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

[jd1008]

On 03/24/2016 02:28 PM, Moritz Barsnick wrote:
> On Thu, Mar 24, 2016 at 12:08:32 -0600, jd1008 wrote:
>> So, setting the option  -s 1920x10180  might be followed by the extra
>> specifiers: input/output ...etc ??
> What the quoted text in your subject says is that the "-s" option can
> be used as an input or as an output option, valid per stream stream.
>
> You can apparently add stream specifiers: "-s:v:0", "-s:v:1". (I have
> never seen it used like that.)
>
> The most common use case is to use it as an output option with one
> output stream. Then it needs to be located after the "-i" input and
> before the output.
>
> Moritz
Just started ffmpeg per your suggestion like so:

ffmpeg -i The_Previous_River_Trip.mp4  -s:v:1 1920x1080 -vcodec 
mpeg1video -q:v 1 -y The_Previous_River_Trip.mp4

and it is proceeding - but with a lot of messages like these:
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