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 Quicktime file without
re-encoding - unfortunately including that nasty gamma shift.
Holger
Nathan Rusch wrote:
I ended up writing an movWriter for Linux for this exact reason. I’m not
exactly sure how to translate Quicktime’s “90%” setting into quantizer
and bitrate parameters, but this should at least give you a bitrate and
quality level somewhere in the same neighborhood.
ffmpeg -r 24 -start_number 1001 -i
/path/to/input_sequence.%04d.jpg -pix_fmt yuvj420p -vcodec mjpeg -f
mov -qmin 0 -qmax 1 /path/to/output/file.mov
You need the '-start_number' flag if your sequence starts at a frame
other than 1 or if you only want to use a subset of a sequence. The '-r'
flag sets the frame rate of the source, and since no target rate is
specified, the same will be used for the output. You can also use
'yuvj422p' for the output '-pix_fmt' value if you want 4:2:2 chroma
subsampling.
Hope this helps.
-Nathan
*From:* Dan Rosen <mailto:[email protected]>
*Sent:* Tuesday, April 30, 2013 4:49 PM
*To:* Foundry <mailto:[email protected]>
*Subject:* [Nuke-users] ffmpeg Photo-JPEG QuickTimes
Hello,
Sorry to use this forum, but hopefully someone can point me in the
right direction to use ffmpeg (given that Nuke cannot properly write out
a Photo-JPEG QuickTime with correct color nor with 90% quality). I am
trying to write out frames from Nuke, with the lut applied in Nuke, and
then compile them into Photo-JPEG QuickTime with 90% quality. There's a
brightness shift that appears to be the pesky gama atom, but the file
does not actually contain the atom so there's no solid way to remove the
shift. I am still testing so the shift maybe something else. Fwiw, I
have found good results with the ProRes codec (no shift).
I have read up on the it online, but all results list "mpeg" as the
format in the Inspector window of QuickTime, but maybe it's correct
since it lists "Photo-Jpeg" in the format int the Properties window.
Any help would be much appreciated. Thanks!
-Dan
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--
Holger Hummel - [email protected]
Celluloid Visual Effects GmbH & Co. KG
Paul-Lincke-Ufer 39/40, 10999 Berlin
phone +49 (0)30 / 54 735 220 - [email protected]
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