[darcybaston]

I've been trying to get 2 hour VHS movies encoded onto two CDs, for viewing on the Mac, using the MP4 codec. After 3 days and lots of iBook fan noise, I have what I believe the best list of variables you can use which balances quality, size, datarate, interlacing, CD consumption etc.

Capture 60 minutes (not 65, but 60. File size gets blown so fast with just a few minutes). This makes a +- 12.6 Gigabyte file (I used DV NTSC format from a Formac StudioTVR)

Resize the 720x480 video capture to 579 x 386

Deinterlace the video ("dinterlacer", http://home.planet.nl/~jeschot/)

NOTE: this deinterlacer software creates a new movie file exactly the same size as the original because the audio is REFERENCED from the original interlaced footage. Do not delete the original interlaced movie until after you've used the deinterlaced version to export to mp4, or you'll have to copy/add the audio from the original interlaced file into the deinterlaced one)

You can't just use the 'deinterlace' option in Quicktime, because the 3ivx codec seems to ignore it.

Quicktime Export settings:
----------------------
Quicktime movie .MOV file, 3ivx codec http://www.3ivx.com
(the 3ivx MP4 encoder puts the Quicktime one to shame)
Use "average bitrate"
Set Max QP 3
Set Min QP 18
add the "adaptive" option
leave the rest to defaults

AAC audio
128k/s

Resulting .MOV file is 676 MB
Datarate is 190.1Kbytes, which I didn't specify, it just ended up that way

And the resulting MP4 encoded Quicktime .MOV file looks gorgeous! Best quality for its size.

I tried to use ffmpegX, but the 'mencoder' part of it refused to do more than 9m57s of encoding before claiming it was finished and exiting. Weird! It is good software though, it encodes very well with good quality. Better than Quicktime that's for sure.

And I'm done fooling around with this. Time to watch and encode movies without any more experimentation!

[Uncle Skeleton]

Originally posted by darcybaston:
Resize the 720x480 video capture to 579 x 386

Whoa right there, mr. How did you arrive at this conclusion? Anyway, dimensions not divisible by 8 lose you hardware acceleration, and not divisible by even 2 are very very bad for more reasons. Also DV pixels are not sqaure. In general, use 512x384 instead. Also you have to remember that your source is VHS, and VHS only has about 240 lines of verticle resolution. That data gets scaled up to 720x480 by the Formac, but that doesn't mean you should save the scaled-up data. You can scale up a little from the original VHS res just for the sake of erring on the side of caution, but really don't bother going above 384x288 if you have a VHS source.

or you'll have to copy/add scaled the audio from the original interlaced file into the deinterlaced one)

NEVER scale the audio. It should just work with Add (not scaled), so try that, but if somehow it doesn't, then scale the VIDEO to the AUDIO, not vice versa. Scaling audio is bad for more reasons than I remember, but the ones I remember are (1) the audio is the right one anyway, (2) it changes the pitch, which humans are more sensitive to (by far) than framerate changes, (3) it changes the sample rate from one that is supported by your sound card to one that is not, forcing the cpu to work during playback to resample in order to feed the sound card, and (4) it often leads to a "soft sync" problem where audio will slowly drift out of sync while playing, but then snap back when you pause (this may sound less bad than hard sync problems, but if you think about it it makes it impossible to fix).

You can't just use the 'deinterlace' option in Quicktime, because the 3ivx codec seems to ignore it

I haven't seen that option in QT to have much of an effect on anything. If you have, I would be interested to hear what it was

AAC audio
128k/s

you can definitely go down to 112, and I usually use 96 for aac

Datarate is 190.1Kbytes, which I didn't specify, it just ended up that way

you should calculate the correct datarate and set it. If you choose a setting that expects a datarate (anything but Constant Quality) and then don't set one, the codec uses an arbitrary default that has nothing to do with your video or target size.

And, um, I'm not trying to be rude with all this, just pointing out a few lesser known pitfalls before someone falls in them.

[darcybaston]

Oh wow...am I the amateur! Thank you so much for pointing out the fallacies in my understanding! VHS is that horrible in resolution? Wow, I didn't know. I thought anything that displayed on a TV was naturally 640x480.

My resizing was arbitrary. I just grabbed the bottom right corner of the QT window and shrunk it a bit smaller then the last time I encoded the movie since the last file was too big. I didn't know about the 8 and 2 division thing. That would explain why these encoded movies are more difficult to play.

I may have erred when I said "add scaled". I probably meant 'add' but I don't remember which one I picked, just that the audio sounded great and didn't drift.

You have saved me from future headaches, thank you so much!

Everyone, I may have fluked.

[Uncle Skeleton]

Originally posted by darcybaston:
VHS is that horrible in resolution?

yes, that's something I never realized until I started capturing video digitally. The TV screen itself does a lot to hide low res and also video noise, but once you start really staring at your captures and looking for faults, you will be able see them on the TV as well. And you can usually see how a VHS tape has horizontal lines where the image is "doubled" to scale up to 480, and broadcast TV doesn't. But only if you're looking for it. It also means you can play your encoded movies on a TV monitor and make them look a lot better (better meaning that you don't see as much digital artifacting, but you also don't see as much detail).

I may have erred when I said "add scaled". I probably meant 'add' but I don't remember which one I picked, just that the audio sounded great and didn't drift.

I understand, but other people will read this and they need to know not to do it too. This is a particularly insidious problem for exactly the reason you describe: most times you don't notice it until long after you've deleted your source files and you can't go back and fix it. It shows on some hardware and not others, or you really have to sit and watch the whole movie without pausing to see it, or you don't see it until your computer is encoding video in the background while you watch, or one of your friends with perfect pitch wants to watch it and can't stand it even though you can't hear the difference. You don't want to say "good enough" now and then decide later on that you wish you had taken the extra 30 seconds and done it right. It's just better if everyone learns from the start that you just don't scale the audio, ever.

It's good that you took the time to write this too. This topic has come up a lot recently and it's good to have a discussion of the whole process all in one place. And it wasn't a waste of your time to try out all the encodes you aready did. Trial and error is the best way to learn something as complex as this.