x264 + xbmc + original xbox

[luxuryliner]

Really one of the most interesting topics around here.
I'm encoding too a lot of movies but never got the quality I wanted. The best thing I've done is upgrading XBMC to the lastest release (9.04.1 fixed) and quality of palyback has increased a lot.
By the side of encoding I'm really happy tofind out that I can limit the bitrate of CQ encoding but I'm asking myself: is there a relation between the vbuf size and the cache size settings in the xbox?

Just a nother little question: is there a way to limit bitrate also in standard MP4 encoding?
TIA
Simon

[mduell]

Hmmm, from testing running maxrate alone has no effect on the encoded bit rate. It just runs to whatever it would without maxrate in advanced settings.

What's the disadvantage to a small bufsize?

I guess I could try raising bufsize and lowering maxrate?

Here's the post about a small bufsize being adverse.

[mduell]

Just a nother little question: is there a way to limit bitrate also in standard MP4 encoding?

What is "standard MP4 encoding" supposed to mean?
Are you talking about ffmpeg (MPEG4 Part 2) rather than x264 (MPEG4 Part 10)?

[Dropnuts]

Hmmm, from testing running maxrate alone has no effect on the encoded bit rate. It just runs to whatever it would without maxrate in advanced settings.

What's the disadvantage to a small bufsize?

I guess I could try raising bufsize and lowering maxrate?

Here's the post about a small bufsize being adverse.

Seeing where the statement in that post is coming from, I'll take the bufsize thing as a given. Doesn't actually say why it's a bad idea though.

I'll do some testing and see how I go.

Cheers.

[Dropnuts]

First of all, thank you to everyone who has given me assistance and advice on this endeavour.

I have now come up with what I believe to be the final settings for encoding video using x264 for use on the xbox + xbmc (http://xbmc.org/)

Here is the preset: http://dl.dropbox.com/u/318691/Software/xbox-x264.plist

I have gone for quality over file size.

I use AC3 or DTS passthrough on the encoding, as this alleviates the xbox CPU of audio decoding, and I have a surround receiver.

At the moment I have tested this mainly on 16:9 or 2.35:1 content. When I find some 4:3 content I will test on it. The only change I can foresee is lowering of output video width/height on 4:3 content.

I will be starting a new thread on the xbmc forums to deal with this preset, and when that is done I will link to it here.

Again, thank you for all your assistance. It's a steep learning curve, but made easier with help.

*edit* Here's the link the xbmc forums with the guide I've done: http://xbmc.org/forum/showthread.php?p= ... post495167

[Dropnuts]

For anyone interested in this, I have created a Wiki entry at XBMC as guide to encoding videos for use with XBMC on the original XBOX.

http://wiki.xbmc.org/index.php?title=HO ... r_the_Xbox

[Dropnuts]

First of all, I know I'm rehashing an old thread here, but I believe this continues on in the same vein.

I've been asked to add to the preset I've made to include a preset for Black & White encoding, and one for encoding of Animated/CGI sources.

As yet I haven't been able to experiment much, but I've been told my original preset, when used with a Black & White sources, causes the xbox to stutter and drop frames. I'm sure I can just lower my max bitrate cap to prevent this happening, but I'm trying to figure out if there is any documentation on encoding Black & White sources using the x264 codec? Perhaps there are some advanced options I can adjust rather than lowering the bitrate?

Anyway, if you can point me in a direction for more info I'd be very grateful.

Thanks.

[creamyhorror]

From a discussion on Doom9 I remember x264 not needing any changes to encode black and white. Someone proposed an alternative, pretty infeasible method involving some sort of separation of channels, but it would require re-summing prior to playback.

I doubt monochrome sources are causing the Xbox to stutter. It could be the high bitrate demands of extremely grainy old films...but that should be taken care of by VBV settings. You'll have to get hold of a specific video that causes problems and test from there.

[jbrjake]

Note that HB does offer grayscale encoding, which strips the U and V (chroma) planes before feeding frames to libx264: http://trac.handbrake.fr/browser/trunk/ ... 264.c#L543

[Dropnuts]

creamyhorror and jbrbrake, thanks for that.

To be honest I forgot about the grayscale switch in filters. I'll have to do some testing and see if this helps at all with grainy black & white sources. Cheers.