Hello, Mark:
Welcome to the ffmpeg-user mailing list. I hope you are able to find out
what you need, and get good use out of *ffmpeg*.
On 2019-04-03 14:01, Mark Scott wrote:
…I need to add 2 seconds of black silent video to the head of
the encoded file. Would this be accomplished by concatenating the original
video file, with a separate video file that has the 2 seconds of black?
That is one way to do it. A better way is to use the video source
"color" <http://ffmpeg.org/ffmpeg-all.html#color> to generate
solid-colour video of the form you need, at run time. Use the audio
source "aevalsrc" <http://ffmpeg.org/ffmpeg-all.html#aevalsrc> to
generate silence. Then use the video filter "concat"
<http://ffmpeg.org/ffmpeg-all.html#concat-3> to concatenate the video
streams together.
Here is the skeleton of "color" and "concat" in use. (I have not tested
this, and I have discarded audio sources, and this should all be one line):
ffmpeg -i in.mov -an -filter_complex 'color=black:duration=2.0 [black];
[black] [0:0] concat=n=2:v=1:a=0 [v]'
-map '[v]' out.mov
On 2019-04-03 14:01, Mark Scott wrote:
…I need to take an Apple ProRes 4444 file, 1920x1080, 23.98 fps, 16 bit
integer stereo audio,
and encode it to be Apple ProRes 422 HQ 1920X1080, 23.98fps 24bit integer
stereo audio….
Obviously, my skeleton above doesn't do all this. Have you worked out
how to make *ffmpeg* do the conversion you need from ProRes 4444 to
ProRes 422 HQ? If so, maybe a good next step is to post the complete,
uncut command line and output which does this conversion to this list.
Maybe someone will be able to help you fold in the "color" and
"aevalsrc" and "concat" filters to that.
On 2019-04-03 14:01, Mark Scott wrote:
I'm very new to ffmpeg and I don't have much experience using command lines
to encode video….
Ah. You are in for an adventure, then. *ffmpeg* can do many things, but
"gently introduce people to use of command lines" is not usually one of
them. :-)
I hope this helps!
--
--Jim DeLaHunt, j...@jdlh.com http://blog.jdlh.com/ (http://jdlh.com/)
multilingual websites consultant
355-1027 Davie St, Vancouver BC V6E 4L2, Canada
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