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x264Encoder is an x264 and libavcodec based QuickTime Media Compressor component. Support avc1, H.264/MPEG-4 AVC Video Media. Support some MPEG-4 AVC features, including Main/High Profile up to Level 5.1. Source codes are included, and free software under GPL V2. Uses libx264.a, libavcodec.a and others from x264 SVN and ffmpeg SVN.

What's New

Version 1.2.27:

Important Note: MyCometG3 (the developer) has been shut down. Every product which has GPL/LGPL license term are freely available under GPL/LGPL, so you are free to fork your own source tree. Every product which does not have GPL/LGPL license term are freely available under 3-clause-BSD.

  • Sync core to x264 git-2120 and libav git-31489.


  • Mac OS X 10.5.8 or later
  • QuickTime 7.7 or later

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x264Encoder User Discussion

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ChadVN Member IconReview+0

This codec works well. Relative to source video, exported x264s match the gamma when viewed in QT7 on the mac, have slightly darker gamma than source in QTX, and close-ish gamma in QT7 on the PC. I say close-ish because on the PC, it's closer than the other x264 codec here on MacUpdate or QT's built in H264, but it's still not perfect.

Reply0 replies
Version 1.2.27
Pettifogger0712 Member IconComment+41

MyCometG3 has been shut down with effect from Jan 4th 2012 :-( Every product which has GPL/LGPL license term is freely available under GPL/LGPL. Every product which does not have GPL/LGPL license term is freely available under 3-clause-BSD

Reply0 replies
Version 1.2.27
Orytek Member IconComment+95

Much better than Apple's h264 codec.
Thanks for the continued updates.
I am getting some great quality from FCPX using this directly with Compressor.
Using a quality encoder like MainConcept used to require a re-encode but I am now getting as good results with x264 and not needing the extra step.

Reply0 replies
Version 1.2.26
Mycometg3 (Developer) Member IconDev+22
Mycometg3 (Developer)

Notice for all users who have decoding problem. (x264Encoder 1.2.19 or later)

If you specified target data rate, some key frame may show broken image, with Apple H.264 Software Decoder. You can check such stream using QuickTime X player.

If you have found decoding problem with output from x264Encoder please try to :
- change Behavior tag - qmin from 0 to 3 or grater value
inside libavcodec settings dialog.
It would make such stream decodable. (Re-encoding is required though)


Such erratic stream should be decodable with Perian 1.2.2.

But current implementation of QuickTime X/QuickTime 7's H.264 software decoder seems to have incompatibility problem (under Snow leopard).

Reply1 reply
Version 1.2.22


Version 1223 fixe the decoding problem for me.

Thank a lot for your good job.

Desterwallaboo Member IconReview+293

OK.... I have to say I normally love this codec. It's considerably faster than Apple's own H264 encoder. However... the last two releases have had very odd playback issues. We've been having bizarre tear/ripping of the imagery. But it's so bizarre. Some machines are able to playback the file without a hitch, but others in the studio have the bizarre tearing issue. All machines are up-to-date in every way. So we cannot figure what the problem is...

Reply3 replies
Version 1.2.20
Mycometg3 (Developer)

Try weightp pred = disabled.
libx264's Weightp change is introduced on:
and implemented under x264Encoder 1.2.19.


Do not use advanced H.264-encoding options, if you encode for QuickTime 7.x.x customers! The H.264-level should be defined as 3.1 or 4.1, if you encode content for this QT-Version.

More Info:


Mycometg3 (Developer)

All limitation in such link is too old.

At least QuickTime 7.6.x support has got advanced features, and if GPU support is available such limitation can vary.

QuickTime 7.6 is released over two years ago, and it provides support for 10.4, 10.5, 10.6. I guess this covers most of active users in the world.
You said "7.x.x" but do you think pre-7.6 is really required to support?

DevTools-Inc. Member IconComment+251

Would be nice, if we could use the command line x264 encoder from QT. MeGUI on the Windows side does exactly this, and it allows you, to specify additional command line options, for newer versions of the x264 command line encoder.

Reply1 reply
Version 1.2.17
Mycometg3 (Developer)

I think this method is exactly faster than command line encoder.(calling libx264 directly instead of calling x264 command as different process)

Would you give me which parameter is required?

Nettet Member IconComment+6

Very nice encoder as long as it actually works. Faster than the h264 included in imovie 09 and smaller files. For some reason I had no problems using it in the beginning of june with version 1.2.12 (or something), but now it crashes in a reproducable way every time I use it in imovie 09. I have tried to upgrade to 1.2.13 but the problem persist.

