XBMC and x264

[esojmc]

I've started playing with h.264 and encoding with x264 with megui and I like the results. I am playing it through a modded x-box runnng somewhat the latest XBMC (1/07). I've finally settled on the following with a resolution of 640 x XXX for playback without any dropped frames:

--pass 2 --bitrate 976 --stats ".stats" --no-fast-pskip --bframes 1 --b-rdo --bime --direct auto --nf --no-cabac --subme 7 --analyse all --8x8dct --qpmin 18 --vbv-maxrate 25000 --qcomp 0.3 --me umh --threads auto --thread-input --progress --no-psnr --no-ssim --output "" ""

My question is, what other options can I play with that will improve quality but not be more CPU intensive for playback. Will setting "number of b-frames" to 2 be harder on the playback CPU. I currently have it set to 1. When I set it to 2 b-frames, B-pyramids open up. What is this, will it help quality and most importantly, will my x-box be able to play it?

Also, I don't have my x-box set to the hi-def mode, it's in standard def right now.

Any suggestions appreciated.

Thanks.

[foxyshadis]

I don't have an xbox so I can't tell you what is or isn't compatible. But --trellis 2 will improve quality with no decoding cost. Increasing references will increase memory use, but a few extra (5 or 6 total) will often give you a little more quality, and mixed references always helps. Extra b-frames and b-pyramid will also typically increase quality (as long as they're adaptive, which is default) without real performance penalities, but again, I can't tell you if it'd be compatible.

Sometimes you can also get better perceptual quality with a cqm, like m4g's. It's worth trying, but they might not be compatible, and might not be worth it compared to the flat matrix anyway.

[nm]

XBMC uses libavcodec, so these should work fine.

[esojmc]

Thanks for the replies.

It seems the only way to get --trellis 2 is to enable CABAC, and I understand CABAC is a CPU killer during playback

Following is my new setting and no skips yet :).

--pass 2 --bitrate 896 --stats ".stats" --ref 3 --mixed-refs --no-fast-pskip --bframes 2 --b-pyramid --b-rdo --bime --direct auto --nf --no-cabac --subme 7 --analyse all --8x8dct --qpmin 18 --vbv-maxrate 25000 --qcomp 0.3 --me umh --threads auto --thread-input --progress --no-psnr --no-ssim --output "" ""

How about "No Dct Decimation" and "Weighted B-Prediction"? What does these do and will enabling them incur a playback penalty?

Thanks.

[bond]

How about "No Dct Decimation" and "Weighted B-Prediction"? What does these do and will enabling them incur a playback penalty?check the decoder comparison sticky. its outdated, but for getting a general info still useful

[esojmc]

FYI - the following x264 options works well (no skips) with XBMC at a resolution of 640 x XXX.

--pass 2 --bitrate 557 --stats ".stats" --ref 5 --mixed-refs --no-fast-pskip --bframes 2 --b-pyramid --b-rdo --bime --weightb --direct auto --nf --no-cabac --subme 7 --analyse all --8x8dct --qpmin 18 --vbv-maxrate 10000 --qcomp 0.3 --me umh --threads auto --thread-input --progress --no-psnr --no-ssim --output "" "" --trellis 1