I'm using the new AMA feature in MC 351 to "offline edit" XDCAM EX (HQ) footage. This is working well, but when I want to transcode the finished edit in order to produce an online quality DVD (either Blu-ray or SD), which DNxHD resolution is recommended for transcoding the XDCAM EX format? (The projects are 1080p/25 and 1080i/50, and the XDCAM EX HQ format has a video bitrate of 35 Mbits/second). Any advice appreciated!

The faster and bigger, the better of course but try with the lowest first, 120 for pal interlaced and 145 for ntsc interlaced

Thanks Tomas. I read somewhere that you should match the bitrate of the format you are working with to the nearest DNxHD resolution. So as the XDCAM EX HQ format has a video bitrate of 35 Mbits/second, I wondered if the DNxHD 36 resolution was perfectly adequate for XDCAM EX, and that anything higher (such as DNxHD 120) would just produce a much larger file without any noticeable gain in picture quality?

DNxHD 36 is the lowest codec for progressive media, you might have a look at page 754 - 755 into the advanced guide to see all the available codecs.

As you can see in the manual, 120 is the lowest codec for interlaced, so it all depends on your source media.

I would recommend to do your final rendering with DnxHd 120 ( if it is pal interlaced you are using ) creates very good results.

If you have space and want even higher quality, you might use 185 .

Emaxy:

but when I want to transcode the finished edit in order to produce an online quality DVD (either Blu-ray or SD), which DNxHD resolution is recommended for transcoding the XDCAM EX format? (The projects are 1080p/25 and 1080i/50, and the XDCAM EX HQ format has a video bitrate of 35 Mbits/second). Any advice appreciated!

Emaxy,
Considering that you will probably want a maximum of 8Mbits/sec for a DVD and probably around 30 Mbits/s for Blu-Ray, I can't see the logic behind bumping up your already 35Mbits/s XDCAM material to 120 or 185 Mbits/s only to bring it back down to the lower bit rates.
Biggest isn't always best in my book.
BUT I don't work with XDCAM so I may be missing an important factor in the equation. 

Regards,
Douglas

Douglas, as already described, there are no 36 mbps DnxHD codecs for interlaced, only progressive, I took that info directly from the advanced manual, hopefully the info given in the manual is correct.

Also, as described, 120 is the lowest speed for Pal interlaced, for Ntsc interlaced it is 145 mbps, I guess that the difference is because of the 25 fps for Pal versus the 30 fps for Ntsc.

Also, not all compression is equal. Going from one low-bitrate codec to another can produce very unplesant results. Whereas taking it up to a less aggressive compression can make future compression work out better.

I've transcoded two XDCAM EX projects I've worked on to DNxHD 120 and been very happy with the results, even when viewed on a large Full HD projection.

Yes, I think that 120 is a very good choice to start with for both progressive and interlaced and if the results not are what you want to, you always have the 185 choice to do a test with.

Hi everyone. Many thanks to everyone for all your advice. I am working with both progressive and interlaced projects. Some suggest transcoding up to at least 120, while Douglas suggests that 36 may be fine, given the low 35 Mbs of the XDCam EX HQ format. I guess I'll just have to do some tests!

Thanks again,

Emaxy