If I open imovie, choose Export with Quicktime and then click settings, the whole system either freezes or imovie crashes. If on the other hand I encode a movie with h264 first and afterwards change the encoder to x264, I can access the settings, make the changes I want and export the movie. Then I can use the x264 codec without any problems as long as I don't try to open up settings - if I do I have to go through the whole process again.

I don't have any skills whatsoever with programming so I don't really have any suggestions to what might be wrong, other than that it seems to have something to do with the settings window. Might be some incompatibility with other programs I have installed. Anybody else have experienced the same?

Reply2 replies
Version 1.2.13
Mycometg3 (Developer)

Please send me crash report
- /Users/xxxx/Library/Logs/DiagnosticReports/app_yyyy-mm-dd-xxxxxx_macname.crash

My E-mail address is written at bottom of README.rtf.


It seems the problems arose from some different decoders I had installed under quicktime. A big thank you to the developer for helping me out with this one. I'm impressed by his dedication to his project.

Mac Adam Member IconComment+154
Mac Adam

I suggest a Auto-Update in the plug-in.

Best Regards

Reply1 reply
Version 1.2.11

I'll second that request.

Symbiotic_ic Member IconReview+4

This is simply great software with excellent developer support.
Highly recommended.

Reply0 replies
Version 1.2.8
Symbiotic_ic Member IconComment+4

Great software! Love the new crf checkbox so I know exactly what I get vs. an analog slider.

My question: What exactly does the "Gamma 2.2" checkbox do?

Background: I have .MTS Panasonic TM700 footage converted to ProRes, editing in Final Cut. The video looks good until I export using "Quicktime Conversion." Using x264 I set nclc=111 (HD) and my output file looks too dark in QuickTime X, QuickTime 7, Movist, VLC. Also if I convert after to a .mkv container (Mkvtoolnix) it's still dark. (meaning it's not just a container error) Setting nclc=111 AND checking the gamma2.2 checkbox fixes the problem.

My problem: I'm scared by checking gamma2.2 I'm actually making a mistake by artificially forcing lighter footage and there's an error somewhere else in my flow. (like user StarHawk79 had) ProRes has native 2.2 gamma, so I don't understand why FCP exports darker footage. I'm on Snow Leopard (10.6.3) / Intel so OS gamma is now 2.2, FCP v7.0.2. I notice if I export to another codec (say Prores Proxy) it's also darker, and I can't fix it. I'm not sure where the problem is.

Thanks in advance!

Reply4 replies
Version 1.2.8
Mycometg3 (Developer)

1. I guess you have to add filter and adjust gamma by yourself.
2. Gamma checkbox is extra parameter, so only nclc is recommended though.

Gamma 2.2 checkbox is intended for data source (non-common yuv color space) which does not have correct color info like nclc. Such professional processing software should NOT use this checkbox.

Under correct quicktime environment, or application which implements nclc correctly; when nclc parameter is specified, gamma 2.2 setting should be ignored (because it is legacy for QT6.5 param).

Under some application/work flow, which does not handle correct nclc settings somewhere, gamma 2.2 spec "may" make better result than nclc only; but it is not correct.


Thank you for your quick and helpful response!

You confirmed what I was thinking: I shouldn't have to use the gamma 2.2 checkbox with Pro apps. I think I found the problem: it's Final Cut Pro. If I use MPEG Streamclip or Compressor to convert ProRes to x264 then the video looks good just by setting nclc=111. If I use FCP "Export Quicktime Conversion" then the video is dark unless I also check "gamma 2.2." I'm guessing it's a FCP bug.

So my solution is always to Send FCP video to Compressor for conversion with x264.

Thanks again! And I'm really looking forward to when those blu-ray settings are debugged and working by the x264 team.


Fundamentally there is a color-space conversion issue to begin with when you're talking "HD video YUV rec709 color-space" vs. computer playback video (RGB) (http://en.wikipedia.org/wiki/RGB_color_space) I found that all H264 format conversion destined for computer playback needs to be adjusted (brightened) i.e., NOT destined for true HD video playback - on a DVD/ TV set etc.


Good point Bluestar, and I attributed the slight color shifts I'm still seeing to this effect. But that's interesting that you needed to brighten footage destined for computer playback. I have to honestly say my last comparisons (admittedly on only 2 scenes) looked so close pre and post-encode that I determined no gamma adj. was necessary. I verified it on 10.6 with a couple of different viewers. (VLC, QTX, Movist) Maybe our setups are different? (I don't have Perian installed, but did at one time and I think that had an influence)

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Version 1.2.27
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Version 1.2.26
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Version 1.2.25
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Version 1.2.24
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Version 1.2.23
> 5 13


Current Version (1.x)


Downloads 111,976
Version Downloads 17,695
License Free
Date 30 Dec 2011
Platform OS X / Intel 32
Price Free
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