Change aspect ratio with MKVMerge from command line?

[Rekrul]

I have a bunch of video files with the wrong aspect ratio. Changing the aspect ratio in MKVMerge via the GUI works fine. I want to be able to do it from the command line, so that I can create a batch file to run unattended. I Googled and found the command line parameters to do it, but it doesn't seem to work. I used;

mkvmerge --aspect-ratio 0:4/3 oldfile.mkv -o newfile.mkv

It remuxes the file, but it still displays at the wrong aspect ratio.

I also tried;

mkvmerge --aspect-ratio 0:1.33 oldfile.mkv -o newfile.mkv

But that didn't work either.

I don't want to explicitly set the display dimensions because I was hoping to make a general purpose script that I could run on any set of files, select the desired aspect ratio and have it process all the files in the directory. If I explicitly set the display dimensions, they may not be optimal for the next set of files I want to change.

I'm using Media Player Classic HC to play the files.

What am I doing wrong?

[butterw]

The command line with latest mkvtoolnix (v53.0) seems to be:
mkvmerge --aspect-ratio 0:4/3 oldfile.mkv -output newfile.mkv

[Rekrul]

I'm using MPC-HC 1.7.13, which is the last official release according to its homepage.

And now I'm confused...

I just ran the same file through MKVMerge, both command line and GUI, intending to see what was different according to MKVInfo, and they BOTH play at the proper aspect ratio!

I swear I used the exact same command line as last time, but this time it worked. It's the exact same version of both MKVMerge and MPC-HC. I haven't changed any settings in MPC-HC or anything else since the last time I tried it.

I tested a couple other files and they work as well. So this is weird...

[butterw]

- v1.7.13 may be the last version featured on the old website, but MPC-HC is still being developed by clsid.
I did check v1.7.13 (now an old version) and this feature works.
Also Works in the latest dev build v1.9.8.157.
- Where you put --aspect-ratio in the command line could possibly have an impact (it's often the case with ffmpeg, which can be quite confusing).
- More likely I suspect, the issue was caused by the setting in View > Frame > Aspect Ratio which must be Default DAR for this to work (not square pixels).

[Rekrul]

- v1.7.13 may be the last version featured on the old website, but MPC-HC is still being developed by clsid.

Confession: My system is quite old, running an old version of Windows and those newer versions don't run for me. I hope to have a newer system in the near future, but for now, this is what I have, so I'm kind of stuck using older versions. Theoretically I could compile the newer versions myself, but I've never had any luck trying to compile source code. If a program doesn't have explicit step-by-step instructions for Windows, it never works for me. As soon as it gets into "Just set these options according to your system..." territory, I'm lost. It always ends up aborting with a cryptic error. I'm sure the problem would be obvious for someone used to compiling code, but I usually have no idea why it fails.

I did check v1.7.13 (now an old version) and this feature works.
Also Works in the latest dev build v1.9.8.157.
- Where you put --aspect-ratio in the command line could possibly have an impact (it's often the case with ffmpeg, which can be quite confusing).

That seems to be the cause. I just tried it with --aspect-ratio as the first parameter and with it later on the command line. Putting it first works, putting it later doesn't. I must not have put it first when I initially tried to do it.

- More likely I suspect, the issue was caused by the setting in View > Frame > Aspect Ratio which must be Default DAR for this to work (not square pixels).

Default DAR is checked.