[FFmpeg-user] cat advice

Carl Eugen Hoyos ceffmpeg at gmail.com
Tue Feb 28 18:05:57 EET 2017

2017-02-28 11:15 GMT+01:00 Rick Corteza <rickcorteza at gmail.com>:
>> On Feb 27, 2017, at 5:11 PM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>> 2017-02-27 5:15 GMT+01:00 Rick Corteza <rickcorteza at gmail.com>:
>>> Prior to joining files with cat I often convert them using
>>> ffmpeg -i inputFile -target ntsc-dvd -qscale 5 outputFile
>>> to make them similar quality before joining.
>>> The problem with doing this is often the aspect ratio even
>>> if I use the -aspect flag.
>> Please elaborate.

> Here is a better explanation:
> Original file - http://www.filedropper.com/original_5 <http://www.filedropper.com/original_5>
> Converted file - http://www.filedropper.com/test_198 <http://www.filedropper.com/test_198>
> Output:
> MacBook:~ mahalko$ /Users/mahalko/Desktop/ffmpeg
> -i /Users/mahalko/Desktop/original.mp4
> -target ntsc-dvd -aspect 464:640 -qscale 5
> /Users/mahalko/Desktop/test.vob

Target ntsc-dvd implies an output file that (closely) follows a certain
specification (that of ntsc dvds) to make sure dvd players can play
the file. This specification includes allowed resolutions and aspect
The aspect option has no effect in your command line because you
requested a dvd-compatible file. The output video looks different
than the input video because that's what you requested on the
command line when specifying dvd-compatibility.

I don't understand what you are trying to do so I have not many
suggestions: If you need dvd output, you should decide how the
video is supposed to look on your tv and (likely) add borders with
the pad filter.
If all you want is concatenation, dvd is not the right format (mpegts
may be) unless all your videos have ntsc resolution and aspect

> ffmpeg version 3.2.4 Copyright (c) 2000-2017 the FFmpeg developers

For future questions, please remember that only current FFmpeg git
head is supported on this mailing list. This is even more true for osx
where no distribution supports shared libraries and therefore no
release support exists at all.

Carl Eugen

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