Avid Media Composer 4.0.5

[Dan Keaton]

Dear John,

Thank you for your insight into this problem.

We will be very happy when Avid decides to increase the size of their input buffer. Then, if my theory is correct, all of these issues will go away.

At this time, editing with our 50 Mbps Long-GOP and any I-Frame Only modes work great.

Based on your finding, it appears that any of our modes will work fine if they are transcoded to DNxHD first, before any cutting is performed. I say this since all of our files should start with an I-Frame.

It would be nice if someone could test, then confirm this.

[Dan Keaton]

Dear Friends,

I am not an Avid expert.

I am assuming that Avid will transcode our MXF files into DNxHD.

However, this may or may not be the case.

Comments from others are most welcome.

[Dan Keaton]

Dear Friends,

I have learned from Mr. Bill Ravens, that Avid 4.0.5 will transcode our Long-GOP files, up to 100 Mbps, to DNxHD. But Avid 4.0.5 will not transcode our 140 and 180 Mbps Long-GOP files.

Also, Edius will transcode our Long-GOP Files, including all bit-rates up to the current maximum of 180 Mbps, to DNxHD.

Of course, one can use I-Frame Only mode, and no transcoding is necessary.

Bill, thank you for the valuable information.

[Perrone Ford]

Originally Posted by Dan Keaton

Dear Friends,

I have learned from Mr. Bill Ravens, that Avid 4.0.5 will transcode our Long-GOP files, up to 100 Mbps, to DNxHD. But Avid 4.0.5 will not transcode our 140 and 180 Mbps Long-GOP files.

Also, Edius will transcode our Long-GOP Files, including all bit-rates up to the current maximum of 180 Mbps, to DNxHD.

Of course, one can use I-Frame Only mode, and no transcoding is necessary.

Bill, thank you for the valuable information.

This seems odd to me.

When I did an import of 100mb Long GOP into Avid MC 4.0.4, it did a fast import as XDCam. It did not transcode to DNxHD. I have not tried other rates but will do so.

Edius SHOULD be transcoding into CanopusHQ and not DNxHD. Is this what you meant?

I'll try more stuff later in the week, but it would be helpful to have more sample material on the dowload page to test. There is mostly 100mb log-gop, 1 IMX and one 220 I-Frame.

[Dan Keaton]

Dear Perrone,

Yes, Avid should import our files as XDCam.

I was attempting to discuss that one can import our files, (as XDCam), then prior to editing, transcode them to DNxHD in Avid.

Bill Ravens ran quite a few tests, with our 180 Mbps Long-GOP files, with various Editors, and found that Edius would transcode these to DNxHD.

Then, he said that Avid would transcode our 50 and 100 Mbps XDCam files to DNxHD.

[Perrone Ford]

Ok, I understand better now. Thanks!

[Mark Job]

Originally Posted by Dan Keaton

Dear Perrone,

Yes, Avid should import our files as XDCam.

I was attempting to discuss that one can import our files, (as XDCam), then prior to editing, transcode them to DNxHD in Avid.

Bill Ravens ran quite a few tests, with our 180 Mbps Long-GOP files, with various Editors, and found that Edius would transcode these to DNxHD.

Then, he said that Avid would transcode our 50 and 100 Mbps XDCam files to DNxHD.

....Dan, you can setup AMC to transcode to DNxHD upon clip import. Here's how it works. Once you're open in Media Composer, go to >Effects Palette>Settings Tab> Scroll Down to Media Creation>Import Tab>Video Resolution Drop Down List> You have several choices and flavours of DNxHD to select from. I think it would be easier to transcode upon import, then import native and transcode everything just prior to export, but you can do it that way as well. I hope this helps.

....Still testing Long GOP 100...Reports soon

[John Mitchell]

Originally Posted by Dan Keaton

Dear John,

Thank you for your insight into this problem.

We will be very happy when Avid decides to increase the size of their input buffer. Then, if my theory is correct, all of these issues will go away.

At this time, editing with our 50 Mbps Long-GOP and any I-Frame Only modes work great.

Based on your finding, it appears that any of our modes will work fine if they are transcoded to DNxHD first, before any cutting is performed. I say this since all of our files should start with an I-Frame.

It would be nice if someone could test, then confirm this.

Hi Dan - correct on the DnxHD front. I haven't tested anything but 100Mbs so I certainly wouldn't jump to any conclusions on other data rates as they may not decode at all in Avid.

I would suggest with LongGOP 100Mbs transcoding to DnxHD 120 which is the closest match - the loss should be minimal if anything measurable.

On the Avid front - are you in contact with Avid product development team? I know they don't give much away on that front.