[Butcher]

yeah i think the stream headroom is set to 0, but i'm fairly sure the mixbins headroom is default.

[pike]

@ j

i tested a dvd-video with stereo pcm 48khz and passthru didnt work for that one either.

my receiver is in the "middle class" and it has a builtin dvd player. the same dvd-video plays fine on the unit.

do you send that audio untouched, or is it re-padded or something?

[Blackwolf]

i have been unable to make anything 48khz 2 channel play since this recent addition. i have tried xvid/divx/wav/vob
all of them i get silence. however when i switch to analog output or i disable dd stereo pass thru it works fine

[jmarshall]

ok, i was setting a flag incorrectly (as encoded, instead of pcm). it worked fine on my receiver, so obviously some are different.

please try the new version in cvs now.

also, i've added butcher's suggestion and now the mcpx route is coming out at full volume whereas it used to have 6db of headroom. this means that all audio coming out, either through the mcpx or through the ac97 route will now be the same level.

i've also come across a killer sample for testing the quality of upsampling.

this file contains some low-level phone dialtones modulated on a very strong 19khz pure tone. the result is that if upsampling is not working too good, then you get "alien" type noises. if the upsampling is working well, then you'll just hear the dialtones.

note that due to the high amplitude, high frequency tone, this sample should be used very carefully.

i suggest that you try it out using headphones with the volume low so that you can recognise what the alien effect sounds like. this sample has the potential to burn out tweeters in poorly designed tweeters.

what it will sound like if the upsampling is working:

dial tones plus you may feel some pressure (start get a headache) if your speaker system passes the 19khz tone well - you probably won't hear the tone, but it is very loud, so you'll feel it if the volume is high enough.

what it will sound like if the upsampling is not working:

dial tones plus "alien" type interference.

what it will sound like if it's clipping:

dial tones plus loud "laser" type sounds.

the file can be obtained here:

udial upsampling test tone

there are 2 flac files in the .zip.

udial.flac - original 44khz sound
udialssrc.flac - same sound upsampled to 48khz using ssrc

the .zip file is password protected. the password is:

dontplayloud

you should be able to easily tell the difference when using xbmc.

please try the second file with the dd stereo pass through both on and off, and let me know how it works.

cheers,
jonathan

[pike]

nice samples!!

naturally passthru is fine with the ssrc one, weird is, it's fine even when passthru is off.

the non ssrc'ed one always plays with the upsampling artifacts.

conclusion, the mcp-x doesnt re-sample already 48khz audio?!

[MrMario64]

well, on my receiver they both sound the same including with pass through on or off.

they both play with a sound of a "siren" through it.
dunno if you would call that a laser or alien

it does upsample, cause the viz is doing nothing on the udialssrc version with pass through on.

sidenote, in a diff thread i posted the problems about &%&^% sound n the beginning of each song. when i select digital out and no passthrough i do not get the &^%&^ sounds. (with this version)

[Butcher]

48 to 48 doesn't require any resampling so the samples are just passed through as is. dsps are digital - if there is nothing to be done to the sound they don't change it at all.

[Butcher]

test, i get the siren on the first sample on both settings and no siren on the second on both settings.

[jmarshall]

thanks for the testing, guys.

butcher:

yep - when it's 48khz already, the only upsampling done is to 24bits then down to 20bits after it does the dsps. (that's why 48khz dd/dts is still destroyed by the mcpx)

i think the best method quality-wise is to upsample in software using ssrc, then pass the resultant 48khz stream through the mcpx. this allows us then to do volume attenuation easily, as well as further eq or whatever.

obviously, this will be an option. most users probably can't tell the difference on normal music, so will prefer to not have the cpu overhead of the software resampling.

mrmario64/others:

try turning digital output off, and play the ssrc'd sample through the analogue out. you should only hear the phone dialtones.

now i'll look at the ssrc.exe code, and encapsulate it so that it's a bit more useable for xbmc.

cheers,
jonathan

[MrMario64]

i think i can blame my speakers for the siren on the 44.1khz sample.

on analog i get no siren on 44.1 but i do get siren on 48 sample then.

my speakers each have their own dsp, then da and then the amp.
so , my speakers prolly make every signal 48 and thats why i get the screwup.

[pike]

a thought... visualizations only work with passthru disabled at the moment, that's a flaw in my eyes. (guess the problem is mplayer?)

would it be possible to send a stream that the vizes can work with also?

[jmarshall]

pike - reason is that the data isn't being sent to the viz as we're using ac97. once i get the 48khz upsampling finished and working, i'll implement it so that it goes through directsound and the xbox mcpx - that way we'll get the viz back, and we can also do volume control/eq etc. in the mcp.

will let you know when i get upsampling going.

[jmarshall]

okay, 48khz upsampling is in cvs now.

it's currently disabled by default, due to the fact that i didn't have time to do a gui option yet

run xbmc once, and get it to resave settings.xml (change a setting then change it back)

then edit e:\tdata\0face008\settings.xml and change the <highqualityresampling> option to true.

all non-video, non-48khz stuff should be upsampled.

turns out that mplayer has this functionality built in

note that i'm not using the highest quality setting yet (it uses integer based polyphase filters) but it passes the udial.flac test.

please take a listen and post your opinions.

cheers,
jonathan

[pike]

so not ssrc? u know one of the reasons ssrc was developed was because it has a nice compromise between quality and cpu usage

anyway, i was thinking, could the "output to all speakers" also benefit from this? ie that audio gets upsampled b4 sent to mcpx (?)

[pike]

oh and btw, "all non-video" only? why not 44.1khz mp3 audio in videos also? (just an example)