[vlc-devel] Re: your vlc audio patch

[Matthew Romaine]

Mark,

Sorry for the late response; I was away from my desk for the past 
couple days.

AC3 has not been tested because it was special cased in the original 
module and I don't have source material to test it out yet.

i've only tested my patch on two devices - RME Hammerfall, which 
deinterleaves multichannel streams, and MOTU 896, which uses single 
interleaved streams.  Combinations of the two (interleaved and 
deinterleaved) should also be possible but is untested :)

as for the error, without looking at the code i think I put in that 
error message to indicate when a different physical format had to be 
chosen but a corresponding channel count wasn't found.  In other words, 
some devices allow for multiple formats under a single stream - i.e. 
"Stream 1" could have two physical formats, one that handles 4 channels 
at 44.1 and another that handles 2 channels at 96.  Due to 
deinterleaved-implementation constraints (and time :), the code 
currently only allows a change in sampling rate, so will basically fail 
if a different physical format in the same stream can not also handle 
the same number of desired channels.  I *think* that's the error you're 
getting.

try debugging in extra verbose mode and you should get a clear sense of 
the possible stream combinations of your device.  what device are you 
using?

if all else fails, follow the Xine model :)

hth,
matt


On 2004/06/22, at 18:41, Mark Wells wrote:

> Matt
>
> Firstly, if you dont have the time to answer this, dont worry i'm sure 
> I'll figure it out. I just thought it was worth asking incase you can 
> put your finger straight on it. Im trying to figure out what 
> capabilities your patch provides, and therefore what the priorities 
> are for continuing where you left off.
>
> As far as I am aware from reading up on the vlc-devel list (correct me 
> if im wrong) your patch should provide successful multichannel support 
> for OS X. The only thing it doesnt do is let you choose how many 
> channels you want to use (ie it always uses the most channels it can 
> find). Right (in theory) ?
>
> I'm testing using an 8-channel audio device (yes, i've uncommented the 
> 8-channel support) and an ac3 audio stream. When I load the stream I 
> get the error "Something is wrong with the physical format indexing 
> i[0] j[2] fmt_idx[5]" I have also tried 6-channel instead, but get the 
> same error. Having looked at my input stream it seems to be a single 
> stream (therefore interleaved) with 9 formats.
>
> I guess all I'm asking is this: were you/others getting this error (ie 
> is this something I need to patch up before addressing the problem of 
> selecting how many channels to use) or is this error new news to you?
>
> Many thanks
>
> Mark
>
> ----------------------------------
> Mark Wells
> Oxford Semiconductor Ltd
> 25 Milton Park, Abingdon, OX14 4SH, UK
>
>
>
> On 15 Jun 2004, at 10:40, Matthew Romaine wrote:
>
>>
>> Mark,
>>
>> 	Just a quick tip, but be sure to go back over the past couple 
>> references to multichannel audio on OSX on the mailing list.  There's 
>> a patch I sent out that should work for all devices now that 
>> interleaved and de-interleaved streams are supported, but it won't 
>> let you choose which option to use.  It should be a trivial fix, but 
>> my hands are currently tied.  I've also commented the code heavily so 
>> anyone should be able to follow.
>>
>> But if you're really gonna fix it up, be sure to look up references 
>> to AUHAL throughout the list to get it done right :)
>>
>> matt
>> ----------------------------------------
>> Matthew M.I. Romaine
>> IMNC Audio Codec Group
>> Sony Corporation
>> phone: 03-5448-6065
>> fax: 03-5448-5617
>> ----------------------------------------
>>
>> -- 
>> This is the vlc-devel mailing-list, see http://www.videolan.org/vlc/
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>>
>
>
>
----------------------------------------
Matthew M.I. Romaine
IMNC Audio Codec Group
Sony Corporation
phone: 03-5448-6065
fax: 03-5448-5617
----------------------------------------

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