[Avid-L2] Re: MXF files from nanoflash device

We've just been working with mxf files recorded on a Nanoflash. We had some problems that were related to the bit-rate the files were recorded at on the Nanoflash. We have plenty of files that exceed 2GB and they import and play fine in Avid. This should help: it's from Greg's post in another thread:

Avid uses our files just fine, if you follow the following rules.

> 1. Use MXF not MOV (Quicktime).

> 2. Use Long-GOP if recording 18/35/50 Mbps.

> 3. Use I-Frame Only if recording above 50 Mbps.

All bit-rates work, when using I-Frame Only.
We try to tell everyone these rules and it is probably in our manual.

We have been waiting for a long time for Avid to increase the size
of their internal buffer.
The problem is that their buffer is too small to hold a whole Long-
GOP, if the bit-rate is above 50 Mbps.

When the editing or playback stops, Avid looks in the internal
buffer for the start of the GOP. If using above 50 Mbps, they can't
find the first frame of the GOP, resulting in the
"decompStream:FillBuffer FIFO too small for read )," error.

So, when using nanoflash XDCam codec, stick with 50Mbps for now, or
use all i-frame, until Avid and the Nanoflash guys get this sorted
out. I was able to use .mov via ama with identical results to
the .mxf, for what it's worth, but in the end, transcoding to DNx was
the only way to make the footage useable. Except, of course, the
nanoflash is often used in conjunction with the on-board HDCam
recorder - consequently there's a backup tape! This is a great hybrid
workflow for people who want a tape element AND file-based workflow.

gh

--- In Avid-L2@yahoogroups.com, "Daniel McCabe" <dmccabe@...> wrote:
>
> Dear Avid Mavens,
>
> I am working on a project that includes some mxf files created on a
> nanoflash device recording a lipstick camera. The recording format was
> 720p at 59.94fps. The files aren't working in MC 4.
>
> I am on the road and not able to see the errors myself but I am told the
> Avid says there are corrupt frames. VLC player reads back the files
> fine. In the field, the nanoflash played back the files without a
> problem.
>
> I'm hearing several theories as to why there are issues, one is based on
> the file size. Some of the files are over 2 gigs. Are there still issues
> with Avid dealing with files over 2 gigs in size? (I've only bumped into
> that exporting OMF for a protools session.)
>
> If that limit exists, anyone got a suggestion how to break the files
> into smaller ones if we can't get them into Avid?
>
> Sorry for the rather vague symptoms. Thanks for any assistance.
>
> D.
>

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