Thanks as usual for your prompt reply and addressing the issue.

John

[Dan Keaton]

Dear John,

If your camera is outputing 1080psf25 (Progressive Segmented Frames), then you should have set the nanoFlashes's Video|Record PSF > Prog(ressive) menu item to checked.

This allows the nanoFlash to convert the 1080psf25 to true 1080p25 prior to recording.

If your camera is outputting 1080psf25, and the above menu item is checked, then the nanoFlash will report in our Frame Rate Display: 1080sf25.

If not, then it will report 1080i50 and the file header wll report 1080i50 and Avid will report it as 1080i50.


Note: Since 1080psf25 and 1080i50 look identical to the nanoFlash, and the HD-SDI specification does not include any way to tell the difference, this is one case where the nanoFlash Video|Record PSF>Prog(ressvie) setting has to be set properly prior to the start of recording.

I hope this helps.

[John Mitchell]

Makes sense Dan - When I look at the specs it says the SDI terminal is 720P/1080i - it doesn't even mention 1080PSF. However the footage recorded by the Nano in no way looks interlaced.

Anyway a JVC problem, along with a 3 frame delay in timecode (compared to in camera recording) and no audio on downconverted SDI to the Nano.

[John Mitchell]

Makes sense Dan - When I look at the specs it says the SDI terminal is 720P/1080i - it doesn't even mention 1080PSF. However the footage recorded by the Nano in no way looks interlaced.

Anyway a JVC problem, along with a 3 frame delay in timecode (compared to in camera recording) and no audio on downconverted SDI to the Nano.

[John Mitchell]

Hi Dan

Any update on the Avid AMA error. There seems to be no practical way around this problem.

Thanks

John

[Dan Keaton]

Dear John,

I do not have an update yet.

I am sorry, but our team has been swamped, and our Avid expert is out this week.

[Eric Mueller]

Hi Dan.

I also submitted a tech support form on the C-D website (I just registered here and wasn't sure how long verification would take), but has there been any resolution to this issue yet. I gave a producer the thumbs up to shoot with a nanoFlash, and now I can't get the footage into my Avid. Very awkward...

Thanks.

[Bill Ward]

John:

What happens when you try to bring the 100mbs files into AVID via import, instead of AMA?

[Chris Medico]

I don't want to overstate the obvious here but the long GOP MPEG-2 standard lists the upper limit as 50mbps (XDCam 4:2:2).

Going above that may work but may not work either. If you want to ensure compatibility you need to stay within the standard. That is ESPECIALLY true with Avid. They are not known for being flexible with that sort of thing. As I know all too well.

[Eric Mueller]

I spoke to the cameraman. Apparently he shot I-frame MXF, not long GOP. Same issue though. How long does CD tech support usually take to return emails?

[Eric Mueller]

Any update or resolution on this matter? I never heard back from Convergent Design support.

[Eric Mueller]

Hi again. Anyone out there?

[Andy Mangrum]

Hello Eric,

We apologize for not responding to your email / support request, It must have been missed, so we apologize.

With your Link to AMA issue what version of AMA are you using? Version 4.1?

Also will a file import work, if the file fails to import via AMA?

Also note we suggest to all users using Avid Media Composer 5.5 and older the following

If you wish to record Long Gop, select 50Mb or below,

If you wish to record I-Frame, Select 140Mb or Above, due to we have had issues with 100Mb in the past, these issues are suppose to be fixed in the latest version of Avid.

Hope that Helps

Best Regards