Newbie lost: stretch deformed image size to OK image size?

[muffin]

Hello,
I'm a new ff user and I have an annoying problem:
I am converting all my videos to H264, so far so good, I am not too convinced by the deinterlace filter but no matter.
My problem is this: I have some xvid divx etc that were made from 720x480 dvds, but those dvx are in a different size: 640x480 or sometimes 640x432 which means the image is deformed.
How can I stretch it so that it's in the right format again - the right proportion of horizontal to vertical? I knoxw how to crop but that's NOT what I want to do obviously.
Do you have any idea how I could do that?
I am at my wits ends I must (shorts wits, I know)

Thanks a lot and best wishes
Muffin

[major]

Try to use the autosize popup menu (select 16:9 or 2.35:1 depending on the content).

[rumplestiltskin]

Set the image pixel size you want in the "Video" tab. I've found the autosize popup not necessarily functional. (This may have something to do with what format you want for the converted file.)

If the original content was 720x480, it's probably DV-Stream so it's -really- 640x480. Remember that TVs are 640x480 and the 720 pixel width is squeezed to fit that screen.

Where do you plan to watch these converted files?

[muffin]

Many thanks for your posting - I have no idea how a vid is constructed so the concept of a 720 horizontal being in fact a 640 is... amazing to me! I'm more than willing to learn!
I plan to watch these on computers (mac) with a fully licensed QT7 (full screen of course) the screens being cinema displays.
Is that important for the size of the image? The shape of the pixels???
if 720 is really 640... does it mean i don't have to change the size when compressing?
gosh - I have a headache trying to understand!
All infos are most welcome!
I don't know if that is related but when I compress a ntsc dvd to h264 the deinterlace filter gives very uneven results (lines on mouth of people talking, fuzzy edges)

Many thanks for your help - I'm new at all this.

Best wishes
Muffin

[rumplestiltskin]

If the videos are 640x480, do they look okay when you play them? If so, then the ratio (of width to height) is okay and should be maintained.

640x480 could be 320x240, for example. It's usually a good idea to keep the new size to a number divisible by 4. (That comes from some instructions I read from another conversion app.)

If your destination is your screen, then you can leave the pixel size alone (although you might try - just for grins - a smaller size just to see if the quality remains what you'd desire; that's a personal issue).

Don't bother deinterlacing. The "fuzziness" could be due to excessive reduction in the picture size. Watch out for a too-ambitious reduction in the bitrate; that will cause video artifacts (and a reduction in "quality"). I've been using 640kbps for videos intended for my iPod and, when plugged into my TV, the quality is okay (but you'd never mistake it for a DVD). Using QT Player Pro, converting to H.264 takes way too long whereas using the MPEG4 setting (in ffmpegX) results in a movie about 20% larger than the H.264 file but conversion is done at 3X real-time (rather than .3x real-time for H.264 in QT Pro).

Hope this helps.

[muffin]

yes this helps, thanks.
Whn you talk about mpg4 in ff do you mean standard mp4 or H264 mp4? I have that option in my list of settings.
Muffin

[rumplestiltskin]

I use the "standard" MPEG4 (not H.264) as the encoding is then extremely fast and, with a slightly higher bitrate, it's similar quality. I've found that the MPEG4 file ends up about 20% larger than the H.264 file.

Don't know if this will help you but I posted a tutorial on ffmpegX here: https://www.videohelp.com/guides.php?guideid=847#847

[rumplestiltskin]

Whups! I see you're in the UK. PAL standard pixel size is different than NTSC pixel size. However, if you're intending to view on your Mac, no alteration in size should be required.

[muffin]

Thanks for the tutorial!
my idea of using H264 is that it make movies of a small file size and it's a standard that should live on for some years, whereas dvx xvid and the lot are coming and going and who knows if we'll be able to read them in 6 or 8 years.
I don't know what to think of the "plain vanilla" mpg4 - infos welcome!

about the UK: my movies are in ntsc and my tv is bi-standard so that would not be a problem.

Thanks!
I'm learning, I'm learning and eager to learn more you know

Muffin