[FFmpeg-user] How do I increase the playback size of a video without rescaling it?

fowman ceperman at gmail.com
Thu Jul 16 20:39:03 EEST 2020

Moritz Barsnick wrote
> With every 1280x720 video? Or just this one?

Just this, but then it's the only one I have :-)

> I'm guessing the latter video is letterboxed, i.e. a large black box
> around it is encoded in the video. If you can share, we could tell. 

Yes it is. My description of being displayed in a small rectangle was trying
to say this. I'm struggling to describe the problem in the correct
terminology so please bear with me.

Here is ffprobe info:

Original .ts file recorded by my Humax:
Stream #0:0[0x931]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002),
yuv420p(tv), 704x576 [SAR 16:11 DAR 16:9], max. 15000 kb/s, 25 fps, 25 tbr,
90k tbn, 50 tbc

1280x720 .mp4 exported from OpenShot:
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720,
14925 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)

The OpenShot export parameters used DAR 16:9 and Pixel Ratio (which I assume
is the same as SAR) of 64:45, although it doesn't set the DAR or SAR in the
file metadata (I did this subsequently with ffnpeg).

I realise that the original .ts video is actually letterboxed, although the
vertical side bars are pretty narrow. I've always assumed that letterboxing
referred to the top and bottom horizontal bars and was just a side effect of
playing a widescreen movie in a 16:9 or 4:3 display. I also did wonder how
the how this original movie played with the correct (at least correct
looking) AR when the DAR is set to 16:9 - the measured AR on my computer
screen is more like 24:10. So it occurred to me - has this video been
letterboxed to play in an AR of 16:9 when its real AR is greater?

Sent from: http://www.ffmpeg-archive.org/

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