[FFmpeg-user] -s[:stream_specifier] size (input/output, per-stream)
jd1008 at gmail.com
Fri Mar 25 18:16:55 CET 2016
On 03/24/2016 07:37 PM, Moritz Barsnick wrote:
> On Thu, Mar 24, 2016 at 17:50:40 -0600, jd1008 wrote:
>> 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.
> I understand, I used to use similar programs, and appreciated that they
> took my ffmpeg created input without reencoding.
> But: mpeg2video is a much more effective codec for DVD. ffmpeg even has
> a shortcut-option "-target dvd" (or "-target pal-dvd", "-target
> ntsc-dvd") which sets several encoding options for DVD compatibility.
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
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?
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