Re: audio/L16

Eric Hyche wrote:
> Ohhh.. so "audio/L16;rate=48000;channels=2" is
> the Content-Type coming from an http server?
>   
Yes. This is what the DNLA test suite gives us.

> I guess I had thought that audio/L16 was the stream
> mime type coming from an RTSP server, in which case
> it would go directly to the pcm renderer.
>
> I think you are right - I think we take the Content-Type
> string directly and don't strip whatever is past the
> ";". You might check the HTTP spec to see what
> it says about Content-Type. I've never seen parameters
> munged onto a mime type like that.
>
> But your fix sounds essentially correct - strip the
> ";rate=48000;channels=2" from the Content-Type so that
> the stream gets picked up by the au file format. The
> rate and channels should get changed to headers in
> the request and then you would need to add code in the
> au file format to look for the parameters in the 
> request headers and add them to the stream header,
> since the PCM renderer will be looking for those
> to be set in the stream header of the audio/L16 stream.
>   
I can persuade the auffrormat plugin to get loaded with this change to 
hxflsrc.cpp:

(hxflrcs.cpp)
if (pMimeType)
{
printf("HXFileSource::AttempToLoadFilePlugin 7\n");

// Ignore anything following a ';' when doing the plugin lookup
char *pTemp = strchr((char*)pMimeType, ';');
if (pTemp)
*pTemp = 0x00;

pPlugin2Handler3->FindGroupOfPluginsUsingStrings(PLUGIN_CLASS, 
PLUGIN_FILEFORMAT_TYPE,
PLUGIN_FILEMIMETYPES, (char*)pMimeType, 0, 0, m_pFileFormatEnumerator);

// Restore full mimetype - this is what gets passed into fileformat
if (pTemp)
*pTemp = ';';
}

I was hoping that would pick out the au fformat and also pass the full 
mimetype through to it..
Can you explain in a but more detail how the sample rate and channels 
should get passed in to the au fformat ? (ie expand on 'headers in the 
request')

> Eric
>
> =============================================
> Eric Hyche ([email protected])
> Technical Lead
> RealNetworks, Inc.  
>
>   
>> -----Original Message-----
>> From: John Stirling [mailto:[email protected]] 
>> Sent: Tuesday, June 10, 2008 12:24 PM
>> To: [email protected]
>> Cc: [email protected]
>> Subject: Re: [Helix-client-dev] audio/L16
>>
>> I've been tracking this down today. Not quite worked it out, 
>> but getting closer..
>>
>> A mimetype of audio/L16 seems to end up in aufformat. It then 
>> fails in there due to lack of a valid header.
>>
>> If I hard code the sample rate etc in aufformat then the file 
>> can play (via pcm/renderer).
>>
>> A mimetype of audio/L16;rate=48000;channels=2 just ends up 
>> with a NO_RENDERER/FILEFORMAT error presumably because it 
>> checks for a match against the complete mimetype string 
>> rather than just the stuff before the ';'.
>>
>> So, I think I need to make the extended mimetype result in 
>> the aufformat being loaded and then I need to extract the 
>> sample rate etc from the stuff after the ';'.
>>
>> Does that sound correct ? Also, if you think that should be 
>> supported already let me know as I can't see it.
>>
>> John
>>
>>
>>
>> Eric Hyche wrote: 
>>
>> 	John,
>> 	
>> 	I would think these streams should play in
>> 	datatype/wav/pcm/renderer.
>> 	
>> 	Eric
>> 	
>> 	=============================================
>> 	Eric Hyche ([email protected])
>> 	Technical Lead
>> 	RealNetworks, Inc.  
>> 	
>> 	  
>>
>> 		-----Original Message-----
>> 		From: [email protected] 
>> 		[mailto:[email protected]] On 
>> 		Behalf Of John Stirling
>> 		Sent: Tuesday, June 10, 2008 4:57 AM
>> 		To: [email protected]
>> 		Subject: Re: [Helix-client-dev] audio/L16
>> 		
>> 		fyi - some sample mime types returned by the 
>> dlna tester:
>> 		
>> 		audio/L16;rate=48000;channels=2
>> 		
>> audio/L16;rate=44100;channels=1:DLNA.ORG_PN=LPCM;DLNA.ORG_FLAG
>> 		S=81100000000000000000000000000000
>> 		
>> audio/L16;rate=44100;channels=2:DLNA.ORG_PN=LPCM;DLNA.ORG_OP=01
>> 		
>> 		
>> 		John Stirling wrote: 
>> 		
>> 			We need to be able to play audio/L16 
>> content (for DLNA 
>> 		compliance).
>> 			
>> 			A sample file is here:
>> 			http://copper.reciva.com/audiofiles/B-LPCM-1.pcm
>> 			(obtained via 
>> http://issues.simplecenter.org/browse/SC-1074)
>> 			
>> 			Would you expect helix to be able to 
>> play this content 
>> 		? If so, is there any HELIX_FEATURE we might be 
>> missing ?
>> 			
>> 			I can see audio/L16 referenced in the 
>> code, but haven't 
>> 		dug much further than that. 
>> 			
>> 			We have audplin.so built and can play 
>> .au, .wav, .aiff content. 
>> 			
>> 			https://datatype.helixcommunity.org/
>> 			only mentions:
>> 			
>> 		
>> 			*	Uncompressed PCM from .wav, 
>> avi, .aiff or .au 
>> 		files and standard RTP streams 
>> 			*	PCM a-law and u-law from .wav, 
>> avi or .au files 
>> 		and standard RTP streams 
>> 		
>> 		
>> 			John
>> 			
>> 			
>> 			
>> 			
>> 			
>> 			
>> 			
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>> 		
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>
>

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