malefunktion:

Okay, I just did a test too. Exported 1920x1080, 25fps, DNxHD 120, 16:9 aspect (important!), interlaced (-flags +ildct)

Ha! Adding the -flags +ildct did the trick (i was assuming that avanti would keep the interlace settings unless i set "Deinterlace", but obviously it didn't).

malefunktion:

Also, 1080i50 HDV is thin-raster 1440x1080, so unless your Avanti/FFmpeg setup isn't rescaling to 1920x1080 then I'm a bit confuzzled.

Yes, Avanti has to upscale the source, as 1440x1080i thin raster isn't supported by ffmpeg. But that's ok for me as the physical sensor resolution of the cameras my students use is even less than 1440 (what can you expect from one chip cmos sensors...), so blowing up 1440 to 1920 pixels won't make the resolution overkill that much worse :-)

As long as I'm coming to a one-step convert + fast import solution, I'm fine. For now...

Thank you again for sharing your insight!

Well there you go.

Glad you've got it working. If you're using a multi-core/processor system you can add the "-threads 8" option in the USER VIDEO OPTIONS area too.

Sounds weird, but even on a dual-core system it improves encoding time over ffmpeg/avanti's default thread detection of 2 (on my system).

I always keep thread allocation to 8 (even in other programs such as Blender, where it also seems to help a wee bit more.)

malefunktion:

I always keep thread allocation to 8 (even in other programs such as Blender, where it also seems to help a wee bit more.)

You obviously don't have 2.47 or better then, Steve.  Blender now automatically assigns threads for you.  You can't manually set that value any more.

I'm using 2.48 and you can set the threads, just uncheck the little racecar icon to the left of the threads slider and you can still choose up to 8

And as I said, I don't know why, but using 8 in both blender and ffmpeg (same when I'm in Linux), it seems to be more efficient.

I should have realised that!  The racecar icon means "auto"!

Hi Malefunktion, I just found this thread after months of wondering how to process my AVCHD footage to get it into my Xpress PRo Academic v 5.5

Since upgrading my HW to a quad core proc, this method you've shown will hopefully work a treat - can't wait to give it a try, thanks!

I was going to buy streamclip but will hold off now!

p.s my source is AVCHD from a 3ccd panasonic camcorder - 1920/1080i fingers crossed it looks good when converted!

Malfunk! Thanks so much for spotlighting Avanti. With your enthusiastic notes, I was able to un-complicate the process of reverse-telecining my 29.97 "film mode"Canon HV20 m2t files (grabbed with HDVSplit) into fast-importing, 23.976 fps progressive media. Excellent post!

Great work.  Dont' want this thread to get lost.

 malefunktion, thanks for the insight into the colorspace problems using ffmpeg and dnxhd, 

I was wondering if since last year you have had any luck in resolving these issues? I'm trying to take quicktime mjpeg images and convert them to dnxhd and then wrap them in an mxf wrapper, to avoid avid ingest times. This colorspace issue is a major problem though.

gerald:

I was wondering if since last year you have had any luck in resolving these issues?

Hi Gerald, it has indeed been a while since I last addressed this topic. As yet I haven't found a suitable method for resolving the colourspace issues. FFmpeg's internal code doesn't yet offer up 601/709 matrix conversions (which I feel is something that it really should by now).

gerald:

I'm trying to take quicktime mjpeg images and convert them to dnxhd and then wrap them in an mxf wrapper, to avoid avid ingest times.

Even if you managed to resolve the colourspace issue, you'd still have to use FFmpeg to create a simple Quicktime MOV with DNxHD specifcation properties, and then FAST IMPORT that clip into XPP or MC.

If I find any solid solution to the colourspace issue, I will post it here and maybe even do a video tutorial on the process.

malefunktion:

As yet I haven't found a suitable method for resolving the colourspace issues. FFmpeg's internal code doesn't yet offer up 601/709 matrix conversions (which I feel is something that it really should by now).

This thread has helped me greatly with my attempts at an ffmpeg appoach to encoding for Avid. I think I have found a colorspace solution.

I have to use ffmbc in order to use the filter that I need. Here is their project home:

http://code.google.com/p/ffmbc/

Here is a page that explains how to compile it (I personally did not complie), along with links to some builds:

http://forum.doom9.org/showthread.php?s=4afdb8fad0620264acb1994c11fb28e1&p=1528421

Here is a link to the build for Windows that I did use:

http://www.mediafire.com/?55doa7h0oikwalz

The key to getting the correct colorspace is the colormatrix filter.

Here is the drag-n-drop .bat file that I created for conversion to DNxHD 175, 1080p, 23.976fps:

ffmbc -threads 8 -i %1 -vf colormatrix=bt601:bt709 -pix_fmt yuv422p -vcodec dnxhd -b 175M -ar 48k -acodec pcm_s16le %~n1_FFM_601-709.mov
pause

My belief is that when ffmpeg and ffmbc create the DNxHD file, it is in Rec.601. By using the colormatrix filter, this tricks it into creating the DNxHD in Rec.709. It is a strange way to get there, but it works!

It seems that a flag needs to be set for the colorspace of the DNxHD conversion. It is defaulting to Rec.601, which is the SD colorspace.

Hope this helps after all this time,

Maury