[FFmpeg-user] -s[:stream_specifier] size (input/output, per-stream)

jd1008 jd1008 at gmail.com
Fri Mar 25 00:50:40 CET 2016

On 03/24/2016 05:28 PM, Moritz Barsnick wrote:
> On Thu, Mar 24, 2016 at 17:05:06 -0600, jd1008 wrote:
>> ffmpeg -i The_Previous_River_Trip.mp4  -s:v:1 1920x1080 -vcodec
>> mpeg1video -q:v 1 -y The_Previous_River_Trip.mp4
> If you have only one video output, you are fine with just "-s
> 1920x1080".
>> warning, clipping 1 dct coefficients to -255..255:02:37.06
>> bitrate=66271.0kbits/s
>> [mpeg1video @ 0xa618f00] warning, clipping 1 dct coefficients to -255..255
> That has nothing to do with a "physical" clipping of the scale, this is
> a mathematical clipping in the mpeg1video encoder. (It may or may not
> lead to visual impact.) I haven't seen this for a while, but I can
> hardly recall when I used mpeg1video. ;-) I couldn't find a source for
> this info, but remember it from "way back when", that changing the
> macroblock decision algorithm may get rid of these warnings: Add "-mbd
> rd" as an output option. (I just tried, it works for me.) So replace
>    [...] -s 1920x1080 -c:v mpeg1video -q:v 1 [...]
> with
>    [...] -s 1920x1080 -c:v mpeg1video -q:v 1 -mbd rd [...]
> I can't guarantee though that you won't still get one or the other
> warning...
> Moritz
> _________________
Thanx a lot!!!
It does work :) :)

Reason I am transcoding into mpeg1 is because the apps that create the 
DVD format for playback on regular DVD's
take them way freaking too long to do the transcoding to mpeg1 (and that 
is what they do to every video I try to
convert to DVD using the dvd creation apps.
ffmpeg seems to do it a lot faster.
So, when is ue these apps and the input video is already in mpeg1 
format, they just proceed to create the
DVD format without transcoding.



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