[FFmpeg-user] Rotate 180 degrees

[Cecil Westerhof]

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:
    real-time:  13m20
    user-time:  92m3
    file-size   620.4 MB

With ultrafast I had:
    real-time:   1m54
    user-time:  12m21
    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

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof