Video convert ratio

[belasoul]

I received a h264 from the editor and used mpeg streamclip to change to DNxHD 36 8bit. Both Videos are 2048 x 1024. But the h264 shows extra black bars / letterbox in the PT Video Window and unfortunetly the DNxHD has no black bars and everything is stretched up/downside. Can you tell what i possibly miss while converting the video in Streamclip?

[henningaround]

Hi!

Assuming that you're using video hardware: Usually Pro Tools puts out video in broadcasts formats. If your video doesn't have a broadcast format, PT adds the letterbox. MPEG streamclip automatically scales it to a broadcast format. Try adding the letterbox yourself in MPEG streamclip to keep original aspect ratio. This peace of software is a little bit outdated, but it's possible :)

Regards
henning

[Vedat]

Export them as 1920x1080 and add letterbox.

[belasoul]

Thank you! Do you know how to determine the amount of letterbox from the source h264 and to translate that to the Streamclip settings?

[henningaround]

I think MPEG Streamclip adds the correct amount of letterbox if you calculate the zoom ratio correctly. Should be around 88% in this case?

[belasoul]

I generated a DNxHD36 with 88% Zoom. The result is closer to the original h264 but there are additional black bars at the sides from zooming. Do you know how to add the exact same letterbox like in the source video?

[henningaround]

You have to calculate the right amount of zoom. I was just guessing 88% :)

[nucelar]

With Mpeg streamclip your best bet is to trial and error the zoom value. We don't know the exact amount of letterbox so how should we know... :) For testing, apart from the small preview window.. : choose a short snippet with in and out point for export testing. when happy, select all and export the whole.

[Kuba Pietrzak]

And this is why I like (and still use) Quick Time Pro.

You just tick "preserve aspect ratio" setting and you're done.


Whatever I receive (cinemascope, insta 1:1, etc.) I convert them to 16:9 with QT without any problem (and math)


Kuba