[FFmpeg-user] cat advice

[Rick Corteza]

> On Mar 1, 2017, at 12:05 AM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 
> 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
> ratios.
> 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
> ratio.
> 
>> 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

Thank you very much!