Does Size Matter?

[Lord Nelson]

So, I was thinking about putting some movies on my 2 gb card eventually and was wondering what size you guys have found is a reasonable compromise between quality and memory? Roughly?

To make things a little clearer, I'm talking about the size of the movie file now not the card.

Nelson

 

[RiX0R]

I'm using a bitrate of 300kbps, and that gives very watchable quality. It does yield a few artifacts, but nothing very distracting.

You could probably go even lower.

 

[Lord Nelson]

I'm using a bitrate of 300kbps, and that gives very watchable quality. It does yield a few artifacts, but nothing very distracting.

You could probably go even lower.

​

ok, so what size would you end up with for a 2 hour movie (very roughly)?

 

[Aninhumer]

I got some episodes of blackadder down to 30mb each (Xvid)
2 hours would be 120mb (but a tad fuzzy)

 

[bacteria]

400kbps using Xvid gives films without artiacts. A 2 hour film is about 360Mb ish.

 

[Lord Nelson]

400kbps using Xvid gives films without artiacts. A 2 hour film is about 360Mb ish.

​

Hmm, that's alot of megabytes. But I guess it was to be expected.

Thanks.

 

[mrsnature]

you can reduce the framerate too depending on the type of movie. For cartoons/anime i normally half it, still good results. Anything with much action will want a higher framerate of course.

 

[Lord Nelson]

you can reduce the framerate too depending on the type of movie. For cartoons/anime i normally half it, still good results. Anything with much action will want a higher framerate of course.

​

Interesting, that.

 

[jaesond]

you can reduce the framerate too depending on the type of movie. For cartoons/anime i normally half it, still good results. Anything with much action will want a higher framerate of course.

​

Interesting, that.

​

It's true. Because most cartoons don't use any shading, or very little of it, they can take up less data because most of the area is just a single color. Less detail, less data needed.

A standard live-action movie that is encoded at 300kbps might have artifacts. A cartoon encoded at 300kbps might as well, but the amount of artifacts will be considerably less.

 

[BradN]

2 pass encoding can help a lot also - with 1 pass, the encoder has to kind of guess what bitrate to use for individual frames, typically ensuring it averages out over some number of frames, but 2 pass encoding lets it analyze exactly where higher bitrates are needed, so it can be more generous at those parts and still keep the correct average bitrate.

 

[Jet Set Willy]

I've got a few films about 110-120 mb (2hrs) by reducing the frame rate to 17 and I think if you tweek the sound settings you save a fair bit without loss of quality (if you don't mind mono instead of stereo). If converting widescreen movies I use 4:3 pan scan and it reduces the border giving a bigger viewing image. I've only got a half gig card so space is valuable for me.

 

[Aaaaaaaa]

Topic : Does size matter
Last Post: Jet Set Willy..


ahahaha...


no

 

[reallynotnick]

I've got a few films about 110-120 mb (2hrs) by reducing the frame rate to 17 and I think if you tweek the sound settings you save a fair bit without loss of quality (if you don't mind mono instead of stereo). If converting widescreen movies I use 4:3 pan scan and it reduces the border giving a bigger viewing image. I've only got a half gig card so space is valuable for me.

​

yuck why 17? It is best to divide it just in 2, so if you have 30fps then 15fps will look the best, even better then 17. At least that is what I have found through experiance, and it does make alot of sense.

I myself am I quality whore. I like mine at 500kps, with 96kbps audio. If only someone would get more codecs supported like mpeg-4 and H.264, then I would go down to 300kbs.

I just feel XVID is very blurry and really hate it, and DVIX does not work well for me.

 

[PokeParadox]

Go here(If you are a windows user): http://www.doom9.org/gknot-main4.htm
Follow the guide and just use the compressibility test for how well the movie will look.
Every encode you make should look fantastic if you do it properly.

 

[rokdcasbah]

you can reduce the framerate too depending on the type of movie. For cartoons/anime i normally half it, still good results. Anything with much action will want a higher framerate of course.

​

Interesting, that.

​

It's true. Because most cartoons don't use any shading, or very little of it, they can take up less data because most of the area is just a single color. Less detail, less data needed.

A standard live-action movie that is encoded at 300kbps might have artifacts. A cartoon encoded at 300kbps might as well, but the amount of artifacts will be considerably less.

​

framerate != bitrate

 

[TheFr00n]

I use XViD (v1.1) to transcode movies down to a manageable size for my GP2x (which I have owned for three whole days now wheeeeeee!).

I have to say that I haven't found 2-pass mode to be either beneficial or necessary. XViD has some very good profiles available for mobile devices.

Here's what I do:

1. I use BeSweet to rip the audio to an OGM file. It makes a smaller file than mp3, and IMHO it sounds better.

2. I use VirtualDubMod to create an OGM file, using ogg audio. I use the resize filter on Lazcos to crush it to 320x240. For compression, I use single pass mode, and the Mobile profile. I use XViD's bitrate calculator to aim for a 75 meg file. Bizarrely, this works out at around 156k/sec - much lower than anything advised on these boards.

And presto! I have small episodes that fit comfortably on an SD card.

Now, granted, they look utter pants blown up fullscreen on a notebook - but they look 100% cool on the GP2X's screen. I'm actually amazed at how good they look. I think that using OGG audio helps: because the audio is that much smaller, there's more room in a small file for video than there would be using MP3.

But you know what the killer tip is? Noise reduction. Even if the video does not appear to need it, there is always a soft film grain present in media that was originally shot on film. Digitally, these represent moving parts of the picture and so require more bits to display. But if you put a noise reduction filter before your resize filter, you flatten out the colours in the static areas of the screen - meaning that XViD's Global Motion Compensation feature can really come into its own. The result is dramatically smaller filesize, with no apparent loss of quality on a display like the GP2X's.

Of course, you must remember to rename the ogm to avi or the GP2x won't play it.