Thanks from here too for this timely discussion! It's worth mentioning I found that using x264 is a great way of rendering h.264 encoded mov files without the gamma shift you get in Quicktime. Again, I would start with 4:4:4 jpegs rendered from Nuke.
On 1 May 2013 20:57, Dan Rosen <[email protected]> wrote: > Thanks for all the tips! I'll try to report back, especially if I can > achieve the exact color match for a Photo-JPEG. Fwiw, rendering QuickTimes > with Shake does have the brightness/gamma shift, but it also/fortunately > has the gama atom, which can be stripped with a command-line tool (there > are some old ones out there from Frantic and Fuel). For some reason an > ffmpeg generated Photo-JPEG QuickTime does not have the gama atom. And I'm > not sure that's the exact shift we're seeing. Maybe it's related to the > pix_fmt flag? > > > On Wednesday, May 1, 2013, Nathan Rusch wrote: > >> Hmm, so after trawling the full 'ffmpeg -help' output, I found that >> switching to using the -framerate flag for the image2 demuxer seems to >> properly set the input framerate, and the output framerate to match. I >> still can't do rate conversions using the -r flag (i.e. I can't set the >> output frame rate independent of that of the input), but at least I can >> control the results now. >> >> May be handy to someone who encounters this issue in the future: >> >> ffmpeg -y -framerate 24 -i /path/to/input_sequence.%04d.**jpg -vcodec >> copy /path/to/output/file.mov >> >> >> -Nathan >> >> >> -----Original Message----- From: Holger Hummel|Celluloid VFX >> Sent: Wednesday, May 01, 2013 3:06 PM >> To: Nuke user discussion >> Subject: Re: [Nuke-users] ffmpeg Photo-JPEG QuickTimes >> >> in this case i was using the legacy/old quicktime player 7.6.6 (1709) / >> quicktime version 7.7.1 (2315). >> i don't like that new qt x player. but i just checked with that one, >> too. same shift. >> >> i used ffmpeg build N-38292-ga4c22e3. so this is for sure not the newest >> build. and yes, that's one of the >> annoying things with ffmpeg, that it's basically developed so 'actively' >> that there's a fairly high chance that things >> break from one build to the next. >> >> Holger >> >> Nathan Rusch wrote: >> >> Are you using whatever the default Quicktime viewer is on OSX these days, >> or are you explicitly using Quicktime 7? The two tend to interpret files >> differently (which I'm sure some engineer somewhere has an explanation >> for), but that might explain why you are seeing a difference. What version >> of ffmpeg are you using? >> >> And yeah, the frame rate thing is very strange. Even running the exact >> same command as you, I haven't been able to set the frame rate when using >> '-vcodec copy' on a .jpg sequence. Perhaps the behavior I'm seeing is a >> regressive bug introduced in one of the newer versions... >> >> -Nathan >> >> >> -----Original Message----- From: Holger Hummel|Celluloid VFX >> Sent: Wednesday, May 01, 2013 2:35 PM >> To: Nuke user discussion >> Subject: Re: [Nuke-users] ffmpeg Photo-JPEG QuickTimes >> >> hey Nathan, >> >> i'm sorry, but i don't understand why that doesn't work for you... >> with the command i wrote in my last mail i'm able to generate quicktimes >> of all sorts of frame rates - even when using '-vcodec copy'. >> i just tested it again before sending the mail. >> >> i was just able to compare the jpg files and the QT on OS X. the gamma >> shift is also visible there. but what's also interesting >> is that there's much more banding visible in the QT compared to viewing >> the jpg. guess i should try an encode process on linux to >> see if that works properly.... >> oh well, this endless pain called QT.... >> >> Holger >> >> >> Nathan Rusch wrote: >> >> Yeah, I normally use the -r flag to set the source and destination frame >> rate, but what I'm saying is that when '-vcodec copy' is passed, the rates >> are all ignored, and ffmpeg assumes 25 fps for both the source and >> destination. This is with ffmpeg 1.2. >> >> As for the lack of gamma shifting, these are being encoded on Linux and >> viewed on OSX. In Quicktime 7, there is no difference between the raw JPEG >> sequence and the resulting .mov. This matches the behavior of files >> exported from Quicktime 7 itself, but files encoded with Shake on OSX *do* >> show a gamma shift when viewed in Quicktime 7. >> >> -Nathan >> >> -----Original Message----- From: Holger Hummel|Celluloid VFX >> Sent: Wednesday, May 01, 2013 1:37 PM >> To: Nuke user discussion >> Subject: Re: [Nuke-users] ffmpeg Photo-JPEG QuickTimes >> >> hey Nathan, >> >> regarding the frame rate: >> you need to specifiy the '-r 24' parameter before the input file '-i >> inputfile.%04d.jpg' then it does set the frame rate >> correctly: >> >> ffmpeg -r 24 -i inputfiles.%04d.jpg -vcodec copy output.mov >> >> what OS do you see that same gamma/brightness of the jpg files as well >> as the resulting QT? >> i'm on windows here so that might be once more the reason for the >> problem i'm having... >> >> cheers, >> Holger >> >> >> Nathan Rusch wrote: >> >> The '-vcodec copy' option is nice, but I've had issues using it in >> conjunction with trying to set the frame rate for the output media; any >> combination of flags attempting to set either the source or destination >> frame rates seem to be ignored, and you always end up with a 25 fps output >> file. >> >> Also, for what it's worth, using ffmpeg to re-encode a JPEG sequence >> doesn't introduce a gamma shift in any scenario I've encountered. >> >> -Nathan >> >> >> -----Original Message----- From: Holger Hummel|Celluloid VFX >> Sent: Wednesday, May 01, 2013 7:50 AM >> To: Nuke user discussion >> Subject: Re: [Nuke-users] ffmpeg Photo-JPEG QuickTimes >> >> unfortunately, i don't know how to get around that nasty >> gamma/brightness shift either. i'd be more than happy to find the >> solution for this. >> but there's another option that you can also use to get a Photo-JPEG >> Quicktme with the exact jpg quality you want. >> you just render out a jpg sequence with the esact setting as you want >> from within Nuke and then use ffmpeg's '-vcodec copy' option. >> this will just copy/wrap the jpg files into a Quickt >> >> > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >
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