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

[Moritz Barsnick]

> Here is something strange or interesting when I add  -target ntsc-dvd
> ffmpeg -i a_short video.mp4 -s 1920x1080 -c:v mpeg1video -q:v 1 -mbd rd 
> -target ntsc-dvd -y a_short_video.mpg
> Playing back the mpg video with ffplay yielded this output:
> 
> Input #0, mpeg, from 
> 'I.Am.Number.Four.2011.1080p.BluRay.H264.AAC-RARBG-2.mpg':
>    Duration: 00:17:28.32, start: 0.528033, bitrate: 3355 kb/s
>      Stream #0:0[0x1bf]: Data: dvd_nav_packet
>      Stream #0:1[0x1e0]: Video: *mpeg2video* (Main), yuv420p(tv), 
> *720x480* [SAR 32:27 DAR 16:9], max. 9000 kb/s, 29.97 fps, 29.97 tbr, 
> 90k tbn, 59.94 tbc
>      Stream #0:2[0x80]: Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s
> 
> And notice, ffplay says that the format is mpeg2 instead of mpeg1.
> Is -target option reducing the resolution and changing the format?

I'm sorry about that. Yes, "-target dvd" does impose some strictness
regarding DVD compatibility. This strictness is meant to lead to
maximum compatibility with hardware DVD decoders, which are allowed to
have their restrictions. This strictness concerns codec details, but
apparently also resolution. (I wasn't aware of that.)

The docs say: "Nevertheless you can specify additional options as
long as you know they do not conflict with the standard, as in:"

What they don't say is what is and what isn't possible to change.

As you're doing something totally non-standard anyway (1920x1080 to
DVD), you might as well ignore this "-target" option and choose
parameters for yourself. If it works (conversion, mastering, playback),
then fine. :-)

Moritz