Optimal video format for XBMC/Xbox

[tarball]

hi,


i recently encoded a couple of videos as divx5 and although the film player without stuttering, the sync between audio and video is fractionally (but noticably) out. if i play the same file on my athlon 1800xp pc (using mplayer) the film player and the audio / video sync looks bang on.
so my question is what video format do people find works best with xbmc with out straining the lil cpu in the xbox??

cheers

[Gamester17]

first if all make sure the codec is supported by xbmc (ex. latest supported divx is 5.03), recomend use res 720x576 or lower for pal and 720x480 or lower for ntsc, max is around 1.5mb combined video/audio stream if mpeg-4 (but recomend at least a little lower). don't recommend vbr audio because mplayer has problems with it sometimes.

[robrob]

i am using divx 5.1 vbr ..(cant remember the odd size) i use dr. divx and am jsut getting used to the settings.

i am seeing a little sync problems in the middle of a film. seems to be worse at other time than others. i am going to continue to play with my settings and try the suggestion mention above.

i would love other folks to post how they config their dvd to divx setup for xbmc.

diggin the product.

[Kb_cruncher]

the new xvid 1.0beta2 gives better quality than divx5.1.i use it with vorbis audio in ogm container exclusively.
the best settings for xvid i have found to be are:-

#h.263(for longer movies)more blurred image
#mpeg(for shorter movies)sharper image
#vhq4(or vhq1 is a bit faster with not much quality loss)
#adaptive quant setting
#4 b-frames
#trellis quantization

all other settings default.

[Kb_cruncher]

the sync between audio and video is fractionally (but noticably) out

i had the very same issue with one movie(out of many) with xbmc but it played back just fine on xbmp and xp.i believe it is an issue with the way xbmc handles synching.xbmp can adjust synch up or down in milliseconds with two controller buttons.i would reccomend using it until xbmc matures some.

so my question is what video format do people find works best with xbmc

all supported formats work well, mplayer can play just about anything.
some codec settings are not supported though either on the xbox or on divx standalone players which are becoming more readily available .make sure that "qpel" and "gmc"(global motion compensation) settings are unchecked to avoid playback problems.this applies to divx and xvid codecs.
although a settopbox decoder chip has just been released that handles both of these - http://www.digitimes.com/newssho....seq=207

with out straining the lil cpu in the xbox

the xbox cpu isn't so little ya know.because the xbox is a dedicated pc(unlike most pc's) with much faster access to memory and graphics than a normal pc.it has been determind to be equivalent to a 1400mhz pc cpu. :d

[billcow]

i've actually found the syncing in xbmc to be significantly better than xbmp in many ways. a lot of files i have that go way out of sync on xbmp stay almost perfect with xbmc. mostly these are files with weird framerates or with odd audio sample rates (i've got a lot of problems with combining pal video and non-44.1khz audio (my xbox is ntsc)). in any case, xbmc handles these a lot better than xbmp.

that said, though, xbmc does have issues with syncing. mainly when you pause, or do something that brings up the osd (either toggling subtitles or showing the time). what seems to happen there is that the sound keeps going normally while the video hangs for a while (from one or two frames worth up to as much as a second or two depending on factors i can't quite figure out).

and of course, there's the problem that you can't adjust the audio syncing manually (actually you can, if you muck around with the input.conf file in the mplayer directory - the lines for down, up, pgdown and pgup are in fact the d-pad buttons with the default keymap.xml. change 'em according to the mplayer docs and you can change all sorts of stuff you wouldn't otherwise be able to).


regarding video formats, i've been ripping dvds with both qpel and gmc for a few months now and haven't had any problems with either xbmp *or* xbmc (that's with divx 5.x, not xvid, i haven't tried xvid with either of those settings). the only files i've encoded that had any problems were a couple constant-quality encodings with xvid, and those were without any fancy settings (b-frames, qpel, and gmc).

in my experience it seems that mplayer (and thusly xbmp/c) handles 2-pass files better for some reason, although it seems odd to me that this would be the case.

the settings i have been using, btw, are as follows:

divx 5.03 (and recently 5.1.1)
2-pass vbr
gmc and qpel both enabled
cbr mp3 audio (lame --alt-preset cbr 160 encoded through besweet)
various container formats (both avi and ogm work well on xbmp/c, but ogm seems to be a tad better, so i've used that on my more recent stuff. i use matroska on anything with more than one commentary track)
for ogm, i add chapter points and subtitles, but i haven't actually checked if the chapters work

i rip using gordianknot (whatever the latest version is)
encode to 1-disc (unless there are two or more commentary audio tracks, in which case i make it 2-discs)
i always run a compression check and set the resolution to either 720xwhatever or whatever gives about 70% of the compression check results, depending on which is less (in other words, i don't go over 720xwhatever). i always leave the resolution at multiples of 16x16 (never bothered with 32x16 like the defaults suggest)

they haven't given me any problems with playback, except on the movies i did in matroska (neither xbmp or xbmc will play them, although i'm using an old build of xbmp, so newer ones might play them fine). i'm low on disc space at the moment, so those tend to stay on my computer instead of ending up on the xbox, so that's not an issue.

one of these days i've been meaning to encode something short in a bunch of different ways to test audio sync and other playback issues (varying vbr/cbr/constant-q, status of qpel/b-frames/gmc, xvid/divx5, ogm/avi/mkv, vbr/cbr/ac3 audio, and so on) with settings that give relatively constant sizes and quality. if i get around to that i'll post the results around here somewhere

[Hullebulle]

and of course, there's the problem that you can't adjust the audio syncing manually (actually you can, if you muck around with the input.conf file in the mplayer directory - the lines for down, up, pgdown and pgup are in fact the d-pad buttons with the default keymap.xml. change 'em according to the mplayer docs and you can change all sorts of stuff you wouldn't otherwise be able to).

you can do this in xbmc (you have to map the function to a button manualy atm).
--> http://www.xboxmediaplayer.de/cgi-bin....=keymap

[Hullebulle]

oh and here is another thread about mapping buttons to adjust av delay.
--> http://www.xboxmediaplayer.de/cgi-bin....4;&#top