Audio passthrough failing on AC3/MP3 encoded content
#1
Hiya!

I recently re-installed XBMC as I managed to figure out how to get it running on W2K. Unfortunately I found out that audio passthrough fails on all non DTS -media.

The debug log is not particularly helpful on the matter, it simply states:

FactoryCodec - Audio: passthrough - Opening
FactoryCodec - Audio: passthrough - Failed

Then proceeds to go back to 2 channel output with no passthrough.

Full log: http://pastebin.com/f4e87a649

Figuring that W2K was the culprit, I booted to XP and did a fresh install - but the problem persisted!

I had a look on http://forum.xbmc.org/showthread.php?tid=43883 but seeing that on the DLL side, msvcr71.dll and MSVCP71.dll are in place (removing them has actually no effect), I think that the problem is not coming from that side.

My original XBMC version was 8.10 Atlantis, I tried upgrading to later SVNs but it has little effect. I'm currently using 17458-jester-ext with Media Player Classic as a workaround, but would much prefer going back the built in player.

Could someone please go through the logs and see if there is anything suspicious that'd point me in the right direction?


5.1 output works like a charm everywhere else, and doesn't have any hiccups with DTS media in XBMC either. Running XBMC on AMD Athlon XP 2800+ with W2K SP4, but the same problem occurs on XP SP3, so it seems to be specific to my system. Audio is provided by integrated NFORCE 2 chipset (CMedia) on the motherboard.

Thanks in advance!
Reply
#2
Haba Wrote:FactoryCodec - Audio: passthrough - Opening
FactoryCodec - Audio: passthrough - Failed

Then proceeds to go back to 2 channel output with no passthrough.

Full log: http://pastebin.com/f4e87a649
Code:
INFO: ffmpeg: Input #0, avi, from 'K:\Series II\Lost\S5\Lost.S05E01.HDTV.XviD-PusherCrew.avi':
INFO: ffmpeg:   Duration: 00:41:47.17, start: 0.000000, bitrate: 1168 kb/s
INFO: ffmpeg:     Stream #0.0: Video: mpeg4, yuv420p, 624x352 [PAR 1:1 DAR 39:22], 23.98 tb(r)
INFO: ffmpeg:     Stream #0.1: Audio: mp3, 48000 Hz, stereo, s16, 128 kb/s
From your log file it seems that there's only mp3 stereo in that file, so there is nothing to passthrough. That's why you'd only get 2 channel analog.
Reply
#3
Hmm, I did another check with AC3 Dolby Digital 5.1ch Sound Test and that works correctly. However, no such luck with another encode that has proper surround when played via MPC with ffdshow (and mp3 as audio format).

I have to admit that I'm not very much up to date how the audio works on modern day encodes. All I know is that ffdshow works it's magic on those files and I get surround sound. So the same is not doable on XBMC?
Reply
#4
Haba Wrote:Hmm, I did another check with AC3 Dolby Digital 5.1ch Sound Test and that works correctly. However, no such luck with another encode that has proper surround when played via MPC with ffdshow (and mp3 as audio format).

I have to admit that I'm not very much up to date how the audio works on modern day encodes. All I know is that ffdshow works it's magic on those files and I get surround sound. So the same is not doable on XBMC?

XBMC won't convert multichannel mp3 into Dolby like ffdshow so you won't be getting surround out of these without using multichannel analog. You can't passthrough mp3 directly since no receiver will natively decode it.
Reply
#5
mitul103 Wrote:XBMC won't convert multichannel mp3 into Dolby like ffdshow so you won't be getting surround out of these without using multichannel analog. You can't passthrough mp3 directly since no receiver will natively decode it.

I was suspecting something of the sort... Well, at least now I know what's the problem. Thanks!

Since I couldn't find any mention of multichannel mp3 in the Trac development roadmap, I guess I'm better off trying to optimize the external player part (i.e making XBMC only play it in the external player when a video file with mp3 audio is present)
Reply
#6
Is there even such a valid thing as multichannel mp3?
Always read the XBMC online-manual, FAQ and search the forum before posting.
Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules.
For troubleshooting and bug reporting please make sure you read this first.


Image
Reply

Logout Mark Read Team Forum Stats Members Help
Audio passthrough failing on AC3/MP3 encoded content0