[FFmpeg-user] Rotate 180 degrees
Cecil at decebal.nl
Tue May 20 11:05:33 CEST 2014
Op Monday 19 May 2014 20:46 CEST schreef Moritz Barsnick:
> On Mon, May 19, 2014 at 20:34:08 +0200, Cecil Westerhof wrote:
>> The result looks reasonable. But is there a better way to do this?
>> A video of 13 minutes takes about as long to be converted. So if
>> there would be a more efficient way …
> The only "common" codec I know of which can be transposed losslessly
> is JPEG. That means you will indeed have to recode. I would assume
> that the filters you are using are quite effective (i.e. don't
> consume the compute power), and that the actual encoding is taking
> all that time. So, in terms of filters, there's nothing you can do.
> In terms of encoding, you could try other x264 presets, compromising
> speed for file size (roughly spreaking). Adding "-preset ultrafast"
> should make things a few times faster, but the resulting file will
> be larger as well.
Thanks. That really made a difference.
Without it I had:
file-size 620.4 MB
With ultrafast I had:
file-size 876.1 MB
The input-file is 1.0 GB with a length of 13:12.
So the time saving is really significant. The difference in file-size
is also big, but in this case I really do not have a problem with it.
And because I need to do ten other operations (at the moment I do not
know how to do it in one) it is very welcome indeed. :-D
Senior Software Engineer
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