Latest post Sat, Jan 14 2012 3:36 AM by FredTex. 25 replies.
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  • Fri, Oct 17 2008 2:58 PM In reply to

    • macjaeger
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    Re: DNxHD compression via ffmpeg

    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!

    MC 3.0 (soft) on 2.4Ghz Intel Core2Quad, 4GB, Win7, 3 Screens hooked to Nvidia GTX260 & 9500GT, 1 TB striping RAID [view my complete system specs]

    not a pro, just a teacher...

  • Fri, Oct 17 2008 3:03 PM In reply to

    Re: DNxHD compression via ffmpeg

    Well there you go. Yes

    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.)

    MSI Neo-2 Platinum Nforce3 Ultra (Bios Rev 1.0D) Athlon64 X2 4200+ (Overclocked to 2 x 2.4GHz) AMD Cool'N'Quiet CPU Throttling 2GB Corsair PC3200... [view my complete system specs]

    "When the waters are at their calmest, that's when folk most want to skim their pebbles." - Me

    "Be water my friend." - Bruce Lee

  • Fri, Oct 17 2008 10:31 PM In reply to

    • jwrl
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    Re: DNxHD compression via ffmpeg

    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.

    MC 7.0.4 - Asus P6T Deluxe V2 mobo - Intel i7 920 2.66GHz - Windows 7 Ult64 SP1 - nVidia Quadro FX 1800 - 16 Gbyte low latency DDR3 RAM - Internal 8 Tb... [view my complete system specs]
  • Fri, Oct 17 2008 10:34 PM In reply to

    Re: DNxHD compression via ffmpeg

    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 Wink

    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.

    MSI Neo-2 Platinum Nforce3 Ultra (Bios Rev 1.0D) Athlon64 X2 4200+ (Overclocked to 2 x 2.4GHz) AMD Cool'N'Quiet CPU Throttling 2GB Corsair PC3200... [view my complete system specs]

    "When the waters are at their calmest, that's when folk most want to skim their pebbles." - Me

    "Be water my friend." - Bruce Lee

  • Sat, Oct 18 2008 5:59 AM In reply to

    • jwrl
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    Re: DNxHD compression via ffmpeg

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

    MC 7.0.4 - Asus P6T Deluxe V2 mobo - Intel i7 920 2.66GHz - Windows 7 Ult64 SP1 - nVidia Quadro FX 1800 - 16 Gbyte low latency DDR3 RAM - Internal 8 Tb... [view my complete system specs]
  • Thu, Jul 2 2009 6:19 AM In reply to

    • seanski
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    Re: DNxHD compression via ffmpeg

    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!

    if it moves and it shouldn't use Gaffa, if it should move and it doesn't, use WD40!

     http://www.youtube.com/seanski44

  • Thu, Jul 2 2009 6:43 PM In reply to

    • itmatters
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    Re: DNxHD compression via ffmpeg

    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!

  • Thu, Jul 2 2009 9:06 PM In reply to

    • Wm Warne
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    Re: DNxHD compression via ffmpeg

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

    Gigabyte 965P-DQ6 (rev 2.0) motherboard, Black Magic Intensity HDMI capture card, core 2 duo 6600 @2.4GHz, 4G ram, Nvidia GeForce 8800 GTS 640 Mb video... [view my complete system specs]
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  • Wed, Jul 15 2009 11:47 PM In reply to

    • gerald
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    Re: DNxHD compression via ffmpeg

     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.

     

     

  • Thu, Jul 16 2009 11:22 AM In reply to

    Re: DNxHD compression via ffmpeg

    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. Wink

    MSI Neo-2 Platinum Nforce3 Ultra (Bios Rev 1.0D) Athlon64 X2 4200+ (Overclocked to 2 x 2.4GHz) AMD Cool'N'Quiet CPU Throttling 2GB Corsair PC3200... [view my complete system specs]

    "When the waters are at their calmest, that's when folk most want to skim their pebbles." - Me

    "Be water my friend." - Bruce Lee

  • Sat, Jan 14 2012 3:36 AM In reply to

    • FredTex
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    Re: DNxHD compression via ffmpeg

    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

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