RE: audio/L16

I just checked httpfsys and it looks like
if we have a Content-Type that looks like:

ContentType: audio/L16;foo=bar

that we will blow away the ";foo=bar"
and only use the "audio/L16" part as
the mime type. Here is the code in httpfsys.cpp:

        // Therefore, we should check to see if there's a ';'
        // in the content type. If there is, then only use the string
        // up to that point
        INT32 lSemi = sMimeType.Find(';');
        if (lSemi > 0)
        {
            // We have a semi-colon, so only use the content-type
            // up to the semi-colon but not include it or anything
            // past it
            sMimeType = sMimeType.Left(lSemi);
        }


I think the problem is at the beginning
of HXFileSource::ExtendedSetup(). It
is getting the Content-Type directly from
the response headers and calling that the
mime type directly. It should be doing what
httpfsys is doing and using only up to
the ";" as the mime type.

Does that make sense?

Eric

=============================================
Eric Hyche ([email protected])
Technical Lead
RealNetworks, Inc.  

> -----Original Message-----
> From: John Stirling [mailto:[email protected]] 
> Sent: Wednesday, June 11, 2008 4:46 AM
> To: [email protected]
> Cc: [email protected]
> Subject: Re: [Helix-client-dev] 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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