Flac->Wav transcoding not working on Cambridge StreamMagic 6

[Andre Gosselin]

I have Cambridge Audio StreamMagic 6 renderer on which I want to experiment with the MinimStreamer Flac->Wav transcoding (setting "stream.transcode" property to "flac:wav"). I created the following directory structure with simple file names and a 16bit/44.1KHz flac file to ease the test:
a\b\c.flac
Using BubbleUPnP as control point, I can see when looking in the track metadata that the stream is set to

Quote:WAV, 16 its, stereo, 44100Hz, 146 MB
http:192.168.0.101:9790/minimserver/*/flac/a/b/c.flac/$!transcode.wav

All this seems correct. Trying to play the track on the StreamMagic 6 renderer however does not work. I get the following inside the log file (set to debug level):

Quote:10:07:35.931 Thread-348: HTTPService: accepted incoming connection
10:07:35.936 Thread-348: HTTPService: waiting for incoming connection
10:07:35.939 Thread-347: HTTPService: received request, Socket[addr=/192.168.0.11,port=4364,localport=9790]
10:07:35.940 Thread-347: HTTPService: adding connection org.jminim.lib.HTTPConnection@2dd55ae7
10:07:35.940 Thread-392: HTTPConnection: reading HTTP request
10:07:35.941 Thread-391: HTTPConnection: writer thread waiting for request
10:07:35.948 Thread-392: GET /minimserver/*/flac/a/b/c.flac/%24!transcode.wav HTTP/1.1
10:07:35.949 Thread-392: Host: 192.168.0.101:9790, Accept: */*, Range: bytes=0-127999
10:07:35.949 Thread-391: HTTPConnection: writer thread processing request
10:07:35.949 Thread-392: HTTPConnection: reading HTTP request
Fri Feb 14 10:07:35 sending HTTP response '404 Not Found: Requested resource not found' to request 'GET /minimserver/*/flac/a/b/c.flac/%24!transcode.wav'
10:07:35.950 Thread-391: HTTPConnection: completed request; socket=Socket[addr=/192.168.0.11,port=4364,localport=9790], keepAlive=false
10:07:35.951 Thread-391: HTTPConnection: closing Socket[addr=/192.168.0.11,port=4364,localport=9790]
10:07:35.951 Thread-391: HTTPService: removing connection org.jminim.lib.HTTPConnection@2dd55ae7
10:07:35.951 Thread-392: HTTPConnection: connection closed by client

According to the log, the renderer appears to have recoded the '$' sign to a '%24' inside it's GET request, to which MinimServer replies with a "404 Not Found" error.

The only way I found to get transcoding working on the StreamMagic is to wrap MinimServer inside a proxy using BubbleUPnP server. The GET request now shows a '$' sign and the track plays OK. Log file contains:

Quote:11:10:57.395 Thread-348: HTTPService: accepted incoming connection
11:10:57.395 Thread-348: HTTPService: waiting for incoming connection
11:10:57.399 Thread-347: HTTPService: received request, Socket[addr=/192.168.0.101,port=55025,localport=9790]
11:10:57.399 Thread-347: HTTPService: adding connection org.jminim.lib.HTTPConnection@5c588ded
11:10:57.400 Thread-496: HTTPConnection: reading HTTP request
11:10:57.407 Thread-495: HTTPConnection: writer thread waiting for request
11:10:57.407 Thread-496: GET /minimserver/*/flac/a/b/c.flac/$!transcode.wav HTTP/1.1
11:10:57.407 Thread-496: Host: 192.168.0.101:58050, Accept: */*, Range: bytes=0-127999, Via: 1.1 (jetty), X-Forwarded-For: 192.168.0.11, X-Forwarded-Proto: http, X-Forwarded-Host: 192.168.0.101, X-Forwarded-Server: 192.168.0.101
11:10:57.408 Thread-496: HTTPConnection: reading HTTP request

I tried the same experiments using a different control point (UPnPlay), with the same results.

I am wondering if this problem is due to a bug in the StreamMagic renderer or not. Is this rewrite of the '$' as '%24' in the GET request (the source of the problem as far as I can tell) a disallowed 'behavior' by the UPnP specification, or a possibility which MinimServer is not prepared to handle ? Accessing MinimServer through a BubbleUPnP server proxy solves the issue, but this can be seen as a workaround which adds an undesirable layer of complexity to a system. Is there somwthing else I could try ? Could MinimServer be modified to handle the StreamMagic 6 behavior, or should the issue be reported to Cambridge Audio ?

Your help would be greatly appreciated.

[simoncn]

(14-02-2014 17:48)Andre Gosselin Wrote:  I am wondering if this problem is due to a bug in the StreamMagic renderer or not. Is this rewrite of the '$' as '%24' in the GET request (the source of the problem as far as I can tell) a disallowed 'behavior' by the UPnP specification, or a possibility which MinimServer is not prepared to handle ? Accessing MinimServer through a BubbleUPnP server proxy solves the issue, but this can be seen as a workaround which adds an undesirable layer of complexity to a system. Is there somwthing else I could try ? Could MinimServer be modified to handle the StreamMagic 6 behavior, or should the issue be reported to Cambridge Audio ?

Your help would be greatly appreciated.

I have read the relevant specifications, and it is debatable whether or not the renderer is permitted to do percent encoding of the reserved URL character '$' when it sends a GET request. However, it appears to be legal for the renderer to do percent encoding of some other URL path characters in a GET request. To handle this, the simplest approach seems to be for MinimServer to accept percent encoding in GET requests for all path characters except '/' (which definitely can't be percent encoded). This change should enable MinimServer to interoperate with the StreamMagic.

I will release an update in the next few days with this change, assuming that it doesn't cause any other problems.

[Andre Gosselin]

(14-02-2014 22:44)simoncn Wrote:  

(14-02-2014 17:48)Andre Gosselin Wrote:  I am wondering if this problem is due to a bug in the StreamMagic renderer or not. Is this rewrite of the '$' as '%24' in the GET request (the source of the problem as far as I can tell) a disallowed 'behavior' by the UPnP specification, or a possibility which MinimServer is not prepared to handle ? Accessing MinimServer through a BubbleUPnP server proxy solves the issue, but this can be seen as a workaround which adds an undesirable layer of complexity to a system. Is there somwthing else I could try ? Could MinimServer be modified to handle the StreamMagic 6 behavior, or should the issue be reported to Cambridge Audio ?

Your help would be greatly appreciated.

I have read the relevant specifications, and it is debatable whether or not the renderer is permitted to do percent encoding of the reserved URL character '$' when it sends a GET request. However, it appears to be legal for the renderer to do percent encoding of some other URL path characters in a GET request. To handle this, the simplest approach seems to be for MinimServer to accept percent encoding in GET requests for all path characters except '/' (which definitely can't be percent encoded). This change should enable MinimServer to interoperate with the StreamMagic.

I will release an update in the next few days with this change, assuming that it doesn't cause any other problems.

Great support ! Thanks a lot, I will wait for this update when it is ready.

[simoncn]

(14-02-2014 22:59)Andre Gosselin Wrote:  Great support ! Thanks a lot, I will wait for this update when it is ready.

This change is now available in MinimServer update 20.

[Andre Gosselin]

(19-02-2014 18:36)simoncn Wrote:  

(14-02-2014 22:59)Andre Gosselin Wrote:  Great support ! Thanks a lot, I will wait for this update when it is ready.

This change is now available in MinimServer update 20.

Works OK. Thanks Simon!