How can I set the Final Dimensions of the video in Avidemux?

[SheerGold]

Hi,

I am using Avidemux v2.8.0 on an Apple Mac running Catalina.

And converting videos in mp4 format into MPEG-4 Simple Profile.

I selected mpeg-4 ASP (xvid).
Aspect ratio 4:3 (PAL).
Encoding Mode: Adv. Simple Level4
Encoding mode: Two Pass - Average Bitrate
Average Bitrate (kb/s): 1500

Some of the files I am converting are 1280×720, aka 720p.

When they are converted they are still in 1280×720.

But 1280×720 is too wide for my Archos AV500 portable video player.
It can play video files at a maximum size of 720 x 576.

Is there any way, in Avidemux, that I can set the Final Dimensions of the video to 720 x 576.
A smaller AR would also be okay.

[DB83]

You really do not help yourself by starting new topics about this rather than continuing the earlier one AND answering the questions.


But I will help you with the basics which you adapt to the different sizes of your source videos.


You use two filters which you will find by clicking the button under the video output format selection or by the filters selection from the video menu (I assume these options are there on the mac version)


1. The first filter is 'add borders'. You must add borders to alter your video size in an equivalent to 720*576 which is a 5:4 ratio. The resultant size would be 1280*1024 so the top border is (1024 - 720)/2 = 152 and so is the bottom border.


2. The second filter is 'swresize'. Now you can simply resize to 720*576 and the video has the same internal dimension.


Now if you want to be ultra safe with a 4:3 AR, the 1024 becomes 960 and the borders become 120 with the resize to 720*540

[SheerGold]

Hello DB83,

Thanks so much.

That works really well.

[SheerGold]

Hello DB83,

Is there a way to get Avidemux to save new settings.

That would be useful when there are different settings needed for different sources.

[DB83]

Some encoder settings can be saved and will automatically load upon restart of the program - see the 'edit' menu.


This does not apply to filters.

[hello_hello]

I'm confused. 1280/720 = 16:9. Unless the source has borders and you crop them, wouldn't you just set 16:9 (PAL) as the encoder aspect ratio and resize 1280x720 to 720x576?

Or, if a non-anamorphic encode is preferred, standard practice when Xvid ruled the world was to resize the width to 720 or less and set the appropriate height for the source.

Source Height / Source Width × Output Width = Output Height.

For a 720p source:
720 / 1280 ×720 = 405

720x404 would be the nearest mod4 height (admittedly there's a chance the player might want mod16). You'd set the encoder aspect ratio to 1:1

When the source isn't 16:9, you can add borders to make it 16:9 before resizing to 720x576 with a 16:9 aspect ratio, or you can use the above formula to calculate the correct height and resize to 720xSomething.

If the source has a 4:3 picture with borders each side for a total of 16:9, it'd be a good idea to crop them and resize to 4:3 dimensions, but that's another story...

[DB83]

Well all I know is that this player has a maximum SAR of 720*576. Surely there is no actual DAR flag in a xVID avi (it's been many a moon since I created one) so a simple 720*576 is going to corrupt a 1280*720 or anything else that is not pure 5:4


So my methods ( I am sure there are others) made the source either 5:4 or forced a 4:3 DAR


And if that player does not have a 16:9 display it would still show 720*404 with letter-boxing. Maybe the OP can clarify why he wanted his encodes for the player (and I assume nothing else) to be '4:3'

[Sharc]

Hi,

I selected mpeg-4 ASP (xvid).
Aspect ratio 4:3 (PAL).
Encoding Mode: Adv. Simple Level4
Encoding mode: Two Pass - Average Bitrate
Average Bitrate (kb/s): 1500

You need to define the new size: 'Filter' button -> swscaleResize -> width:720 height:576 (untick lock aspect ratio)

[SheerGold]

I only selected 4:3 because that is what I had been using previously, and it seemed to work for most videos.

If a different AR would give better results, I'd like to give that a try

[hello_hello]

Xvid can set a display aspect ratio. If I remember correctly DivX had home theatre profiles requiring an aspect ratio, so I assume Xvid adopted that idea too.

Mind you, setting a display aspect ratio when the output is AVI might be a bit hit and miss in respect to player support, but it looks like SheerGold is going with MP4.

I still have an old VFW Xvid flavour installed, so I had a look, and it suggests limiting the size to 352x576 for "Advanced Simple @ L4" but doesn't enforce it. "Advanced Simple @ L5" is the one that officially supports 720x576.
L4 has more restrictive VBV settings so maybe SheerGold's player needs those even if it can handle the 720 width?

[hello_hello]

If a different AR would give better results, I'd like to give that a try

A possible spanner in the works when resizing to dimensions such as 720x404, is some primitive players expect mod16 dimensions (width and height divisible by 16). You'd have to test other heights and if it doesn't play or display correctly then DB83's method might be easier, although.....

I'm pretty sure some old players (the ones pre-installed in cars years ago) assume all videos are either 16:9 or 4:3 (whatever the aspect ratio of the display is) and they'll stretch the video to fill the display no matter what the dimensions are. If that's the case you'll have to add borders so the output with borders is 16:9 or 4:3 (whichever the player expects) or it'll display stretched or squished, so that's something you should check. It mightn't be an issue, but it's definitely worth testing.

Edit: I did a quick search and found this:
https://www.cnet.com/reviews/archos-av500-mobile-dvr-review/
Once you're actually playing video on the Archos AV500 or an external TV, you can adjust the aspect ratio using any of these three settings: Auto, Maximized, or Full Picture.

So it's probable/possible "Auto" will display any resolution/DAR correctly, assuming it was encoded using the correct DAR, if required.

[DB83]

^^ According to that review, the screen is WS at 480*272 - not exactly 16:9 but is mod 16.


So a simple resize from 1280*720 to 480*272 might suffice.


$500 in 2005 !!!! That is serious money.

[SheerGold]

Do you mean:
resize from 1280*720 to 480*272, WITHOUT applying the 'add borders' filter
or
resize from 1280*720 to 480*272, AND APPLY the 'add borders' filter, 152 to both top and bottom borders?

[DB83]

The first one. And now the DAR is 16:9 and not 4:3


It was the 720*576 that threw me since it appears that is really for output from the player to a tv.