Video size setup for beginners

[entos]

Hi to all of you!


First of all, thank you for this wonderfull application, it is very handy, just i need some help.

As i read through this forum, i just realised, almost everyone is familiar with ffmpeg or ffastrans "coding", and " dealing with variables" but unfortunately I did not.
My workflow is VERY simple. My Source is a1080p (1920x1080) DNxHD85.mov coming directly from DavinciResolve. I have h264 encoder, with "same as soure" settings. As far as i figured out %i_width% and %i_heigtht% would control the output's video size. And i have a destinaton folder.

Everything is running fine, but the encoded output.mp4 size is 1440x1080. If i enter 1920 x 1080 in the video size box, the output result is stretched horizontally. (despite mediainfo says it is 1920x1080).

How do i control the output.mp4 video size? What should i do if i would like to have a different video size as the source? Do i have to make a custom ffmpeg encoder? Can anyone help out with the right custom command? I just try to figure out, how does ffmpeg works with this help: http://rodrigopolo.com/ffmpeg/ but for this code, nothing happend: (which I am not surprised, since it makes no sense i think )

ffmpeg -i [INPUT] -s 1920x1080 -aspect 16:9 -r 25 -b 5000 -bt 5000 -vcodec libx264 -pass 1 -vpre fastfirstpass -an [OUTPUT].mp4 && ffmpeg -y -i [INPUT] -s 1920x1080 -aspect 16:9 -r 25 -b 5000 -bt 5000 -vcodec libx264 -pass 2 -vpre hq -acodec libfaac -ac 2 -ar 48000 -ab 256 [OUTPUT].mp4

Sorry for the noob thread, i did not found any guide for beginners.
+ question: Is there any way, to move the source files into an another folder, when the encode process finished?

Thanks.

[admin]

Hi entos, thank you for using FFAStrans and welcome to the forum!

Are you 100% sure the source is not 1440x1080? The %i_width% variable is taken from the horizontal resolution of the source file, aspect ratio not taken into account. So, if FFAStrans creates 1440x1080 output, it's getting it from somewhere....it's not just making things up

Like you already have done you control the output resolution by replacing the video size variables in the MP4-encoder. That's all there is to it.

I advise you to learn some ffmpeg NOT by using the page you linked to. It's parameters are autodated and won't work. Start with just the basics and expand from there.

Source files can be moved using the "Command executor" node. Click the question mark (?) in the node and you will see an example on how you can move/copy originals.


-steinar

[entos]

Hello Steinar!

Thank you for your reply.
Yep, im sure my source is 1920x1080, at least that's resolve and media info says.
I have uploaded a test source, and the result, so if anyone wants to play whit it, don't hesitate.

Code: Select all

https://drive.google.com/open?id=1dlOCCkLygBDTswoYgW82o4kF_4ts9wnm

Thank's.

[admin]

Take a look at this: https://en.wikipedia.org/wiki/List_of_A ... le1440_3-1

From the DNxHD specs: 85 Mbit flavor is subsampled to 1440x1080, so it's anamorph HD stored with a sample aspect of 4:3 (1440:1080=4:3). Same as 16:9 in SD is anamorph SD (4:3). So each pixel is stretched horisontally by a factor of 1.33333 (4/3) to make up a 16:9 display. That's why it LOOKS like "real" HD but is in fact not.

I really don't know why MediaInfo or Resolve camouflage this fact but ffmpeg does not. However, the MP4-files generated by FFAStrans behaves exactly like the original: 1440x1080 with Sample Aspect Ratio of 4:3 and Display Aspect Ratio of 16:9. Now, I see that it would be a good thing to add an option to disregard aspect ratios of the original when creating MP4 files. That way you could force the MP4 to 1920x1080 with a SAR of 1:1 so it would look normal with "correct" properties. I will look at this for the next version.

Hope this clarifies.

-steinar

[entos]

Hello!

Now it is clear.

Thank you for your kind answer.
I will check back later for new release.

Cheers!